Hi Eddy - Can't argue with success! Hope it holds....
By the way, there IS voltage stabilization in the R-4, an 0B2 at V14. This supplies +150 VDC Regulated to the 100 kHz Calibrator, the PTO and the BAND oscillator.
When you said that the frequency drifted 'slowly' when the voltage drops and drifts 'quickly' when the voltage comes back up, I was on board with your filament regulation idea as that's the sort of behavior I would expect.
73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs <www.k4oah.com> Diane and Edward Swynar wrote:
Hi Again Everone, ...Just a brief post-script to this thread... Monitoring the T-4X transmit frequency on my R-4 sure has highlighted the fact that load changes on the AC mains have a detrimental effect upon that receiver. Whenever the forced-air electric furnace / heat-pump in the adjoining room would start, the frequency of the R-4 would creep (and no, it wasn't my frequency that was changing, it was the station I was listrening to). A look at the schematic shows no obvious precautions taken with the R-4 to stabilize critical voltages. I wonder if anyone has ever added a VR tube after-the-fact to their R-4 to stabilize things...? And if so, was it worth the effort...? ~73~ de Eddy VE3CUI - VE3XZ
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