[Amps] choke resonances

[Phil Clements]

> Choke design is not rocket science.  One needs a dipmeter and some kind
> of a winder.  I use a hand crank drill,  Winding HV-RF chokes is
> described on my Web site.

Agreed, Rich...
It was truly a piece of cake until the WARC bands came into
being. 20-17-15-12-10 meters have such close spacing that
it is difficult to produce a choke that will install in any layout
without problems. The resonances can change from what
they were on the test bench. Some manufacturers (Henry,
Creative, etc.) use two chokes to get continuous coverage
from 1.8-30 mhz. The Ameritron/RF Parts choke comes close
to being a cure-all if you don't operate in the 11-13 mhz region.
The B&W 800 and 802 chokes which are still very popular,
do not have sufficient L for 160 meters, although some amp
manufacturers used them anyway. (Alpha 77, etc.) If the Ameritron
choke is too large for your box, the best bet is as Rich suggests;
add a second choke and relay switch it.

(((73)))
Phil, K5PC