Skip,
My narrow filter is 500 Hz. Tuning in PSK63 signals has not been problem
with the narrow filter but I have mostly used the SSB stock filter to view a
wide bandwidth I will give QPSK on PSK63 a try later today and report back.
Typically QPSK requires a little more precision tuning but it should work
okay.
I think it might be a useful think to try an informal PSK63 "Sprint" to
test the contesting capabilities of PSK63 and the"too fast for contesting"
concerns that the RTTY folks have raised.
I'll put together a Sprint and announce later today.
Andy K3UK
----- Original Message -----
From: "Howard Teller" <hteller@comcast.net>
To: <RTTY@contesting.com>
Sent: Saturday, May 24, 2003 10:50 AM
Subject: PSK63
> Hello RTTY contesters! I just joined this reflector, so please excuse me
while I find my way around...
>
> After reviewing all the comments I could find regarding PSK63, I made some
quick tests this morning by setting my ICOM-761 to CW mode with a 500 Hz
filter in place. This is the most narrow filter I have, as this rig is 10
years old and has no DSP IF filters.
>
> Using WINPSK for receiving PSK63 as explained on the PSK63 webpage at
http://www.qsl.net/kh6ty/psk63, I set the AFC range to +/- 50 Hz (under
Settings) and transmitted on a dummy load from my totally separate second
IC-761 system, also using WINPSK on PSK63, set the waterfall cursor to the
center of the 500 Hz-wide waterfall, and looked to see how quickly I was
able to find, hear at a particular familiar pitch, and tune in a PSK63
transmission to get good print without using a mouse, but only the tuning
knob of the IC-761. The tuning knob of the IC-761 has a fixed rate of 5 KHz
per revolution.
>
> It seemed to me like it was as easy as tuning RTTY for good print. If this
holds true for you seasoned contesters, then this might be a solution to the
AGC capture by unwanted strong signals outside the passband of interest. I
think the reason it works is that the AFC takes care of the fine tuning, so
once you are within 50 Hz or so, the AFC quickly does the rest and print is
good over a relatively broad range of manual tuning.
>
> I would like very much for some of you to try tuning PSK63 using whatever
narrow filters you have and let everyone know about your experience. PSK63
activity can be found daily now around 14073 (true RF frequency) on 20
meters. If you start with a SSB filter, set the transceiver dial to 14072,
USB, and look for signals twice as wide as PSK31 around the center of the
wide waterfall. Once you know there are signals to tune in, switch to a
narrow filter and give it a try. PSK63, because of the baud rate, "warbles"
faster than PSK31, and has more of a "rasping" sound than a warble.
>
> In reviewing the messages for this month regarding PSK63, I also noticed
some comments that PSK63 is actually too fast for contesting! If this is the
case, then the low error rate of PSK63 can be made even lower by using
QPSK63. Perhaps some of you can try this with WinPSK by selecting QPSK (USB)
and having your QSO partner do the same. Turnaround time was the big problem
with PSK31 and that is why we pursued PSK63, which not only cuts turnaround
time, but transmits the exchange faster, so maybe we could be concentrating
on QPSK63 as the preferred mode. However, QPSK63 has some additional
turnover delay compared to BPSK63, but I tested it with a mock exchange this
morning and both BPSK63 and QPSK63 seemed to take about 6 seconds to start,
trasnsmit the exchange, and return to receive on my IC-761. The additional
delay was not noticeable.
>
> 73, Skip KH6TY
>
>
|