[Boatanchors] More National NCX-3 problems - Chirp on CW

[Glenn Little WB4UIV]

The VFO should not shift frequency when you key the rig.
I think that you really mean 8.7 MHz rather than the 8.7 milliHertz that 
you wrote.
I would guess that you have a frequency determining capacitor that is 
Voltage sensitive.
When you go to transmit the Voltage change changes the capacitance 
slightly, causing the frequency shift, much as a varicap would do to FM 
an oscillator.

73
Glenn
WB4UIV



On 1 /29/2020 8:58 PM, Mark V Johnson wrote:
> Team,
>
>   
>
> I'd appreciate the teams wisdom as I continue to get my NCX-3 operational.
>
>   
>
> I'm getting great SSB reports, but I do get reports of chirp on CW.
>
>   
>
> I did the recommended  mod as per the National 1966 service bulletin - RF
> choke in the B+ at the 0A2 regulator - but I still have chirp.
>
>   
>
> When I put a receiver near the transceiver and tune in the VFO signal -
> 8.7mhz - I can hear a chirp as I key the rig.  The plate and screen voltages
> of the 12AU6 VFO tube - V5 - are rock solid. No movement what so ever. The
> 8.7mhz signal when measured on my freq. counter drops ever so slightly as I
> key the radio.
>
>   
>
> Am I chasing the wrong area??? Maybe the "keyed" VFO signal is OK and what
> I'm hearing is a change in the signal as the radio goes from receive to
> transmit. In other words, as long as the keyed signal is steady, which it
> seems to be, I'm OK???
>
>   
>
> Of course in a world filled with ultra modern transceivers that measure down
> to the Hz, maybe the old boat anchors have no place doing CW on the bands. I
> love it when I'm on SSB with this old beast I'm informed my signal is off a
> few hertz. But that editorial is not pertinent to my question...sorry!
>
>   
>
> Suggestions?
>
>   
>
> Much appreciated!!
>
>   
>
> Mark V Johnson
>
> VE3LU/VE3DJU
>
>   
>
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-- 
-----------------------------------------------------------------------
Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"