[ARC5] BC-453 mods

[Kludge]

Getting caught up here (i.e., taking a break from the NAVP)

-----Original Message-----
From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of Kenneth G. Gordon
> Making the 1st IF regenerative in any of the models is easily done, 
> and makes a big difference for weak signals....not so much for strong 
> ones.

Back during my Novice days, several WW II AAF radiomen beat me soundly about
the head and shoulders when they discovered I was trying to operate
converted command equipment.  They were quite emphatic about the fact that
they ran perfectly well unmodified as long as I fed them properly and paid
attention to the antenna requirements.  The only real Tx mod they went with
was making them crystal controlled which was necessary at the time.  They
had no objection to my running them with a 400v B+ source which was good
since that's what I had for power transformers.  

After listening to the 80 & 40m Novice bands, they made two suggestions, one
of which was to make one IF stage regenerative.  (The other was an external
mechanical modification to allow a better tuning rate across the Novice
portion of the bands.)  The basic method was the same, a gimmick cap from
plate to grid and a pot in the cathode to control regeneration.  

Several of my converted pieces - Rx & Tx - that didn't become parts sources
for other projects became test beds for an assortment of ideas.  Since there
are some pre-perverted units in storage now, they will be used for a
continuation of those experiments including things like a regenerative
detector and other really cool stuff.

> The main problem I always had when trying to replace tubes with FETs 
> is that an FET is basically a triode. For multi-grid tubes, this is 
> often a real problem.

Not really.  The added grids are only necessary because of the
eccentricities of electron activity inside a tube and can be ignored as far
as the actual operation of the stage goes.  Even something like a pentagrid
converter can be broken down into its actual functional blocks, an
oscillator and a mixer, both of which can readily be executed as triodes.
(I'm a great fan of the Vackar oscillator & Pullen mixer so I'd probably go
for having four FETs plus the necessary passive "glue" in there but that's
just me. :-) )  

Best regards,
 
Michael, WH7HG ex-K3MXO, ex-KN3MXO, WPE3ARS, BL01xh ex-Mensa A&P PP BGI 
Escapee from the Home for the Terminally Weird
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Hiki Nô!