[Heath] Results of experiment with reactivation of 5

[Kenneth G. Gordon]

On 8 Aug 2012 at 20:18, pmarkavage at juno.com wrote:

> I would be interested in what the modified input circuitry is (new coils,
> different caps for each band)?

As you probably know, Pete, there are several different methods for adjusting the input SWR 
to a more reasonable level. Mine had been done by an EE for the ham I bought it from, a lady 
who is blind. He simply adjusted the capacitors' values where needed (not all of them need to 
be changed) so that SWR at the middle of each band was as low as possible.

The coils were never changed or modified.

I adjusted the slugs in the coils for minimum SWR between my exciters and the amp. My 
system was different from Charlotte's since I was using a different length of coax.

> Evidently, through the life of the SB-200,
> Heathkit did it several ways.

Although I wasn't aware of that, I am not surprised. For instance, in the DX-35, Heathkit used 
three different final amp grid circuit designs. The first one didn't provide enough grid drive on 
10 meters.

And in the SB/HW transceivers, Heahtkit used something like 6 or 7 different designs for the 
"S" meter circuitry, finally settling on one that worked reliably in late SB-102s.

Heathkit engineers seemed to keep a pretty sharp eye on their gear, and would modify it for 
better performance in many cases.

I can point you to at least three different methods for minimizing input SWR for the SB-200, 
none of which require modifying the coils.

A very "minimalist" approach was published in ER magazine some time ago, in fact.

If you need those, let me know.

vy 73,

Ken W7EKB