Amateur Television (ATV)





In mid-2015, MDARC converted the downlink transmitter of its ATV system to be fully digital. We are now able to transmit four channels of HD quality content in the same bandwidth that the old analog transmitter required. This also means that a digital receiver is needed to receive the MDARC ATV signal. Analog reception is no longer operational. Our uplink receiver can now handle both analog and digital, however. So if you are transmitting into our system in analog, your existing analog equipment will still work.

Check into the following nets on W6CX 147.06 MHz + 100 PL repeater:
    * Tech Net on Tuesdays @ 18:00 hours local
    * ATV Net on Thursday @ 20:00 hours local
    * Bathrobe Net on Sundays @ 09:00 hours local

System Outputs:
MDARC's digital ATV (DATV) repeater transmits on 1244.50 MHz.
You may also watch us live on the Internet at w6cxatv.mdarc.org.

You may also find it at https://batc.org.uk/live/w6cxatv.

System Inputs:
The repeater's receiver provides multiple inputs for you to transmit into; four digital and two analog:

Digital Inputs:     1292.50 MHz
                            1273.00 MHz
                              915.00 MHz
                              430.00 MHz

Analog Inputs:    1270.00 MHz FM
                              427.25 MHz AM
                            

Receive Equipment

So what do you need to receive MDARC's DATV signals? Here's a short list:
  • High gain antenna tunable to 1240 MHz . Vertical polarity.
    Most ATV-ers recommend a yagi pointed at Mt. Diablo's North Peak.
  • RG-6 or better coax
  • DC blocking adapter
  • Digital TV "free to air" satellite receiver: DVB-S2 with HDMI and Composite out
  • HDMI or Composite video monitor or TV
  • HDMI or Composite cable, depending on the interface between the DVB receiver and your monitor.
You may also need one or more adapters to convert from the antenna connector (usually an N-type) to the F-connector on the RG-6 coax.

Transmit Equipment

If you are planning to buy or build an ATV transmission system, MDARC recommends going digital. You will need:
  • Color camera.
  • Line level audio.
  • 1270 MHz FM transmitter (email wb6asu@icloud.com for details).
  • Raspberry Pi 3+ with Acampo PC board (email wb6asu@icloud.com for details).
  • DATV Express board with all needed hardware (see their web page for details, www.datv-express.com).*
  • Downeast Microwave 1200 Amp. 50mw to 3 W. or equal (see http://www.downeastmicrowave.com/).
  • LMR400 or better coax.
  • 1290 MHz high gain yagi antenna. Vertical polarity.
  • Various other cables to connect it all together.
*Some of us are using instead a Harmonic MV-50 Encoder w/ Harmonic PSM-3600 Satellite Modulator.

Some needed specs:
  • DVB-S
  • QPSK 3/4 or 1/2
  • Symbol rate 2.222 MB/s

More Information:
Subscribe to these Yahoo groups:

MDARC Digital ATV Repeater Block Diagram