[TenTec] 1210 LO stability

[Mark Whatley]

I'm new to this site so please forgive me if this has been covered.

I have a 1210 transverter that I built about a year ago and finally got around to getting it on the air recently. I seemed to be
working fine for local ragchewing but I did get a report that it was drifting in frequency by a 100 Hz or so. My intentions were
to use the 1210 to work meteor scatter using the new digitial modes and so I became concerned about this report of frequency 
drift. The IF rig is a Yaesu FT-1000. 

I connected a dummy load and began to run some tests. I first checked the FT-1000 and found it to be very stable.
But the counter showed that, sure enough, the carrier freq from the 1210 did drift rather badly 
over a short term test. I ran the WJST program to simulate a contact and in about 10 minutes the frequency had drifted about 180
Hz. I attributed this to the slight heating effects in the transverter. It returned to approximately the starting frequency in a couple of 
hours after I stopped transmitting. At first I was counting the output frequency (144.250 Mhz). I then counted the LO freq (116.0 Mhz) just to make sure and noted the same results. I have since left the unit on for weeks and noted that the LO frequency can
vary over about a range of +60 and -40 Hz during the day without any transmissions.

I have readjusted the LO several times and still see the same results.

Has anyone experienced this beside me? Has anyone proposed a solution?

Thanks,
Mark K5XH


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