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Re: AIDC 3373 and a newbie to 2.4Ghz



Kevin and Group ,

     Here is what I have seen..

Lot's clipped

> listening at MA28-50 and MA240-250.  Farthest distance was 44,000km,
nearest
> was 9,500km.  I have the 3'x2' barbeque dish, and an untouched AIDC3373.

We have identical setups.  I have never copied at 44,000 km  at 9,500 my
setup will hear it, but probably not decode anything.  AO40Rcv will try to
sync, but never suceed.  I have gotten blocks in a little closer, and I have
gotten good CRC blocks closer still.

> I'm new to 2.4G, but not at all new to satellites or RF.  I've worked
AO-10
> and AO-13 extensively.  I have no test equipment for 2.4, nothing to
> generate a signal... Actually nothing to generate an RF signal at all
except
> for various HF, VHF and UHF transmitters. I do have a 1.2G xverter (in
need
> of repair!).

I have no special test gear for  S-Band either. I lashed together a harmonic
generator (5 1/2 Watt 47K Ohm resistors in parallel with a 1N4005 diode) as
seen on K5OE's web page.   My handheld will TX out of band, so I did the
following.  If you feed the 'harmionic generator' with  141.175 MHz the 17th
harmonic comes out at 2399.975 MHz (141.180 yields 2400.060 MHz / 144 MHz
yield 2448.000 MHz)  I think you get the picture.  Spin around the expected
output of the converter until you find the signal.  Repeat this with several
different frequencies being fed into your 'harmonic generator'.  The
frequency of the down conversion should remain constant.  My downconverter
always downconverts by 2277.988 MHz (i.e. 2400.060 MHz into the
downconverter shows up at 122.072 MHz on my receiver).

> 1) How acurate is the frequency of these downconverters....  How large a
> search range should I use to find 2401.318?  100Khz?  500Khz?  1Mhz?

They are not acurate, by ssb standards, but they should be repeatable!  Note
my above paragraph.

> 2) Whats the simplest way to create a test signal on 2400?  My 1.2G
xverter
> is in need of repair, but even so, i use my IC-706 for the IF for that
too.
> I have HF thru 440Mhz working, and a frequency counter that goes to 1Ghz.

The quick and dirty 'harmonic generator' seems sufficent.

>
> 3) What test equipment might I find useful, plentyful (read as cheap) for
> use up here?  I do enjoy home brewing, but I'm usually at a loss as to
what
> to build for 1Ghz+.  I'm completly a newbie with regard to MMIC's and
stuff
> (altho they sure do seem like "connect the dots" and they just work!)
>
I've gotten close enough decode using FODTrack to point the antennas, and
adjust the doppler completely unattended.  Nothing special here.  I might
add I also put some time and effort in re-aligning my antennas.  The 2' x 3'
dish seems to be narrower (no real suprise) than my 2 meter and/or 70 cm
Yagi.  I just 'eyeballed it' on the North star.

73, and Good Luck,
Joe
ka0yos@amsat.org


> Thanks in advance!
> Kevin Uhlir
> N0BEL

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