Re: [digitalradio] ANNOUNCE: PocketDigi 1.0.11 released

[Jaak Hohensee]

Thank you, Vojtech!

PocketDigi and PDA is nice and serious toy for field enthusiasts. Now 
it´s better.

I personally miss DominoEX. I use only PocketDigi for digitalradio.


72, Jaak
ES1HJ/QRP

Vojte(ch Bubník wrote:


Hi gang.

I released PocketDigi 1.0.11 at http://pocketdigi.sourceforge.net. 
 There are following new features 
implemented: RSID, PSK63F, PSK125, sampling rate conversion, tx 
delay/tx tail/ats3 preamble/postamble settings, keyboard accelerators, 
Handheld PC 2000 improvements, Waterfall FFT optimization and basic 
Smartphone support.


RSID is the famous Reed Solomon ID of Patrick Lindecker F6CTE. Patrick 
added this feature into his MultiPSK software year ago. Until now only 
MultiPSK (and since last week also Cesco's FDMDV?) implemented this 
feature. Instead of CW ID or Image ID, a sequence of 15 MFSK tones is 
sent at the beginning of every TX to identify mode and center of 
frequency of the following data stream. RSID has very high redundancy, 
so if the RSID is decoded with zero or one error, there is extremely 
low probability of false detection. The feature is very handy to 
automatically detect mode and submode of rare modes and therefore 
encourages experimentation. Also it is easy to tune MFSK16 mode as no 
tuning is needed at all. I found RSID very useful with ATS-3b 
transceiver, at it has only narrow not very flat CW filter. Even if 
the whole digital signal does not fit into the filter, if the mode has 
high enough redundancy and is strong enough, it will be still decoded 
if tuned properly. But without seeing the whole spectrum of the signal 
on waterfall, it is very difficult to tune it. With RSID receive on, 
one only needs to get the RSID signal into receiver passband to make 
sure the signal will be tuned correctly.


PSK63F is a nice mode invented by Nino Porcino IZ8BLY. It is a 
crossbreed between MFSK16 and PSK63. It uses convolution code and 
varicode of MFSK16, but for hardware layer it uses binary phase 
shifting at 63.125Bd. PSK63F tries to fight ionospheric flutter by 
faster phase modulation and forward error correction. It is well known 
that BPSK31 does not survive polar flutter. BPSK63 is better, but one 
loses 3dB. For DX work, PSK63F could gain back that 3dB and still show 
lower sensitivity for polar flutter.


PSK125 is nothing more than 2x faster, 2x wider and 3dB less sensitive 
BPSK than PSK63.


I finally added sample rate conversion. It took me a bit longer, 
because it is done in fixed point arithmetic again to make it 
computationally feasible on Windows CE devices. I have good experience 
with my iPaq 3630 and Jornada 720, they show very little clock error. 
But my new laptop shows as high as 4% error on TX and 2% on RX. Even 
PSK31 did not work at that level of clock error.


With the release of ATS-3b kit by Steve KD1JV, I received reports 
about having trouble to get the communication interface working. 
ATS-3b is controlled by Manchester modulation generated by sound card, 
which is translated to digital levels by a simple slicer. Some sound 
cards generate ugly transient response at the start and end of sound. 
I added four new parameters to control the shape of transient 
response: TX delay, TX tail, ATS3 preamble and ATS3 postamble. The 
first two are silence intervals. The next two are intervals of 
Manchester idle tone. The idle tone is shaped by raised cosine 
function now to minimize clicks, if it is longer than 50msec. Also 
Jornada 720 generates some ugly click about 200msec after sound output 
opening. I was not able to find out the cause, but setting TX delay to 
250ms either avoids the click or at least shifts the modulation after 
the click.


I added keyboard accelerators for accessing menu from keyboard. 
According to Microsoft GUI guidelines for Pocket PC platform, one 
shall not use keyboard accelerators. They work on my device though, so 
I leave them there. Menu pops up at Alt-T for tools, Alt-M for Modem, 
Alt-A for mAcros etc. F1-F12 execute macros on desktop.


Until now, I relied on testing of Handheld PC 2000 build by Helge 
Tefts. Last month I bought Jornada 720 on e-bay for whooping 
$40+shipping. I did some user interface improvements on that platform, 
made some missing features available like context menus on RX/TX 
windows etc. Jornada 720 has a two LiIon cell accu. I bet ATS-3b may 
be powered from the handheld's accu.


I replaced complex FFT by a real FFT for waterfall calculation, which 
lowers current consumption. Now all the DSP calculation uses less 
current than user interface updates + FEC and certainly less than 
backlight on my iPaq 3630. This is quite interesting. It shows that 
for HAM radio digital modems and PDA sized display, DSP CPU will be 
probably counter-productive as DSP is usually clumsy for general 
purpose computing. To improve current consumption even more, I would 
probably need to replace some stock user interface components from 
Microsoft like 

Re: [digitalradio] ANNOUNCE: PocketDigi 1.0.11 released - JT65

[Patrick Lindecker]

Hello Votjech,

Why do you think to propose JT65 to your program. It would be quite nice to be 
able to do far QSOs with a Pocket PC and a small mobile QRP station.

I have studied part of the JT65 code (TX part). It seems, a priori, not very 
complex and quite classical. 

I'll propose Delphi code or pseudo code for what I have understood.

73
Patrick

Re: [digitalradio] ANNOUNCE: PocketDigi 1.0.11 released

[Sholto Fisher]

Good job Vojtech! I don't have a Windows CE machine but I have the i386
version of PocketDigi on my Win2K system and it works very nicely. The
RS ID feature, by being incorporated in other software besides MultiPSK,
may be one of the best things 2008 will bring.

73 Sholto
KE7HPV.

[digitalradio] ANNOUNCE: PocketDigi 1.0.11 released

[Vojtěch Bubník]

Hi gang.

I released PocketDigi 1.0.11 at http://pocketdigi.sourceforge.net. There are 
following new features implemented: RSID, PSK63F, PSK125, sampling rate 
conversion, tx delay/tx tail/ats3 preamble/postamble settings, keyboard 
accelerators, Handheld PC 2000 improvements, Waterfall FFT optimization and 
basic Smartphone support.

RSID is the famous Reed Solomon ID of Patrick Lindecker F6CTE. Patrick added 
this feature into his MultiPSK software year ago. Until now only MultiPSK (and 
since last week also Cesco's FDMDV?) implemented this feature. Instead of CW ID 
or Image ID, a sequence of 15 MFSK tones is sent at the beginning of every TX 
to identify mode and center of frequency of the following data stream. RSID has 
very high redundancy, so if the RSID is decoded with zero or one error, there 
is extremely low probability of false detection. The feature is very handy to 
automatically detect mode and submode of rare modes and therefore encourages 
experimentation. Also it is easy to tune MFSK16 mode as no tuning is needed at 
all. I found RSID very useful with ATS-3b transceiver, at it has only narrow 
not very flat CW filter. Even if the whole digital signal does not fit into the 
filter, if the mode has high enough redundancy and is strong enough, it will be 
still decoded if tuned properly. But without seeing the whole spectrum of the 
signal on waterfall, it is very difficult to tune it. With RSID receive on, one 
only needs to get the RSID signal into receiver passband to make sure the 
signal will be tuned correctly.

PSK63F is a nice mode invented by Nino Porcino IZ8BLY. It is a crossbreed 
between MFSK16 and PSK63. It uses convolution code and varicode of MFSK16, but 
for hardware layer it uses binary phase shifting at 63.125Bd. PSK63F tries to 
fight ionospheric flutter by faster phase modulation and forward error 
correction. It is well known that BPSK31 does not survive polar flutter. BPSK63 
is better, but one loses 3dB. For DX work, PSK63F could gain back that 3dB and 
still show lower sensitivity for polar flutter.

PSK125 is nothing more than 2x faster, 2x wider and 3dB less sensitive BPSK 
than PSK63.

I finally added sample rate conversion. It took me a bit longer, because it is 
done in fixed point arithmetic again to make it computationally feasible on 
Windows CE devices. I have good experience with my iPaq 3630 and Jornada 720, 
they show very little clock error. But my new laptop shows as high as 4% error 
on TX and 2% on RX. Even PSK31 did not work at that level of clock error.

With the release of ATS-3b kit by Steve KD1JV, I received reports about having 
trouble to get the communication interface working. ATS-3b is controlled by 
Manchester modulation generated by sound card, which is translated to digital 
levels by a simple slicer. Some sound cards generate ugly transient response at 
the start and end of sound. I added four new parameters to control the shape of 
transient response: TX delay, TX tail, ATS3 preamble and ATS3 postamble. The 
first two are silence intervals. The next two are intervals of Manchester idle 
tone. The idle tone is shaped by raised cosine function now to minimize clicks, 
if it is longer than 50msec. Also Jornada 720 generates some ugly click about 
200msec after sound output opening. I was not able to find out the cause, but 
setting TX delay to 250ms either avoids the click or at least shifts the 
modulation after the click.

I added keyboard accelerators for accessing menu from keyboard. According to 
Microsoft GUI guidelines for Pocket PC platform, one shall not use keyboard 
accelerators. They work on my device though, so I leave them there. Menu pops 
up at Alt-T for tools, Alt-M for Modem, Alt-A for mAcros etc. F1-F12 execute 
macros on desktop.

Until now, I relied on testing of Handheld PC 2000 build by Helge Tefts. Last 
month I bought Jornada 720 on e-bay for whooping $40+shipping. I did some user 
interface improvements on that platform, made some missing features available 
like context menus on RX/TX windows etc. Jornada 720 has a two LiIon cell accu. 
I bet ATS-3b may be powered from the handheld's accu.

I replaced complex FFT by a real FFT for waterfall calculation, which lowers 
current consumption. Now all the DSP calculation uses less current than user 
interface updates + FEC and certainly less than backlight on my iPaq 3630. This 
is quite interesting. It shows that for HAM radio digital modems and PDA sized 
display, DSP CPU will be probably counter-productive as DSP is usually clumsy 
for general purpose computing. To improve current consumption even more, I 
would probably need to replace some stock user interface components from 
Microsoft like RX window by a custom one or get back to a custom design with 
very small monochrome display and simple user interface.

Ondra OK1CDJ bought himself a Smartphone HTC S710. The device does not have a 
touch screen and did not show menu in PocketDigi-1.0.10. Smartphone only 
ac