Lowbandwidth DATV is possible using Digilite and Tutioune

F6DZP
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Location: Poitiers - France
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Lowbandwidth DATV is possible using Digilite and Tutioune

Postby F6DZP » Mon Aug 25, 2014 9:20 am

Hello,

Since this summer we are testing with Evariste F5OEO DATV at very low SR, down to 250 kS/s.
it works very well with the image that is not too ashamed to face our old VHS recordings.

H264 coding with RaspberryPi putting IQ directly in second part of Digilite
( or a PC software coding with a graph)
Tutioune3200 or Tutioune1600 that can work today down to 176 kS/s
You can see a sample of what I get here: http://www.vivadatv.org/viewtopic.php?f=72&t=332

It's a start, but it shows that narrowbandwidth DATV is now a solution in sight and we can explore this area on our bands.

We should be able to get off SR 100KS / s.
These widths as narrow bands induced should concern DX men I guess.

73 to all.

Jean Pierre F6DZP

F6DZP
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Joined: Fri May 27, 2011 9:59 am
Location: Poitiers - France
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Re: Lowbandwidth DATV is possible using Digilite and Tutioun

Postby F6DZP » Tue Aug 26, 2014 10:50 am

Today I have tested successfully SR 125 kS/s

result can be observed : http://www.vivadatv.org/viewtopic.php?f=72&t=332&p=950#p950

73
Jean Pierre F6DZP

F6DZP
Posts: 146
Joined: Fri May 27, 2011 9:59 am
Location: Poitiers - France
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Re: Lowbandwidth DATV is possible using Digilite and Tutioun

Postby F6DZP » Tue Aug 26, 2014 12:48 pm

last test with Full HD 1920x1080 at SR 400 kS/s
same link to observe results.

Jean Pierre F6DZP

G4EWJ
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Location: Wirral

Re: Lowbandwidth DATV is possible using Digilite and Tutioun

Postby G4EWJ » Tue Aug 26, 2014 12:56 pm

Today I have tested successfully SR 125 kS/s


Excellent. We can now do DATV on Top Band (160m)!

How are you generating the audio?

Brian

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Re: Lowbandwidth DATV is possible using Digilite and Tutioun

Postby F6DZP » Tue Aug 26, 2014 5:25 pm

for the last tests I have shown these 2 days, H264 and audio were generated by my PC
these has been made by my side principally to observe receiving system and find how to tune well my receiving system.
When we are using very low rate, the biggest challenge is more the receiving part than the Tx part.

Last week I received H264 from Evariste F5OEO made by a RaspberryPi sending IQ in a Digilite.
for the moment with Raspberry, sound is not good or doesn't exist. Evariste is working to add some little USB audio card to resolve this last step.

Jean Pierre F6DZP


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