[Collins] 51S-1 vs. 75S-xx

[Dr. Gerald N. Johnson]

On Tue, 2007-09-04 at 08:24 -0400, Merle wrote:
>     Good Morning Dr. Jerry..
> 
> Very interesting story about your boss !  Sounds like the 56' Chevy. tells a story. Nothing wrong being frugal. Thanks for your knowledgeable input, as usual. The ease of operation of the 51S-1 is no doubt my problem !  However, like all Collins equipment, they are all great radios.
> 
> Best 73  Merle
> 
Yet while designing there I found a bias to engineering. No value
engineering, no discussion about "Do we absolutely need this component?"
rather "This circuit isn't perfect, what can we add to make it better?"
Which was different than the consumer radio and TV circuits I'd worked
on fixing them before graduation. The design challenge was less without
the economic component. Yes it was great to do whatever it took to make
it work, but had there been that economic component the challenges would
have been greater. And working on the 821A-1 there should have been
economic challenge because we spent 3 years at 3/4 million a year for
engineering and Art sold them for the purchase parts price to break into
a new market. But there wasn't that economic challenge, there was only
the challenge of making the biggest and most complex Collins transmitter
ever work to exceed the customer's specifications.

I guess I did input some value engineering, I wanted a bypass capacitor
for many feed throughs from the PA cathode and grid compartment but I
didn't want to bypass the leads individually because of the voltage
involved and it was modulated (grounded screen). So I thought about
using a ring of ceramic with metalization top and bottom to support an
aluminum plate carrying low voltage feed throughs. When I priced time
and cost of such a custom hunk of ceramic, I gave up that idea and used
a ring of 1000 pf Centralab 850s to support the plate and no one ever
tried to show it wasn't effective and it cost a whole lot less than the
custom ceramic piece. I don't think that ever was put in a working paper
so Art didn't get to second guess those options. My boss liked it and
we built them that way.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer