Thread: Rotel RVC240
View Single Post
Old 16th Sep 2020, 12:03 am   #2
SiriusHardware
Dekatron
 
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 4,999
Default Re: Rotel RVC240

Before getting in too deep about the way this works, the fact that this radio has 'Delta Tune' means that the frequency of the 10.240MHz oscillator (and therefore the channel receive frequencies) are intentionally pulled off frequency when the DT switch is set to either + or -, so any adjustment aimed at setting the frequency of the 10.240MHz oscillator while measuring it MUST be done with the DT switch in the '0' position and in receive mode.

The effect of the DT switch is overridden in TX mode, so the simplest way to set the frequency of the 10.240MHz oscillator is to adjust CT2 so that the TX frequencies are spot on, and don't worry too much about the exact reading you get when measuring the frequency of the 10.240MHz oscillator afterwards.

Then in receive mode, the measured frequency of the 10.240MHz oscillator will shift lower than normal when the DT switch is moved to minus, and higher than normal when the DT switch is shifted to plus.

Has the DT switch wiring been tampered with, or has the DT switch been 'borrowed' for some other purpose? If so, the person who did that may not have strapped the disconnected wires in the right state to hold the DT at '0'.
SiriusHardware is offline   Reply With Quote