Is the KIO2 line needed with external amp and auto-tuner?

[dw-4]

A number of you from the group have really helped me out incredibly!!
**** Huge thanks ****

THIS GROUP ROCKS!!!  :~]

I run an SGC-237 auto-tuner outside the house.
Its the best setup I've ever had, and I don't want to lose its
functionality.

I plan on locating the external 100 watt amp box for the K2 in a
different room.
It will be located in a room where I have power supplies and coax
line going outside to the auto-tuner.

Since I already have an auto-tuner functioning, I'm wondering if there
is any need for the RS232 control line from the K2 to the amp box.

I think perhaps at minimum, there is an RF-detect signal that must come
back from
the amp to the K2... if I understand the KIO2 document.

Thanks again ALL.
Duane
N1BBR

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[Don Wilhelm-4]

Duane,

Not to put a damper on your plans, but to serve as a caution.  The
AUXBUS signal is a one wire communications channel between the K2 and
its options.  If the length of the cable becomes too long, there will be
significant delay between a query and a response on that AUXBUS signal
which will produce errors - the first may likely be that the remote
option (KP100/KAT100) will not be recognized by the K2.   Those signals
are not all RS-232 levels, they are internal K2 signals, and that is why
the connector on the K2 is labeled "AUX IO" - do not connect a standard
computer serial port cable directly to the K2, it will cause damage to
the K2.

If I recall, the signaling has been tested out to 6 feet of cable, but
it sounds like your plans will require more cable length than that.

Please let us know how long a cable you have used and whether it
performed without problems, I am certain several others would like to
know too.

73,
Don W3FPR

dw wrote:

> A number of you from the group have really helped me out incredibly!!
> **** Huge thanks ****
>
> THIS GROUP ROCKS!!!  :~]
>
> I run an SGC-237 auto-tuner outside the house.
> Its the best setup I've ever had, and I don't want to lose its
> functionality.
>
> I plan on locating the external 100 watt amp box for the K2 in a
> different room.
> It will be located in a room where I have power supplies and coax
> line going outside to the auto-tuner.
>
> Since I already have an auto-tuner functioning, I'm wondering if there
> is any need for the RS232 control line from the K2 to the amp box.
>
> I think perhaps at minimum, there is an RF-detect signal that must come
> back from
> the amp to the K2... if I understand the KIO2 document.
>
> Thanks again ALL.
> Duane
> N1BBR
>  
>

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[Jim Brown-10]

On Fri, 06 Mar 2009 18:04:04 -0500, Don Wilhelm wrote:

>If I recall, the signaling has been tested out to 6 feet of cable, but
>it sounds like your plans will require more cable length than that.

The primary issues with cable length are noise pickup and capacitance.
Both can be helped a lot by using CAT5 for the serial connection. Dedicate
one pair to each signal line, and connect the return of each pair to the
connector shell, not pin 5.  CAT5 is very low capacitance, and the very
high twist ratio rejects noise and RFI. Going to the connector shell
bypasses the pin 1 problem at each end.

I work in pro audio, and we often have sound equipment in racks buried in
the bowls of the building, but need to remote control that gear for tuning
the system from within the auditorium. Doing what I've described, we often
use serial over 200 ft of CAT5 at very reasonable data rates with no
problems. BTW -- the RS232 standard originally quoted cable length as a
limit, but was later revised to define it on the basis of capacitance.

73,

Jim Brown K9YC


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