Amateur television is a fascinating part of the hobby covering all aspects of video production, editing, transmission and reception of television signals - whether across town or across the world by the geostationary QO-100 satellite.
One of the aims of the BATC is to help members get on the air. To do this the BATC has come up with the Portsdown project which is easy enough for most people to successfully build at home and gives you the basics of a very credible DATV transceiver (It can also be upgraded to receive DATV)
The Portsdown is based around the popular Raspberry Pi 4 single board computer, an Adalm Pluto SDR, and controlled by a seven-inch touchscreen.
Hundreds of these have been built by amateurs around the world and part of its success is down to the club prescribing the key components/design (and you sticking to them...) and following simple build instructions. Yes I know radio amateurs (me included) like to tinker and experiment but at this stage it really helps our volunteers help you. That way, if there are any problems, it's easy to offer support via the BATC forum. And if you still can't get it going bring it along to one of our Portsdown clinics which are held at most rallies the BATC attends.
So let's run through the basics:
The best way forward
We often get asked how do I start to receive or transmit ATV?
Like most areas in amateur radio there are lots of ways to do this but let's spend our money (and time) wisely and put together something tried and tested.
This approach means you are more likely to be successful, and if you really get into DATV, these building blocks can be reused to make even more sophisticated equipment.
Really easy ATV
Probably the easiest way to get on the air with ATV is by using drone analogue FM transmitter/receiver modules - take a look at this page which shows you how to join in the fun on 5.6GHz for around £20.
This is enough to get good quality pictures over several miles over line-of-sight paths with simple aerials - though with a better aerial and a good portable location at both ends of the link - it is possible to work hundreds of miles during favourable atmospheric conditions.
This BATC forum post by one of our members shows what distances can be worked, and fun can be had, using very basic equipment: https://forum.batc.org.uk/viewtopic.php?f=75&t=5437
The BATC is running a ladder contest to encourage activity using this simple equipment - see https://batc.org.uk/contests/6cm-ladder/
Receiving Digital ATV
Most amateur ATV signals are Digital using the DVB-S format and BATC has developed some low cost and easy to build systems for both receive and transmit.
Most of our DATV receive solutions use the same home-built USB tuner card called a MiniTiouner. https://wiki.batc.org.uk/MiniTiouner_hardware_Version_2
The MiniTiouner PCB and other "hard-to-get" components can be bought from the BATC shop https://batc.org.uk/category/usb-receivers/ - the remainder are standard leaded (no surface mount) components, available from all major suppliers. and can easily be put together in an evening.
The Ryde receiver
The easiest way to receive DATV signals is to build a BATC designed Ryde Set-top top box based on a Raspberry Pi4 (you can buy a pre-programmed SD card from our shop) and the Minitiouner USB receiver PCB. The Ryde can be controlled using any Infra Red remote control and can drive either an HDMI or composite video monitor.
See this wiki page for more details on the Ryde receiver.
With this you can receive local DATV activity from 2m to 13cm, including digital TV repeaters, and with a satellite dish and LNB, you can watch the activity on QO-100. See this page for more details on QO100
MiniTiouner PC based software
The free MiniTiouner software runs on a Windows PC and uses the same MiniTiouner hardware.
See this page for more details.
The Portsdown receiver
By plugging in the standard MiniTiouner USB card, the Portsdown transciever system becomes a fully functioning DATV receiver.
See https://wiki.batc.org.uk/The_Portsdown_DATV_transceiver_system for more details.
BATC advanced receiver hardware and Winterhill software
The BATC has also developed a single motherboard capable of hosting a Raspberry Pi 4 and 2 satellite tuners.
See this wiki page for this advanced receiver solution.
Antennaes and pre-amps
You will need the normal aerials, filters/pre-amps and/or LNB depending on the band you want to receive. Having said that it is relatively sensitive enough on its own to be able to receive nearby activity - and probably your local digital TV repeater.
Consumer Set top boxes
You can use a consumer STB to receive DATV but most set-top boxes do not go below 1 Msymbol or 1 MHz bandwidth and most DATV signals use rates less than this.
Some repeater outputs and the QO100 beacon can be received on a set-top box as they use higher symbol rates.
Tuning to a DATV signal
To tune to a DATV signal you must know the symbol or data rate in Msymbols or ksymbols. You will also need to know the frequency.
If you are using a Ryde, Portsdown or Minitiouner receiver you will be able to enter the frequency and symbol rate directly and just go to receive.
If you are using a set-top box, you must add the wanted signal frequency to the LNB local oscillator to find the frequency you must tune to. For example if you are wanting to receive a signal on 1249MHz and the STB is set for an LNB LO of 9750 you need to tune the receiver to 10,999 MHz.
The BATC Portsdown system is the way go. It is Raspberry Pi 4-based but you can buy a pre-programmed SD card from BATC so there is no programming or computer wizardry at all. This plus a touch screen and a Pluto SDR, which simply plugs in to the Pi's USB socket, will give you a simple to use touch screen DATV transmit system.
For more details see https://wiki.batc.org.uk/The_Portsdown_Transmitter
Again if you want more information, or need some help, have a look in the Portsdown section of the BATC forum: https://forum.batc.org.uk/viewforum.php?f=103
This basic system will give you a full blown DATV transmit system from 50MHz up to 3.4GHz with good picture quality. Again you will need filters and amplifiers for the band of your choice.
DATV transmit and receive in one box
Since the release of Portsdown software in autumn 2019 that included the LongMynd receiver you can plug the MiniTiouner USB tuner hardware in to the Portsdown system and it will display the pictures, thereby becoming a full DATV transceiver and replacing the need for a PC.
Note you can not use the Pluto or Lime SDR to receive DATV signals but they can be used to provide a band viewer to help align your antennas etc.
The Portsdown 4 software includes everything you need - just make sure you have the latest build - and plug your tuner card in to the Pi's USB port. See https://wiki.batc.org.uk/Portsdown_4_Pluto for more details.