[WriteLog] RTTY SO2R Basics

[David Hachadorian]

----- Original Message ----- 
From: "K3MQ" <k3mq at bwave.com>
To: <writelog at contesting.com>
Sent: Monday, September 04, 2006 9:55 PM
Subject: [WriteLog] RTTY SO2R Basics


> I'm considering going SO2R for RTTY contesting. I've read 
> enough info online
> to get totally confused regarding hardware.
>
> I now have a IC-756 ProII using a Microkeyer interface 
> into an XP computer.
> I have rig control and am using FSK. Software is Writelog. 
> Antennas are quad
> for 10-20m and a multband windom.
>
> I will probably get a 756 or 756 Pro I for second unit 
> (can't live without
> band scope). I will probably use a different multiband 
> wire to get started
> with second rig.
>
> I want to run FSK on second radio with rig comtrol. I 
> should be able to
> select antennas directly on radios without external 
> switcher since I am not
> sharing any antennas.
>
> I intend to only use SO2R for rtty, no other modes, and I 
> want to use just
> one computer.
>
> The question is, what additional hardware do I need? Is a 
> second interface
> (MicroKeyer) needed? That is the point of confusion. I 
> presume I need two
> soundcards, but how does the signal get from the second 
> soundcard to the
> second rig without a second interface?


I don't know what a microkeyer is. I don't have anything 
like that. You need only one soundcard. Wire up a stereo 
1/8" plug for sound card "line in."
left radio goes to tip, right radio goes to ring. Connect 
each wire to "audio out" of the two rigs. If you have a 
problem with hum getting into the sound card (listen to it 
on the sound card speaker output to check), put audio 
isolation transformers in each line.

You need 4 serial ports.
1. rig 1 control
2. rig 2 control
3. fsk rig 1
4. fsk rig 2
Here is a reasonably priced card that will give you up to 6 
serial ports using only one irq:
http://www.newegg.com/Product/Product.asp?Item=N82E16815124025

The fsk interface consists of one transistor and one 
resistor. You can find the diagram here: 
http://www.aa5au.com/rttyinterface.html

If your antennas are within about 100 feet of each other, 
you will need two sets of bandpass filters, such as the 
Dunestar 6 band units.

The WX0B Six-Pac will switch 6 antennas between two radios.

Dave Hachadorian, K6LL
Yuma, AZ











































.