[RTTY] New contesting PSK faster than RTTY

[Richard Ferch]

On Sun May 4 20:07:23 EDT 2003, Don Hill AA5AU said:

> I'd be willing to try it, but it's still going to be AFSK.  Where do we
> get the software?
>
> AFSK - if I wanted to send audio to my radio, I'd go hunt for my
> microphone...
>
> RTTY Forever,
> Don AA5AU

Hi Don,

It's basically the same as PSK31 except at twice the speed (and therefore
twice the bandwidth). So far, the only code I have seen for it is in KH6TY's
experimental version of the PSKCore.dll file at
http://www.qsl.net/kh6ty/psk63/ - the actual file is at
http://www.qsl.net/kh6ty/psk63/psk63core.zip .

In addition to the dll itself, you need a PSK program that uses the PSKCore
dll. I could be wrong, but I don't think WriteLog is one. Those that I am
aware of includeWinPSK (http://www.qsl.net/ae4jy/winpsk.htm), WinPSKse
(http://www.winpskse.com/) and Zakanaka
(http://www.qsl.net/kc4elo/oldfiles.htm) plus several others (I can give
more links if anyone is interested). Many of these programs do not have much
in the way of contesting features (one exception being RCKRtty), but they
can be used to test the characteristics of the mode.

KH6TY's recommendation for using the new file is to keep two copies of your
chosen PSK program in separate folders, one with the original PSK31 PSKCore
dll and the other with the new PSK63 version of the dll. An alternative
method would be to place two renamed copies of the dll (e.g. pskcore31.dll
and pskcore63.dll) in the same folder with the software, and create a couple
of little batch files to delete the old pskcore.dll file and make a copy of
the required one and name it pskcore.dll, then start the PSK software.

One small "bug" to watch out for - the original PSKCore dll returns the
audio frequency, but the new experimental one returns the frequency divided
by two (I guess you can figure out from this how the new version works!).
This means that the waterfall in the PSK software is compressed, and you
will have to zoom in one step more than you would in PSK31.

So far the two QSOs I have had in this mode were somewhere around 14074.3
kHz true frequency - one with KH6TY (in SC) and one with PJ2MI. My radio
dial was set around 14072.9 in USB, and the reported audio frequency was
about 700 Hz (actually 1400). I haven't heard KB2EOQ yet, but that's not too
surprising on 20 meters - we're in each other's skip zone. Yep, here W5BBR
is in a PSK63 QSO with KB2EOQ on 14074.4 - Bill has a strong signal here,
but I can't see any sign of Andy at all.

Yes, it's AFSK, so you have to watch out for overdriving (no ALC indication,
sound card output level not too near the top). OTOH, it's faster than RTTY
(around 100 wpm, more or less - the characters are variable length, so it's
hard to be precise), and it occupies less bandwidth (nominally 63 Hz). It
will be interesting to see whether it actually works out. I wouldn't expect
it to have much impact on existing PSK31 ragchewing, because most hams
cannot type fast enough to justify the increased bandwidth over PSK31. For
contesting and DXing, where you can rely almost completely on macros, it
seems to have more promise. Certainly the idea of fitting several QSOs into
the same bandwidth as a single RTTY QSO without giving away anything in
speed is an interesting one.

Besides, Don, this way you can actually make use of the USB mode on your
radio without having to find your microphone (gee, I know one of those
things came with my radio, but I'm darned if I know where I put it!). I
suspect this mode will be most interesting to people who can use narrow
filters in USB or LSB mode. If your radio insists on making you use wide
filters in SSB, it might not be quite so attractive.

73,
Rich VE3IAY