AMATEUR TELEVISION

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AMATEUR TELEVISION
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What is Fast Scan ATV?

• Fast scan TV is the transmission of real time
  TV pictures just like you see on your TV set

ATV allows visual QSOs so you can see your contact
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ATV Bands and Frequencies

• 70cms typically 435 436.5 Mhz

Monochrome transmission if using AM modulated
carrier
Colour permissible if using Vestigial Side-band
(VSB)
Colour and audio permissible when using digital
transmission techniques which are currently under
development by various suppliers (based on DVB-T)
standards
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ATV Bands and Frequencies

• The 23cms amateur band ranges from
• 1.240 to 1.325 GHz
• ATV simplex 1240 1260Mhz
• ATV repeater inputs typically are
• 1248, 1249, 1255 and 1280Mhz

Repeater outputs range from 1308 1318Mhz
Full colour video and audio using either AM or
FM Modulation
Nationwide network of ATV repeaters
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ATV Bands and Frequencies

• The 13cms Amateur band ranges from
• 2.310Ghz to 2.450Ghz

2.322 to 2.355Ghz 2.370 to 2.390GHz ATV
Simplex operation and ATV repeater inputs
Repeater outputs on 2.435, 2.440 and recently
Being allocated to 2.420Ghz
Full colour video and audio using either AM or
FM Modulation
Nationwide network of ATV repeaters
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ATV Bands and Frequencies

• The 10Ghz amateur band ranges from
• 10.000 to 10.500GHz

ATV Repeater outputs typically 10.065 10.240
ATV Repeater inputs 10.315, 10.340 10.425Ghz
ATV Simplex operation typically between 10.225
to 10.250, from 10.350 to 10.368 and 10.412 to
10.437
Full colour video and audio using either AM or
FM Modulation
Nationwide network of ATV repeaters
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How much does it cost?Tx and Rx

• 70cm As little as 10
• 23cm About 150
• 13cm About 150
• 10Ghz About 50

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Video sources

• Most people own a video camera and they can be
  utilised readily for ATV use.
• When in camera mode, most output a video audio
  signal on the AV output socket.
• Their sensitive microphones provide excellent
  audio from anywhere in the shack

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Video sources
Modern digital video cameras often have video out
for viewing photos on your TV set and provide a
ready video source for ATV use. The memory cards
can also Be loaded with test-cards made on a PC
using MS paint or Paint Shop Pro etc and
displayed using your digital camera via the video
output.
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Video sources

• CCTV cameras are available for a very modest
  price, some as low as 20 new for a colour camera
• They are ideal for permanent installation into
  the shack and many budget cameras are supplied
  with a wide angle 3.6mm lens which is ideal for
  shack views

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Video sources

• Digital photo viewers allow for cheap and easy
  test-card generation.
• They are available from 29 and accept most types
  of digital camera memory cards.
• Test-cards can be downloaded from the internet
  ready to use.

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• DEMO

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Dont throw out that old computer! A BBC,
Spectrum, or Amiga amongst others are great for
Test-cards
Video sources

• A PC fitted with a video card with TV out can
  provide a great video source. Live video from
  your webcam, photos, AVI video files etc.

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Operating P reports
ATV calling and talkback frequency is
144.750Mhz

• ATV signal reports are given using the P grade
  which ranges from 0 to 5
• Example

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P0 Trace of a picture barely visible extreme
noise and often unstable
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P1 Picture visible but very noisyOnly larger
objects can be seen
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P2 More picture detail visible but noisy with
weak and unstable colour content
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P3 Good picture detail with small items visible,
good colour but still noisy
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P4 Very good picture with slight noise visible
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P5 Perfect picture with no noise
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70cms (435Mhz) Band Equipment
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70Cms

• 70cms ATV can be received using an
• up-converter such as the Microwave Modules
• or Fortop converters between your 70cm antenna
  and television receiver

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70Cms

• Some TVs and video recorders also tune down well
  below 430Mhz especially older models
• Also, all analogue cable TV boxes

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70cms
Suitability can be checked by using a low power
transmitter on 435Mhz Tune the receiver to BBC1
and carefully tune down lower If you receive a
blank picture stop transmitting. If the TV
displays static when not transmitting and a blank
screen when the transmitter is on you should be
able to receive ATV
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• DEMO

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70Cms

• Transmitting ATV can be achieved by using a ready
  built transmitter such as the MTV435
• by Microwave Modules

These can often be found on Ebay for about 40
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70Cms

• Mini-kits in Australia currently produce a
  transmitter kit for about 35

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70cm Modulators

• A quick and cost effective way to get onto 70cm
  ATV is by using a modulator

An old radio can be easily be modified
If done correctly, the radio can still be used
for standard voice operation
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Points AB are the video input
Example of a Simple modulator
E is the modulated supply to the collector of the
PA final transistor
Closing the switch (SW1) allows the radio to
function as normal
CD is the v supply and common
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Modifications to a typical PA
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Remove Collector Decoupling Components
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Isolate the collector of the final transistor
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Connect the Modulator
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Completed Modification
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23cm (1.2Ghz) Band Equipment
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Complete 23cm Transceiver

• LCD Controller

Transmitter Receiver
G6ALU 20W Power Amplifier kit
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Junk box antenna for 23cm

• Parts Required

The XYLs best flan dish 30cm diameter
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Junk box antenna for 23cm
Parts Required

• A Plastic Conduit Box

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Junk box antenna for 23cm
Parts Required

• Some 2.5mm diameter
• copper wire

A short length of RG213 or better
A plastic cable gland to suit coax
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Strip a length of wire 48cms long and bend 90º in
centre
Bend again 90º as shown
And again to produce the double quad as shown
below
Each side of the quad should measure 6cm
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Drill a hole in the centre of the dish and
conduit box to fit the gland.Strip 5mm on the
end of the coax as shown and tin the braid and
centre core
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Next, fit the conduit box onto dish with the
cable gland entry at the rear of the dish. Insert
the coax through the gland from the rear.

• Solder the element to the coax with the centre
  bend of the element to the centre and the open
  ends to the braid. The element should be 3cm from
  the dish

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Use a soldering iron to heat the wire to melt the
box while pressing down on the element to fix
into position
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Use hot-melt glue gun to seal the connections and
then fit the lid to the conduit boxVSWR should
be lt 1.31Adjustment is made by adjusting the
distance of the quad element from the back plane
Gain is approximately 11 12dBi (8.5 9.5dBd)
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23cm RX from the Junk Box

• An old analogue satellite receiver can be used to
  receive 23cm ATV. Simply connect the 23cm antenna
  to the LNB input. If there is no preamplifier in
  line, the DC LNB voltage must be disabled first
  of use a DC blocking capacitor in series with the
  coax centre conductor.

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13cm (2.3Ghz) Band Equipment
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Complete 13cm Transceiver

• LCD Controller

Transmitter Receiver
Spectrian 30W Power Amplifier
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A Junk-box Antenna for 13cm

• Bi-quad antennas are easy to build and make a
  very simple and cost-effective antenna for local
  working 13cm ATV and for receiving GB3GG

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Construction

• Cut a piece of copper clad
• board 123mm x 123mm

Next cut a piece of ½ inch copper pipe 50mm long
Cut a 2mm notch half way down the pipe as shown
and file square
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Insert the pipe through the board so the notched
end is 16mm as measured from the copper side of
the board

• Drill a hole in the centre of the board and use a
  reamer to make exact fit to the pipe

Solder the pipe to the board ensuring a good
electrical connection and physical rigidity
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This is the elementEach side should
measure30.5mm

• Strip the earth wire from 2.5mm twin and earth
  and cut a length to 244mm

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Find half way point and fold into a sharp 90º bend

• Find half way point and bend again as shown

Bend again to make a square Bend both sides to
produce the quad shape as below
Ensure both sides measure 30.5mm outside
diameter Ensure symmetry
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Solder the open ends of the element to the copper
pipe as shown The bend should sit inside the
copper pipe notch but not touch the pipe. The
element should be 16mm from the copper board
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Strip 30mm from coax as shown

• Fold back braid and strip
• insulation flush with braid. Cut centre conductor
  to leave 5mm as shown

Insert the coax into the copper pipe So the coax
is flush with the bottom Of the notch and solder
the centre conductor to the element as
shown. Ensure the centre is not shorted to The
braid
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Crimp the cable to the rear as shown. If a crimp
tool is not available then carefully solder the
braid to the pipe at the front

• Completed Bi-quad antenna
• VSWR should be lt 1.31
• Adjustment is made by adjusting the distance of
  the quad element from the back plane
• Gain is approximately
• 11 12dBi (8.5 9.5dBd)

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Vertically Polarized
Horizontally Polarized
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3cm (10Ghz) Band Equipment
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Complete 3cm Transceiver

• Gunn Diode Modulator

Gunn Oscillator
LNB
Analogue Satellite Receiver
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Gunn Oscillators

• Gunn diode oscillators can be obtained for about
  5. They can often be found in Dual-Tec PIRs
  and other Doppler type detectors

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Modules can be tested by applying 7v between the
gunn diode and ground.Using another module,
connect a 50uA meter between the receive diode
and ground

• Here are the connections of a typical Doppler
  head.
• There are usually 3 connections, 7v (gunn diode),
  0v and receive diode

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The above circuit is a simple way to transmit
10Ghz video using a Gunn oscillator. It is video
only with no audio provision for simplicity

• Simple 10Ghz Modulator

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10Ghz ATV bits Where to buy
Bob Platts G8OZP   01283-813392Gunn Diode
Modulator BoardsModified LNB'sReceiver
Kits24cm Pre-amps
George Lewczenko G6AKC   01366-728773Gunn Diode
TX Modules

• S. Marshall G6NHG  
• 01827-8979202
• 20db Horns Slotted
• Waveguide Antennas

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23cm Where to buy
Tonna 23cm Antennas (Waters and Stanton) 20636
Tonna 23cm (ATV) (1240 - 1260MHz) 35 el Yagi
64.95 20650 Tonna 23cm (ATV) (1240 - 1260MHz) 55
el Yagi 84.95 Comtech Modules ATV
Controller www.13cm.co.uk 23cm PA Kit Steve
Drury G6ALU www.radio-kits.co.uk 23cm
Preamp kits
www.mini-kits.com.au 23cm Preamp (ready built)
Bob Platts G8OZP   01283-813392
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13cm Where to buy

• Waters and Stanton
• 20745 Tonna 13cm (2300 - 2400MHz) 25 el Yagi
  69.95
• Comtech Modules ATV Controller
  www.13cm.co.uk
• Spectrian Power Amplifier
• Ebay Seller ID Pyrojoseph
• Search for
• 30W Class A Linear RF amplifier 2.3-2.45 GHz
  2304 ATV