>
> Here's a method I invented but never published until now.
>
> I used a vacuum relay (single pole single throw or RJ-1 in a pinch) at the
> center of the two 90uH chokes to connect to a 1000pF cap to ground. When
> the relay was open you were on 160 meters, when the relay was closed the
> choke connected to the grounded 1000pF capacitor. Even though the two
> chokes were still in series the first and second chokes by being bypassed
> in
> the center made the plate end choke the active unit.
>
>
> Once Henry started building 160 meter amplifiers, they physically shorted
> across a chunk of the plate choke (no cap) this works too but I liked my
> method better. Maybe because it was my method?
>
> BOB DD
Creative Electronics has been using this method for 25+ years on their amps
that cover 160 meters. I have bought the caps (.01mfd @ 10kv) and the relays
from them for several projects over the years. Another plus is that you just
need an ordinary relay because all DC is blocked by the capacitor. Henry
amps required a robust relay to do the job. I also used this method when
modifying Alpha 77SX/DX's for better performance on 160m. You save the price
of a HV or vacuum relay.
(((73)))
Phil, K5PC
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