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Re: AIDC-2733 gain measurement



We haven't retuned the filters yet. I wanted to get a baseline before
deciding whether or not I needed to. Guess I should. Will that bring the
gain back up to 30+ dB?

Art

----- Original Message -----
From: Mahlon Haunschild <mahlonhaunschild@home.com>
Cc: amsat-bb <amsat-bb@AMSAT.Org>
Sent: Monday, April 02, 2001 5:00 PM
Subject: Re: [amsat-bb] AIDC-2733 gain measurement


> Art,
>
> In stock configuration, the AIDC 3733's frequency response is specified
> only down to 2500 MHz, so your results as stated are inconclusive.  Did
> you measure its conversion gain anywhere else?  Did you re-tune the two
> comb filters to 2400 MHz before you measured it, or are they still tuned
> for the stock bandwidth?
>
> regards,
>
> Mahlon - K4OQ
>
> Art Goldman wrote:
> >
> > All:
> >
> > While we wait for our 144 Mhz crystals to arrive, I took my
> > 3733 and put it back on the Agilent signal generator and
> > spectrum analyzer. This time I had the N Adapter in place of
> > the dipole, so I could more accurately measure conversion
> > gain.
> >
> > With 2401.323 Mhz, -80 dBm input I got 123.358 Mhz, -58.86
> > dBm output
> >
> > So at our frequencies, I see a conversion gain of only 21.14
> > dB, which is considerably less than the 37 dB gain printed
> > on the side label.
> >
> > Does this correlate with other measurements?
> >
> > Reason for asking: while in beautiful downtown Atlanta the
> > signals were S9+ on Sunday, in rainy and depressed Maryland
> > (the Terps lost to Duke) we didn't hear a peep. So we're
> > trying to figure out where the problem lies. (And yes, we
> > remembered the time change; had the latest keps; and a
> > reasonably accurate antenna alignment). We tried both a DEM
> > converter and the AIDC, both on a parabolic grid antenna.
> > The AIDC had the integral dipole. I've yet to try the N
> > adapter hookup.
> >
> > How much effect should we expect shooting through a maple
> > tree with no leaves on it? Enough to completely null the
> > signal?
> >
> > Any other ideas?
> >
> > Tks,
> > Art, N3OY
> >
> > ----
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> ----
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