[TowerTalk] Coax Losses on 160 and 75?

[Jim Brown]

On Fri,8/5/2016 11:03 PM, Richard (Rick) Karlquist wrote:
> No, this isn't the real deal.  A 2 port vector network analyzer
> with full 2 port calibration is the real deal.  The wattmeter
> approach has many error effects that are difficult to account
> for. 

Right. I've never considered using wattmeter(s) to measure loss in coax. 
Now I use a DG8SAQ-designed VNWA (vector network analyzer). Very good 
accuracy.

Before that, I used an HP generator as a source and an HP Spectrum 
Analyzer as an RF voltmeter. Using that for measurement, I could clearly 
see variation in the apparent loss below 2 MHz -- this was as a result 
of the mismatch between this coax (Zo of a real line is complex and 
varies with frequency) and the constant 50 ohm load and source 
terminations. BTW -- I was measuring a sample about 1,200 ft long.

73, Jim K9YC