[TowerTalk] AVA7-50 reel info

[Jim Brown]

On Sat,9/10/2016 10:49 AM, Bryan Fields wrote:
> An o-scope with a TDR would be the best method. This would get you a length to
> within a few inches.

Yes. Depending on the frequency at which the capacitance meter operates, 
the error could be quite large.

Another method -- measure it as a stub. Look for nulls in the impedance 
when measured with an antenna analyzer. With the other end open circuit, 
if the analzyer goes low enough in frequency, the lowest frequency will 
tell you the length at which it is a quarter wave. if the analyzer does 
not go low enough, the lowest resonance you may see 3/4 wave, 1.25 wave, 
etc.

I do TDR with my VNWA. If you're considering buying an antenna analzyer, 
this one is an awfully good choice, and a real bargain. It's a real 
Vector Network Analzyer, so it can measure gain through a system, and it 
does TDR. It goes to 1.3 GHz, and it self powers from the USB port of 
the computer that runs it! And it's a real bargain, about $650 shipped 
to your door. You want the 3e version with the calibration kit. I don't 
recommend the case.

http://sdr-kits.net/VNWA3_Description.html

73, Jim K9YC