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.

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

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