A Look at ATV with Pat Fitzpatrick EI2HX
My first step into ATV (amateur television) took place in 2005 when I met up with Michael EI5GG, the late Dermot EI2AK, Mark EI9FX, Tony EI4DIB and Jim EI-970 at Dermot’s home overlooking my home town of Drogheda, County Louth.
After a couple of meetings at Dermot’s home and at the club house of Dundalk Amateur Radio Society EI7DAR I got my first pieces of atv equipment An old analogue satellite receiver and a Severen side aerial for 1.2 GHz (which is a 38 element beam) from the stores of Dermot and Seamus GI4SZW, a member of EI7DAR.
The only modifications that had to be done to the satellite receiver was to use the remote control and go into the satellite setup menu and change the audio to the 6MHz setting and to disable the 12-18 volts output for the LNB . You could instead solder a capacitor (44pf) across the coax at the aerial to inhibit the voltage as you could install a small preamp at a later stage.
That night I connected my aerial to the receiver with regular satellite coax which was only about 3 meters long as the aerial was in my shack/bedroom/design studio. So with the TV switched on and the aerial pointing out the window in one hand and the microphone of the 2 meter rig in the other one I called Dermot and he sent me a signal and after a few seconds of aerial waving I had received my first ATV pictures from Dermot who only lived about 5km away and there he was in full colour and perfect sound (P5).
If only all of my ATV experiments would be as easy. A short time later at a rally in the UK I purchased my first ATV transmitter from Giles G1MFG. The power output was 50mw and also purchased was another aerial, this time a 9 element loop Yagi plus some coax for 1.2GHz.
When I got home I made a sked with Dermot and later that day I sent a signal to him and after a few moments he tuned me in. Also at Dermot’s home was Mark EI9FX and he asked me to transmit a signal to him later that night.
Mark lives about 20km from me and my signal was weak as I was still pointing my beam at Dermot’s QTH whitch turned out to be nearly on the same beam heading as Mark’s. I went out to my mast and with my mobile phone I rang Mark . So with phone on shoulder, armstrong rotator ready , the 50mw blasting away, Mark watching his TV, I started turning, and after a few minutes Mark tuned me in at a P5 but only with
his pre-amp on. I was only a P2 with the pre amp off .
My next (DX) contact was with Tony who lives less than 1km from me. Tony was using a satellite receiver like mine to receive me. I was to have many more ATV sessions with Tony on 1.2GHz both portable and mobile but that’s another story.
To date I have always bought my antennas. My latest antennas are a 35 and a 55 element Tonna. The ATV TX units are available as kits . The main 50mw unit comes as a complete board. There are amplifiers available from 700mw to your wallet’s limits (or your governments) . All the bits and bobs I have bought are powered by 12 volts DC.
You can get some equipment that use 24 volts or 48 volts. But as I wanted to use my equipment /p without bringing inverters or generators with me I stuck with the 12v. The TX boards I use came finished with a SMA connector. There are connectors that you can get to change it to a N type . It is a lot easier to connect an N to N when you are portable in the wet and cold . I am sure you won’t just go out in the sunny days and warm nights would you?
Take it from me some of the best days and nights I had on ATV were the wet and windy ones. Bring a flask of tea with you and some kitchen roll (to dry your hands with ….cheeky) Even the new TX units I have came as unboxed boards and no DC leads. I wanted to set something up that was for home use and portable so I got some waterproof boxes ( Maplins or your local electrical store ) and some panel mount connectors.
As with any part of the hobby you pick up items as you go along to the rallies or the web. Most of my equipment I bought off the stalls of these people in the UK and Friedrichshafen rally in Germany over the years.
Their web sites are as follows:
www. lechner-cctv.de www.dgove.de
www. id-elektronik.de www.pe1acb.nl
You can also google these people on the net:
G1MFG, G6NHG Stuart Marshall and Bob Platts G8OZP.
Some terms for ATV:
P0 total noise, no picture visible
P1 high noise, weak picture
P2 high noise, fair picture and fair detail
P3 noise visible, strong picture with recognizable detail
P4 slight noise, very strong picture good detail
P5 perfect picture and audio
In the next issue we will look at 1.2 GHz and 10GHz projects
Happy hunting .
Pat EI2HX.
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