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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

I found the headphone jack on the front panel PCB only had audio going to the left channel in my stereo headset. I pulled everything apart, and discovered that there was no PCB trace going to the

Gordon, I think just measuring the SWR into the antenna system using a short 5 to 10 foot of coax from matchbox to antenna analyzer? gives a pretty good indication of where things will start getting

Jack, It's not an accident that mine is similar. Thanks for the pointer to the cheap metal film 3W resistors a few months ago! Mine's much uglier, just twisted the ends together, though kept the

There's a file named ubitx_cat.ino, so I'm guessing yes. A good way to find out is to download the code and look at it. Jack, W8TEE

Stock firmware support cat control ? Just I want to know.

Jerry --- likely that a simulator would tell you how much and how quickly reactive components add in as you move away from the exact resonant frequency. It does seem that significant reactive

Jerry: We did the same thing: but then put it in a quart can filled with mineral oil. It will take 250W for 5 minutes without damage to the components. (However, you could probably cook French Fries