Recently I modified my SB-220 to incorporate vacuum-relay QSK. In the
process I did very little to change the RF cabling under the chassis, but
the input side relay did require a total of 3 inches of small diameter coax
to connect to the existing cabling.
To my surprise, these physically small changes have had a relatively
significant effect on input SWR, particularly on 40M, where the input SWR
now indicates close to 2:1 on my TS-930. The TS-930 doesn't mind, but a
(probably) related phenomenon concerns me. On 40m, when I have adjusted
both the tune and load caps for maximum output at about 110 watts of drive,
the plate current is indicating ~ 850 ma. key down, where previously it
indicated about 750 ma. with identical driving power and antenna.
Any idea why this is happening, and should I be concerned? Is it real, or
is it a measurement error, perhaps related to the high input SWR?
73, Pete N4ZR
Sometimes a tower is just a tower
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