[Collins] KWM-2

[Antonio Sanches de Magalhaes]

"Dr. Gerald N. Johnson, electrical engineer" wrote:

> Likely the VOX time constant capacitor is leaky. If its still a black
> beauty it IS leaky. You might try lowering the anti-vox gain, that
> should lengthen the VOX delay also.
>
> In my schematic, C 47, C48 and C188 contribute to VOX time constants.
> Leakage in any will shorten the VOX delay. I don't see a VOX delay pot,
> but that may just mean my schematic is old.
>
> Its the nature of the radio to transmit with a high audio tone. CW is
> generated by sending a tone through the audio chain and the audio
> frequency is chosen so that only the fundamental passes through the
> mechanical filter. If an 800 Hz tone was used, there would be two or
> three CW signals at 800 Hz spacing. When the 1600+ Hz tone is used the
> filter prevents the audio harmonics from causing multiple carrier
> outputs. The key controls the second audio and the second transmit
> mixer.
>
> There have been mods, mostly (as I recall) involving adding an effective
> RIT to the PTO (already present in the form of the sideband calibration
> correction shift) to allow the receiver to listen up about 800 Hz. I
> don't have any of those details.
>
> 73, Jerry, K0CQ, Technical Advisor to the CRA
> --
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.

Dear Jerry,

Thank you very much for your help.

Best regards,
Antonio=CT1TE