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R: Re: SNR measurements



Hi Russ,

Since modern VHF receivers do not allow to switch ON/OFF the AGC control
i use a second converter 144-146/28-30 MHz and i send the converted 10
meters signal in to an old very good HF receiver DRAKE R-4C and i use it
for traffic and sun-noise measurements as well.

The AO40 nominal  2401.323 MHz  MB frequency is than converted and
received at 29.323 MHz and so on for the passband on traffic.

This procedure allow me to give a new life to an old HF receiver and
prevent to damage the AO40 downconverter transmitting in to it as
frequently appens using a VHF 2 meters tranceiver.

All  good HF receivers have the provision to switch ON/OFF the AGC
control and to set different time constants Fast-Medium-Slow, for example.

Many radio hams have an old HF receiver and an old 144/28 MHz
downconverter full of dust in their garrets that can be immediately
revisited and used for sun noise measurements and traffic on AO40

Make it "Strong and Stupid" using the Ham Radio ingenuity and
buy only a parabolic dish with a feed and only a 2400/144 MHz
downconverter because probably the rest of it  to receive AO40 is
already in your hands !

73" de i8CVS Domenico

----- Original Message -----
From: Russ Renaud <ae517@freenet.carleton.ca>
To: <amsat-bb@AMSAT.Org>
Sent: Wednesday, February 19, 2003 6:02 PM
Subject: [amsat-bb] Re: SNR measurements


> >Unfortunately Step 1 is not nearly as easy as it sounds; of all the
radios
> >I've ever owned in 27 years, only my (HF) TS-850S allows you to turn off
> >the AGC.  My FT-726R doesn't do that.  Hopefully the other popular radios
> >(FT-847 seems to be it) do.
>
> Can you switch off AGC on the FT-847?  I've been looking for a cheap
> receiver that could do so to use with my transverter to be able to make
> accurate sun/noise measurements, but this sounds like another excellent
> reason to buy an 847...
>
>
>
> --
> 73 de va3rr/aa8lu
> http://www.qsl.net/va3rr
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
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>









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