[Antennas] Diminishing Returns

[Rick Karlquist]

> meter fed from the same transmitter, steady carrier) and the signal was
> received over a
> thousand feet away and relayed back on the 440 band by a linear translator
> and measured on
> a spectrum analyzer.  (everything was pre-tested)
>     Ron  KA4INM - I'm proud to be Chuck's pop!
> ______________________________________________________________
>
> I'd LIKE to see THAT "Linear translator"....sorry but that was a waste of
> time and not very accurate in signal strength...just have a spectrum
> analyzer with a live human 1000ft away taking readings. Would have been
> more
> accurate.

I own several spectrum analyzers, but I don't drag them out
for antenna testing.

What I do is turn down the RF gain on the HF radio until the
AGC is inactive.  Then I connect the audio from the headphone
jack to an HP Multimeter that displays AC volts in decibels.
This is actually quite accurate, as long as you keep the AGC
out of the act, and don't let the audio clip.  Use a sensitive
range on the meter.  If you can't get a multimeter with
decibels, you can just display AC volts and use a calculator
to convert to decibels.

The audio could be sent over wires or over UHF rig.  In the
latter case, it is important to use only a few kHz of deviation
to avoid any effects from the speech clipper.  The nonlinearity
of the speech clipper could ruin the accuracy.

I chuckled at your comment about no one using 16 radials.  I
have 120 radials under one of my verticals.

Rick N6RK