[amsat-bb] Re: Thanks for all the ...

i8cvs domenico.i8cvs at tin.it
Sat Jan 21 13:06:53 PST 2012

----- Original Message ----- 
From: "Andre" <sats at pe1rdw.demon.nl>
To: <amsat-bb at amsat.org>
Sent: Saturday, January 21, 2012 8:12 PM
Subject: [amsat-bb] Re: Thanks for all the ...

> Good point, a preamp is to cancel out the cable losses, anymore and you 
> are just boosting the background noise and not improving the reception.
> So if your cable is very short there is not point in using a preamp.
> 73 Andre PE1RDW

Hi Andre, PE1RDW

It depends on the noise figure NF of your receiver.
Lets suppose the NF of your commercial receiver is as usually in the order
of 6 dB, then a preamplifier with a NF = 0.5 dB and 15 to 20 dB gain will
improuve your (S+N)/N ratio even if the lenght of your coax cable between
the antenna and receiver is very short.

73" de

i8CVS Domenico

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