[Elecraft] K3 ALC polarity fix

[Jerry Flanders]

Most amps in common use provide a negative-going ALC voltage. And 
most rigs in common use are compatible with this. The K3, however, 
requires a positive-going voltage.

According to the K3 FAQ at 
http://www.elecraft.com/K3/K3FAQ.htm#SignalArchitecture , " Once ALC 
is working to our satisfaction, we'll provide simple interfacing 
information that will allow the use of negative control voltages 
(probably a resistive divider pulled up to a positive supply, or at 
most an op-amp circuit)."

The ALC appears to be working OK now. If this is correct, I would 
like Elecraft to give me the information to build the interface circuit.

Whether or not someone on this list thinks that ALC is not necessary 
or not wise in the average ham station is not important to me at this 
time - the engineers at Yaesu do not agree with you concerning their 
Quadra amp. They tell me that I must connect ALC for emergency 
protection of the finals.

Quoting from my Quadra's manual p4.:
"The ALC cable must be connected between
the transceiver and VL-1000 to
prevent overdrive of the amplifier, and especially
to facilitate the proper operation of the
protection circuitry if sudden antenna system
problems should cause the SWR to rise to dangerous
levels."

Jerry W4UK (Two Quadras, One K3 with another K3 on order.)