There are 4 boards, that can be mounted piggy-back three one each other.
This link works in split frequencies, althought are halfduplex due to the
nature of the gunnplexer. For this reason you must set one side of the
link to 'high freq' and the other to 'low freq' in the 10mbuff board with
jumpers J5 and J6 to activate the AFC in only one side. All boards can
be made single sided, althought then the microstrip used won't be as such
thing, but with the low IF frequency used, really doesn't matter much.
The NS LM6181 can be a replacement pin compatible for the OPA603. Althought
probably some resistor adjustment should be necessary for better performance.
The 24GHz gunnplexer can be mounted in the PCB, but the 10GHz must be
wired, and the adjust divider of the power supply must be changed to modify
the output to about 8V. Althought the LM317T voltage regulator tab are
very close to the gunnplexer body, MUST be isolated, since the tab are
connected to the output voltage!. The voltage adjust range are aprox. between
5-6V, that are the range specified for the 24GHz units. This new one have
a 0.75dB improvement over the previous, that at this stage could be noticeable,
thanks to the Alan WA9GKA recommendation of arrange the transformer like
a transitor with an emiter resistor decoupled by a capacitor to maintain
the mixer diode loading at DC, and bypassing it at RF. Single side PCBs.
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