[Collins] Winter Projects

[Gerald]

On Thu, 2005-07-14 at 16:49 -0500, K3PID wrote:
> Well I'm lining up the work for a long cold winter and I am planning on a
> lot of help from the group! First I have my T-368 that  need to do just a
> little work on ( new speech amp), second is the rebuild of the Chicago
> Electronics 20A that I just purchased and it need work, and third is the
> design and construction of the 160 - 10 meter VFO utilizing the Collins
> 70E-8A.
> 
> That ought to take me into spring don't you think?
> 
> 73
> K3PID
> Ron H.
> .
> 
That's Central Electronics I believe. Located at Chicago. Had one of
those once. The 70E-8A is not an appropriate VFO for the CE 20A. The
70E-8A is designed for CW and AM from 160 through 10 by multiplication,
not by heterodyning. The 20A was designed to use a modified 5.3 to 7 MHz
command set as VFO, retuned to cover 5 to 5.3 MHz. Some bands used
harmonics of that tuning range. With the coil heat shrunk to the form
and the capacitor made of zero temperature coefficient Invar, the
command transmitter stability can be as fine as the Collins PTO. The
70E-8A is an appropriate VFO for the T-368.

There are circuits using the 70E-8A in Radio Handbooks from Editors and
Engineers 11th and 12th editions.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer