Re: Valve frequency multipliers

On Tue, 04 Feb 2025 09:36:38 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 1 Feb 2025 15:30:40 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
>

legg <legg@nospam.magma.ca> wrote:
>
[...]

 
I'd be more selective of the crystal frequency. Two triplers might get
you there with a lot less grief.

>
I regret to say I think you are right   :-(
>
Quintuplers just don't seem to work in those circuits so I have placed
an order for a 16.656 Mc/s crystal, which will triple-triple to 149.904
Mc/s.  That will mean bringing the VFO down to a range of 3.904 to 5.904
Mc/s, which should be relatively easy. 
>
Revised block diagram at:
http://www.poppyrecords.co.uk/other/Transceiver/BlockDiag6a.gif
>
It will make image rejection in the second receiving mixer a little more
difficult  The transmitting mixer is intended to be balanced, so
rejecting 149.904 Mc/s instead of 150.000 Mc/s from the output will not
be any more difficult but I may require an extra tuned circuit in the
later part of the transmitting chain to reduce the level of image
frequency.
>
I just hope the new crystal will work in the same circuit as the old one
and I won't have all the hassle of redesigning it.

>
That should have been 6CX8 (6CM8)from the article.
>
There are functioning models for 6BL8 (ECF80), which
has a pentode/triode combination.
>
I expect just as big a problem in modeling would be in
coupling/filter magnetic components.
>
Oscillators never do . . . .
>
RL

Some fraction of my income comes from an instant-start TCXO-accurate
triggered 50 MHz LC oscillator. That was developed with Spice (and a
PowerBasic program.)