[Heathkit] SB200 SWR Meter

[manualman at juno.com]

I've never found the SWR position on the SB-200 to be accurate so I never
use it. Forward power is OK  when just tuning for maximum power.
Diode anode connection on each sensing wire is critical and they must be
an identical dimension connection from each end. 
I had one SB-200 years ago which, for whatever reason, one of the sense
wires was about 1/4 inch shorter then the other one. I replaced both
sense wires with two of equal length but didn't make much difference in
SWR reading. Also, the relay contacts can add a bump in the SWR reading.

Pete, wa2cwa




On Tue, 25 Oct 2022 22:42:06 +0000 (UTC) Bruce Hudler WK3A via Heathkit
<heathkit at mailman.qth.net> writes:
> Been working on a few SB200's lately and have a question on the SWR 
> meter. Over the years I've not really paid any attention to them, as 
> I guess we all have better things to measure with. 
> The amp I'm working on seems to be not very accurate with the SWR on 
> the antennas and the HN31 dummy load. It reads 1.5 to 1 on the dummy 
> load. Even higher on antennas. 
> This circuit and components are used in other stuff so I'm sure 
> there are millions of them out there. 
> Reworked the circuit with new 1N191 diodes, 100-ohm resistors ok, re 
> centered the rods and measurements. No difference. Checked a couple 
> of different bands, not much difference.
> Not much there, maybe they are all that way  :) 
> Any thoughts? Thanks
> 
> Bruce WK3A