Re: SSB 23cm masthead preamp update


Alan G0XBV
 

-----Original Message-----
From: 'mike' mb.golfmad@... [ukmicrowaves]
To: ukmicrowaves
Sent: Thu, 13 Aug 2015 18:31
Subject: Re: [ukmicrowaves] SSB 23cm masthead preamp update

My coax is LDF 4-50 not as stated LDF 2-50, this should have a loss about 0.2dB in the length I use...
At 144Mhz maybe!  Using Westlake's online calculator it comes out at 0.7dB @ 1296, Mike (you did say 10m?).  So adding 0.2 for your relay and 0.6 for the DB6NT, that comes to 1.5.  Same as the pre-amp, if it's working correctly.  In my head (FWTW!!!!), I reckon that doing that that in/out test I mentioned previously would show an increase in 's' meter reading, but pretty much zilch change using that crude (but ballpark) FM s/n test.  That would at least establish it is working as expected. If you still had ambition, you could try a hotter device in it.  I'm not qualified to add to that min. NF info for terrestrial use on this band, but I would doubt it's any less than what you have been advised.
Al G0XBV

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