[MAMS] Alcatel MDR 4000 L.O. Modules

Ace Pilot acepilot at bloomer.net
Mon Jul 20 21:15:17 EDT 2015



I have a pile of these local oscillator modules from our retired 
microwave radios at work.  They oriiginally were set up for output 
around 6 GHz.  What are they being used for now?

They are turning into beacon transmitters on 902 MHz.

Here is my Rev 2 version I built up tonight...I take out the original 
filter and installed these variable caps and brass shim stock to form 
tuned circuits at 902 MHz. Yes, I thought of that!  The two filters 
couple through the space between them, which is quite a distance, giving 
very nice selectivity.  Works like a champ.  Output at 902 MHz is -29 
dBm, which drives a PA brick module inside the unit to about 1W.  I can 
add a small pre-amp IC and get up to 13W out if needed.  Good thing hams 
are not limited to 1W on the band, like the unlicensed users on the 
shared band.  In fact, I run Single Side Band at 200W from home...

With appropriate fillter installed, these LOs can be used from 200 MHz 
up to a bit over 6 GHz with ease...just have to tune for the desired 
crystal harmonic.  My crystal is at 100.2600 MHz for a final frequency 
of 902.340 MHz.  I intend to build beacons for 1296, 2304, 3456 and 5760 
MHz using these modules.





Here is what the PA module will look like when installed...




N0EDV
EN45fa
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