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Re: AO-40 reception?

The beacon is now off between MA 100 and MA 180.



----- Original Message -----
From: "Edward R. Cole" <al7eb@ptialaska.net>
To: <amsat-bb@AMSAT.Org>
Sent: Tuesday, 26 June 2001 15:14 UTC
Subject: [amsat-bb] AO-40 reception?

> Yesterday I took out my Drake #2, completely unmodified and bench checked
> it with my diode signal source [800 MHz x3] and it worked just fine.
> 2401 at 123.000 exactly!  Later at home it was 122.995.
> In the evening I set up my coffee can diode source on top of my step
> about 15-foot in front of the dish.  I now have the Kuhne MKU-232A preamp
> mounted on the 5-turn helix feed of the 33 inch dish feeding the "new"
> Drake via 12-foot of LMR-400.  I used the confer bias-tee to feed power to
> the Drake [produces S-3 noise floor with 2.4G preamp off].  ao40s_2 shows
> that I should see the transponder noise floor for a squint of zero.
> Applied power to everything and have about S-7 noise floor on the FT-847.
> Sun noise rises about 1/2 s-unit.  With -20 dBm at 800.439 MHz into the
> diode-gen I got a whopping strong signal [2401.317].  I was able to lower
> the drive to -65 dBm to find the threshold [MDS] level.  That just shows
> on the FFTDSP waterfall display.  Of course I have no idea what signal
> level the diode produces at 2400 MHz.  I could calculate space loss for 15
> feet but...
> Initially the Drake drifted about 200 Hz but settled down to about 30 Hz
> over several minutes [and not sure the signal generator is that stable at
> 800 MHz]...interestingly the generator's [IFR-500] third harmonic has a
> definite FM note and produces a trace about 10-15 Hz wide on the
> With the coffee can diode-gen on the ladder I was able to check antenna
> pointing; best I can tell azimuth beamwidth ~10 degrees.  Pointing appears
> to line up well.  Interestingly, I could detect [barely] the first
> sidelobes on either side of the main-lobe!
> At 0537utc AOS of AO-40 was predicted by NOVA at az=90.3.  Since MA=144.8,
> I waited for the satellite to rise.  At 0600utc, MA=150 and the beacon
> should be on; az=94.2, el=2.1 but this put me into the trees, yet.  Still
> decided to look for the signal with FFTDSP and ao40rcv.   I continued
> local 2330 [0730utc] when az=109.5, el=9.8 but could not detect anything.
> The squint was >90.
> So a couple questions:  Did anyone copy the beacon from 0600-0730utc.  Was
> it turned on?  Anyone successful copying when squints are this high?
> was ~65,000 km.
> I have a feeling my system is close to operational, but???   Today I will
> take Drake #1 to work and determine what failed [see if the LO is working
> and test with diode-gen source].  I suspect the front-end is gone as
> noise-floor dropped from S-3 to zero and no signal could be found even
> driving the diode with +10 dBm [Drake #2 was loud with -20 dBm and
> detectable with -40 dBm].  I may have made a "Duck" out of my first Drake!
> {see the article in the current Amsat Journal}
> Fun 'n games in the arctic midnight sun!
> Ed

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