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So, here's what you'll discover after stabilizing the B+ voltage to the D201 VFO circuit.

Keying the mike causes the heater voltage to drop ever so slightly. The change in heater temperature this causes will make the VFO drift a couple dozen or more Hz while you're keyed up. It will return to the frequency where it was receiving when you unkey.

We wire the front-panel clarifier to be active while receiving with the VFO. The trimpot that takes the place of the clarifier while transmitting gets set to make the transmit frequency agree with the 12 o'clock clarifier receive frequency. But this is still just a band-aid fix. Best I can tell the only proper cure would be to regulate the heater voltage on V302. About the time I considered trying this, the FCC dropped the morse code requirement for a ham license. The 11-meter sidebanders in my neck of the woods all evacuated to the ham bands. Couldn't justify the expense with no 11-meter sideband customers any more.

But that's my experience with this issue. Your mileage may vary.

73

<blockquote data-quote="nomadradio" data-source="post: 804856" data-attributes="member: 22">So, here&#039;s what you&#039;ll discover after stabilizing the B+ voltage to the D201 VFO circuit. Keying the mike causes the heater voltage to drop ever so slightly. The change in heater temperature this causes will make the VFO drift a couple dozen or more Hz while you&#039;re keyed up. It will return to the frequency where it was receiving when you unkey. We wire the front-panel clarifier to be active while receiving with the VFO. The trimpot that takes the place of the clarifier while transmitting gets set to make the transmit frequency agree with the 12 o&#039;clock clarifier receive frequency. But this is still just a band-aid fix. Best I can tell the only proper cure would be to regulate the heater voltage on V302. About the time I considered trying this, the FCC dropped the morse code requirement for a ham license. The 11-meter sidebanders in my neck of the woods all evacuated to the ham bands. Couldn&#039;t justify the expense with no 11-meter sideband customers any more. But that&#039;s my experience with this issue. Your mileage may vary.73</blockquote>

[QUOTE="nomadradio, post: 804856, member: 22"] So, here's what you'll discover after stabilizing the B+ voltage to the D201 VFO circuit. Keying the mike causes the heater voltage to drop ever so slightly. The change in heater temperature this causes will make the VFO drift a couple dozen or more Hz while you're keyed up. It will return to the frequency where it was receiving when you unkey. We wire the front-panel clarifier to be active while receiving with the VFO. The trimpot that takes the place of the clarifier while transmitting gets set to make the transmit frequency agree with the 12 o'clock clarifier receive frequency. But this is still just a band-aid fix. Best I can tell the only proper cure would be to regulate the heater voltage on V302. About the time I considered trying this, the FCC dropped the morse code requirement for a ham license. The 11-meter sidebanders in my neck of the woods all evacuated to the ham bands. Couldn't justify the expense with no 11-meter sideband customers any more. But that's my experience with this issue. Your mileage may vary. 73 [/QUOTE]

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