[time-nuts] fast freq. synthesis schemes

Lasse lasse.moell at swipnet.se
Thu Oct 15 14:25:31 UTC 2009

   Ahhh memories! One slow summer I spent a few weeks bringing 4 (four)
   dead AilTech 360 back to factory specs... They all suffered from cold
   soldering joints (and a few bad transisitors). Both the 180MHz and the
   1,8GHz units

   We later upgraded to Comstron FS2000-2 which suffered from the very
   same problem with bad soldering joints. I was keeping those alive with
   the aid of a rubber hammer, but later reverted to resolder all the
   filter tabs within the units.

   Met the designer of both the 360 and the Comstron, Robert Papaiek, and
   he was a bit offended when I complained about the poor "design". It was
   all due to production was the answer :)

   Never-the-less our PTS seems to work ok, but needs some TLC with the
   coarse tuning pots after 5-10 years... One of our PTS-1000 had a very
   odd problem which was traced to a faulty molded screened inductor from
   Coilcraft. Had a nice discussion with the QC guys at Coilcraft and
   Michael Lohrer at PTS, and we all decided this was a "one off" :)

   Analogue Direct Synthesis is the way to go if you want fast switching
   into microwaves. You can get infinite resolution by just adding another
   decade module, and they are all the same...  The draw-back is you need
   plenty of filters and proper sheilding to get specral purity. There
   should be plenty of reading on the web


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