I frequently trawl the digital frequencies for ANY mode. I would say
that the most used modes on HF , in order, are...
PSK31
PACTOR
RTTY
SSTV
PACKET (300)
Feld Hell.
Olivia
MFSK16
ALE
Throb
PSK63
MT63
AMTOR
Chip 64
DominioEX.
PAX2
CCW.
VOICE (the digital mode in Multipsk)
Contestia
RTTYM
PSK10
While they may be sinusoids, they are not steady state. The tones
are switched and their phase may change depending on the modulation.
An example would be the first cycle of a sinusoid applied to
capacitor or an inductor. You will get some distortion. How much
is the question. Phase
Try gmfsk or the new cousin fldig if you want a free multi-mode digital
program that does CW.
Or you coud use PocketDigi built for desktop windows. It is actually a port of
gMFSK to Pocket PC and desktop windows. http://pocketdigi.sourceforge.net
73,Vojtech OK1IAK
Need a Digital mode QSO?
Hi gang.
The whole group delay fuss is pointless in my opinion because of the
constraints that are put on the operating modes by our lovely ionosphere. I do
not think that group delay is an issue at 100Bd symbol speed.
The flattness of the passband is more an issue but it is something that the
Rick,
Please explain group delays. I am unfamilar with that term in reference to
transmitting equipment.
Walt/K5YFW
-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 20, 2006 4:28 PM
[stuff deleted]
Another thing that I came
Jim,
I agree, but we are talking about a test. The test signal would have to
have a signal that either sweeps or is shifted in frequency. This would be
a test like a two tone test. A two tone test is not a real world test, but
it is made with very specific signals and the results are well
Don't jump to conclusions. It may not be your filter. It maybe
your audio stages. Typically, amp bandwidth is specified at the -3
dB points. If you have a preamp and one audio stage, then tones at
the extremes, say 300 and 3000 would be 3 dB down from one at the
center of the passband in
Your comments are excellent. The only nitpick I would have is that
I (and I emphasize the word I) don't know that the average ham
tranceiver can even meet the constraints imposed by the ionsphere.
This means less than optimum operation regardless of conditions.
I know from experience
At 06:41 AM 9/21/2006, you wrote:
Rick,
Please explain group delays. I am unfamilar with that term in
reference to transmitting equipment.
Walt/K5YFW
I am not Rick, but you can find the definition here:
http://en.wikipedia.org/wiki/Group_delay
Regards,
Chuck AA5J
Need a Digital mode
Although I am not an engineer, my understanding is that group delay is
the phase shifting signals experience as they go through circuits such
as filters. A non linear response as you go across the filter bandwidth
means that different tones will be affected differently and cause
smearing of
Some time ago telcos used to offer analog leased-data lines services -
two-way end-to-end lines, on a terrestrial 300-3400 Hz channel.
To be able to accomodate a 9600 bit/s data signal, the lines had to be
equalised both in frequency and group delay, according to ITU-T M.1020
Recommendation. So
You don't need FEC for that but arq.
Rein PA0R
On Thu, 2006-09-21 at 09:44 +1000, Brett Owen Rees VK2TMG wrote:
I would like to see a very narrow FEC PSK mode which
could be used when condx are very tough. Better to get something
through
slowly than not at all.
Need a Digital mode QSO?
Vojtech,
A nice writeup in QST on your Pocket PC software.
Walt/K5YFW
-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Thursday, September 21, 2006 12:49 AM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Don't hear much clamor about,
I think I was not clear enough at my latest message.
The equalisation process had to be done in both ways, end-to-end - a
loopback test was not acceptable.
Regards,
EA3DU
-Mensaje original-
De: Sergio Manrique Almeida [mailto:[EMAIL PROTECTED]
Enviado el: jueves, 21 de septiembre de
Since I cannot do all the different modes, I keep wondering what is really the
observed speed (throughput) and robustness. In the old days, on CW you gave
an RST, QSB, QRN reports and assumed that an individual could 100% copy your
signal at the speed you were sending or ask QRS. Of course
Which could (probably does) account for the higher price of commercial HF
communications radios. So why do Codan radios cost so much more than say the
ICOM IC-F7000?
Walt/K5YFW
-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Thursday, September
I agree and this concern has been considered in this thread. The modem
used in the MIL STD 188-110 MARS ALE implementation was modified to
accommodate amateur rigs. With the exception of SDR radios, COTS radios
will typically have a 2.4 to 2.7 KHz transmit bandwidth. I agree that if
these
Hello Jerry,
PAX2 monitored a QSO on 30 meters, it was way to slow, I
don't feel it is a viable keyboard mode.
If the number of retries is high (in noisy conditions) the speed can be low but
in normal conditions the speed is 50 wpm after protocol (rough speed before
protocol: 115 wpm).
It is
The point is that 3 kHz bandwidths may not be appropriate to achieve
the best performance. As pointed out in other messages, the phase
delays are worst at the edges of the bandwidth. This means with a
typical amateur radio, you may only want to use 1.8 or 2.0 kHz to
achieve the best group
The problem is that the smearing is additive. The transmitter
adds some, the ionsphere adds more, then the receiver even more. In
order to maximize the phase coherence, the ionsphere should be the
only contributor. I recognize that economic costs may impact this.
But again, I just wanted
Just a quick example. In order to achieve a flat passband of 3 kHz
you may really need an amplifier whose bandwidth is 10 or even 20
kHz. To achieve this, you probably can't use just one single stage
of audio amplification with a simple emitter bypass electrolytic
capacitor, you'll need
Recently I've been reading odd bits and pieces about portable PSK
operating, and the other evening I was looking at a picture of a
Windows mobile pocket PC with a built in keyboard.
Knowing absolutely nothing about the activity, could someone who
operates portable PSK tell me what
jgorman01 wrote:
Just a quick example. In order to achieve a flat passband of 3 kHz
you may really need an amplifier whose bandwidth is 10 or even 20
kHz. To achieve this, you probably can't use just one single stage of
audio amplification with a simple emitter bypass electrolytic
Call Vojtech, OK1IAK, off list. He has written PSK software for the PocketPC
and it is downloadable from his website. Vojtech is a somewhat regular on this
list.
Walt/K5YFW
-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Thursday, September 21,
Prior to the wide deployment of MIL-STD-188-110 equipment, most U.S. military
HF data communications used RTTY/ASCII modes through encryption devices. These
were large and not really field portable.
Later a small encryption device came out where you input plain text and an
encrypted text was
Op amps may very well be a good solution for a very linear
amplifier. However, my point is how many current amateur radios use
this much more expensive solution in their audio chains? My
transceivers are dated, as I suspect many hams are, but not so old
that they couldn't have used op
At 05:14 PM 9/21/2006, you wrote:
Prior to the wide deployment of MIL-STD-188-110 equipment, most U.S.
military HF data communications used RTTY/ASCII modes through
encryption devices. These were large and not really field portable.
Hi Walt,
The MIL-STD-188-110 parrale16 tone modem with or
try OLIVIA under brutal conditions it does better than PSK, and almost as
well as CW . bonus is the FEC which works very well
John
VE5MU
- Original Message -
From: Vojtìch Bubník
To: digitalradio@yahoogroups.com
Sent: Thursday, September 21, 2006 12:00 AM
Subject: Re:
Rick,
Yes I had trouble printing 100% of what Mac WN3C was transmitting during
the inital 8/500 contact, we did go to 16/500 and the print came back to
90%.
After discussing the settings with Mac it became apparent that there was
several issues that was causing problems on Mac's end. The
Thats typical with most rigs, I have a FT1000mp and i notice a
significant variance in Power out depending on where in the passband I
am, thats why when and before I start a QSO through my CAT interface I
issue a macro command to move the receiving frequency to where I want it
in the passband,
Here is an interesting paper on parallel modem design using very high
baud rates. One thing that does seem to stand out is the SNR that is
required to make this kind of modem work on HF. This design uses a pilot
tone reference and tubo codes and even with baud rates of ~ 2000 it
attains bps
following this modem/bw thread thru many rigs
so i don't think anyone has offered their ideas on which of the current
rigs will pass audio the best.
am in market for one that will pass a digisstv signal using
hamdream/hampal and digitrx (rdft)
this afternoon i was messing with my ft920
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