Sunday, 5 November 2017


Have plannes to also test and work on 23 cm with a 1.9m dish I have.
Its a deep one with f/d at 0.3 so a septum without choke or other beamforming seems correct and after discussions with Ronny SM7FWZ the work started.
Completed it fairly quickly but final tumimg will be done when positioned in the dish.
Did not fully acheive the data read about but some 25 dB in return loss and isolation seems acceptable.

Ordered some SAV541+ Hemt transistor which arrived last week and I put them into a yu1aw preamp and the results looks promising.
It is not 100% stable and poor input match but still lower Nf and will be worked with some more.
It might end up in another design as the input filter was not as sharp as I want it.
Any suggestions are wellcome.

Made some rework of the amplifier as well and one thing I noted when very carefully checked the assembly was the small coaxial stubs used as capacitors was mounted 2mm away from the instruction so I changed that and redraw the 50V DC supply part completely and checked the lowpass filter.
Nothing found in the LP filter and when assembled back together again the results was even worse than before.
30A current gave some 300W out so completely off.
Did change the positions of the coaxial stubs again in the other direction and that seems to be the way to go as 30A now was 600W and thats how I worked it during the weekend now.
Blew a new decoupling cap too so did a second rebuild of that and then it was stable.
Will continue optimizing placement of stub cap for further improvement but not right now.

Did work the second part of ARRL too and the D44 DXpedition fairly easy but have caught a severe cold and is constantly coffing and has slept in total maybe 10 hours since a bit tired at this point.

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