[TowerTalk] TAPR VNA cables

[Jim Lux]

Some of you folks probably have the TAPR VNA designed by N5EG that is sold by TenTec (a nifty device, by the way, although it doesn't do well with interfering signals.. its internal receiver is not narrow band)

I discovered when fooling with the beta software that the 1 meter (theoretically 39.37") cable supplied with the VNA by TenTec is actually less than 36" long.  You get a 1m and a 3m cable, along with the short and load cal standards, which are all used in the calibration process.  Having the short cable 90cm long instead of 100cm created a problem in the cal process. The actual length isn't critical, but it needs to be over a certain length, and 90cm is a hair too short, at least with the beta software.

The cables are actually made by Cable Xperts (part number CXP058ASM1M) and it's possible that it was accidentally mismarked, or that's within the manufacturing tolerances, or they measure the 1 meter before trimming the coax to put the connectors on or something.

Anyway, if you have one of these VNAs, you might want to check the length of the cables.  (my 3m cable is actually 3.07m long)


Jim, W6RMK