I noticed something similar last night when doing
this. I've not operated since so I don't have any
experience with the result.
At temp of 45 deg or thereabouts the tone started
back up. But it didn't rapidly shift or do
anything bizarre, just increased slowly as the
temp went to 52 deg. Then I locked in the
compensation; have to do RefCal today.
I was surprised that the tone didn't just keep
going down until temp reached 52 deg.
It would be good to know if this is normal or I
need to redo the temp comp procedure (hopefully not).
73, Phil w7ox
On 3/18/14, 7:37 AM, Bob wrote:
Anybody else having issues with non-linear
oscillator changes around 40C? I've done the
extended temp calibration 3 times (each time
takes about 2 hours), and someplace between 38C
and 42C the calibration goes crazy. Up to that
point as the temperature gradually increases the
tone shifts lower. But around that 38-42C spot
it start rapidly shifting up in tone and down in
tone (frankly all over the place). When you
actually use the KX3 it is obvious that there is
something bad happening around there because you
can hear signals start to wildly drift around in
the receiver as the rig temp moves through that
range. That makes me think that the values
obtained by the calibration process are not
accurately reflecting true changes in internal
oscillator frequency.
I contacted the factory. Their best advice was
to do the calibration again but use an
electronic heat source (like a 50 ohm dummy
load) under the KX3 with a variable power supply
running the dummy load to get a more linear
temperature increase. I haven't done that yet,
but my three prior attempts have had a pretty
linear temperature increase (one changing the
rig temp about 1C per minute from 15C up to 60C).
73, Bob, WB4SON
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