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R: looking higher..10GHz?



Hi Mark, N8MH

2560 MHz (S) uplink for P5-A Transponder Experiment on board of P3-E
is not a correct frequency because the maximum allowed frequency for the
Amateur Satellite Service is 2450 MHz as showen in the frequency table
planned for P3-E wich is available in the AMSAT-DL site at

http://www.amsat-dl.org/p3e/tabelle.htm

About the feed on the ebay it is a rectangular feed horn made for 10368 MHz
with a gain of 9 dB so that it is good to illuminate a dish with a F/D ratio
of 0.6 like an offset dish as you can calculate and verify using the program
HDL_ANT  version 3b3 from Paul Wade W1GHZ (N1BWT)

On the other side the above feed horn is linearly polarized and it is ideal
for 10 GHz tropo communications at 10368 MHz

For satellite applications with 10450 MHz downlink of AO40 I have built
a Chaparral feed using a circular waveguide with two SMA coaxial to
wavelenght transitions to get RHCP and LHCP because at the time of
construction the direction of circular polarization for the X band antenna
on AO40 was not available.

I have the above Chaparral feed on a 60 cm prime focus dish with F/D= 0.38
with a home built low noise HEMT preamplifier and I actually get 3.5 to 4
dB of sun-noise with a solar flux in the average of 108 sfu at 2800 MHz
during the last week.

Unfortunately due for the X band TX failure on AO40 I never had the chance
to test the above setup on satellite except for sun-noise experiments.

For 10450 MHz I have built a transverter from a Kit for 10368 MHz sold by
DB6NT changing the XTAL local oscillator and retuning it to get in frequency
10450-10452 MHz with an IF from 146 to 148 MHz using obviously only
the receiving part of it.

When P3-E will fly I will be ready but I belive that to became a reality in
2005/2006 P3-E needs generous donations from the amateur community
otherwise........come back to the HF or use the BB to communicate
worldwide.

I hope this help

73 de

i8CVS Domenico

----- Original Message -----
From: Mark L. Hammond <mlhammond@charter.net>
To: Amsat List <amsat-bb@amsat.org>
Sent: Sunday, March 20, 2005 2:03 AM
Subject: [amsat-bb] looking higher..10GHz?


> I saw this tonight:
>
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5761236048&;
rd=1
>
> Also, please consider the following from:
http://www.amsat.org/amsat-new/express/
> P5-A Transponder Experiment: 2560 MHz (S) uplink and 10450 MHz (X)
downlink. Also usable as a linear
> transponder with approximately 50 KHz bandwidth.
>
> Inasmuch as P3E is destined to have 10GHz down, I wonder what type of dish
might match up with this feed?  It seems like a very inexpensive feed, if it
makes sense to consider.  If not, it's like throwing money away ;)
>
> Can anyone share their thoughts on this feed and what type of dish might
match up?  (Of course, the issue of a 10GHz downconverter comes to mind,
too!!)
>
> Thanks,
>
> Mark L. Hammond  [N8MH]
> ----
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