[Milsurplus] 12BY7 with tiny crystals?

[Mike Feher]

>From all I read on different reflectors, the HC-49s tend to crack in most
tube circuits. They were really intended for SS stuff. 73 - Mike 

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
<milsurplus-bounces at mailman.qth.net> On Behalf Of David Stinson
Sent: Friday, June 3, 2022 10:02 PM
To: milsurplus at mailman <milsurplus at mailman.qth.net>
Subject: [Milsurplus] 12BY7 with tiny crystals?

 

 

Have any of you tired to use the little, short and oval "half size" HC-49S
crystals in their DX-100 or other similar rig?

These are the tiny things you see in those inexpensive "QRP" kits on Amazon.

 

I ask because I'm working 20 minutes here, an hour there to get a Bendix 430
fishing boat radio running. "Stock" uses HC-6 xtals.

 

 <https://photos.app.goo.gl/FyLFwDbMXvWnCtCe6>
https://photos.app.goo.gl/FyLFwDbMXvWnCtCe6

 

The little "shorties" won't give enough drive to run the Bendix circuit:

 

 <https://photos.app.goo.gl/QXfQXAVjrtf1WosL6>
https://photos.app.goo.gl/QXfQXAVjrtf1WosL6

 

No buffer or multiplier here. Note the crystal is between the plate and
signal grid and has 310V B+ on it.

 

Here is the DX-100 transmitter circuit, minus the crystal switch and
clamper. The crystal is between the signal grid and the screen grid- a
variation of the Electron Coupled?

 

 <https://photos.app.goo.gl/vfi99ePHKKk6vGHz7>
https://photos.app.goo.gl/vfi99ePHKKk6vGHz7

 

I'm wondering if the 12BY7 in the DX-100 configuration would perform better
with the "shortie" crystals than the Bendix circuit. What do you think?

 

TNX OM ES 73 DE Dave AB5S

 

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