[Elecraft] Wish list - PBT

Lyle Johnson [email protected]
Sun Apr 7 12:48:01 2002


Hello!

> I can't possibly imagine how Drake could sue for that.
>
> Passband tuning was a feature of my Collins 75A-4 built in
> the late 1950s!  They were probably the first to offer it.

Collins used a mechanical ganging of two linear PTOs to effect passband
tuning in the 75A-4 in 1955.

Drake used a tunable filter at 50 kHz in the 1-A 1957.  But circa 1974,
Drake used an oscillator/mixer scheme for the first time to effect passband
tuning with the R-4C.  This is the method that was at issue with Icom if I
recall correctly.

Note that Kenwood used passband tuning in the TS-820 without patent
problems - they either used a different method to attain it or paid a
royalty.

In any event, 1974 + 17 = 1991, so the patent will have expired and you can
do passband tuning to your heart's content, unless, since 1985, the patent
office has issued yet another patent for an obvious technique.

Enjoy!

Lyle KK7P