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50mhz activity

Posted: Sun Jan 13, 2019 10:33 am
by G4HTZ
Just been reading about G4FRE 50mhz tests ....having returned a few months ago from our middle age gap year to Spain ..I am gradually putting the station back together ...having recently acquired a tilt over 15m mast makes antenna work a lot easier.

Anyway I remembered I had a RN electronics 144 to 50mhz transverter ...guessing this would be suitable for using with my portsdown and minitoune RX ...must box them up one day !!! ....I also have a Gemini dual band 50/70 mhz linear amp which puts out about 300w guess it might be ok for about 100w narrowband datv ??? .... antennas available dual band 6/4m moxon or 3+3 dualband innovantennas yagi ...both about 6dbi gain

So guess the above should work well on 51 mhz ????

Qth here is only 3m asl on east Essex coast ...500m to North Sea ....great sea path to continent..not so good for uk ..but who knows !!!

If anyone interested in any 50mhz tests sometime I will try and get it hooked up ...if not will leave it all in the loft !!!

Steve G4HTZ JO01JN

Re: 50mhz activity

Posted: Sun Jan 13, 2019 12:45 pm
by g8vpg
My experience has been that amateur "linear" amplifiers sold for ssb/cw use are not good enough for digital ATV use. We really need class A linears, which you can tell because they draw a heavy bias current with no drive.
73 Shaun.

Re: 50mhz activity

Posted: Sun Jan 13, 2019 12:52 pm
by g0mjw
LDMOS devices as used in the Gemini can produce reasonable power, say 30W if you turn up the bias. As long as the cooling can cope.


Re: 50mhz activity

Posted: Sun Jan 13, 2019 1:38 pm
by G4HTZ
Hi Shaun and mike
Ok thanks for information...that's a pity re the Gemini amp .