[amsat-bb] Re: TS2000 ~436.798 MHz Birdie Solution

[Andrew Glasbrenner]

Hi John,

Thanks for writing that up. With a simple diagram, it would make an excellent Journal article (hint hint).

I should also point out that High Sierra Microwave makes a UHF to HF converter, the 435M7 near the bottom of the page at http://www.hsmicrowave.com/page12.html . It outputs to 10 to 13 Mhz, but that should be no different than 10m for newer rigs like the TS-2000. The noise figure looks really good, and I expect the quality to be much better than the Hamtronics. The owner is a big AMSAT supporter too.

73, Drew KO4MA


-----Original Message-----
>From: John Papay <john at papays.com>
>Sent: Nov 30, 2011 10:49 AM
>To: amsat-bb at amsat.org
>Subject: [amsat-bb] TS2000 ~436.798 MHz Birdie Solution
>
>As many of you know, my satellite radio is a TS2000X.
>If you have visited my satellite webpage, you have seen
>many recordings of AO-27 and SO50 from AOS to LOS.  Most
>of these recordings were made when I was not sitting in
>front of the radio.
>
>At first I used a uhf mobile to hear AO-27 and SO-50.  The
>problem was that those radios were not computer controlled
>so you had to tune for the doppler.  That worked fine when
>I was in the shack, but it didn't work when I was away.  The
>obvious solution was another radio that didn't have the birdie
>problem, or a simple UHF to 10M downconverter which wouldn't
>have the birdie problem.  Back in the day, UHF and VHF down-
>converters were very popular because we didn't have a lot of
>DC to Light radios out there.  Now these converters are sitting
>in junk boxes and are long forgotten by their owners.
>
>One of the more popular manufacturers of these inexpensive
>downconverters was Hamtronics.  They made all kinds of stuff
>for repeaters etc.  At first their products were not that great,
>but they evolved into some better designs including their
>UHF to 10m downconverters.  Unfortunately most downconverter
>manufacturers stopped making them when the devices they were using
>became obsolete and unavailable.  The use of current production
>devices required a redesign of their PC boards and since the demand
>was no longer there, these products were abandoned.
>
>I was fortunate to find a Hamtronics converter on a qrz.com posting
>from several years back.  It never sold back then and the owner still
>had it.  I purchased it and ran some tests on it against the receiver
>in the TS2000.  It turned out that the downconverter had a slightly
>better sensitivity than the TS2000!
>
>The big concern when using a converter or preamp is the fear of
>transmitting into it and smoking the front end.  But the TS2000
>has an auxiliary antenna jack which is receive only and perfect for
>a downconverter output on HF.  As Drew mentioned, SatPC32 can
>compensate for a downconverter and tune the TS2000 for doppler
>in the 10m band.  This allowed me to track AO-27 AO-51 and SO-50
>unattended and make all those recordings without any human
>intervention.
>
>A coaxial transfer relay was inserted into the uhf antenna line so
>that when the converter was in use, the UHF antenna was switched
>to the downconverter input (which outputs to the aux antenna jack
>on the TS2000) and the UHF antenna jack on the TS2000 is switched
>to a dummy load.  So if you transmit on UHF, power goes into the
>dummy load and all equipment is safe.  When I want to transmit on
>UHF (VO-52 and AO-7 mode B), the coax relay switches the UHF antenna
>back to the UHF antenna port on the TS2000.  The downconverter is out
>of the antenna circuit at this point.  I did not use the downconverter
>when operating on FO-29 so the aux antenna jack had to be switched to
>normal in the tS2000, menu #18 (FO-29 is a linear bird that outputs on
>UHF, currently not working).
>
>Every owner of a TS2000 that operates satellites needs a UHF to 10M
>downconverter.  Hamtronics is making a VHF to 10M downconverter now.
>If everyone emailed them to encourage them to make a UHF model, they
>might just do it.  The only other solution is to make one yourself,
>or find a used downconverter or transverter that is gathering dust on
>someone's shelf.  I now have an IC910H and am doing comparisons against
>the TS2000.  My first impression it that I prefer the TS2000 but that
>might be because I'm so familiar with it.  I use another TS2000 in the
>mobile sat truck but don't have a downconverter for it.  I simply use
>a uhf mobile for receive on AO-27 and SO-50 since I'm in front of the
>radio and don't run it unattended.  I have a coax switch to switch
>the UHF antenna from the TS2000 to the UHF mobile.
>
>Now that AO-51 is silent, all of the FM operation is on SO-50 and AO-27.
>If you have a TS2000, you'll want to investigate the use of a downconverter.
>
>73,
>John K8YSE
>
>
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