Upgrade of the scalar network analyzer « D6 », by Manoes

Manoes, a reader of this blog, have send to me a description of a set of modifications for the « D6 » analyzer (My words remains in italics).

Mod’s I made.

I did put a lot of C’s 100pf on existing and newly made places on the powerline traces.
I also did try one on the input C it did not have effect that I expected but…… my measurement could be false, maybe someone can do it again.
Upside

Upside of the board;  maybe I forgot some C’s to mention but better one to much then one  forgotten

Underside of the board a lot of them, the places are experimental found…..
Just try and error with a non-conductive plier!!
Also I made some new screening on the upside and underside of the board.
I did change the SMA connectors for a wider type witch has nuts on the outside.
Before I put the whole board inside the cabinet I glued some conductive foam on the board it did give a bit better result.
All the measurements are made with input and output closed with 50 Ohm the last picture is input and output connected with a short SMA cable.

New screening under

Changed screening upside and new SMA connectors

Changed connectors

Yellow before mod’s, green after mods without casing and no foam.
Yellow before mod’s, green after mod’s board inside casing, new SMA and conductive foam.
Trace in/ out connected with mod’s : -3 dB input and -6 dB output and changed 120 kHz. Filter

All the measurements are made with the above mods. Terrible enough my spectrumanalyser is broken during the measurements so I can not produce better pictures as above ones. I do hope to repair the old boy when I have the time to live and fun to do it. (High tension unit defect, transformer into smoke so I have to made a new one by hand .
Software VMA of our friend Vitor Martins Augusto.
Grtz, Manoes

For several months i don’t understand why the frequency response curve of this analyzer deteriorated when we exceeded 3GHz. By drastically reducing this problem Manoes give me an answer.
I will add an option on SNASharp to be able to trace the frequency response of an analyzer by disabling the calibration, this can help to understand how a hardware modification work.

David.

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