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- Опубликовано: 5 июл 2024
- This "part 2" video summarizes the build, tune and test of a trapped EFHW antenna for the 20, 30 and 40m amateur radio bands. My previous video:
• #387: How to build an...
...shows the process of building and tuning the low power / QRP traps that I purchased in kit form from N7KOM. See additional links in the previous video for details. My resulting wire lengths were:
UNUN to 20m trap: 30'-2.5" (about 9.21m)
20m to 30m trap: 4'-7.5" (about 1.41m)
30m trap to end: 8'-6" (about 2.59m) 
Наука
I have basically no familiarity with RF outside of your videos--you communicating with something 1000 miles away made me smile; that is so cool
Why not get your license and join us? There is always room on the air for someone new
Hi Alan! Another great video! 73 OM!
Well done! I like that you show that the resonance doesn't need to be "perfect". For QRP, under 1:1.5 is gonna be great. No need to fret about getting exactly 1:1. Hope to QSO with you on this antenna soon! 73!
That's the biggest spool of wire wrap wire I've ever seen!
It’s not wirewrap wire. It is 26 gauge stranded.
@@w2aew Looks just like my spool of 26 ga WW wire! Only bigger!
Your trapped EFHW turned out great! Nice compact, lightweight package. Thanks for the detailed tuning process explanation. 73, Patrick KF4LMZ
Thanks for the part 2 of your antenna! As well as being a ham I’m a bit of a bird nerd and that sounded like some very vocal Northern Cardinals. Thanks again.
Yeah, lots of them around here.
Great video (as always) Alan. Your style of tuning matches mine - cut the wire long and tune it up.
That was great, would love to see more hand-on and dyi build videos from you!
Great QRP on a beautiful summer, sir.
Great video, Alan. As usual!
Nice video, thanks!
1 word Alan... Waygos. The twisty connectors are so 70s.
I like this.
1st couple of mins until you panned away from the table it looked like you might be at the beach but the birds didn't sound right :)
I keep telling myself I'm gonna learn code I need to just get on with it. Maybe with the grand kid if I can get her out of the pool long enough. Your video catalog makes a nice reference library.
👍Thank you sir.
Alan, these videos are very timely for me as I ordered N7KOM's trap kit last week while on vacation and it will be delivered today. I also intend to make a 40/30/20 EFHW. I was wondering if you happened to test it on 10 meters. I've been using the Par 40/20/10 that was trapped on 20 and worked well on 10. After I trimmed it down to 30 meters instead of 40, I haven't been able to get the SWR low on 10 and the curve is strange, not just off frequency.
I haven’t tested it on 10.
Curious what you have for counterpoise with this setup? I get away with 25' of coax for my full size EFHW, but I can easily see needing a better "ground" with the higher radiation resistances you get from a loaded antenna, especially on the lower frequencies.
Just the shield of the 25’ coax feeder. Counterpoises aren’t as critical for EFHW antennas due to their high feedpoint impedance.
@@w2aew Not critical, but you can't skip them entirely either. Every circuit needs a ground reference, and you do have different radiation resistances with all those traps. It would be worth trying a 50' piece of coax. $5 says your match improves by more than the difference in coax loss would account for on 40M.
Is it possible to have even more traps? Say, one for 17, 15, 12, and even 10? Or will that not work for some reason?
It's possible, but the interactions in tuning would likely be complex, and the added weight of the traps might not be worth it.
I noticed two things.
(1) When you made the traps, the 20 m trap was resonant just a bit below the lower end of that band, not right in the CW portion where I would have expected.
(2) When you tuned the antenna, the 20 m portion of it was a bit shorter than the usual half wave length.
I wonder if these two things are related?
David VE7EZM
All interrelated I’m sure.
I wanted to see
the traps being built, according to the desired frequency
Watch the previous video, #387, on my channel.
ruclips.net/video/KIEZmwB8AHw/видео.htmlsi=N9ZylVF16Ad2Kl3c
Sir,
Make videos on RF analyser
I have already done a complete review of the RigExpert AA-55 Zoom. ruclips.net/video/Q2HDuv84mkw/видео.html
I dont know why Im still subscribed to your channel
@bobby9568 Probably because like the rest of us, you realize that Allen puts out some great, educational content! Have a great day! 73
@@BobGarrett66 its because i thought it had great content ten years ago but now its not that great anymore, sorry
@@bobby9568 And you're so incompetent that you can't properly unsubscribe?
Please, let me know the type of content that you’d like to see more of!
if you want to criticize, criticize with a purpose. Otherwise, your words are just not worth typing and reading.
any problem with your ears? turn back the volume!
It really wasn’t that loud, it is just that the camera’s microphone is heavily biased to sound in front of the camera.