BATC Forum

Hi there,

I have been experimenting with the Realtek DVB-T dongle and the SDR# software, so much so that I am now actively considering getting a foundation licence. In the meantime I would like to try and receive any 70cm digital ATV activity in my area. Is there any software out there that can decode digital ATV on my Realtek dongle?

Hello and Welcome to the hobby.

There are no suitable software packages because

The sample rate of the RTL Dongle is not high enough to decode DVB-S at the bandwidths we currently
use for DATV.

Terrestrial TV standards DVB-T 8/7/6 channel spacing are not currently used because of their use of
spectrum although they will fit on the 23 cms band. So you can't use your dongle as a DVB-T receiver.
Unless of course someone is experimenting with commercial standards on 23 cms

The DVB-T that is actually being sent tends to be 2/3/4 MHz channel spacing and uses a bespoke
receive dongle, Hides UT100D (it is not compatible with your DVB-T dongle)

If you do want to receive Amateur DATV you would need to purchase an inexpensive DVB-S dongle
or buy a cheap DVB-S set top box. Then you need to be near someone (or a repeater) that is actually
sending DATV.

I hope I have not put you off

- Charles G4GUO

Thank you for your kind response! I do have a USB DVB-S2 tuner so I will connect my antenna to that. The LO frequency is 9.750 GHz for my satellite LNB so presumably I would need a different LO frequency. What software would you recommend?

Best regards

Richard

Hello Richard,

That should work, the normal trick is to set the LNB frequency to 10 GHz.
Then when you tune a frequency you just need to add a 1 to the front.
For example if you wanted to tune to 1316 MHz you would set it to
11316 MHz. I am not sure where you are but you will need to find
the output frequency of your local repeater (if you have one) and
also set the symbol rate. Usually 4 MS/s is used on 23 cms.

- Charles

Most activity is on 23cms so your DVB-S dongle should be fine for that, although a preamp would also help.
If your interest is in 70cm you would also need to convert the 437MHz signal to a frequency the dongle can use, a lot of us are using the SUP2400 70cms upconverter available for £5 to BATC members in the Shop https://www.batc.org.uk/shop/hardware-and-kits but some modification is required to use it, see http://www.m0dts.co.uk/index.php?tag=DATV&item=90

Best regards
Colin G4KLB