Frequency Adjustment on XV144

[Guy-10]

I have had an XV144 transverter for a couple of years,
and have been very happy with it.
It has the Oven option for the 116MHz LO crystal.

I have noticed a frequency error on my overall system of about 200Hz,
but have been unable to track this down properly until I had
a good GPS-locked Signal Generator and Counter.

Careful measurement now shows that the Transceiver calibration
is only 10Hz out (pretty good!), whereas the crystal frequency
in the XV144 is 115.999 814 MHz, which is 186Hz low.
This may not seem much, but in these days of really narrow band
working it is irritating.

I can of course calibrate it out by setting the transceiver high,
but has anyone got a fix to trim the crystal frequency upwards?
There is no provision in the circuit for frequency adjustment.

Guy  VK2KU
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[Ron D'Eau Claire-2]

Guy, VK2KU wrote:

I have had an XV144 transverter for a couple of years,
and have been very happy with it.
It has the Oven option for the 116MHz LO crystal.

I have noticed a frequency error on my overall system of about 200Hz, but
have been unable to track this down properly until I had a good GPS-locked
Signal Generator and Counter.

Careful measurement now shows that the Transceiver calibration is only 10Hz
out (pretty good!), whereas the crystal frequency in the XV144 is 115.999
814 MHz, which is 186Hz low. This may not seem much, but in these days of
really narrow band working it is irritating.

I can of course calibrate it out by setting the transceiver high, but has
anyone got a fix to trim the crystal frequency upwards? There is no
provision in the circuit for frequency adjustment.
---------------------

The is an adjustment, Guy. It's in the K2, not the XV. You have an offset
adjustment in the TRN menu in the K2 that allows you to adjust for any
offset. Go to the trn number you have assigned to your XV144 in the K2's
menu, Press MENU so On is underlined, then tap DISPLAY to cycle through the
other menu options for that transceiver. One of the settings is OFS or
"offset" which allows you to compensate for any reasonable error in the XV's
L.O. frequency.

Ron AC7AC

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[Ron D'Eau Claire-2]

Hi, Johnny:
 
I haven't tried it. I have worked with enough overtone oscillators enough to
know they can be very cranky things if not set up right.
 
The usual method involves putting an inductor in series with the crystal or
a trimmer capacitor across it.
 
Perhaps there are some engineers on the reflector here who can offer more
specific advice.
 
Ron AC7AC

-----Original Message-----


Hi Ron,
 
I am using XV144 with my IC7800.  Therefore, it would be useful if I could
fine tune the XV144.  Is there any way to do it?
 
73
 
Johnny Siu VR2XMC

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