DATV-Express SSB / FM Radio Transmitter

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G4GUO
Posts: 728
Joined: Tue Feb 16, 2010 12:51 pm

DATV-Express SSB / FM Radio Transmitter

Post by G4GUO » Tue Sep 12, 2017 3:01 pm

Terry G1LPS asked me to make this available.
Copy it to a folder and start it up!
What is it?
It is a simple 70 MHz to 2.4 GHz all band SSB + NBFM radio transmitter for DATV-Express
that I wrote 2 years ago. It uses constant envelop SSB.

No warranty, no worries!

https://www.dropbox.com/s/gze4wc9j0xbeb ... m.zip?dl=0

- Charles

G4GUO
Posts: 728
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express SSB / FM Radio Transmitter

Post by G4GUO » Mon Jan 01, 2018 3:57 pm

Little know fact, you can use DATV-Express with GNU-Radio
https://github.com/csete/gr-datvexpress

- Charles

G0EID
Posts: 25
Joined: Thu Oct 17, 2013 3:19 pm

Re: DATV-Express SSB / FM Radio Transmitter

Post by G0EID » Mon Jan 01, 2018 7:38 pm

Hi Charles,
GNU-Radio is a bit of a beast to run portable or on the bench for setting-up...
Now you have the hardware abstraction layer clear in your mind.
Please have a think about supporting the SSB / FM Utilities on the Lime and Pluto boards too..
Happy new year.
Dave

G4GUO
Posts: 728
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express SSB / FM Radio Transmitter

Post by G4GUO » Mon Jan 01, 2018 9:03 pm

Hello Dave,

I thought I would advertise Alex's OZ9AEC work as he did the port some while ago
and I doubt anyone other than me has tried using it. Looks like I am going to have to
bite the bullet and figure out using GNU-Radio for DVB-S2X soon myself as I need to do
some receiver testing. My biggest problem is finding space for all these wretched
computers!

Have you tried SDR Angel for Lime/Pluto? https://github.com/f4exb/sdrangel

I think Mike G0MJW has used it on a Windows machine.

- Charles

g0mjw
Posts: 2329
Joined: Sat Sep 20, 2014 9:15 am

Re: DATV-Express SSB / FM Radio Transmitter

Post by g0mjw » Mon Jan 01, 2018 9:43 pm

G4GUO wrote:
Mon Jan 01, 2018 9:03 pm

Have you tried SDR Angel for Lime/Pluto? https://github.com/f4exb/sdrangel

I think Mike G0MJW has used it on a Windows machine.

- Charles
I did and it worked. The interface is a little strange but OK once you understand it.

Gnuradio works on Windows too - sort of.

Mike

ON7KGK
Posts: 9
Joined: Mon Feb 15, 2016 8:47 am

Re: DATV-Express SSB / FM Radio Transmitter

Post by ON7KGK » Mon Dec 03, 2018 9:35 am

Dear Charles,
Do you think that transmitting a complete ssb envelope to Es-Hail sat2 uplink will be a problem?
I don't know how to obtain suppressed-carrier SSB. Perharp with gnu-radio blocks ?
Thank you.
Best 73's ON7KGK

G4GUO
Posts: 728
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express SSB / FM Radio Transmitter

Post by G4GUO » Mon Dec 03, 2018 11:55 am

Do you mean an application like (which only runs on Express Hardware)?
Screenshot 2018-12-03 11.51.54.png
Screenshot 2018-12-03 11.51.54.png (26.6 KiB) Viewed 4472 times
- Charles

ON7KGK
Posts: 9
Joined: Mon Feb 15, 2016 8:47 am

Re: DATV-Express SSB / FM Radio Transmitter

Post by ON7KGK » Mon Dec 03, 2018 12:05 pm

Yes Charles, I use that software you showed in your reply and I always a carrier with my modulation.
I suppose that it will be more convenient to send suppressed-carrier ssb modulation to Es-Hail sat.
Thank you.

G4GUO
Posts: 728
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express SSB / FM Radio Transmitter

Post by G4GUO » Mon Dec 03, 2018 12:53 pm

I see, the carrier is due to imbalance in the I and Q being sent to the modulator,
to get rid of it a calibration routine would have to be added like the
DATV-Express software has. The SSB app does not have one.

Because DATV-Express is transmit only it is necessary to use a receiver
to monitor the carrier while manually adjusting the I and Q.
Screenshot 2018-12-03 12.49.48.png
Screenshot 2018-12-03 12.49.48.png (16.15 KiB) Viewed 4461 times
I suspect very few people bother to use that when sending DATV.

- Charles

ON7KGK
Posts: 9
Joined: Mon Feb 15, 2016 8:47 am

Re: DATV-Express SSB / FM Radio Transmitter

Post by ON7KGK » Mon Dec 03, 2018 1:10 pm

Yes you are right but here I just want to use my datv express board for both usage (datv and SSB).
It will be very useful if you could add the IQ calibration functionnality to your datvexpress sdr software.
Do you think it is possible for you (I mean in your freetime) ?
Thank you
Michaël ON7KGK

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