[AMRadio] FW: Homebrew receiver

[Donald Chester]

There are several beam defection tubes in circulation during
>the 60's time frame. Unfortunately, none of them are directly
>interchangeable with each other unless one is willing to rewire several
>pins on the tube socket. Spec wise they are very close to each other.

If anyone  has the data, maybe you  could post a list of all the beam 
deflection tubes of that era.  I think they were widely used in tube-type 
color TV's.   Sometimes the TV ones are cheaper than the 7360, but on the 
other hand, the cheap sweep tubes of the 60's now cost several times more 
than 6146B's.

One problem I  had with the 7360 was that the a.c. filament current would 
introduce hum into the circuit.  The magnetic field from the filament would 
modulate the beam deflection enough to modulate it slightly at 60~.  I am 
sure this was never a problem with the  slopbucket rigs of that era since 
everything below about 500~ was rolled off anyway to produce "communication 
quality", but it was certainnly noticeable in my homebrew SSB generator.  Of 
course there is a very simple fix: use reasonalbly well filtered DC on  the 
filament.  I have found that to be necessary even with the 12AX7 1st 
amplifier stage of my mic preamp.

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