Getting started in Amateur Television. Noel Matthews G8GTZ

Transcription

1 Getting started in Amateur Television Noel Matthews G8GTZ

2 Getting started in ATV What is ATV? Which band and where? Analogue or digital? BATC video portal How do I get on air? It s not all about radio! Who are the BATC? ATV why not!

3 What is Amateur Television? ATV is a niche area of amateur radio Includes video production, editing and transmission Covers classic camera restoration right through to transmitting live pictures using Raspberry PI from balloons! Real freedom to experiment ATV generally refers to fast scan TV

4 ATV - the bands 70cms Digital only on 437MHz Real potential for DX 23cms Analogue and digital Activity on repeaters and simplex 13cms Currently analogue and digital Repeaters and simplex 3.4 GHz The new band! Digital only 10 GHz Repeaters and simplex

5 Analogue Amateur TV Up to 10 years ago, everything was analogue Bands 70cms 8 MHz AM! 23cms 16 MHz FM 3cms 16 MHz FM And it worked well

6 G to PA on 3cms at sea level!

7 Analogue vs Digital The world is going digital MPEG-2 SD compresses 270Mbit/s to 2Mbit/s MPEG-4 compresses HD at 1.3Gbit/s to 8 Mbit/s 99% reduction in bit rate but still better than VHS quality? watch the background and grass! Compressed video is much more efficient to transmit Freeview = 6 SD channels in place of 1 PAL signal in 8MHz! Hence the commercial pressure to go digital

8 ATV is going Digital The move to digital is happening Been experimenting for over 10 years Pressure on spectrum eg 13cms More modern image and new challenge Broadcast standards are being adopted DVB-S at 2 or 4 Msymbols 4 MHz vs 16 MHz Significant bandwidth gains and better pictures when it s there!

9 Digital vs Analogue DVB-S QPSK, 1.6 Msymbols, ½ FEC ~ 1.6 MHz FM analogue 16 MHz deviation ~ 30 MHz

10 So how do I get started? Go to The internet portal for all amateur television Most UK ATV repeaters are streamed live Watch your local repeater and join in with the discussion on the chat window

11 BATC.TV - activity nights Up to 18 UK Amateur TV repeaters 16 international repeaters from Australia, USA, Ireland and Argentina. Night Repeater/Group Comments Time Sunday GB3SQ - Bournemouth G8AJN member stream 8pm Monday VK2RTS Sydney VK2CRJ member stream 11:00am GB3IV Isle of Wight Talkback on GB3IW 8pm Tuesday GB3TM 7pm GB3HV - Reading Live club meeting on 4 th Tuesday 8pm Wed VK7OTC DATV experimenters evening 10:30am GB3BH - Watford 8pm GB3ZZ - Bristol GBNQ - Cornwall 8pm 8pm Thursday GBPV - Cambridge 7pm GB3TB - Torbay 8pm GB3UT - Bath 8pm Friday GB3GG - Grimsby 8pm GB3EN - Enfield 8:30pm

12 BATC.TV not just repeaters Bringing amateur radio to a wider audience Live events Club talks National Hamfest GB70DAM HAB launches The archive Amateur radio s youtube EME 2012 AMSAT colloquim Microwave RT

13 But how to get on air... 23cms ATV is the place to start If you have a reasonable narrow band station you are half way there! Buy a Comtech Tx and Rx module Use existing pre-amp and PA But what about digital?

14 DATV how to, the Rx bits 23cms is easy! Use a FTA satellite receiver with low noise pre-amp at mast head And some filtering! 70cms is more difficult Use a Directv SUP2400 upconverter Available from the BATC shop Needs a few simple mods Takes 437MHz to 1963 MHz Directly feeds a FTA satellite receiver

15 23cms rx in the shack FM rxr Pre-amp Switch/ splitter/ amp Digital rxr

16 DATV transmit QPSK modulator MPEG encoder SSB transverter Power Amp

17 DATV Tx equipment Ex broadcast equipment Works well but big, noisy and hot! BATC Digilite project Use PC and TV card to digitise video DIY project for modulator and upconverter BATC DTX1 Complete encoder, modulator & upconverter Covers 150MHz to 2GHz Available from the BATC shop

18 DATV the Tx RF bits The transmitter must be linear Original modulators output an IF Use SSB transverters backed off for good linearity to get to final frequency Modern designs use direct I&Q modulation at RF frequency (up to 13cms) Need good linear PAs with high duty cycle Modern 28v FET amps are ideal

19 ATV repeaters 30 repeaters around the UK Most repeaters now have a DATV input 23cms & 70cms Some have switchable DATV output GB3TM is now digital by default Digital in, Digital out looks superb!

20 But that's not all... ATVers are involved in video production Historic camera and vehicle restoration ISS HAM TV Possible very narrow band VHF ATV

21 How to get involved There is probably a repeater near you! Listen on MHz The ATV calling channel But easiest of all go to

22 The BATC 800+ members worldwide Publishes CQ-TV in e and paper format Runs highly successful streamer Active ATV community online forum Supports projects such as Digilite Represents ATV community on ETCC Runs BATC shop for hard to get bits Annual convention (2 weeks time) Only 4 for a cyber membership!

23 ATV is alive and well in the digital age! Thank you and don't forget to visit batc.tv