#efhw — Public Fediverse posts

Beautiful spring afternoon for a #amateurradio #hamradio #pota #parksontheair activation with a #straightkey with my #heathkit #hw8 CW #morsecode #qrpradio Transceiver into a #qrp #EFHW #tenntenna transformer.

Been really enjoying the EFHW antenna for sure! I'm coloring the markers by band now, 'cause that seems way more interesting. I'm especially happy to get Nova Scotia this weekend!

Red=80m Green=40m Blue=20m Purple=17m

#hamRadio #amateurRadio #POTA #parksOnTheAir #ssb #efhw #17m #20m #40m #80m

Holy cow this weekend was insane on HF. I ended up with 142 SSB POTA contacts, on all bands from 40 meters to 10 meters. It was so much fun! The colors are listed in the image's ALT text. I think I need a vacation after all that!

#HF #POTA #hamRadio #amateurRadio #10m #12m #15m #17m #20m #40m #insanity #EFHW

Spending this weekend working the new EFHW antenna, I got 96 POTA contacts across 10, 12, 17, 20 and 40 meters! All SSB, no digital! I am beyond happy with how it performs, and it even managed to get my last 2 states needed for hunting all 50 states in POTA!

#hamRadio #amateurRadio #SSB #POTA #EFHW #10m #12m #17m #20m #40m

Well, it was such a nice day yesterday that I decided to put up the new EFHW antenna! Took a couple hours to get it in place and get it tuned up. It definitely works much better than I was expecting!

Managed to get the tune so I don't need to use any tuner at all on all bands that it supports! Everything is under 2:1 SWR and some are even nearly 1:1 which I really didn't expect!

The markers are color coded for the bands that I got contacts on. Green ones for 40 meters, orange ones for 30 meters, blue for 20 meters, cyan for 15 meters, and yellow for 10 meters!

I can definitely recommend this antenna ( myantennas.com EFHW ) without question.

#hamRadio #amateurRadio #POTA #EFHW #10m #15m #20m #30m #40m

Back out of my hibernation den for some #qrp #pota #parksontheair CW #morsecode #amateurradio #hamradio activation with the #heathkit #hw8 and #camalback #ministraightkey #telegraphkey into #EFHW and #tenntenna 49:1 from Uncle Walt

Engineering challenges of the completed QRP EFHW coupler

Kudos to Kits and Parts, the United States Postal Service and the Canada Post dog sled teams who fearlessly fought their way through blizzards on the frozen barren tundra into the wild white yonder to safely deliver my package of toroid cores. But, as soon as I had unpacked the goodies I realized I may have fired off the order with excessive haste. I ordered some medium sized Type 2 and Type 6 powdered iron toroids for my occasional QROp (20 watts) projects and some smaller ones for QRP. How small? Too small! In my haste I had ordered 25 T37-2 and 25 T37-6 cores. These cores are so small that winding inductors on them requires a great deal and patience and dexterity – I have neither.

When life hands you lemons …

When life hands me self-inflicted lemons I tend to fill my head with expletives that are best not spoken in polite company. Then I find ways to cover up my mistakes. T37 cores are really only suitable in the stages of a transceiver prior to the final PA. Could they possibly be persuaded to handle the full 4.5 watts output of my revered antique Yaesu FT-817?

I reminded myself that this is Ham Radio Outside the Box and in that spirit I would find a way to use those lilliputian cores in my project. There were two screaming demons haunting my thoughts on this. A toroidal core can overheat due to being too small to handle the power applied to it. Or it can simply reach magnetic saturation causing it to fail to perform as expected.

I remembered an old trick used by hams who enjoy pumping out so much power they risk blowing holes in the ionosphere. They use multiple stacked toroid cores to share the load. Would that work with the tiny cores I had at my disposal? I decided to take the risk, but first test the idea on the bench before venturing out into the Big Blue Sky Shack.

But how to test the idea?

If a core can’t handle the power applied to it it will get hot. If the core reaches magnetic saturation it will no longer function as expected. I figured a simple way to test for these conditions on the bench would be a keydown test into a 2.5Kohm dummy load. I used two stacked T37-6 cores, held together with electrical tape and then by the wire wound through them. The setup was almost identical to the “20 minute” version published in the previous post, except that the inductor was now the toroidal core version.

The tuned circuit, dummy load and transceiver were hooked up on the bench and then, with very little trepidation (if I blew up the inductor I had more wire, more cores), I keyed up the full four and a half watts from the transceiver for 30 seconds while monitoring the SWR on my Norcal QRP power meter. Did it survive the test?

The Norcal QRP power meter indicated a rock steady SWR throughout the test. The cores may have increased in temperature but not enough to be detectable when touched with my fingers at the end of the keydown. Not a scientifically rigorous test but it inspired confidence in the viability of the solution. Stacking two cores increases the depth through which the wires pass through the core and that may compensate for the smaller diameter.

And now – that pesky polyvaricon

The 3D printing revolution hasn’t yet penetrated the basement laboratories of Ham Radio Outside the Box. Instead I am limited to good old-fashioned engineering techniques in my build projects. It is amazing what can be achieved with an extensive collection of materials and a few simple tools. That is exactly how I approached the challenge of attaching a regular quarter-inch knob to the stubby, irregular shaft of a polyvaricon.

The basic idea has already been covered on this blog but it has now been refined into a reproducible technique that is rugged and reliable enough to survive the rigors of being bumped over the steep and rocky terrain encountered along the north end of the Niagara Escarpment. The solution to the challenge is to construct a short quarter-inch diameter adapter shaft than can be securely attached to the polyvaricon. The basic material used is a steel drinking straw. Now that plastic straws have been declared a deadly hazard to the survival of the human race, steel straws are becoming quite easy to find.

Two tools were required; a Dremel for cutting a slot in one end of a section of the straw, and a small tube cutter for cutting the adapter shaft to the correct length. The adapter shaft is secured to the polyvaricon by means of a long, fine bolt and a small washer. Scavenging polyvaricons from dirt cheap thrift store AM/FM radios ensures the correct size of bolt is obtained. I did have to grind down the washer a little when the adapter shaft was fitted to ensure it slid into the knob nicely. Building the adapter shaft took about a half hour of delicate work while wearing a magnifying lens to enhance my degenerating vision. I imagine making something similar with a 3D printer would take as long.

I have another project developing on the workbench which involves the same inductor core tricks and polyvaricon mods as outlined here. It is a wideband L-match and if it works I’ll publish the details here in a couple of weeks. On the other hand, if it doesn’t work …

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Woo! The MyAntennas 7510-1K EFHW antenna got here! I'm so excited, and am just waiting for some coax to get here so I can mount and get it all set up! It feels so high quality, so I'm really looking forward to seeing how it performs. I'll finally be able to get on something other than 10m, 12m or 6m! YAY!

#hamRadio #hamShack #antennas #hf #efhw

So, I've done it. I ordered an EFHW antenna from myantennas.com, which covers 75m-10m! I still have to pick up a few other things to make it all connect in to my shack, but I will finally be able to get on other bands soon! Now to just hope for a good enough day to get on the roof and hook up coax and lightning blocks and get everything all mounted. I'm so excited!

#antennas #hf #efhw #amateurRadio #hamRadio #hamShack

Finally the rain has stopped and the Sun is out allowing me to trimmed/tuned 40 - 15 meter #HamRadio #AmateurRadio #EFHW antenna with #SWR 1.25:1 and lower on all #CW #Morsecode portions of my #Heathkit #HW8

Due to weather I made a 40 - 10 Meter #EFHW with Walt #NE4TN #QRP #TennTennas #UNUN specifically for portable use with my #Heathkit #HW8 and got a #HWA7 Power Supply for QTH from one of the BEST Brick & Mortar Ham Radio Stores #r_lelectronics

Pre-dawn #hamradio #amateurradio #pota #parksontheair activation setup with #ft817 #qrpradio into #qrp #EFHW

HUGE grin for today's Early Bird #hamradio #morsecode CW #parksontheair #pota activation because #radioblackout produced 20m opening into VK land using @Youkits #hb1b with 4040-10m #EFHW antenna up 35feet. #amateurradio is AWESOME BABY

#SOTA OE/TI-527 Unterberghorn is easily accessible by funicular. It’s about an hour’s walk from the top station to the summit (300 vertical meters). We took the walk down, but I can’t recommend that since it is mostly in the woods and the views are not that spectacular. The operating position on the summit is very comfortable and allows for a full #40m #EFHW to be erected. #HamRadio #SummitsOnTheAir #Amateurfunk #qrp #mtr3b #morsecode #hiking #mountains #tyrol #austria

After arriving at the hotel I thought it was time for a small activation: #SOTA DL/CG-110 Walmberg is the closest summit to our location. The ascent has some nice views over Reit im Winkl and despite the trees on the summit there was plenty of space to put up the #EFHW. 33 QSOs on #40m and #20m in 28 minutes - now a quick shower and off to the restaurant with my wife! #HamRadio #SummitsOnTheAir #Amateurfunk #qrp #mtr3b #morsecode #hiking #mountains #chiemgau #bavaria

I’m currently testing a new #EFHW for #40m, #20m, #15m and #10m. On some #SOTA summits there is not enough space to put up a full 20 m long antenna. So I have designed this one which is like a linked #EFHW, but you’re able to remove the outer half and get an antenna of just about 10 m length (for the #20m and #10m bands). #HamRadio #SummitsOnTheAir #ParksOnTheAir #Amateurfunk #mtr3b #morsecode #hiking #mountains

I've been spending time with my #qrp #EFHW #endfedantenna & #qrp #ft817 #qrpradio lately. Made the perfect throw up over 40' for today's #amateurradio #hamradio #pota #parksontheair activation operating CW #morsecode

Absolutely Insane. Got #pota #parksontheair site activated with CW #morsecode on 40 meters in 10 minutes with 0.5 watts from #ft817 #qrpradio into sloper #EFHW up 35'. #amateurradio #hamradio is AMAZING

I didn't forget battery today BUT will try activating #hamradio #amateurradio #pota #parksontheair #QRPp at 0.5 watts with #ft817 #qrpradio into #EFHW antenna CW #morsecode

When you forget your 12v 3Ah #Bienooo battery, this is what 2.5 watts will give you during an Early Bird #POTA #parksontheair #MorseCode CW #amateurRadio #HamRadio activation using the internal #FT817 battery into an #EFHW

A hint of fog on my Early Bird crisp #hamradio #amateurradio #pota #parksontheair activation with the #ft817 #qrpradio into a #qrp 40 - 10 meter #EFHW #endfedantenna and @sotabeams #travelmast

#QRP in the garden test #EFHW #Antenna #Amateurfunk #hamradio vy73

@n1vux @ai6yr @rhcmuts.bsky.social

I just put a pool noodle on my #EFHW cuz we have a back yard full of people.

According to the #POTA map it’s possible to activate two entities directly at Saint-Malo: FR-5420 and FR-5421. So I set up my emergency #elecraftax2 antenna at the mole and hit the waves on #20m in #morsecode with 10 W of output power. There was no space to put up the #efhw without endangering the other pedestrians here. It went surprisingly well with 13 QSOs in 45 minutes. #HamRadio #ParksOnTheAir #Amateurfunk #elecraftkx2 #morsecode #hiking #travel #Bretagne #Brittany #France

Logbuch einer #Nordsee Reise:

Tag 1: #EFHW mit 10m Draht und meinem ersten selbstgebauten #UnUn läuft, aber nicht wirklich Platz zum Aufbau. Kommunica Power #HF-1-Pro mit Magnetfuss auf Auto ums verrecken nicht resonant zu bekommen.

Tag 2: #EFWH zerschnitten und als Gegengewicht an der #HF-1-Pro genutzt. Läuft, aber bei jedem Husten ist das SWR im a****. Außerdem: IC-705 lässt sich per USB laden. Sehr praktisch!

vy73 aus JO44fq

#hamradio

As soon as I arrived on today's first summit the rain stopped: Quirl #POTA DE-0882, DE-0785 (#WWFF DLFF-1068, #GMA DA/SX-192) was followed by Pfaffenstein #POTA DE-0882, DE-0875 (#WWFF DLFF-0745, #GMA DA/SX-295). A big thank you to all the callers for the nice pileup on #40m #ssb while on Quirl - that is something I'm not really used to. And I liked it! #SaxonSwitzerland #Saxony #HamRadio #Amateurfunk #hiking #mountains #qrp #morsecode #20m #2m #70cm #fm #ParksOnTheAir #elecraftkx2 #efhw

Normally I strictly refrain from abusing the summit cross as a fixation for my #antenna mast. But this time on #SOTA DM/SX-109 Steinberg (#WWFF DLFF-0056, #POTA DE-0040) the distance to the bench fit so perfectly for my #20m #efhw that I couldn’t resist. #HamRadio #SummitsOnTheAir #ParksOnTheAir #Amateurfunk #qrp #qcxmini #morsecode #hiking #mountains #2m #70cm #fm

Went #qro portable before the rain arrives with my #ft891 and #EFHW during today's #k1usn SST. #amateurradio #hamradio cw #morsecode

Brought out MoPower for this morning's #parksontheair #pota activation. #ft891 with Walt's #ne4tn #tenntenna transformer into 100 watt #EFHW #endfedantenna #amateurradio #hamradio

Different antenna today #qrp #EFHW #endfedantenna with 49:1 unun using @qrplabs #qrpradio #qrp #qcxmini #portapaddle for #amateurradio #hamradio #morsecode #parksontheair #pota activation. Sporting colors from across the pond. #unionjack #cyclingjersey and socks

Fantastic morning doing #morsecode into a #qrpradio #qcxmini #amateurradio #hamradio #pota #parksontheair activation using 9V/200Mah battery into a @Tuftelndotnet #EFHW antenna up almost 50'. 38 #QSOs on 40 meters.

Brought along Master Yoda for some #qro power for this morning's #parksontheair #pota #amateurradio #hamradio #ssb #morsecode activation with my #ft891 #mfj971 #tenntenna 49:1 transformer and #EFHW #endfedantenna

Fun day operating portable "LITE"! #QCXMINI #cw #morsecode 200mAh 9V battery #qrpguys mini tuner into #EFHW #radioadventure paddle. #QRPp Less Filling than #QRP or #QRO but giving the same Great Taste of #amateurradio #hamradio

Bada Bing & Bada Boom the #qcxmini #qrpradio #ContinuousWave #morsecode twins work great with my @Tuftelndotnet #diyantenna #40m #20m #linked #EFHW for #parksontheair #pota activation. #amateurradio #hamradio

My #ADK #POTA trip to Limekiln Lake was a success.

180+ QSOs & 3 activations - all on solar power in a forest with too much shade AND most of my time on the #lateshift.

I managed to work stations on 10, 20, 40, and 80 meters. I was successful on FT4 , FT8, and SSB. While I tried #RTTY, I never got a call back. I'll keep trying, however.

All this was done with a #XieguG90 and an 80m #EFHW up 15-20ft.