[NLRS] Give Away - BC-221M Signal Generator/BC-459A Modified Transmitter

[Gerald]

On Fri, 2005-12-30 at 11:31 -0600, Bud Patten wrote:
> 
> 
> Hi Gang,
>    I have an antique WWII BC-221M Signal Generator which I believe still
> works.  It covers 125 KHz to 20 MHz. and includes its original calibration
> book.  Someone built an AC power supply for it and of course that is
> included.  Be advised it is a collectors item rather than a "quality" signal
> generator.

Actually the BC-221 family is less of a signal generator and is
primarily a frequency meter. Obsolete in the era of frequency counters,
but a very high quality oscillator. The tuned circuit is of the best
quality with the capacitor made of silver plated invar (zero temperature
coefficient of expansion) that is suitable for use as a variable
standard value calibrated capacitor. As a VFO the BC-221 can be second
only to digital synthesis or a crystal for stability, probably is better
than the legendary Collins PTO.

Most of the frequency range is on harmonics.

> 
> I also have a modified (for VFO) BC-459A WWII transmitter with all tubes and
> is (I believe) operational.  This little gem was put up on the shelf when I
> switched from 50.4 (am) to 50.125 (ssb) back in the dark ages.

Not quite as stable as the BC-221 but nearly as good with the coil
windings shrunk to the coil form and the capacitor made of invar again.
Removing heat by using transistors instead of tubes either of these can
approach the stability and phase noise of a good crystal oscillator.
> 
> If one of you has any use for either of these goodies I will be happy to
> deliver either to an NLRS breakfast or hold it until you can stop by my
> place at Stacy, MN (25 mi. north of St. Paul just off I-35) for pick-up.
> 
> 73 es Happy New Year,
> 
> Bud
> w0lcp

I already have at least one of each.


-- 
73, Jerry, K0CQ
Dr. Gerald N. Johnson, electrical engineer
All content copyright, Dr. Gerald N. Johnson