----- Original Message ----- From: "Alan Beck" [email protected] To: [email protected] Sent: Friday, June 01, 2012 7:55 PM Subject: [amsat-bb] one last thing
Sorry for generating another email.
I am using a 432 to 7 mhz downcoverter at the antenna.
Alan
Hi Alan,VY2WU
In your installation with the downconverter at the antenna it is possible that your 75 feet of coax cable RG8X will directly pick up some strong signal radiated into the 7 MHz band IF because the shielding of the braid of a RG8X is not very efficient.
A better solution is to put a 432 MHz low noise preamplifier at the antenna and the downconverter in the shack.
The low noise preamplifier should have at least a NF=0.8 dB and gain G= 20 dB
I remember when I was receiving the Meteorological satellites transmitting into 136 - 138 MHz using an antenna mounted downconverter with an IF from 26 to 28 MHz and I was interfered by local CB stations transmitting on 27 MHz
73" de i8CVS Domenico