[Elecraft] Remote Antenna Tuner

[Don Wilhelm]

Fran and all,

WARNING - do not connect RS-232 signals to pins 6, 7, 8 and 9 of the KIO2
connector!

I know the connector looks like an RS-232 serial port, but it is NOT (Don't
connect a regular RS-232 cable to the KIO2 either - it will kill the K2).
The only pins that conform to RS232 are TXD and RXD, chassis ground and
signal ground - pins 1, 2, 3 and 5.  The other signals are analog (VRFDET)
or CMOS level digital  (AUXBUS).

I assume that there may be timing issues quite apart from the drive
capability.  I am not certain what timing assumptions Wayne made with the
KAT100 design.  The signal timing constraints must be addressed before I can
even think about how to extend the signal drive distance - the signal
propogation delay is the problem, not the drive capability.

Gee Wayne, how about some KAT100 timing AUXBUS information for us.  I know
you want to keep the actual AUXBUS signalling proprietary to Elecraft, but
what are the timing constraints for communication with the tuner -
publishing those timings does not have to expose the entire AUXBUS.

73,
Don W3FPR

----- Original Message ----- 

| For those who wish to remote an Elecraft tuner using a separate control
line
| I suggest you start by looking at
|   http://dbserv.maxim-ic.com/appnotes.cfm/appnote_number/723
| This is a good starting point for information to convert the RS-232
signals
| to RS-422 or something that will make the long distance run.  All you
should
| need is a single IC (Maxim has some good choices) and a weather-proof
| enclosure for the tuner.
|
| Note that I have no affiliation with anyu of these companies and I am not
an
| EE.  I just know that I have seen RS-232 function correctly over distances
| of 500 feet which is well beyond that specified.  I also know that RS-422
is
| specified to be even better because it uses differential signals.  The web
| site above provides the technical information needed to make the
conversion
| with minimal parts count.
|
|