35 ohm coax for QRP?

Started by Tru, January 22, 2021, 11:12:23 PM

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From my understanding (which may very well be off) more ohms is better for power handling (around 75 ohms is ideal) while fewer is better for reception (around 35 ohms is ideal) and 50 Ohms was right in the middle of those two, so that's why it's used. But for QRP we're not using high power, so why not chose a lower ohm coax for better reception?


I'm not so sure about that, i.e. 75 ohms is better for power handling or 35 ohms is better for reception. I would think feed line loss at the desired frequency would be the most important factor. Maybe others can chime in here.

I do know that at HF frequencies, feed line loss isn't as much of a problem as it is at VHF frequencies. Also we operate in the field or portable, so feed line lengths are much shorter than fixed installations. That being said, QRP can use lossy feed lines and still work very well.

Imho, the most important factor to having good reception is a low noise floor. So I would want a feed line that doesn't act as an antenna and add to my noise floor. Also, a separate receive antenna could help in some high-noise environments.