> Anyone out there with an idea of an optimum HV choke, in order to avoid
resonances, for the following conditions:
>
> Plate impedance = 2500 ohms
> HV = 5kV
> freq = 1.8 - 30 MHz
>
> Inductance ? Winding ? Sections ? Physical size ?
>
> Best 73s de Lars / SM3BDZ
I assume you are requiring continuous coverage 1.8-30 mhz
with no resonances anywhere. The way Henry, Alpha, and
Creative Electronics do this is with two chokes and a relay.
The Henry 8-K Ultra, which is close to the operating perameters
you listed uses a 19uh and a 184 uh choke mounted at right angles
to each other. The big choke is shorted out with a relay above 20 meters.
The others use similar schemes; Creative does not short the big choke.
They pull two parallel 4700pf 6kv disk ceramic caps to ground that
are attached at the connection between the two chokes. I like that
idea because it removes the D.C. from the relay contacts.
With 9 ham bands, let alone continuous coverage, it is almost
impossible to find a place to "park" the resonance using only one
choke.
I purchase my chokes and relays from Henry and Creative. This
has eliminated all my problems in this area, and saves many hours
of labor when putting a new amp design together.
(((73)))
Phil, K5PC
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