[RFI] Coaxial Choke

[Andy]

> The material in the ARRL Handbook is woefully out of date and quite
> inadequate.

I'm not sure if "out of date" is exactly right in this context (neither the
coax nor the theory changed, did they?), but I believe you are right that
air would coax chokes are inadequate for HF.  OK for VHF, maybe for the
upper HF bands too, but not as a general HF band choke.  Not nearly enough
impedance to choke off common-mode currents.

There was an email thread about this on one of the many other email lists I
subscribe to, saying pretty much the same thing.  To be effective at HF, one
must use some ferrite core(s) to make an effective choke.

Andy