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#amateurradio2 — Public Fediverse posts

Live and recent posts from across the Fediverse tagged #amateurradio2, aggregated by home.social.

  1. Ham Radio Outside the Box @[email protected] ·

    A Year End Compendium of Outside the Box Antenna Ideas

    We have reached the end of another year of crazy ideas here at Ham Radio Outside the Box and a repeat of last year’s severe winter has gotten underway in southern Ontario. The daily temperature high remains well below freezing and the ground is buried under a thick blanket of snow already. I have tried to “Keep Warm and Carry On” with more off-the-wall outdoor antenna experiments but succumbed to the biting wind and had to retreat to the warmth of the shack.

    Here in the nice toasty warmth of my basement “Comms Room” I am surrounded by radio equipment, electronic gizmos, tools and almost enough wire to lay a new transatlantic cable. I also have computers. One of the computers runs the incredible HamClock program giving me instant access to updated solar propagation conditions, the current location of the International Space Station and real time data on the International HF beacon project.

    Another computer is the one on which I am typing this post now. I recently realized that I have written so many posts related to field portable antennas I have built and tried that it would be a useful exercise to re-read them all. Heck, I surprised myself with some of the ideas that were posted and forgotten, but will now be resurrected. So, to end the year, I have composed a compendium of 35 of those posts – old and not-so-old – as a reference for readers to explore. I hope you may find some useful information for your own deployments.

    I should stress that these are not all tried and tested designs. Some have worked so well I intend to keep them in my hambag for field portable radio operations. Others … well they were useful learning opportunities. Even if you only pick up a couple of tips such as the simplest, quick release method of attaching an antenna wire to the top of a pole the read will be worth your time.

    NB: If you find any of these posts particularly interesting you can use the “Print” function on your computer and select “Save to PDF” or “Print to file” to keep a local copy.

    ZZZZZ … ZZZZ … ZZZ

    Ham Radio Outside the Box will now go into hibernation until the new year. Until then my best wishes go out to all in the hope that you will enjoy whatever religious or secular festival you celebrate at this time of year. Stay out of the cold!

    https://hamradiooutsidethebox.ca/2025/11/04/a-simple-fix-for-my-broken-telescopic-whip/

    https://hamradiooutsidethebox.ca/2025/08/29/two-resonant-simple-wire-antennas-for-pota/

    https://hamradiooutsidethebox.ca/2025/09/23/a-simple-low-profile-multiband-antenna-for-pota/

    https://hamradiooutsidethebox.ca/2025/08/05/rapid-deployment-field-expedient-random-wire-antenna-ideas/

    https://hamradiooutsidethebox.ca/2025/07/23/does-an-antenna-top-hat-really-work/

    https://hamradiooutsidethebox.ca/2025/07/11/an-outside-the-box-version-of-the-delta-loop-antenna/

    https://hamradiooutsidethebox.ca/2025/05/21/reviving-a-webster-band-spanner-a-1950s-manual-screwdriver-antenna/

    https://hamradiooutsidethebox.ca/2022/08/15/vertical-antenna-redesigned/

    https://hamradiooutsidethebox.ca/2022/07/30/no-antenna-no-problem/

    https://hamradiooutsidethebox.ca/2022/06/21/80m-band-antenna-fits-into-just-1-square-foot/

    https://hamradiooutsidethebox.ca/2021/12/17/an-easy-t2lt-portable-antenna/

    https://hamradiooutsidethebox.ca/2021/11/08/a-portable-vertical-antenna/

    https://hamradiooutsidethebox.ca/2021/09/13/a-most-unusual-antenna/

    https://hamradiooutsidethebox.ca/2025/05/14/matching-an-efhw-antenna-a-third-way/

    https://hamradiooutsidethebox.ca/2025/04/23/ssefhw-another-shortened-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2025/03/19/a-simple-antenna-that-is-omnidirectional-directional-and-nvis/

    https://hamradiooutsidethebox.ca/2025/03/05/a-quick-and-easy-qrp-emergency-field-antenna/

    https://hamradiooutsidethebox.ca/2025/01/16/a-top-loaded-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/12/12/a-clefhw-antenna/

    https://hamradiooutsidethebox.ca/2024/11/13/antenna-height-matters-true-or-false/

    https://hamradiooutsidethebox.ca/2024/10/09/the-titanic-40m-field-expedient-backpack-portable-antenna/

    https://hamradiooutsidethebox.ca/2024/08/16/how-does-the-speaker-wire-no-counterpoise-antenna-work/

    https://hamradiooutsidethebox.ca/2024/07/18/a-neat-trick-with-a-20m-efhw-wire-antenna/

    https://hamradiooutsidethebox.ca/2024/03/13/an-improved-self-supporting-low-footprint-field-expedient-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/03/06/antennas-a-riddle-wrapped-in-a-mystery-inside-an-enigma/

    https://hamradiooutsidethebox.ca/2024/02/14/a-most-unusual-vertical-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2023/12/06/a-simpler-field-expedient-rybakov-antenna-for-winter/

    https://hamradiooutsidethebox.ca/2023/11/05/an-upside-down-antenna/

    https://hamradiooutsidethebox.ca/2023/10/19/using-a-municipal-flagpole-for-an-antenna-fine-business/

    https://hamradiooutsidethebox.ca/2023/02/15/the-vp2e-a-strange-but-proven-antenna/

    https://hamradiooutsidethebox.ca/2023/02/09/what-in-heavens-name-is-a-rybakov-antenna/

    https://hamradiooutsidethebox.ca/2023/01/14/a-magic-ground-mobile-antenna/

    https://hamradiooutsidethebox.ca/2025/01/23/an-off-center-fed-sleeve-dipole/

    https://hamradiooutsidethebox.ca/2024/07/12/cutting-my-losses/

    https://hamradiooutsidethebox.ca/2023/10/24/an-itsy-bitsy-teeny-weeny-upside-down-hf-whip/

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #counterpoise #cw #outdoorOps #portable #pota

    #amateurradio2 #antennas #counterpoise #cw #outdoorops #portable
  2. Ham Radio Outside the Box @[email protected] ·

    A Year End Compendium of Outside the Box Antenna Ideas

    We have reached the end of another year of crazy ideas here at Ham Radio Outside the Box and a repeat of last year’s severe winter has gotten underway in southern Ontario. The daily temperature high remains well below freezing and the ground is buried under a thick blanket of snow already. I have tried to “Keep Warm and Carry On” with more off-the-wall outdoor antenna experiments but succumbed to the biting wind and had to retreat to the warmth of the shack.

    Here in the nice toasty warmth of my basement “Comms Room” I am surrounded by radio equipment, electronic gizmos, tools and almost enough wire to lay a new transatlantic cable. I also have computers. One of the computers runs the incredible HamClock program giving me instant access to updated solar propagation conditions, the current location of the International Space Station and real time data on the International HF beacon project.

    Another computer is the one on which I am typing this post now. I recently realized that I have written so many posts related to field portable antennas I have built and tried that it would be a useful exercise to re-read them all. Heck, I surprised myself with some of the ideas that were posted and forgotten, but will now be resurrected. So, to end the year, I have composed a compendium of 35 of those posts – old and not-so-old – as a reference for readers to explore. I hope you may find some useful information for your own deployments.

    I should stress that these are not all tried and tested designs. Some have worked so well I intend to keep them in my hambag for field portable radio operations. Others … well they were useful learning opportunities. Even if you only pick up a couple of tips such as the simplest, quick release method of attaching an antenna wire to the top of a pole the read will be worth your time.

    NB: If you find any of these posts particularly interesting you can use the “Print” function on your computer and select “Save to PDF” or “Print to file” to keep a local copy.

    ZZZZZ … ZZZZ … ZZZ

    Ham Radio Outside the Box will now go into hibernation until the new year. Until then my best wishes go out to all in the hope that you will enjoy whatever religious or secular festival you celebrate at this time of year. Stay out of the cold!

    https://hamradiooutsidethebox.ca/2025/11/04/a-simple-fix-for-my-broken-telescopic-whip/

    https://hamradiooutsidethebox.ca/2025/08/29/two-resonant-simple-wire-antennas-for-pota/

    https://hamradiooutsidethebox.ca/2025/09/23/a-simple-low-profile-multiband-antenna-for-pota/

    https://hamradiooutsidethebox.ca/2025/08/05/rapid-deployment-field-expedient-random-wire-antenna-ideas/

    https://hamradiooutsidethebox.ca/2025/07/23/does-an-antenna-top-hat-really-work/

    https://hamradiooutsidethebox.ca/2025/07/11/an-outside-the-box-version-of-the-delta-loop-antenna/

    https://hamradiooutsidethebox.ca/2025/05/21/reviving-a-webster-band-spanner-a-1950s-manual-screwdriver-antenna/

    https://hamradiooutsidethebox.ca/2022/08/15/vertical-antenna-redesigned/

    https://hamradiooutsidethebox.ca/2022/07/30/no-antenna-no-problem/

    https://hamradiooutsidethebox.ca/2022/06/21/80m-band-antenna-fits-into-just-1-square-foot/

    https://hamradiooutsidethebox.ca/2021/12/17/an-easy-t2lt-portable-antenna/

    https://hamradiooutsidethebox.ca/2021/11/08/a-portable-vertical-antenna/

    https://hamradiooutsidethebox.ca/2021/09/13/a-most-unusual-antenna/

    https://hamradiooutsidethebox.ca/2025/05/14/matching-an-efhw-antenna-a-third-way/

    https://hamradiooutsidethebox.ca/2025/04/23/ssefhw-another-shortened-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2025/03/19/a-simple-antenna-that-is-omnidirectional-directional-and-nvis/

    https://hamradiooutsidethebox.ca/2025/03/05/a-quick-and-easy-qrp-emergency-field-antenna/

    https://hamradiooutsidethebox.ca/2025/01/16/a-top-loaded-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/12/12/a-clefhw-antenna/

    https://hamradiooutsidethebox.ca/2024/11/13/antenna-height-matters-true-or-false/

    https://hamradiooutsidethebox.ca/2024/10/09/the-titanic-40m-field-expedient-backpack-portable-antenna/

    https://hamradiooutsidethebox.ca/2024/08/16/how-does-the-speaker-wire-no-counterpoise-antenna-work/

    https://hamradiooutsidethebox.ca/2024/07/18/a-neat-trick-with-a-20m-efhw-wire-antenna/

    https://hamradiooutsidethebox.ca/2024/03/13/an-improved-self-supporting-low-footprint-field-expedient-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/03/06/antennas-a-riddle-wrapped-in-a-mystery-inside-an-enigma/

    https://hamradiooutsidethebox.ca/2024/02/14/a-most-unusual-vertical-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2023/12/06/a-simpler-field-expedient-rybakov-antenna-for-winter/

    https://hamradiooutsidethebox.ca/2023/11/05/an-upside-down-antenna/

    https://hamradiooutsidethebox.ca/2023/10/19/using-a-municipal-flagpole-for-an-antenna-fine-business/

    https://hamradiooutsidethebox.ca/2023/02/15/the-vp2e-a-strange-but-proven-antenna/

    https://hamradiooutsidethebox.ca/2023/02/09/what-in-heavens-name-is-a-rybakov-antenna/

    https://hamradiooutsidethebox.ca/2023/01/14/a-magic-ground-mobile-antenna/

    https://hamradiooutsidethebox.ca/2025/01/23/an-off-center-fed-sleeve-dipole/

    https://hamradiooutsidethebox.ca/2024/07/12/cutting-my-losses/

    https://hamradiooutsidethebox.ca/2023/10/24/an-itsy-bitsy-teeny-weeny-upside-down-hf-whip/

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #counterpoise #cw #outdoorOps #portable #pota

    #amateurradio2 #antennas #counterpoise #cw #outdoorops #portable
  3. Ham Radio Outside the Box @[email protected] ·

    A Year End Compendium of Outside the Box Antenna Ideas

    We have reached the end of another year of crazy ideas here at Ham Radio Outside the Box and a repeat of last year’s severe winter has gotten underway in southern Ontario. The daily temperature high remains well below freezing and the ground is buried under a thick blanket of snow already. I have tried to “Keep Warm and Carry On” with more off-the-wall outdoor antenna experiments but succumbed to the biting wind and had to retreat to the warmth of the shack.

    Here in the nice toasty warmth of my basement “Comms Room” I am surrounded by radio equipment, electronic gizmos, tools and almost enough wire to lay a new transatlantic cable. I also have computers. One of the computers runs the incredible HamClock program giving me instant access to updated solar propagation conditions, the current location of the International Space Station and real time data on the International HF beacon project.

    Another computer is the one on which I am typing this post now. I recently realized that I have written so many posts related to field portable antennas I have built and tried that it would be a useful exercise to re-read them all. Heck, I surprised myself with some of the ideas that were posted and forgotten, but will now be resurrected. So, to end the year, I have composed a compendium of 35 of those posts – old and not-so-old – as a reference for readers to explore. I hope you may find some useful information for your own deployments.

    I should stress that these are not all tried and tested designs. Some have worked so well I intend to keep them in my hambag for field portable radio operations. Others … well they were useful learning opportunities. Even if you only pick up a couple of tips such as the simplest, quick release method of attaching an antenna wire to the top of a pole the read will be worth your time.

    NB: If you find any of these posts particularly interesting you can use the “Print” function on your computer and select “Save to PDF” or “Print to file” to keep a local copy.

    ZZZZZ … ZZZZ … ZZZ

    Ham Radio Outside the Box will now go into hibernation until the new year. Until then my best wishes go out to all in the hope that you will enjoy whatever religious or secular festival you celebrate at this time of year. Stay out of the cold!

    https://hamradiooutsidethebox.ca/2025/11/04/a-simple-fix-for-my-broken-telescopic-whip/

    https://hamradiooutsidethebox.ca/2025/08/29/two-resonant-simple-wire-antennas-for-pota/

    https://hamradiooutsidethebox.ca/2025/09/23/a-simple-low-profile-multiband-antenna-for-pota/

    https://hamradiooutsidethebox.ca/2025/08/05/rapid-deployment-field-expedient-random-wire-antenna-ideas/

    https://hamradiooutsidethebox.ca/2025/07/23/does-an-antenna-top-hat-really-work/

    https://hamradiooutsidethebox.ca/2025/07/11/an-outside-the-box-version-of-the-delta-loop-antenna/

    https://hamradiooutsidethebox.ca/2025/05/21/reviving-a-webster-band-spanner-a-1950s-manual-screwdriver-antenna/

    https://hamradiooutsidethebox.ca/2022/08/15/vertical-antenna-redesigned/

    https://hamradiooutsidethebox.ca/2022/07/30/no-antenna-no-problem/

    https://hamradiooutsidethebox.ca/2022/06/21/80m-band-antenna-fits-into-just-1-square-foot/

    https://hamradiooutsidethebox.ca/2021/12/17/an-easy-t2lt-portable-antenna/

    https://hamradiooutsidethebox.ca/2021/11/08/a-portable-vertical-antenna/

    https://hamradiooutsidethebox.ca/2021/09/13/a-most-unusual-antenna/

    https://hamradiooutsidethebox.ca/2025/05/14/matching-an-efhw-antenna-a-third-way/

    https://hamradiooutsidethebox.ca/2025/04/23/ssefhw-another-shortened-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2025/03/19/a-simple-antenna-that-is-omnidirectional-directional-and-nvis/

    https://hamradiooutsidethebox.ca/2025/03/05/a-quick-and-easy-qrp-emergency-field-antenna/

    https://hamradiooutsidethebox.ca/2025/01/16/a-top-loaded-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/12/12/a-clefhw-antenna/

    https://hamradiooutsidethebox.ca/2024/11/13/antenna-height-matters-true-or-false/

    https://hamradiooutsidethebox.ca/2024/10/09/the-titanic-40m-field-expedient-backpack-portable-antenna/

    https://hamradiooutsidethebox.ca/2024/08/16/how-does-the-speaker-wire-no-counterpoise-antenna-work/

    https://hamradiooutsidethebox.ca/2024/07/18/a-neat-trick-with-a-20m-efhw-wire-antenna/

    https://hamradiooutsidethebox.ca/2024/03/13/an-improved-self-supporting-low-footprint-field-expedient-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/03/06/antennas-a-riddle-wrapped-in-a-mystery-inside-an-enigma/

    https://hamradiooutsidethebox.ca/2024/02/14/a-most-unusual-vertical-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2023/12/06/a-simpler-field-expedient-rybakov-antenna-for-winter/

    https://hamradiooutsidethebox.ca/2023/11/05/an-upside-down-antenna/

    https://hamradiooutsidethebox.ca/2023/10/19/using-a-municipal-flagpole-for-an-antenna-fine-business/

    https://hamradiooutsidethebox.ca/2023/02/15/the-vp2e-a-strange-but-proven-antenna/

    https://hamradiooutsidethebox.ca/2023/02/09/what-in-heavens-name-is-a-rybakov-antenna/

    https://hamradiooutsidethebox.ca/2023/01/14/a-magic-ground-mobile-antenna/

    https://hamradiooutsidethebox.ca/2025/01/23/an-off-center-fed-sleeve-dipole/

    https://hamradiooutsidethebox.ca/2024/07/12/cutting-my-losses/

    https://hamradiooutsidethebox.ca/2023/10/24/an-itsy-bitsy-teeny-weeny-upside-down-hf-whip/

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #counterpoise #cw #outdoorOps #portable #pota

    #pota #portable #outdoorops #cw #counterpoise #antennas
  4. Ham Radio Outside the Box @[email protected] ·

    A Year End Compendium of Outside the Box Antenna Ideas

    We have reached the end of another year of crazy ideas here at Ham Radio Outside the Box and a repeat of last year’s severe winter has gotten underway in southern Ontario. The daily temperature high remains well below freezing and the ground is buried under a thick blanket of snow already. I have tried to “Keep Warm and Carry On” with more off-the-wall outdoor antenna experiments but succumbed to the biting wind and had to retreat to the warmth of the shack.

    Here in the nice toasty warmth of my basement “Comms Room” I am surrounded by radio equipment, electronic gizmos, tools and almost enough wire to lay a new transatlantic cable. I also have computers. One of the computers runs the incredible HamClock program giving me instant access to updated solar propagation conditions, the current location of the International Space Station and real time data on the International HF beacon project.

    Another computer is the one on which I am typing this post now. I recently realized that I have written so many posts related to field portable antennas I have built and tried that it would be a useful exercise to re-read them all. Heck, I surprised myself with some of the ideas that were posted and forgotten, but will now be resurrected. So, to end the year, I have composed a compendium of 35 of those posts – old and not-so-old – as a reference for readers to explore. I hope you may find some useful information for your own deployments.

    I should stress that these are not all tried and tested designs. Some have worked so well I intend to keep them in my hambag for field portable radio operations. Others … well they were useful learning opportunities. Even if you only pick up a couple of tips such as the simplest, quick release method of attaching an antenna wire to the top of a pole the read will be worth your time.

    NB: If you find any of these posts particularly interesting you can use the “Print” function on your computer and select “Save to PDF” or “Print to file” to keep a local copy.

    ZZZZZ … ZZZZ … ZZZ

    Ham Radio Outside the Box will now go into hibernation until the new year. Until then my best wishes go out to all in the hope that you will enjoy whatever religious or secular festival you celebrate at this time of year. Stay out of the cold!

    https://hamradiooutsidethebox.ca/2025/11/04/a-simple-fix-for-my-broken-telescopic-whip/

    https://hamradiooutsidethebox.ca/2025/08/29/two-resonant-simple-wire-antennas-for-pota/

    https://hamradiooutsidethebox.ca/2025/09/23/a-simple-low-profile-multiband-antenna-for-pota/

    https://hamradiooutsidethebox.ca/2025/08/05/rapid-deployment-field-expedient-random-wire-antenna-ideas/

    https://hamradiooutsidethebox.ca/2025/07/23/does-an-antenna-top-hat-really-work/

    https://hamradiooutsidethebox.ca/2025/07/11/an-outside-the-box-version-of-the-delta-loop-antenna/

    https://hamradiooutsidethebox.ca/2025/05/21/reviving-a-webster-band-spanner-a-1950s-manual-screwdriver-antenna/

    https://hamradiooutsidethebox.ca/2022/08/15/vertical-antenna-redesigned/

    https://hamradiooutsidethebox.ca/2022/07/30/no-antenna-no-problem/

    https://hamradiooutsidethebox.ca/2022/06/21/80m-band-antenna-fits-into-just-1-square-foot/

    https://hamradiooutsidethebox.ca/2021/12/17/an-easy-t2lt-portable-antenna/

    https://hamradiooutsidethebox.ca/2021/11/08/a-portable-vertical-antenna/

    https://hamradiooutsidethebox.ca/2021/09/13/a-most-unusual-antenna/

    https://hamradiooutsidethebox.ca/2025/05/14/matching-an-efhw-antenna-a-third-way/

    https://hamradiooutsidethebox.ca/2025/04/23/ssefhw-another-shortened-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2025/03/19/a-simple-antenna-that-is-omnidirectional-directional-and-nvis/

    https://hamradiooutsidethebox.ca/2025/03/05/a-quick-and-easy-qrp-emergency-field-antenna/

    https://hamradiooutsidethebox.ca/2025/01/16/a-top-loaded-end-fed-half-wave-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/12/12/a-clefhw-antenna/

    https://hamradiooutsidethebox.ca/2024/11/13/antenna-height-matters-true-or-false/

    https://hamradiooutsidethebox.ca/2024/10/09/the-titanic-40m-field-expedient-backpack-portable-antenna/

    https://hamradiooutsidethebox.ca/2024/08/16/how-does-the-speaker-wire-no-counterpoise-antenna-work/

    https://hamradiooutsidethebox.ca/2024/07/18/a-neat-trick-with-a-20m-efhw-wire-antenna/

    https://hamradiooutsidethebox.ca/2024/03/13/an-improved-self-supporting-low-footprint-field-expedient-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2024/03/06/antennas-a-riddle-wrapped-in-a-mystery-inside-an-enigma/

    https://hamradiooutsidethebox.ca/2024/02/14/a-most-unusual-vertical-antenna-for-20m/

    https://hamradiooutsidethebox.ca/2023/12/06/a-simpler-field-expedient-rybakov-antenna-for-winter/

    https://hamradiooutsidethebox.ca/2023/11/05/an-upside-down-antenna/

    https://hamradiooutsidethebox.ca/2023/10/19/using-a-municipal-flagpole-for-an-antenna-fine-business/

    https://hamradiooutsidethebox.ca/2023/02/15/the-vp2e-a-strange-but-proven-antenna/

    https://hamradiooutsidethebox.ca/2023/02/09/what-in-heavens-name-is-a-rybakov-antenna/

    https://hamradiooutsidethebox.ca/2023/01/14/a-magic-ground-mobile-antenna/

    https://hamradiooutsidethebox.ca/2025/01/23/an-off-center-fed-sleeve-dipole/

    https://hamradiooutsidethebox.ca/2024/07/12/cutting-my-losses/

    https://hamradiooutsidethebox.ca/2023/10/24/an-itsy-bitsy-teeny-weeny-upside-down-hf-whip/

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #counterpoise #cw #outdoorOps #portable #pota

    #amateurradio2 #antennas #counterpoise #cw #outdoorops #portable
  5. Ham Radio Outside the Box @[email protected] ·

    What really determines the efficiency of an antenna?

    Is it Standing Wave Ratio (SWR)?

    It is common knowledge that when an antenna has high SWR some of our transmitted power is wasted instead of being transmitted. But is this really true? The trouble with “common knowledge” is that it spreads without further scrutiny. “It must be true because that’s what everybody thinks”. But let’s consider another perspective.

    What happens to our signal when it meets an antenna with high SWR? Some of the signal is radiated while the rest is reflected back down the transmission line to its source – the transceiver. What happens to the reflected signal when it reaches the transceiver? It is re-reflected back towards the antenna and the cycle repeats.

    So does all the signal eventually get radiated? No. Energy is lost (RED ALERT from the physics department: Energy can neither be created nor destroyed, only converted from one form to another). Ok, my apologies to the physics department, some of the energy is converted to heat as our signal passes along the transmission line and through any ununs, baluns, impedance transformers or other devices en route. Further energy is converted to heat due to the resistance of the wires and the impedance of the transmission line itself.

    Thus, on every trip between the transceiver and the antenna, some of our transmitted RF is converted to heat. If the antenna has a high SWR some of our signal travels back and forth between the transceiver and the antenna multiple times and becomes further attenuated on each trip. Therefore, if we can reduce the loss of RF (due to conversion to heat) as it passes through any devices along the journey between the source (transceiver) and load (antenna) we will improve the efficiency of our antenna system.

    How can we do that?

    One simple way to achieve that is to correct for the high SWR right at the antenna. A remote tuner can do that. A loading coil will compensate for the high capacitive reactance of a short antenna, but loading coils can be inefficient because of wire resistance. This is especially true in the case of base-loading coils on a quarter-wave vertical antenna. The current is highest at the base of the antenna so more RF energy will be lost to heat (P=I^2*R) than with a center-loading or top-loading coil.

    So the real culprit is not SWR, but the insertion loss of ununs, baluns, impedance transformers, loading coils, transmatches and any other “energy conversion” devices, including the transmission line itself, through which our signal has to pass.

    Insertion loss of Ham Radio Outside the Box’s 4:1 ununs

    In the previous post I reported on my build of field test versions of a 4:1 unun and a 4:1 balun to compare how each would handle the task assigned to them. Now the job I set myself was to transform what might be called the “Ugly Sisters” builds into something with the good looks of Cinderella. And Cinderella had to be an unun tough enough to withstand rough treatment out in the Big Blue Sky Shack through all four Canadian seasons (Late Winter, Brief Summer, Early Winter, Deep Winter).

    QRP 4:1 unun

    I built two versions of a 4:1 unun; one for QRP and another for what I like to call QROp. “QROp” is an unofficial label I have adopted to mean about 20 watts or so. Twenty watts will give a 1 S-unit advantage over 5 watts – maybe just enough for our signal to poke its nose above the noise floor when propagation conditions are not so good.

    QROp unun

    There are 2 main differences between the QRP and the QROp versions: The QRP unun uses a BNC connector and a 4:1 transformer wound on a tiny FT82-43 toroid. The QROp version uses an SO-239 connector and a 4:1 transformer wound on an FT140-43 toroid.

    If we look at the tables below, we can see that the QRP version may have a little too much insertion loss. When we are trying to do as much as we can with as little as possible every milliwatt is wanted. As the wonderful friendly folks on the big Canadian island of Newfoundland like to say: “A little’s a lot if it’s all you’ve got”.

    Insertion Loss effects of the Ham Radio Outside the Box QRP unun

    BandQRP (5 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.390.438.612m0.370.418.215m0.350.397.817m0.340.387.614m0.330.377.430m0.320.367.240m0.350.397.880m0.730.7715.4

    Insertion Loss effects of the Ham Radio Outside the Box QROp unun

    BandQROp (20 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.241.085.4012m0.231.035.1515m0.220.994.9517m0.210.944.7014m0.200.904.5030m0.200.904.5040m0.200.904.5080m0.220.994.95

    A little extra heat in winter

    You would think Canadians wouldn’t mind a little extra heat in winter. It’s true, but not when the source of that heat is our precious transmitted RF. In case you were wondering, the amount of RF converted to heat by inefficient devices is mostly undetectable. If it can be easily detected the “magic smoke” can’t be far behind. When it’s 253 Kelvins outside you just ain’t gonna notice when the temperature rises to 254 Kelvins (note: the physics department advised me to use Kelvins to avoid confusion between degrees Fahrenheit and degrees Celsius).

    Oh no! There’s more?

    Yes indeed. An unun does not attenuate Common Mode Current (CMC). For that we need a Common Mode Current Choke (CMCC). CMC is the current on the outer surface of a coax braid. Differential mode current is carried on the core and inner surface of the coax braid. Does a CMCC also have insertion loss? Yes, but how much? Let’s take a look.

    Insertion Loss of a QRP (5 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.250.285.612m0.220.255.015m0.210.244.817m0.190.214.214m0.170.193.830m0.150.173.440m0.140.163.280m0.130.153.0 QRP CMCC

    Insertion Loss of a QROp (20 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.180.814.0512m0.160.723.6015m0.150.683.4017m0.130.592.9514m0.110.502.5030m0.100.462.3040m0.090.412.0580m0.080.371.85 QROp CMCC

    The (not so) grand total of RF going up the chimney

    BandTotal QRP (5W) % RF power lost to heatTotal QROp (20W) % RF power lost to heat10m14.29.0912m13.28.7515m12.68.3517m11.87.6514m11.27.0030m10.66.8040m10.06.5580m18.46.80

    The white bearded man in the red suit and his flying reindeer might be grateful for a few watts of heat going up the chimney at this time of year, but those of us in the frozen barren tundra of the northern states and provinces, as well as licensed ham dwellers in other cold lands, may not see things the same way.

    What can we conclude?

    If we only consider the insertion loss – in this example – of the 4:1 voltage unun and the Common Mode Current Choke and ignore resistive losses in the transmission line, and possibly insertion loss in a transmatch (“tuner”), we can determine the potential efficiency of our antenna system.

    • For our QRP devices the efficiency varies between 81.6% and 90% across the bands
    • For our QRO devices the efficiency varies between 90.9% and 93.5% across the bands

    This conclusion is based on the assumption that there is no loss in the antenna itself. We are treating the antenna, the transmission line, unun and CMCC as the “antenna system”. I have made no allowance for SWR losses for the reasons stated in the introduction to this post.

    What a load of old codswallop!

    I am an expert in the sense that “X” is an unknown quantity and “spurt” is a drip under pressure. I may be completely wrong; I may have fallen off my horse and bumped my head on a rock. I may have come to a fork in the road and taken it as Yogi Berra once famously said. If you would like to correct me on any wrong assumptions please do so. I receive a lot of direct emails from readers and, while they are most welcome, if you write a comment to this post instead it may trigger an interesting technical discussion here.

    A big thank you to all the new and many existing subscribers to Ham Radio Outside the Box. It is people like you who make writing these posts so worthwhile. I appreciate every one of you.

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #cw #outdoorOps #unun

    #amateurradio2 #antennas #cw #outdoorops #unun
  6. Ham Radio Outside the Box @[email protected] ·

    What really determines the efficiency of an antenna?

    Is it Standing Wave Ratio (SWR)?

    It is common knowledge that when an antenna has high SWR some of our transmitted power is wasted instead of being transmitted. But is this really true? The trouble with “common knowledge” is that it spreads without further scrutiny. “It must be true because that’s what everybody thinks”. But let’s consider another perspective.

    What happens to our signal when it meets an antenna with high SWR? Some of the signal is radiated while the rest is reflected back down the transmission line to its source – the transceiver. What happens to the reflected signal when it reaches the transceiver? It is re-reflected back towards the antenna and the cycle repeats.

    So does all the signal eventually get radiated? No. Energy is lost (RED ALERT from the physics department: Energy can neither be created nor destroyed, only converted from one form to another). Ok, my apologies to the physics department, some of the energy is converted to heat as our signal passes along the transmission line and through any ununs, baluns, impedance transformers or other devices en route. Further energy is converted to heat due to the resistance of the wires and the impedance of the transmission line itself.

    Thus, on every trip between the transceiver and the antenna, some of our transmitted RF is converted to heat. If the antenna has a high SWR some of our signal travels back and forth between the transceiver and the antenna multiple times and becomes further attenuated on each trip. Therefore, if we can reduce the loss of RF (due to conversion to heat) as it passes through any devices along the journey between the source (transceiver) and load (antenna) we will improve the efficiency of our antenna system.

    How can we do that?

    One simple way to achieve that is to correct for the high SWR right at the antenna. A remote tuner can do that. A loading coil will compensate for the high capacitive reactance of a short antenna, but loading coils can be inefficient because of wire resistance. This is especially true in the case of base-loading coils on a quarter-wave vertical antenna. The current is highest at the base of the antenna so more RF energy will be lost to heat (P=I^2*R) than with a center-loading or top-loading coil.

    So the real culprit is not SWR, but the insertion loss of ununs, baluns, impedance transformers, loading coils, transmatches and any other “energy conversion” devices, including the transmission line itself, through which our signal has to pass.

    Insertion loss of Ham Radio Outside the Box’s 4:1 ununs

    In the previous post I reported on my build of field test versions of a 4:1 unun and a 4:1 balun to compare how each would handle the task assigned to them. Now the job I set myself was to transform what might be called the “Ugly Sisters” builds into something with the good looks of Cinderella. And Cinderella had to be an unun tough enough to withstand rough treatment out in the Big Blue Sky Shack through all four Canadian seasons (Late Winter, Brief Summer, Early Winter, Deep Winter).

    QRP 4:1 unun

    I built two versions of a 4:1 unun; one for QRP and another for what I like to call QROp. “QROp” is an unofficial label I have adopted to mean about 20 watts or so. Twenty watts will give a 1 S-unit advantage over 5 watts – maybe just enough for our signal to poke its nose above the noise floor when propagation conditions are not so good.

    QROp unun

    There are 2 main differences between the QRP and the QROp versions: The QRP unun uses a BNC connector and a 4:1 transformer wound on a tiny FT82-43 toroid. The QROp version uses an SO-239 connector and a 4:1 transformer wound on an FT140-43 toroid.

    If we look at the tables below, we can see that the QRP version may have a little too much insertion loss. When we are trying to do as much as we can with as little as possible every milliwatt is wanted. As the wonderful friendly folks on the big Canadian island of Newfoundland like to say: “A little’s a lot if it’s all you’ve got”.

    Insertion Loss effects of the Ham Radio Outside the Box QRP unun

    BandQRP (5 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.390.438.612m0.370.418.215m0.350.397.817m0.340.387.614m0.330.377.430m0.320.367.240m0.350.397.880m0.730.7715.4

    Insertion Loss effects of the Ham Radio Outside the Box QROp unun

    BandQROp (20 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.241.085.4012m0.231.035.1515m0.220.994.9517m0.210.944.7014m0.200.904.5030m0.200.904.5040m0.200.904.5080m0.220.994.95

    A little extra heat in winter

    You would think Canadians wouldn’t mind a little extra heat in winter. It’s true, but not when the source of that heat is our precious transmitted RF. In case you were wondering, the amount of RF converted to heat by inefficient devices is mostly undetectable. If it can be easily detected the “magic smoke” can’t be far behind. When it’s 253 Kelvins outside you just ain’t gonna notice when the temperature rises to 254 Kelvins (note: the physics department advised me to use Kelvins to avoid confusion between degrees Fahrenheit and degrees Celsius).

    Oh no! There’s more?

    Yes indeed. An unun does not attenuate Common Mode Current (CMC). For that we need a Common Mode Current Choke (CMCC). CMC is the current on the outer surface of a coax braid. Differential mode current is carried on the core and inner surface of the coax braid. Does a CMCC also have insertion loss? Yes, but how much? Let’s take a look.

    Insertion Loss of a QRP (5 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.250.285.612m0.220.255.015m0.210.244.817m0.190.214.214m0.170.193.830m0.150.173.440m0.140.163.280m0.130.153.0 QRP CMCC

    Insertion Loss of a QROp (20 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.180.814.0512m0.160.723.6015m0.150.683.4017m0.130.592.9514m0.110.502.5030m0.100.462.3040m0.090.412.0580m0.080.371.85 QROp CMCC

    The (not so) grand total of RF going up the chimney

    BandTotal QRP (5W) % RF power lost to heatTotal QROp (20W) % RF power lost to heat10m14.29.0912m13.28.7515m12.68.3517m11.87.6514m11.27.0030m10.66.8040m10.06.5580m18.46.80

    The white bearded man in the red suit and his flying reindeer might be grateful for a few watts of heat going up the chimney at this time of year, but those of us in the frozen barren tundra of the northern states and provinces, as well as licensed ham dwellers in other cold lands, may not see things the same way.

    What can we conclude?

    If we only consider the insertion loss – in this example – of the 4:1 voltage unun and the Common Mode Current Choke and ignore resistive losses in the transmission line, and possibly insertion loss in a transmatch (“tuner”), we can determine the potential efficiency of our antenna system.

    • For our QRP devices the efficiency varies between 81.6% and 90% across the bands
    • For our QRO devices the efficiency varies between 90.9% and 93.5% across the bands

    This conclusion is based on the assumption that there is no loss in the antenna itself. We are treating the antenna, the transmission line, unun and CMCC as the “antenna system”. I have made no allowance for SWR losses for the reasons stated in the introduction to this post.

    What a load of old codswallop!

    I am an expert in the sense that “X” is an unknown quantity and “spurt” is a drip under pressure. I may be completely wrong; I may have fallen off my horse and bumped my head on a rock. I may have come to a fork in the road and taken it as Yogi Berra once famously said. If you would like to correct me on any wrong assumptions please do so. I receive a lot of direct emails from readers and, while they are most welcome, if you write a comment to this post instead it may trigger an interesting technical discussion here.

    A big thank you to all the new and many existing subscribers to Ham Radio Outside the Box. It is people like you who make writing these posts so worthwhile. I appreciate every one of you.

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #cw #outdoorOps #unun

    #amateurradio2 #antennas #cw #outdoorops #unun
  7. Ham Radio Outside the Box @[email protected] ·

    What really determines the efficiency of an antenna?

    Is it Standing Wave Ratio (SWR)?

    It is common knowledge that when an antenna has high SWR some of our transmitted power is wasted instead of being transmitted. But is this really true? The trouble with “common knowledge” is that it spreads without further scrutiny. “It must be true because that’s what everybody thinks”. But let’s consider another perspective.

    What happens to our signal when it meets an antenna with high SWR? Some of the signal is radiated while the rest is reflected back down the transmission line to its source – the transceiver. What happens to the reflected signal when it reaches the transceiver? It is re-reflected back towards the antenna and the cycle repeats.

    So does all the signal eventually get radiated? No. Energy is lost (RED ALERT from the physics department: Energy can neither be created nor destroyed, only converted from one form to another). Ok, my apologies to the physics department, some of the energy is converted to heat as our signal passes along the transmission line and through any ununs, baluns, impedance transformers or other devices en route. Further energy is converted to heat due to the resistance of the wires and the impedance of the transmission line itself.

    Thus, on every trip between the transceiver and the antenna, some of our transmitted RF is converted to heat. If the antenna has a high SWR some of our signal travels back and forth between the transceiver and the antenna multiple times and becomes further attenuated on each trip. Therefore, if we can reduce the loss of RF (due to conversion to heat) as it passes through any devices along the journey between the source (transceiver) and load (antenna) we will improve the efficiency of our antenna system.

    How can we do that?

    One simple way to achieve that is to correct for the high SWR right at the antenna. A remote tuner can do that. A loading coil will compensate for the high capacitive reactance of a short antenna, but loading coils can be inefficient because of wire resistance. This is especially true in the case of base-loading coils on a quarter-wave vertical antenna. The current is highest at the base of the antenna so more RF energy will be lost to heat (P=I^2*R) than with a center-loading or top-loading coil.

    So the real culprit is not SWR, but the insertion loss of ununs, baluns, impedance transformers, loading coils, transmatches and any other “energy conversion” devices, including the transmission line itself, through which our signal has to pass.

    Insertion loss of Ham Radio Outside the Box’s 4:1 ununs

    In the previous post I reported on my build of field test versions of a 4:1 unun and a 4:1 balun to compare how each would handle the task assigned to them. Now the job I set myself was to transform what might be called the “Ugly Sisters” builds into something with the good looks of Cinderella. And Cinderella had to be an unun tough enough to withstand rough treatment out in the Big Blue Sky Shack through all four Canadian seasons (Late Winter, Brief Summer, Early Winter, Deep Winter).

    QRP 4:1 unun

    I built two versions of a 4:1 unun; one for QRP and another for what I like to call QROp. “QROp” is an unofficial label I have adopted to mean about 20 watts or so. Twenty watts will give a 1 S-unit advantage over 5 watts – maybe just enough for our signal to poke its nose above the noise floor when propagation conditions are not so good.

    QROp unun

    There are 2 main differences between the QRP and the QROp versions: The QRP unun uses a BNC connector and a 4:1 transformer wound on a tiny FT82-43 toroid. The QROp version uses an SO-239 connector and a 4:1 transformer wound on an FT140-43 toroid.

    If we look at the tables below, we can see that the QRP version may have a little too much insertion loss. When we are trying to do as much as we can with as little as possible every milliwatt is wanted. As the wonderful friendly folks on the big Canadian island of Newfoundland like to say: “A little’s a lot if it’s all you’ve got”.

    Insertion Loss effects of the Ham Radio Outside the Box QRP unun

    BandQRP (5 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.390.438.612m0.370.418.215m0.350.397.817m0.340.387.614m0.330.377.430m0.320.367.240m0.350.397.880m0.730.7715.4

    Insertion Loss effects of the Ham Radio Outside the Box QROp unun

    BandQROp (20 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.241.085.4012m0.231.035.1515m0.220.994.9517m0.210.944.7014m0.200.904.5030m0.200.904.5040m0.200.904.5080m0.220.994.95

    A little extra heat in winter

    You would think Canadians wouldn’t mind a little extra heat in winter. It’s true, but not when the source of that heat is our precious transmitted RF. In case you were wondering, the amount of RF converted to heat by inefficient devices is mostly undetectable. If it can be easily detected the “magic smoke” can’t be far behind. When it’s 253 Kelvins outside you just ain’t gonna notice when the temperature rises to 254 Kelvins (note: the physics department advised me to use Kelvins to avoid confusion between degrees Fahrenheit and degrees Celsius).

    Oh no! There’s more?

    Yes indeed. An unun does not attenuate Common Mode Current (CMC). For that we need a Common Mode Current Choke (CMCC). CMC is the current on the outer surface of a coax braid. Differential mode current is carried on the core and inner surface of the coax braid. Does a CMCC also have insertion loss? Yes, but how much? Let’s take a look.

    Insertion Loss of a QRP (5 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.250.285.612m0.220.255.015m0.210.244.817m0.190.214.214m0.170.193.830m0.150.173.440m0.140.163.280m0.130.153.0 QRP CMCC

    Insertion Loss of a QROp (20 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.180.814.0512m0.160.723.6015m0.150.683.4017m0.130.592.9514m0.110.502.5030m0.100.462.3040m0.090.412.0580m0.080.371.85 QROp CMCC

    The (not so) grand total of RF going up the chimney

    BandTotal QRP (5W) % RF power lost to heatTotal QROp (20W) % RF power lost to heat10m14.29.0912m13.28.7515m12.68.3517m11.87.6514m11.27.0030m10.66.8040m10.06.5580m18.46.80

    The white bearded man in the red suit and his flying reindeer might be grateful for a few watts of heat going up the chimney at this time of year, but those of us in the frozen barren tundra of the northern states and provinces, as well as licensed ham dwellers in other cold lands, may not see things the same way.

    What can we conclude?

    If we only consider the insertion loss – in this example – of the 4:1 voltage unun and the Common Mode Current Choke and ignore resistive losses in the transmission line, and possibly insertion loss in a transmatch (“tuner”), we can determine the potential efficiency of our antenna system.

    • For our QRP devices the efficiency varies between 81.6% and 90% across the bands
    • For our QRO devices the efficiency varies between 90.9% and 93.5% across the bands

    This conclusion is based on the assumption that there is no loss in the antenna itself. We are treating the antenna, the transmission line, unun and CMCC as the “antenna system”. I have made no allowance for SWR losses for the reasons stated in the introduction to this post.

    What a load of old codswallop!

    I am an expert in the sense that “X” is an unknown quantity and “spurt” is a drip under pressure. I may be completely wrong; I may have fallen off my horse and bumped my head on a rock. I may have come to a fork in the road and taken it as Yogi Berra once famously said. If you would like to correct me on any wrong assumptions please do so. I receive a lot of direct emails from readers and, while they are most welcome, if you write a comment to this post instead it may trigger an interesting technical discussion here.

    A big thank you to all the new and many existing subscribers to Ham Radio Outside the Box. It is people like you who make writing these posts so worthwhile. I appreciate every one of you.

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #cw #outdoorOps #unun

    #unun #outdoorops #cw #antennas #amateurradio2
  8. Ham Radio Outside the Box @[email protected] ·

    What really determines the efficiency of an antenna?

    Is it Standing Wave Ratio (SWR)?

    It is common knowledge that when an antenna has high SWR some of our transmitted power is wasted instead of being transmitted. But is this really true? The trouble with “common knowledge” is that it spreads without further scrutiny. “It must be true because that’s what everybody thinks”. But let’s consider another perspective.

    What happens to our signal when it meets an antenna with high SWR? Some of the signal is radiated while the rest is reflected back down the transmission line to its source – the transceiver. What happens to the reflected signal when it reaches the transceiver? It is re-reflected back towards the antenna and the cycle repeats.

    So does all the signal eventually get radiated? No. Energy is lost (RED ALERT from the physics department: Energy can neither be created nor destroyed, only converted from one form to another). Ok, my apologies to the physics department, some of the energy is converted to heat as our signal passes along the transmission line and through any ununs, baluns, impedance transformers or other devices en route. Further energy is converted to heat due to the resistance of the wires and the impedance of the transmission line itself.

    Thus, on every trip between the transceiver and the antenna, some of our transmitted RF is converted to heat. If the antenna has a high SWR some of our signal travels back and forth between the transceiver and the antenna multiple times and becomes further attenuated on each trip. Therefore, if we can reduce the loss of RF (due to conversion to heat) as it passes through any devices along the journey between the source (transceiver) and load (antenna) we will improve the efficiency of our antenna system.

    How can we do that?

    One simple way to achieve that is to correct for the high SWR right at the antenna. A remote tuner can do that. A loading coil will compensate for the high capacitive reactance of a short antenna, but loading coils can be inefficient because of wire resistance. This is especially true in the case of base-loading coils on a quarter-wave vertical antenna. The current is highest at the base of the antenna so more RF energy will be lost to heat (P=I^2*R) than with a center-loading or top-loading coil.

    So the real culprit is not SWR, but the insertion loss of ununs, baluns, impedance transformers, loading coils, transmatches and any other “energy conversion” devices, including the transmission line itself, through which our signal has to pass.

    Insertion loss of Ham Radio Outside the Box’s 4:1 ununs

    In the previous post I reported on my build of field test versions of a 4:1 unun and a 4:1 balun to compare how each would handle the task assigned to them. Now the job I set myself was to transform what might be called the “Ugly Sisters” builds into something with the good looks of Cinderella. And Cinderella had to be an unun tough enough to withstand rough treatment out in the Big Blue Sky Shack through all four Canadian seasons (Late Winter, Brief Summer, Early Winter, Deep Winter).

    QRP 4:1 unun

    I built two versions of a 4:1 unun; one for QRP and another for what I like to call QROp. “QROp” is an unofficial label I have adopted to mean about 20 watts or so. Twenty watts will give a 1 S-unit advantage over 5 watts – maybe just enough for our signal to poke its nose above the noise floor when propagation conditions are not so good.

    QROp unun

    There are 2 main differences between the QRP and the QROp versions: The QRP unun uses a BNC connector and a 4:1 transformer wound on a tiny FT82-43 toroid. The QROp version uses an SO-239 connector and a 4:1 transformer wound on an FT140-43 toroid.

    If we look at the tables below, we can see that the QRP version may have a little too much insertion loss. When we are trying to do as much as we can with as little as possible every milliwatt is wanted. As the wonderful friendly folks on the big Canadian island of Newfoundland like to say: “A little’s a lot if it’s all you’ve got”.

    Insertion Loss effects of the Ham Radio Outside the Box QRP unun

    BandQRP (5 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.390.438.612m0.370.418.215m0.350.397.817m0.340.387.614m0.330.377.430m0.320.367.240m0.350.397.880m0.730.7715.4

    Insertion Loss effects of the Ham Radio Outside the Box QROp unun

    BandQROp (20 watts) UNUN Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.241.085.4012m0.231.035.1515m0.220.994.9517m0.210.944.7014m0.200.904.5030m0.200.904.5040m0.200.904.5080m0.220.994.95

    A little extra heat in winter

    You would think Canadians wouldn’t mind a little extra heat in winter. It’s true, but not when the source of that heat is our precious transmitted RF. In case you were wondering, the amount of RF converted to heat by inefficient devices is mostly undetectable. If it can be easily detected the “magic smoke” can’t be far behind. When it’s 253 Kelvins outside you just ain’t gonna notice when the temperature rises to 254 Kelvins (note: the physics department advised me to use Kelvins to avoid confusion between degrees Fahrenheit and degrees Celsius).

    Oh no! There’s more?

    Yes indeed. An unun does not attenuate Common Mode Current (CMC). For that we need a Common Mode Current Choke (CMCC). CMC is the current on the outer surface of a coax braid. Differential mode current is carried on the core and inner surface of the coax braid. Does a CMCC also have insertion loss? Yes, but how much? Let’s take a look.

    Insertion Loss of a QRP (5 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.250.285.612m0.220.255.015m0.210.244.817m0.190.214.214m0.170.193.830m0.150.173.440m0.140.163.280m0.130.153.0 QRP CMCC

    Insertion Loss of a QROp (20 watts) Common Mode Current Choke (CMCC)

    BandQRP (5 watts) CMCC Insertion Loss (dB)RF Power Lost (watts)% RF Power Lost10m0.180.814.0512m0.160.723.6015m0.150.683.4017m0.130.592.9514m0.110.502.5030m0.100.462.3040m0.090.412.0580m0.080.371.85 QROp CMCC

    The (not so) grand total of RF going up the chimney

    BandTotal QRP (5W) % RF power lost to heatTotal QROp (20W) % RF power lost to heat10m14.29.0912m13.28.7515m12.68.3517m11.87.6514m11.27.0030m10.66.8040m10.06.5580m18.46.80

    The white bearded man in the red suit and his flying reindeer might be grateful for a few watts of heat going up the chimney at this time of year, but those of us in the frozen barren tundra of the northern states and provinces, as well as licensed ham dwellers in other cold lands, may not see things the same way.

    What can we conclude?

    If we only consider the insertion loss – in this example – of the 4:1 voltage unun and the Common Mode Current Choke and ignore resistive losses in the transmission line, and possibly insertion loss in a transmatch (“tuner”), we can determine the potential efficiency of our antenna system.

    • For our QRP devices the efficiency varies between 81.6% and 90% across the bands
    • For our QRO devices the efficiency varies between 90.9% and 93.5% across the bands

    This conclusion is based on the assumption that there is no loss in the antenna itself. We are treating the antenna, the transmission line, unun and CMCC as the “antenna system”. I have made no allowance for SWR losses for the reasons stated in the introduction to this post.

    What a load of old codswallop!

    I am an expert in the sense that “X” is an unknown quantity and “spurt” is a drip under pressure. I may be completely wrong; I may have fallen off my horse and bumped my head on a rock. I may have come to a fork in the road and taken it as Yogi Berra once famously said. If you would like to correct me on any wrong assumptions please do so. I receive a lot of direct emails from readers and, while they are most welcome, if you write a comment to this post instead it may trigger an interesting technical discussion here.

    A big thank you to all the new and many existing subscribers to Ham Radio Outside the Box. It is people like you who make writing these posts so worthwhile. I appreciate every one of you.

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #cw #outdoorOps #unun

    #amateurradio2 #antennas #cw #outdoorops #unun
  9. Ham Radio Outside the Box @[email protected] ·

    POTA PERformer radials – can we make a compromise?

    There has only been one light snowfall in southern Ontario so far this season – just a few centimeters that melted away within a couple of days. In anticipation of upcoming heavier snowfalls and a semi-permanent white blanket that will last until spring, I bravely shrugged off the chilly outside air and set up my Ham Radio Outside the Box version of the POTA PERformer antenna out in the backyard to experiment with radial lengths.

    The cunningly repaired broken shortened whip with a capacitive top hat, to compensate for its inductive reactance on the 20m band, sat atop my custom spike mount that, despite falling temperatures, could still be pushed into the ground about 25cm (10 inches). Two radials were attached each of which sloped down to a fiberglass stake about a foot (30cm) above ground. The radials are approximately 5m (17ft) long for the 20m band with links to shorten the wires for the 17m and 15m bands.

    Now, to find a shortcut

    The objective for the day’s tests was to investigate whether compromises could be made in the radial lengths. Why? Later in the winter, when the snow lies deep and crisp and even, it can become a real chore to wade through accumulations of the infernal white stuff to adjust the radial lengths for band changes. I have adopted 2mm banana plugs for the links – a great idea in the summer, but maybe I neglected to consider what will happen when even a few snow flakes freeze on those tiny connectors in the winter!

    So, how to minimize pedestrian excursions through the challenges of winter operating conditions to accommodate band changes? The POTA PERformer is an efficient antenna but it was designed in California where the climate is just a little milder than in Ontario. Should I go back to using a random wire antenna – like the Rybakov – until spring comes around again?

    I could perhaps use “fan radials” i.e. separate radials for each band. That would probably work but setting them up might still involve wading through deep snow. In the past I have used ground radials laid on the snow – a multiband arrangement that requires no adjustment for band changes, but is less efficient.

    Back to the backyard tests; what did I find out?

    • First, my approximately 16.5ft (~5m) raised radial wires provided an acceptable SWR (less than 2:1) on 20m and 17m (with the whip length shortened for 17m).
    • Second, the same wires – with the links adjusted for 15m and the whip shortened again – gave an acceptable SWR on 15m, 12m and 10m.

    So, is this a result? Maybe not. There is a potential for lost efficiency when the radiating element is shorter than the counterpoise. Let me explain.

    Let’s assume we are using a field portable version of the POTA PERformer in which the feedpoint remains quite close to the ground – maybe 1 to 1.5 meters. The two radial wires slope away from the feedpoint to an end point even lower to the ground. Now, if we examine the current distribution on a halfwave dipole, we can see that the maximum current, and therefore the point at which maximum RF is radiated, is located in the center of the dipole.

    We would like the high current point to lie within the radiating element, not the counterpoise. For the purposes of this discussion we are going to refer to the two radial wires as “the counterpoise”.

    Going back to my backyard tests, I found that:

    • a 20m counterpoise “worked” on the 17m band.
    • a 15m counterpoise also “worked” on the 12m and 10m bands.

    In each of these cases the radiating element was shorter than the counterpoise.

    Referring to the accompanying diagrams we can see that the high current point, in each case, lies within the counterpoise.

    Does this finding matter?

    Changing the radiating element versus counterpoise balance creates an antenna that looks very much like an Off Center Fed Dipole (OCFD).

    If an OCFD is mounted high enough above ground it doesn’t matter at all although two things need to be considered here:

    1. Changing the radiating element versus counterpoise lengths changes the impedance at the feedpoint.
    2. The overall length of the dipole might change unexpectedly. This can be seen with Greg KJ6ER’s Challenger antenna which is a vertical OCFD halfwave dipole that is shortened by laying part of the counterpoise wire on the ground.

    A relatively small change in the ratio between the radiating element versus counterpoise lengths changes the feedpoint impedance, but this can be compensated by adjusting the whip length to still obtain a usable SWR.

    However, we cannot compensate for the proximity to ground of the counterpoise in the POTA PERformer. If the current maximum occurs at the feedpoint (1 to 1.5 meters above ground) very little power is lost. But, if the current maximum occurs below the feedpoint we are going to keep the earthworms warm in winter.

    Not the best plan

    So we can conclude that using a 20m counterpoise on 17m risks losing some of our RF energy to the ground. The same applies for using a 15m counterpoise on 12m and 10m. The following diagram summarizes this.

    The way forward

    “Fan radials” may still be a solution but they require some careful experimentation. There is interaction between the wires for each band due to mutual capacitance. This is compounded when multiple bands are involved. To make matters worse, when used out in the Big Blue Sky Shack where the wind doth blow through the wires and changes the interaction, who knows what wild swings in SWR may occur? The radio I have dubbed my “very clever poodle” (QMX: see last post) will not take kindly to that.

    A final thought

    I have watched several videos in which a very short whip is mounted on a picnic table and used with a single long counterpoise wire draped down to and across the ground. Sometimes the “Magic (Tune) Button” assists in finding an SWR that keeps the radio smiling. Contacts get made, so what’s the problem? I hope the above discussion answers that question.

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #counterpoise #ground #outdoorOps #pota #qmx

    #amateurradio2 #antennas #counterpoise #ground #outdoorops #pota
  10. Ham Radio Outside the Box @[email protected] ·

    POTA PERformer radials – can we make a compromise?

    There has only been one light snowfall in southern Ontario so far this season – just a few centimeters that melted away within a couple of days. In anticipation of upcoming heavier snowfalls and a semi-permanent white blanket that will last until spring, I bravely shrugged off the chilly outside air and set up my Ham Radio Outside the Box version of the POTA PERformer antenna out in the backyard to experiment with radial lengths.

    The cunningly repaired broken shortened whip with a capacitive top hat, to compensate for its inductive reactance on the 20m band, sat atop my custom spike mount that, despite falling temperatures, could still be pushed into the ground about 25cm (10 inches). Two radials were attached each of which sloped down to a fiberglass stake about a foot (30cm) above ground. The radials are approximately 5m (17ft) long for the 20m band with links to shorten the wires for the 17m and 15m bands.

    Now, to find a shortcut

    The objective for the day’s tests was to investigate whether compromises could be made in the radial lengths. Why? Later in the winter, when the snow lies deep and crisp and even, it can become a real chore to wade through accumulations of the infernal white stuff to adjust the radial lengths for band changes. I have adopted 2mm banana plugs for the links – a great idea in the summer, but maybe I neglected to consider what will happen when even a few snow flakes freeze on those tiny connectors in the winter!

    So, how to minimize pedestrian excursions through the challenges of winter operating conditions to accommodate band changes? The POTA PERformer is an efficient antenna but it was designed in California where the climate is just a little milder than in Ontario. Should I go back to using a random wire antenna – like the Rybakov – until spring comes around again?

    I could perhaps use “fan radials” i.e. separate radials for each band. That would probably work but setting them up might still involve wading through deep snow. In the past I have used ground radials laid on the snow – a multiband arrangement that requires no adjustment for band changes, but is less efficient.

    Back to the backyard tests; what did I find out?

    • First, my approximately 16.5ft (~5m) raised radial wires provided an acceptable SWR (less than 2:1) on 20m and 17m (with the whip length shortened for 17m).
    • Second, the same wires – with the links adjusted for 15m and the whip shortened again – gave an acceptable SWR on 15m, 12m and 10m.

    So, is this a result? Maybe not. There is a potential for lost efficiency when the radiating element is shorter than the counterpoise. Let me explain.

    Let’s assume we are using a field portable version of the POTA PERformer in which the feedpoint remains quite close to the ground – maybe 1 to 1.5 meters. The two radial wires slope away from the feedpoint to an end point even lower to the ground. Now, if we examine the current distribution on a halfwave dipole, we can see that the maximum current, and therefore the point at which maximum RF is radiated, is located in the center of the dipole.

    We would like the high current point to lie within the radiating element, not the counterpoise. For the purposes of this discussion we are going to refer to the two radial wires as “the counterpoise”.

    Going back to my backyard tests, I found that:

    • a 20m counterpoise “worked” on the 17m band.
    • a 15m counterpoise also “worked” on the 12m and 10m bands.

    In each of these cases the radiating element was shorter than the counterpoise.

    Referring to the accompanying diagrams we can see that the high current point, in each case, lies within the counterpoise.

    Does this finding matter?

    Changing the radiating element versus counterpoise balance creates an antenna that looks very much like an Off Center Fed Dipole (OCFD).

    If an OCFD is mounted high enough above ground it doesn’t matter at all although two things need to be considered here:

    1. Changing the radiating element versus counterpoise lengths changes the impedance at the feedpoint.
    2. The overall length of the dipole might change unexpectedly. This can be seen with Greg KJ6ER’s Challenger antenna which is a vertical OCFD halfwave dipole that is shortened by laying part of the counterpoise wire on the ground.

    A relatively small change in the ratio between the radiating element versus counterpoise lengths changes the feedpoint impedance, but this can be compensated by adjusting the whip length to still obtain a usable SWR.

    However, we cannot compensate for the proximity to ground of the counterpoise in the POTA PERformer. If the current maximum occurs at the feedpoint (1 to 1.5 meters above ground) very little power is lost. But, if the current maximum occurs below the feedpoint we are going to keep the earthworms warm in winter.

    Not the best plan

    So we can conclude that using a 20m counterpoise on 17m risks losing some of our RF energy to the ground. The same applies for using a 15m counterpoise on 12m and 10m. The following diagram summarizes this.

    The way forward

    “Fan radials” may still be a solution but they require some careful experimentation. There is interaction between the wires for each band due to mutual capacitance. This is compounded when multiple bands are involved. To make matters worse, when used out in the Big Blue Sky Shack where the wind doth blow through the wires and changes the interaction, who knows what wild swings in SWR may occur? The radio I have dubbed my “very clever poodle” (QMX: see last post) will not take kindly to that.

    A final thought

    I have watched several videos in which a very short whip is mounted on a picnic table and used with a single long counterpoise wire draped down to and across the ground. Sometimes the “Magic (Tune) Button” assists in finding an SWR that keeps the radio smiling. Contacts get made, so what’s the problem? I hope the above discussion answers that question.

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #counterpoise #ground #outdoorOps #pota #qmx

    #qmx #pota #outdoorops #ground #counterpoise #antennas
  11. Ham Radio Outside the Box @[email protected] ·

    POTA PERformer radials – can we make a compromise?

    There has only been one light snowfall in southern Ontario so far this season – just a few centimeters that melted away within a couple of days. In anticipation of upcoming heavier snowfalls and a semi-permanent white blanket that will last until spring, I bravely shrugged off the chilly outside air and set up my Ham Radio Outside the Box version of the POTA PERformer antenna out in the backyard to experiment with radial lengths.

    The cunningly repaired broken shortened whip with a capacitive top hat, to compensate for its inductive reactance on the 20m band, sat atop my custom spike mount that, despite falling temperatures, could still be pushed into the ground about 25cm (10 inches). Two radials were attached each of which sloped down to a fiberglass stake about a foot (30cm) above ground. The radials are approximately 5m (17ft) long for the 20m band with links to shorten the wires for the 17m and 15m bands.

    Now, to find a shortcut

    The objective for the day’s tests was to investigate whether compromises could be made in the radial lengths. Why? Later in the winter, when the snow lies deep and crisp and even, it can become a real chore to wade through accumulations of the infernal white stuff to adjust the radial lengths for band changes. I have adopted 2mm banana plugs for the links – a great idea in the summer, but maybe I neglected to consider what will happen when even a few snow flakes freeze on those tiny connectors in the winter!

    So, how to minimize pedestrian excursions through the challenges of winter operating conditions to accommodate band changes? The POTA PERformer is an efficient antenna but it was designed in California where the climate is just a little milder than in Ontario. Should I go back to using a random wire antenna – like the Rybakov – until spring comes around again?

    I could perhaps use “fan radials” i.e. separate radials for each band. That would probably work but setting them up might still involve wading through deep snow. In the past I have used ground radials laid on the snow – a multiband arrangement that requires no adjustment for band changes, but is less efficient.

    Back to the backyard tests; what did I find out?

    • First, my approximately 16.5ft (~5m) raised radial wires provided an acceptable SWR (less than 2:1) on 20m and 17m (with the whip length shortened for 17m).
    • Second, the same wires – with the links adjusted for 15m and the whip shortened again – gave an acceptable SWR on 15m, 12m and 10m.

    So, is this a result? Maybe not. There is a potential for lost efficiency when the radiating element is shorter than the counterpoise. Let me explain.

    Let’s assume we are using a field portable version of the POTA PERformer in which the feedpoint remains quite close to the ground – maybe 1 to 1.5 meters. The two radial wires slope away from the feedpoint to an end point even lower to the ground. Now, if we examine the current distribution on a halfwave dipole, we can see that the maximum current, and therefore the point at which maximum RF is radiated, is located in the center of the dipole.

    We would like the high current point to lie within the radiating element, not the counterpoise. For the purposes of this discussion we are going to refer to the two radial wires as “the counterpoise”.

    Going back to my backyard tests, I found that:

    • a 20m counterpoise “worked” on the 17m band.
    • a 15m counterpoise also “worked” on the 12m and 10m bands.

    In each of these cases the radiating element was shorter than the counterpoise.

    Referring to the accompanying diagrams we can see that the high current point, in each case, lies within the counterpoise.

    Does this finding matter?

    Changing the radiating element versus counterpoise balance creates an antenna that looks very much like an Off Center Fed Dipole (OCFD).

    If an OCFD is mounted high enough above ground it doesn’t matter at all although two things need to be considered here:

    1. Changing the radiating element versus counterpoise lengths changes the impedance at the feedpoint.
    2. The overall length of the dipole might change unexpectedly. This can be seen with Greg KJ6ER’s Challenger antenna which is a vertical OCFD halfwave dipole that is shortened by laying part of the counterpoise wire on the ground.

    A relatively small change in the ratio between the radiating element versus counterpoise lengths changes the feedpoint impedance, but this can be compensated by adjusting the whip length to still obtain a usable SWR.

    However, we cannot compensate for the proximity to ground of the counterpoise in the POTA PERformer. If the current maximum occurs at the feedpoint (1 to 1.5 meters above ground) very little power is lost. But, if the current maximum occurs below the feedpoint we are going to keep the earthworms warm in winter.

    Not the best plan

    So we can conclude that using a 20m counterpoise on 17m risks losing some of our RF energy to the ground. The same applies for using a 15m counterpoise on 12m and 10m. The following diagram summarizes this.

    The way forward

    “Fan radials” may still be a solution but they require some careful experimentation. There is interaction between the wires for each band due to mutual capacitance. This is compounded when multiple bands are involved. To make matters worse, when used out in the Big Blue Sky Shack where the wind doth blow through the wires and changes the interaction, who knows what wild swings in SWR may occur? The radio I have dubbed my “very clever poodle” (QMX: see last post) will not take kindly to that.

    A final thought

    I have watched several videos in which a very short whip is mounted on a picnic table and used with a single long counterpoise wire draped down to and across the ground. Sometimes the “Magic (Tune) Button” assists in finding an SWR that keeps the radio smiling. Contacts get made, so what’s the problem? I hope the above discussion answers that question.

    Help support HamRadioOutsidetheBox

    No “tip-jar”, “buy me a coffee”, Patreon, or Amazon links here. I enjoy my hobby and I enjoy writing about it. If you would like to support this blog please follow/subscribe using the link at the bottom of my home page, or like, comment (links at the bottom of each post), repost or share links to my posts on social media. If you would like to email me directly you will find my email address on my QRZ.com page. Thank you!

    The following copyright notice applies to all content on this blog.


    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

    #amateurRadio2 #antennas #counterpoise #ground #outdoorOps #pota #qmx

    #amateurradio2 #antennas #counterpoise #ground #outdoorops #pota
  12. Ham Radio Outside the Box @[email protected] ·

    POTA PERformer radials – can we make a compromise?

    There has only been one light snowfall in southern Ontario so far this season – just a few centimeters that melted away within a couple of days. In anticipation of upcoming heavier snowfalls and a semi-permanent white blanket that will last until spring, I bravely shrugged off the chilly outside air and set up my Ham Radio Outside the Box version of the POTA PERformer antenna out in the backyard to experiment with radial lengths.

    The cunningly repaired broken shortened whip with a capacitive top hat, to compensate for its inductive reactance on the 20m band, sat atop my custom spike mount that, despite falling temperatures, could still be pushed into the ground about 25cm (10 inches). Two radials were attached each of which sloped down to a fiberglass stake about a foot (30cm) above ground. The radials are approximately 5m (17ft) long for the 20m band with links to shorten the wires for the 17m and 15m bands.

    Now, to find a shortcut

    The objective for the day’s tests was to investigate whether compromises could be made in the radial lengths. Why? Later in the winter, when the snow lies deep and crisp and even, it can become a real chore to wade through accumulations of the infernal white stuff to adjust the radial lengths for band changes. I have adopted 2mm banana plugs for the links – a great idea in the summer, but maybe I neglected to consider what will happen when even a few snow flakes freeze on those tiny connectors in the winter!

    So, how to minimize pedestrian excursions through the challenges of winter operating conditions to accommodate band changes? The POTA PERformer is an efficient antenna but it was designed in California where the climate is just a little milder than in Ontario. Should I go back to using a random wire antenna – like the Rybakov – until spring comes around again?

    I could perhaps use “fan radials” i.e. separate radials for each band. That would probably work but setting them up might still involve wading through deep snow. In the past I have used ground radials laid on the snow – a multiband arrangement that requires no adjustment for band changes, but is less efficient.

    Back to the backyard tests; what did I find out?

    • First, my approximately 16.5ft (~5m) raised radial wires provided an acceptable SWR (less than 2:1) on 20m and 17m (with the whip length shortened for 17m).
    • Second, the same wires – with the links adjusted for 15m and the whip shortened again – gave an acceptable SWR on 15m, 12m and 10m.

    So, is this a result? Maybe not. There is a potential for lost efficiency when the radiating element is shorter than the counterpoise. Let me explain.

    Let’s assume we are using a field portable version of the POTA PERformer in which the feedpoint remains quite close to the ground – maybe 1 to 1.5 meters. The two radial wires slope away from the feedpoint to an end point even lower to the ground. Now, if we examine the current distribution on a halfwave dipole, we can see that the maximum current, and therefore the point at which maximum RF is radiated, is located in the center of the dipole.

    We would like the high current point to lie within the radiating element, not the counterpoise. For the purposes of this discussion we are going to refer to the two radial wires as “the counterpoise”.

    Going back to my backyard tests, I found that:

    • a 20m counterpoise “worked” on the 17m band.
    • a 15m counterpoise also “worked” on the 12m and 10m bands.

    In each of these cases the radiating element was shorter than the counterpoise.

    Referring to the accompanying diagrams we can see that the high current point, in each case, lies within the counterpoise.

    Does this finding matter?

    Changing the radiating element versus counterpoise balance creates an antenna that looks very much like an Off Center Fed Dipole (OCFD).

    If an OCFD is mounted high enough above ground it doesn’t matter at all although two things need to be considered here:

    1. Changing the radiating element versus counterpoise lengths changes the impedance at the feedpoint.
    2. The overall length of the dipole might change unexpectedly. This can be seen with Greg KJ6ER’s Challenger antenna which is a vertical OCFD halfwave dipole that is shortened by laying part of the counterpoise wire on the ground.

    A relatively small change in the ratio between the radiating element versus counterpoise lengths changes the feedpoint impedance, but this can be compensated by adjusting the whip length to still obtain a usable SWR.

    However, we cannot compensate for the proximity to ground of the counterpoise in the POTA PERformer. If the current maximum occurs at the feedpoint (1 to 1.5 meters above ground) very little power is lost. But, if the current maximum occurs below the feedpoint we are going to keep the earthworms warm in winter.

    Not the best plan

    So we can conclude that using a 20m counterpoise on 17m risks losing some of our RF energy to the ground. The same applies for using a 15m counterpoise on 12m and 10m. The following diagram summarizes this.

    The way forward

    “Fan radials” may still be a solution but they require some careful experimentation. There is interaction between the wires for each band due to mutual capacitance. This is compounded when multiple bands are involved. To make matters worse, when used out in the Big Blue Sky Shack where the wind doth blow through the wires and changes the interaction, who knows what wild swings in SWR may occur? The radio I have dubbed my “very clever poodle” (QMX: see last post) will not take kindly to that.

    A final thought

    I have watched several videos in which a very short whip is mounted on a picnic table and used with a single long counterpoise wire draped down to and across the ground. Sometimes the “Magic (Tune) Button” assists in finding an SWR that keeps the radio smiling. Contacts get made, so what’s the problem? I hope the above discussion answers that question.

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    #amateurRadio2 #antennas #counterpoise #ground #outdoorOps #pota #qmx

    #amateurradio2 #antennas #counterpoise #ground #outdoorops #pota