[amsat-bb] Drake 2880

[Jesse Morris <w4mvb@xxxxxxxx>]

Good afternoon to all,

I completed an experiment with one of my fried converters today that
might be of interest to some.  A few days ago I had tried to install a
MGF1302 and a device I bought on ebay a few months ago without success. 
I could not get the bias set up properly (I think because I didn't know
what I was doing) so I decided to go ahead and start the G0MRF mod.  I
cleaned off all the SM components in the front end except the coupling
caps and the bypass caps.  I also took the unit out of the case and
rewired the P/S for 10 volts at the front end supply pad and installed
ground wires for the source leads.  After I put it back together I
decided to stick a MMIC in it to see what it would do.  (I had already
damaged the input hairpin anyway.)  I installed a MAR-3 with a 160 ohm
bias resistor and when I lit it off ther was 4.7 volts on the output lead
of the MMIC and I had an S9 signal from my test source on the work
bench!.  I don't know how much worse it is now than it was before but it
can't be too much worse since I never saw much more signal than that when
I was first testing the unit.

I plan to use it this way to do some more antenna tests so I wont blow up
any more GASFETs!  Depending on how strong the signal is when I get back
to the antenna tests I might try to listen to AO40 with it this way.

It really is possible to do some of this microwave stuff without
sophisticated test equipment!

73 de Jess - W4MVB
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