[Amps] close to off topic - how to read antenna R + jX ??

Ian White G3SEK G3SEK at ifwtech.co.uk
Mon Feb 28 04:58:24 EST 2005


Steve Thompson wrote:
>
>G3SEK wrote:
>> I used to have one too, but let mine go after building N2PK's
>> 50kHz-60MHz Vector Network Analyser.
>The N2PK thing is very nice, but for those who aren't familiar with the 
>kit, the HP 8405 VVM goes up to 1000MHz.
>
Fair point (though with decreasing accuracy).

One point that has emerged from N2PK's work is that the 60MHz sweep 
range of the basic instrument can be shifted upward to any higher 
frequency by using a 'transverter'. This looks a lot like a conventional 
high-performance transverter for VHF/UHF/microwave DXing.

For impedance measurements, you connect a suitable VHF/UHF/microwave 
bridge to the I/O ports of the transverter, and then away you go. The 
open-short-load calibration is done at the signal frequency, so the 
transverter is inside the error-correction loop. It's making the error 
correction work harder, of course, but the basic power of the instrument 
is still there.


-- 
73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek


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