Yes 200 WPM will do but 300-400 WPM or faster would be much better if the same SNR was maintained. However, if going to 300-400 WPM increases the SNR by 5 to 7 dB, then that would be acceptable.
For the time being, MT63 seems to be the mode that we will have to use for file transfers and perhaps MFSK16 for keyboard-to-keyboard communications. With gMFSK, its no problem to switch from MT63 to MFSK16.
Walt/K5YFW
-----Original Message-----
From: digitalradio@yahoogroups.com
[mailto:digitalradio@yahoogroups.com]On Behalf Of KV9U
Sent: Wednesday, March 15, 2006 9:26 PM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Another look at ALE
Walt,
Initially you had indicated that:
"I would like a robust keyboard-to-keyboard mode that would accept typing at about 50-60
WPM. Also a robust mode that could send data files at 200 WPM and be robus enough to work right down in the noise."
That is exactly what MT-63 does. However, now you are indicating you want at least 300-400 and preferably 400-600 wpm which is a whole different category of speed. Is that possible with any common ham mode other than possibly Pactor 2 and 3 which track together into the noise at around 1000 wpm at -10 db according to the ECJones site?
I still have not understood what P2 and P3 have that is all that special and allows them to run as fast as they do (not to mention they are also ARQ modes). If we had non ARQ modes with similar modulation, why would not that run at a similar rate of transmission even if you did not adjust for adaptive speeds.
73,
Rick, KV9U
DuBose Walt Civ AETC CONS/LGCA wrote:
>Understand that I have used MIL-STD-188-110a and FS-1052(?) modems (modes)
>when I was in the AF Reserve. I used MIL-STD-188-110a and c (I think) in
>February of 1990 in US Air Force test, then in California during joint
>services test in the summer of 1990 and while in Saudi in the fall of 1990.
>I don't think they are as robust as some of the amateur radio digital modes.
>
>Yes, we've used MT63 VERY successfully and it meets 90% of our needs...the
>2K Long Interleave is VERY robust...about as robust as we need. If we want
>a faster turn-around, we will go to short interleave and/or 1K short
>interleave.
>
>The only problem is that the throughput is lower than we need. MT63 2K Long
>Interleave seems to have a SNR of less than 0 dB on a CCIR Channel (probably
>between -5 and -7 DB SNR) and the throughput is 200 WPM...we would like to
>see 400-600 WPM or at least 300-400 WPM.
>
>We aren't concerned about band width. Even if the ARRL proposes 3.5 KHz max
>band width, I think that another proposal going to 6 or 8 KHz for OFDM type
>modes would be acceptable to the FCC as this is "good physics/good
>electronic engineering" and in keeping with good amateur radio practices.
>
><Personal Opinion>
>If the FCC says NO to a wider bandwidth, then the choice may be to go to
>Congress pointing out how the FCC is prohibiting technical research/
>experimenting and advancements in communications technology as Part 97 says
>amateur radio operators should and ask Congress to review the matter. The
>only reason I say this is that I have talked to three Republican Congressmen
>and two Democratic Congressmen and they agree that if nothing else besides
>providing support/auxiliary communications during an "Incident" or disaster,
>hams should be experimenting and should have the opportunity to experiment
>within the ham bands to the maximum extent possible in developing
>communications techniques...even if they are not directly applicable to
>commercial or government communications.
></Personal Opinion>
>
>73,
>
>Walt/K5YFW
>
>
>
>
>DuBose Walt Civ AETC CONS/LGCA wrote:
>
>
>>
>>
>>I might mention that our net operations and net control stations operate
>>much like a state or local EOC (I worked many years in a large city EOC).
>>
>>When I think of what I would like in a mode to support the type of
>>communications I was involved in (and I think most of the disaster relief
>>agencies such as the Red Cross, Salvation Army and the like), I would like
>>
>>
>a
>
>
>>robust keyboard-to-keyboard mode that would accept typing at about 50-60
>>WPM. Also a robust mode that could send data files at 200 WPM and be
>>
>>
>robust
>
>
>>enough to work right down in the noise.
>>
>>
>>
>>
>>
>>
>>
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