[Amps] Cheap network analyser on eBay

[David Kirkby]

Ian White GM3SEK wrote:
> David Kirkby wrote:
> 
>>The N2PK VNA
>>http://users.adelphia.net/~n2pk/VNA/VNAarch.html might well be better, 
>>but I gather is not simple to build.
>>
> 
> Just to be clear: the only thing that's "not simple" about the N2PK 
> board is that it uses surface-mount components. That may be new to some 
> people, but it really isn't hard.
> 
> The payback is that there's no setup needed at all.  If you build the 
> N2PK board carefully, it's plug-and-play.

It should like it is a better bet then.

I have quite an admiration for HP and their instruments and often feel 
their used kit is better value than the cheap junk on the ham market. 
But that N2PK device is clearly not "cheap junk".

BTW, has anyone got the N2PK borad working under UNIX/Linux? Seems a 
shame if you need a Windoze PC to use it. Also, I'm not sure how much 
longer parallel ports will be on PCs.

I recently purchased a HP 5370B time interval counter. That measures the 
time between two events, which can be the zero crossing of sine waves. 
The maximum time is 10s, but resolution is 20ps, rms jitter typically 
30ps, and its possible with calibration to make absolute measurements to 
100ps accuracy. But relative measurements can be made to sub ps with 
averaging.

You can easily see the time delays (i.e. phase change) introduced by 
adding a couple of SMA connectors in a line. That could I think easily 
be used to make reflection measurments on an antenna, but it would only 
give phase, not amplitude.

If anyone owns an HP 5370B, and wants the user and service manual, I 
borrowed one from someone, scanned it, and have put it on the web.

http://www.g8wrb.org/useful-stuff/time/HP-5370B/


-- 
David Kirkby,
G8WRB

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/