[Central-Electronics] CE 458 VFO Output Level

[Jim Candela]

 Paul,
   Remember that the BC458 has to work differently band to band. On 40m, the VFO frequency is tripled, and then when beating against 9 Mhz, the difference puts you on 40m. The 1625 plate tuning and VFO tuning must track. Then over the years, the insulators on the CE added coils degrade and get lossy. 

   I would play with those coils, and the preset for the plate tuning capacitor. I have drilled a hole in the side before to get a straight shot with a screwdriver to peak the plate for resonance to get maximum output.

   On one of the links I gave you to AM FONE, I discuss the 40m problem which also includes the Mixer tank circuit Q.
I repast the links here for the group.

http://amfone.net/Amforum/index.php?topic=37143.0

  

http://amfone.net/Amforum/index.php?topic=27305.0

  

http://amfone.net/Amforum/index.php?topic=42220.msg306536#msg306536


JimWd5JKO

    On Wednesday, May 22, 2019, 6:48:26 AM CDT, Paul Christensen <w9ac at arrl.net> wrote:  
 
 I recently acquired a NOS CE-modified 458 VFO.  However, when connected to a
CE 20A transmitter I'm seeing low output level, depending on the band, from
0.5V to 3.0VAC.  40m is the lowest level.  It seems to me the output level
should be higher when terminated into the CE 20A.  The measurement is taken
with a scope at the octal accessory connector.  Link coupling adjusted to
maximum level.

Can anyone confirm what reasonable levels to expect from the 458 VFO?

Paul, W9AC

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