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R: I'm Up and ready.



Vince

If your 3" dish and feed are working you should receive about 4 dB of sun
noise to day with NF=0,94 dB but it depends on the metod that you are using
to measure it.

1) Disconnect the AGC from your receiver

2) Put your receiver working linearly on SSB with its product detector

3) Reduce the RF control to minimum gain all  CCW

4) Increase the audio gain control to maximum gain all CW

5) connect an AC voltmeter 5 volt fs to the audio output

6) Put the antenna on the cold sky usually towards the North Star

7) Increase now the RF level control until you get a convenient 0 dB base
    line voltage,usually 2 volt AC  and call this voltage V2   

8) Put the antenna on the sun,you should hear an increase of  noise,
     read the new audio AC voltage and call this voltage V1

9)  Sun Noise (S+N)/N = 20 log    ( V1/V2 )  in dB
                                                      10

Make your sun-noise measurement when the sun is high above the horizon 

If your receiver has not the provision to switch OFF the AGC than look at a
even minimum increase of level in your S-meter

I am including the program NOISE.EXE to compute the sun-noise that you
should receive introducing in it the antenna and receiver data + the
solar flux unit ( sfu ) at 2800 MHz from NOAA

Since the most part of  2 meter receivers cannot switch off the AGC i use
a second converter 144/28 MHz  connected to an HF receiver Drake R-4C
tuned on 29,350  MHz to do this type of measurements.


73" de i8CVS Domenico

----- Original Message -----
From: Vince Fiscus, KB7ADL <vlfiscus@mcn.net>
To: <amsat-bb@AMSAT.Org>
Sent: Sunday, August 25, 2002 12:58 AM
Subject: [amsat-bb] I'm Up and ready.


>
> The dish is next to the rotor, now all I need is AO-40 to show up with a
> low squint.  I tried seeing if I could get solar noise pointing at the
sun,
> but didn't notice any. The .94 dB noise figure on the downconverter is
> probably to noisy to see an increase.
>
> KB7ADL
>
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org












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