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Allison, I haven't messed with it, but Kees' AQRP VIA includes the following feature: "Calibration data (Open/Short/Load) is captured and recorded for all frequency steps between Start and Stop

This is my portable antenna and coupler :?https://m0ukd.com/homebrew/baluns-and-ununs/end-fed-half-wave-antenna-tuned-coupler-efhw/ 73 Nikos de SV9CVJ

Its possible someone got standard HC49... not the shorter 49u like mine.? it actually does make a difference as the quartz inside has a different cut. Premium build, no.? It has all the bugs.

Tim, your the go to then as you know know why its important. ;) Yes the BITX (20/40/17...) are similar but not the same as uBitx. The biggest change is the second conversion as that opens up a few

That's worked for me at least. Of the wire is already trimmed for say 14.2? changing the transformer should show a different SWR for the real feed point resistance.? Resonance should not change for

You pretty much got it.? That is how Danny (myantennas owner) explains it in a blog post at https://myantennas.com/wp/efhw-8010-is-this-the-ultimate-magic-antenna/.? I referred to it way back in

* The matching box is this one:??https://www.ebay.com/itm/191226640113 That is a 1:9 random wire box.? Expect RF on the coax if the ground lug is not used with a .25 wave wire. The SWR may be good

Allison, I can't speak for others, but the reason I use squares of integers is because I can do the math in my head:-) You are right, no reason why it can't be a different ratio, just means trimming

Sunil, Thanks for the update. An issue: I found on my front panel PCB that pins 2 and 5 on the headphone jack were not connected together (tip and ring), so that I only heard audio in the left side of

For some reason there is a religion for squares of integers 6/7/8 yielding one to 36, 49 and 64. There is no reason why the winding could not be 2t:13t for 6.5 turns ratio or 1:42.5 or 2 to 15 turns

With a short coax, I saw the same pattern of VSWR peaks and troughs as a long coax,? just that the peaks were higher with the short coax.? As expected.

This took for a hour. :) // hiro, JJ1FXF

There are some general reasons for that.? One being the 1:64 transformer is more difficult and most installed wires are at a lower height so the feed point resistance is lower. Also 50*49 is 2450,?

Hi Sunil, Do you have any plans to make a case that will House a 3 1/2" or 5" Nextion display ? Kevin Rea K6REA

Seems that most EFHW impedance matching transformers are wound on ferrite or powdered iron cores. For experimental purposes it should be possible to use air-core (PVC or Acrylic, or wooden cores)

Got it Jerry. I read your voltage as peak to peak rather than peak. My bad. The resonant frequency of a wire that is multiple half wave lengths long does not occur at integer multiples of the base

Let me rephrase that, I know what the difference is between the two, I just don't know if one performs better than another as I use both and can't tell any difference in performance. Joel N6ALT

That's a great antenna, I have one right in front of me. The price is right also. I don't what the difference between 1:49 vs 1:64, but both seem to work the same, you just have to cut the wire to

Just to avoid any confusion: Please note that this topic was for BitX40, not ubitx. The file ubitx_cat.ino won't work on a BitX40. Back to Praba's question: The stock firmware v1.01 for BitX40 only

Probably old news for most, but i just stumbled upon it. Http ://qrpguys.com Noticed the EFHW no tuner antenna uses a 64:1 instead of 49:1 unun transformers. Bo W4GHV