[WriteLog] SO2V on RTTY - progress so far
Ian White, G3SEK
G3SEK at ifwtech.co.uk
Sun May 9 17:32:24 EDT 2004
On Saturday I threatened to report back on the SO2V trial, so here it
is... (it's quite long, so if this isn't your thing, you'd better stop
The everyday RTTY setup here is a 1000MP Mk1 with a HB control/audio
interface, and a PC running WL and MMTTY under Win98SE. PTT is on the
rig control port RTS, and keying is FSK through a second serial port,
using the opto interface described in the WL Help pages.
The aims were:
* To get the sub-rx working as an effective second transceiver
* To have dual receive capabilities, either in-band split or dual
diversity on the same frequency.
So here goes...
Using the very helpful information from the web pages of W9ALS and
AA5AU, I added a second sound card which was fed from the sub-receiver
line-level audio output through the usual isolating transformer. This
operated with a second RTTYrite/MMTTY combination,
It's the same setup as you would use for SO2R, but both radios are
inside the MP. The web pages explain how to start the RTTYrite/MMTTY
software two times over, and get each one pointing to the correct sound
card and radio. When it's all done, you have:
* Radio L = Radio 1 = VFO A (main rx) in the MP
* Radio R = Radio 2 = VFO B (sub-rx).
It's tricky to start this setup, because the two instances of MMTTY
always start with both configurations the same - including both windows
in exactly the same place - so one of them always has to be reconfigured
every time you re-start. Also it's different each time you re-start, so
there are several combinations to learn. It's not difficult, but
definitely not something to learn about during the contest!
WL, RTTYrite, MMTTY and the sound cards are all configured as if they
were going to be hooked up to two totally separate radios. To make it
work with the single MP, Radio R (sub-rx on VFO B) has to be told to get
its frequency information from the "rig connected to COM1" - you can't
get the actual frequency information from VFO B.
The second FSK output from the second RRTYrite has to go through its own
separate COM port and opto interface, so you'll definitely need an extra
serial card. The output of the second interface is simply connected in
parallel with the first, so either one can key the radio.
So how did it play in the Volta?
Receiving through the two sound cards is excellent. With DUAL selected
on the MP, you can tune the band with both VFOs at the same time, and
watch two totally separate RTTY outputs. With DUAL off, you can have
diversity decoding of the main rx audio - the sub-rx is muted, and
doesn't have be tuned to the same frequency as the main rx.
The problem is that in order to keep a single coherent bandmap (we're
talking single-band split, remember) you *must* tune the band and enter
the station frequencies from the main VFO A. That is the only VFO for
which WL knows the true frequency. If you enter stations from the VFO B
window, they all appear on the VFO A frequency... which is probably your
Transmitting works fine. WL sends the messages to the correct callsign
on the highlighted entry line - but *you* have to make sure it's going
out on the correct frequency. When you swap log entry lines, you *must*
remember to press the correct red TX button on the MP as well - WL will
not do this for you. And if you forget... well, you know what happens!
That's how learned to keep the TX on VFO A, almost all the time. When
running, I ran on VFO A and tuned the rest of the band between-times on
VFO B. When S&Ping, I swapped the two VFOs and used the sub-rx to keep
an ear on the run frequency.
Was it worth the effort? Yes, I think so. It's not for everyone, but it
certainly increases the potential of a
The main issues now, I think, are about better support in WL for SO2V:
making the TX frequency follow the entry window when it swaps, and
getting the actual frequency of the second VFO.
73 from Ian G3SEK
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