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From: john larkin <JL@gct.com>
Newsgroups: sci.electronics.design
Subject: Re: Valve frequency multipliers
Date: Tue, 04 Feb 2025 07:41:19 -0800
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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.)