[Moon-net] Ts-2000 fan chirp

[Martin Andrew]

Hi Richard,

Have the same problem but on 1296MHz with a TS-2000X.
Strangely, not seen any mods or cures for the problem.
I also have a Yaesu FT-847 which suffered from a similar problem. This was 
cured by fitting a crystal heater and foam around the main reference 
crystal.
I wonder if a similar mod could be done on the TS-2000X. Will have a look at 
the component layout to see whether fitting foam round the crystal is 
possible, if not maybe a crystal heater. Heaters can be obtained in Europe 
from http://www.db6nt.com
By the way, drift was measured at nearly 150Hz on 1296MHz.

Regards,
Martin,
GM6VXB,
IO97AQ.
----- Original Message ----- 
From: "richard allen" <rca at rcallen.com>
To: <ntms at itexas.net>
Cc: <moon-net at list-serv.davidv.net>
Sent: Sunday, April 01, 2007 6:15 PM
Subject: [Moon-net] Ts-2000 fan chirp


>
> When testing my new ts-2000x on some 437 MHz cw satellite signals I
> noticed some frequency variations that were abnormal. My concerns are
> how well this radio would perform on various weak-signal modes where
> good calibration and stability is important.
>
> I was tracking several satellites and correcting for Doppler shift.
> When all is working correctly and the frequencies and Keplerian elements
> are correct this will produce a  fairly straight line down my waterfall
> display.  When I saw these abnormalities, I fired  up my z3801
> oscillator and fed it into the ts-2000 first listening to the 128th
> harmonic  of the 10 MHz output.  The radio was tuned in upper sideband
> to 1279.999000 MHz which would yield a beat note of 1000 Hz.  I was glad
> to see that the radio was only about 150 Hz off but over time I noticed
> a cyclical frequency variation with about a 20 minute period.
>
> The first thought was that the z3801 had not yet stablised but after
> doing a new survey and waiting for all to settle down, the signal was
> still varying.  After monitoring for several hours, I checked the local
> channel two video carrier at 55.25000 MHz and could  see a small
> variation on it also. As the channel two carrier shifted down by a few
> Hertz, I noticed that the fan in the ts-2000 had just turned on.
>
> Sure enough, the cyclical pattern matched the fan cycling on and off.  I
> posted an example waterfall on my website.
>
> You can view it at http://www.rcallen.com/ts2k-fan.gif ...
>
> The plot starts at about 13:00 utc on April Fool's Day but,
> unfortunately, it is not a joke.
>
>>From 13:00 thru about 13:33 shows several fan cycles.  The ts-2000 was
> tuned to 1279.999000 MHz and in upper sideband mode. As can be seen, the
> frequency changes down to 800 Hz when the fan comes on and then peaks
> back up to about 900 Hz at fan cutoff.  While this is well within the
> +-0.5 ppm specification of the radio, it may be a problem for operating.
> Offset I can handle but drift is another matter.
>
> After 13:41, I switched to tracking the Argentinean ham satellite
> LUSAT/LO-19.  It's cw beacon is nominally on 437.12545 MHz and with a M2
> 70 cm eggbeater antenna, peaks about 20-30 dB out of the noise.  The
> apparent frequency smear is from the fact that I was only updating the
> radio's frequency every 10 Hz.  The Doppler shift makes the apparent
> frequency move more than the program can keep up with at 1 Hz
> increments.
>
> At marker 6, at about 13:47, the fan came on causing a drop in pitch.
> The satellite peaked in elevation at 13:49:49 at 25 degrees.  The fan
> then went off at about 13:53 shown by marker 7.  The satellite went on
> to set at 13:57.
>
> At marker 8 I switched the radio to 439.999000 MHz USB, the 44th
> harmonic, and monitored another fan on/off cycle indicated approximately
> by markers 9 and 10.
>
> Any suggestions as to how I can stabilise the radio would be
> appreciated.  I think I will first try to modify it so that the fan
> stays on continuously.  The master oscillator is a  TCXO at 15.6 MHz and
> it may be possible to replace it with an external oscillator slaved to
> my z3801.  Some of the shift might also be a voltage drop when the fan
> comes on.
>
> Please feel free to forward this to any other interested vhf reflector.
>
> Regards,
>
> Richard W5SXD
>
>
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