I’d like to make egg beater antennas like the M2 VHF and UHF listed in the wiki.
I am starting with round to max out the overhead signal, not square egg beaters. It is very hard to find detailed instructions that describe the wiring diagram of even common antennas like turnstiles. Where are elements connected, if elements are one piece or cut, if elements are parallel or in series, etc.
I’ll be happy to add a detailed write up to the wiki when done.
I’ve looked at lots of design pdfs and am looking at two options for wiring, both by ON6WG / F5VIF.
The Revisited version makes sense on the balance. Both versions are shorted on themselves; both hoops short to each other and to the two wires to the receiver. With amplification this turns into a heater. This seems wrong to me but is this a valid way to wire antennas?
Secondly, does anyone know of a cheap noise generator that I could use for spectrum analysis, cheap SWR tuning?
DC short does not equate to RF short, so expect to see a lot of antennas shorted in such fashion. With amplification, the coaxial cable will end up heating up if and only if there is a significant mismatch between the antenna and the transmission line at the particular frequency of the input signal.
To deal with balanced/unbalanced problems (if present; always consult your references), you can make use of a balun.
To measure SWR, a signal or noise generator is not sufficient to measure the S11 reflection of an antenna. You will need a vector network analyzer (VNA), which is capable of measuring the reflection coefficient (return loss) of your antenna as a function of frequency. This is equivalent to the meaning of SWR that you are likely more familiar with.
VNAs have gotten quite inexpensive over the last few years, so an instrument like the NanoVNA could work for you.
Thanks for clarifying on the RF short and mismatch.
That NanoVNA looks perfect! There is also a larger NanoVNA-f with FreeRTOS, but I ordered the regular one from Amazon that is supposed to come with the calibration and battery. Type 1 White.
Please do report your results and add to the wiki with what you find, @dru2!
I made the square eggbeater design once, and it didn’t impress me much. But, it was also without LNA at the time and they are pretty much mandatory for omni antennas…
Would love to see a circular eggbeater homebrew success!
