[amsat-bb] Re: one last thing

[i8cvs]

----- Original Message ----- 
From: "Alan Beck" <becka at eastlink.ca>
To: <amsat-bb at amsat.org>
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