N2PK Vector Network Analyzer

[David]

Has anyone here built Paul's Vector Network Analyzer
http://users.adelphia.net/~n2pk/VNA/VNAarch.html

I am wanting to know what needs to be done to enable the unit to work up in
the 2m band.

Thanks in advance.

[Ian White, G3SEK]

David wrote:
>Has anyone here built Paul's Vector Network Analyzer
>http://users.adelphia.net/~n2pk/VNA/VNAarch.html
>
>I am wanting to know what needs to be done to enable the unit to work up in
>the 2m band.
>
The fundamental sweep range cannot be extended up to 144MHz because the
DDS won't go that high.

Very accurate narrowband swept measurements can be made using a
"transverter" adaptor, which is under development. The DDS is
up-converted to the measurement frequency, using a conventional mixer
and a stable LO, and the response from the DUT is down-converted.

Broader-band swept measurements can be made by overdriving the detector
and using harmonic responses (with but with some obvious risks of
spurious responses also).


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

[Ian White, G3SEK]

David wrote:
>Has anyone here built Paul's Vector Network Analyzer
>http://users.adelphia.net/~n2pk/VNA/VNAarch.html
>
>I am wanting to know what needs to be done to enable the unit to work up in
>the 2m band.
>
The fundamental sweep range cannot be extended up to 144MHz because the
DDS won't go that high.

Very accurate narrowband swept measurements can be made using a
"transverter" adaptor, which is under development. The DDS is
up-converted to the measurement frequency, using a conventional mixer
and a stable LO, and the response from the DUT is down-converted.

Broader-band swept measurements can be made by overdriving the detector
and using harmonic responses (with but with some obvious risks of
spurious responses also).


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