[BC] Re: Hello

[Johnson, Richard]

On Tue, 20 Mar 2007, Tom Bosscher wrote:

> Yup, and one was sold to WKLA, Ludington, Michigan. That
> transmitter could not go over 40% modulation without running
> over 20-50% distortion. I spent a lot of time working with
> clueless people at the factory who could not tell us
> anything. Factory sent their "best" out to the site, and
> left the transmitter worse than when they came in.
>

Well the transmitter didn't use any tricks. It was class AB
high-level modulated. If it wouldn't modulate something was
wrong with a very conventional HI-FI audio amplifier (no pulse-width
schemes). BYW, It's the same circuit "borrowed" by Crown years
later. The output transistors were stacked in series to get the
necessary voltage capability.

> 	So, just how many did Cetec-Sparta sell, and how many were
> still on the air 18 months after they were bought?
>

I stayed at Cetec-Sparta for over two years after that transmitter
was in production. I'm not aware of any systemic problems although
I don't know how many were delivered. We ran these things at one
NAB convention under arcs, sparks, shorts, and opens, just to show
potential customers that solid-state transmitters had "arrived."

When Cetec-Sparta went under, we were in the process of type-
accepting a 2.5 kW version so the basic design was solid. However,
once Sparta was in receivership, owned by the Columbian cartel,
all bets were off. Anybody with any technical acumen, including Paul
Gregg, headed for the hills!

> 	tom, I was there, bosscher
>
> Johnson, Richard wrote:
>>
>> Hello,
>> ... The very first 1 kilowatt solid-state AM broadcast
>> transmitter ever type accepted by the FCC was the Cetec/Sparta
>> SS-1000. This was designed by me while I worked for Paul Gregg
>> and Bill Overhauser.
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Richard B. Johnson
Project Engineer
Analogic Corporation


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