Re: {Collins} S line zero-beat issue in Transceive Mode?



I didn't look at the schematics --and it's been too many years-- but in the
transceive mode with the 2 cables connected, would the BFO crystals in the
transmitter matter? It seems like there was a reason that I had to trim the
BFO crystal in the 75S-3  rather than the 32S-3.

73, Mike
www.w0btu.com

On Sun, Nov 23, 2014 at 6:27 PM, Gary Follett <dukeshifi@xxxxxxxxxxx> wrote:

> Would it not be simple enough to add trimmer caps across the BFO crystals
> in the transmitter? The mechanical,filters,are very correct in terms of
> passband position so the error in crystal frequency can only cause one or
> the other sideband to be incorrectly positioned anyway. I picked the
> transmitter, for this alteration since the effects old be less noticeable
> for,the user. By adding these trimmers, you would zero beat the TX and RX
> just the way you do when matching USB and LSB on the PTO.
>
> Alternatively, one could ditch the notion of using the PTO offset for
> matching USB and LSB and use the TX keying line to pull the PTO's when
> going fro TX to RX. This would be quite easy to do.
>
> Getting two new XTALs from INRAD is no guarantee these will operate on the
> same frequency anyway. Either of the simple alterations I just described
> will accomplish the feat perfectly.
>



This archive was generated by a fusion of Pipermail (Mailman edition) and MHonArc.