[pskmail] Re: Alpha Testers for fast modes
- From: Bernard Dekok <kc9sgv@xxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Tue, 20 Mar 2012 11:17:13 -0500
Email: kc9sgv AT gmail dott com
On Tue, Mar 20, 2012 at 11:16 AM, Bernard Dekok <kc9sgv@xxxxxxxxx> wrote:
> Hi John,
>
> As a daily user of ACARS in the aeronautical VHF band, I have a certain
> expectancy of what should be achieved with data over VHF.
>
> Please email me a copy too, and I will test via my two VHF stations into
> dummy loads.
>
> Best 73,
> And please keep up your excellent work.
>
> Bernie,
> KC9SGV
> Chicago.
>
>
> On Tue, Mar 20, 2012 at 10:37 AM, Karel Fassotte <karel.fassotte@xxxxxxxxx
> > wrote:
>
>> Hello John I was realy waiting for this possibility.
>> Ik will find some stations overhere to do the testing.
>> HR-PE2KFA/HC1AKP
>> 73 Karel
>>
>>
>> 2012/3/20 John Douyere <vk2eta@xxxxxxxxx>
>>
>>> Hello Pskmail operators,
>>>
>>> I am ready to send, off list, a few copies of a special alpha Fldigi
>>> with new modes for testing.
>>>
>>> This first batch of new modes is targeted specifically at the fast FM
>>> (normally VHF/UHF) links as they require a clean bandwidth of up to 2400Hz
>>> and will suffer badly in the standard SSB passband. So please do not use
>>> the wider ones on HF.
>>>
>>> Also note that their baud rate is above the Amateur HF bands Baud limit
>>> in the USA for all but two of the PSK modes.
>>>
>>> Note that I am separately preparing a USA HF Amateur version with only
>>> modes below 300Baud and one for HF outside of the USA with faster Baud
>>> rates.
>>>
>>> In this version, the top speed provides 3200 words per minute or 19200
>>> characters per minute (using the Fldigi definition). In tests I got a 17124
>>> characters text file to be downloaded in just under one minute in
>>> compressed format, including repeats and ARQ overheads, so I think this
>>> could be interesting.
>>>
>>> Unfortunately as this point I have not been able to get my existing
>>> version of the Windows cross-compile to work, so it is for Linux only until
>>> I get this to work.
>>>
>>> Instead of creating new mode designations I have simply re-mapped the
>>> existing list of modes we use for Pskmail into a new set.
>>>
>>> That has the advantage of making the tests simple by just using the
>>> temporary Fldigi program on both sides without any change in Pskmail. All
>>> features will be the same including the configurable mode list. The only
>>> drawback is that the timeouts are still related to slower modes so will be
>>> in some cases way too long (like 30 seconds for the PSK63 -> PSK1000R
>>> mode). But the objective is to review the modes not the Pskmail performance
>>> itself.
>>>
>>> Of course these modes are usable with FLARQ of the NBEMS suite.
>>>
>>> I expect to have about 5 to 6 new modes from the list below retained in
>>> the final "FM implementation". They will then get their new designation and
>>> RSIDs.
>>>
>>> All these final modes will also be integrated in the Pskmail V2
>>> (integrated Java modems) and in the Android version of Pskmail (they
>>> already run on my HTC Desire).
>>>
>>> I have arranged these test modes in a similar order of robustness as the
>>> ones they replace.
>>>
>>> Here is the mapping:
>>>
>>> Original mode New Temporary Mode
>>> Speed Bandwidth (-3dB)
>>>
>>> PSK63 1 Carrier PSK1000R
>>> 880WPM 1000Hz
>>>
>>> PSK125 1 Carrier PSK1000
>>> 1600WPM 1000Hz
>>>
>>> PSK250 6 Carriers PSK250
>>> 2400WPM 2000Hz
>>>
>>> PSK500 2 Carriers PSK1000
>>> 3200WPM 2400Hz
>>>
>>> PSK125R 2 Carriers PSK500
>>> 1600WPM 1200Hz
>>>
>>> PSK250R 2 Carriers PSK1000R
>>> 1760WPM 2400Hz
>>>
>>> PSK500R 14 Carriers PSK125
>>> 1540WPM 2400Hz
>>>
>>> I have also re-mapped the MFSK and THOR modes the following way:
>>>
>>> Original mode New Temporary Mode
>>> Speed Bandwidth (-3dB)
>>>
>>> MFSK16 MFSK64
>>> 240WPM 960Hz
>>>
>>> MFSK32 MFSK128
>>> 480WPM 1920Hz
>>>
>>> THOR8 THOR44-Double spaced
>>> 156WPM 1600Hz
>>>
>>> THOR11 THOR44
>>> 156WPM 800Hz
>>>
>>> THOR22 THOR88
>>> 312WPM 1600Hz
>>>
>>> The MFSK64 mode is the same as the current one but that way we get to
>>> have an RSID associated with it for our tests (the MFSK16 RSID).
>>>
>>> The double spaced THOR44 is targeted mostly at NVIS conditions (4 dBs
>>> better than the single spaced one) so I don't think it will provide a
>>> benefit for FM paths.
>>>
>>> The MFSK/THOR modes should be of most interest for poor FM links (where
>>> the noise is high).
>>>
>>> In some Pskmail tests I did over VHF, the THOR modes were virtually as
>>> sensitive in FM as in SSB (I think Skip Teller - KH6TY - has an article
>>> in QST about this).
>>>
>>> Due to the required bandwidth I would suggest a waterfall audio centre
>>> frequency of 1750 or 1800Hz for FM transmissions.
>>>
>>> These preliminary modes specifications are published in the Pskmail wiki
>>> to respect the regulation. See http://pskmail.wikispaces.com/newmodes
>>>
>>> I have not made the source code available yet as it is preliminary but
>>> of course it will be released under GPL in due course and I hope integrated
>>> in the mainstream Fldigi.
>>>
>>> Could you please feedback the following information which is of most
>>> interest to me:
>>>
>>> 1. Any issue with the software itself.
>>>
>>> 2. CPU load of the different modes on your computer (approximate average
>>> and peak value - use the "top" command in a terminal).
>>>
>>> 3. The modes that Pskmail mostly settle on, the ones it has problems
>>> with and what were the conditions of the test (signal strength, quieting
>>> etc...).
>>>
>>> 4. More advanced: when frames are damaged, does it tend to be in
>>> the beginning, the middle or at the end?
>>>
>>> From my Pathsim tests and initial field trials I would bet on the
>>> following set: PSK1000R, 2 x PSK1000R and 2 x PSK1000 as a useful mode list
>>> for FM transmissions, plus a couple of FSK modes, but let's see what you
>>> find out in the field.
>>>
>>> To get a copy, email me off list at <my callsign> at gmail dot com
>>>
>>> Have fun,
>>>
>>> All the best,
>>>
>>> 73, John
>>>
>>
>>
>
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