Broadcast Communications

Since high school I have been interested in broadcast communications. I use to listen to AM radio at night and was fascinated with the stations travelling longer distances.


RTLSDRScanner and my Ku-Band Satellite Dish

I graphed spectrograms of my satellite dish tuned to Optus D2, Optus D1 and Intelsat 19.

My Ku-Band Satellite Dish

Actual spectrograms and details of the hardware used have been included in the project page.

See /RTLSDRScanner/


C-Band Satellite Dish Examination

A friend asked me to have a look at the C-Band dish in the backyard of their home that was left behind by the previous owner.

C-Band Satellite Dish Examination

Details of the examination have been included in the project page.

See /122East2014/


FM Radio Database

Melbourne has had FM radio since the 1980s. The first stations included EON FM 92.3, Fox FM 101.9 and ABC FM 105.9. Today you will find around 40 stations across the entire FM spectrum.

Place your mouse over a station frequency in the following diagram to show the name of that station. Click a station frequency to see more details on that station.

FM Radio Stations
Melbourne FM Radio Spectrum.

The spectrum is colour coded as follows:

  • Green frequencies are full strength Melbourne stations
  • Purple frequencies are medium strength Melbourne stations
  • Pink frequencies are low strength micro stations
  • Orange frequencies are Geelong stations
  • Red frequencies are regional stations

    Frequency Spectrogram of FM radio from Mt. Dandenong

    Frequency Spectrogram of FM radio from Mt. Dandenong

    The FM spectrum was shared with TV channels 3, 4 and 5. Channel 3 and 4 use to be used by ABC TV in Ballarat and Traralgon and have since been moved to UHF thus releasing space for radio stations.

    I have an interest in long distance FM station reception. Back in the 1990s it was easier to receive non Melbourne stations as the spectrum was not flooded with local stations. In the 2000s the band has many more narrow cast community stations that are located closely to each other.

    During the 1990s the federal government allowed a large number of narrow cast test stations to use the FM band. A small number of these stations are now allocated on the Melbourne air waves. Test stations not heard today include Hitz FM, Kix FM, Street FM, Melbourne Gospel Radio and Monash University Student Radio.

    Many of these test stations were on air for 1 to 4 weeks at a time. The frequencies of 89.9, 90.7 and 91.5 were heavily used for test transmissions. These frequencies overlapped with ABC TV 3 in Ballarat and only had low powered tests. These frequencies now allow permanent full strength stations.

    Place your mouse over a hot spot to show the name of that station. Click a hot spot to see more details on that station.

    FM Radio Stations
    Melbourne FM Radio Layout.


    Digital Television

    During 2014 the Melbourne Digital Television stations were restacked after the digital switchover. The analogue 2, 7, 9, 10 and 28 services were turned off on December 10 2013.

    • The first digital change was to move SBS from UHF 29 to VHF 7
    • The low power Melbourne Community Television will remain on UHF 32 until a future decision is made
    • The unassigned digital channel is on VHF 10
    • The available VHF 9 frequency is to be used for DAB+ radio services
    • UHF 28 will be used for digital television in regional Victoria
    • UHF 35 will be used for digital television in regional Victoria
    • VHF 2 is no longer being used for television

    Frequency Spectrogram of Freeview from Mt. Dandenong

    Frequency Spectrogram of Freeview from Mt. Dandenong

    The following is an updated list of transmitter frequencies for Mt Dandenong as of 2014. The Amateur Television service is to be changed to QPSK in the near future.

    au-Melbourne

    Here is the above data in a file for download au-Melbourne


    TeleText

    Back in 1986 I purchased the DSE Teletext kit. I successfully assembled it and used it to decode the 7-Text service on Channel 7.

    Teletext is a digital service that is transmitted inside the unused space of the vertical blanking area of analogue TV pictures. In recent times a backward compatible service is transmitted inside newer digital tv services.

    Teletext Hardware Photo
    Assembled Teletext Hardware.

    Shown above is the teletext hardware that I assembled. The main components of the system are teletext PCB, RF modulator to output on channel 0, television tuner to receive VHF and UHF tv stations, two mains power transformers for 240 volts and the infra-red remote control receiver. The chassis is made of a metal alloy and has mounting holes for components, infra red diode and cables.

    Teletext Printed Circuit
    Printed Circuit (click to enlarge).


    DSE TeleText 1987.

    Shown above is Channel 7 page 121. This is a news item page for the Australian Open Golf at Royal Melbourne Golf Club on Sunday 27th November 1987. An advertisement for the Sun newspaper is found at the bottom and contains a blinking red icon.


    DSE TeleText 1988.

    Show above are examples of Austext pages about the World Cup Golf held at Royal Melbourne Golf Club in 1988.


    DSE TeleText 1989.

    Finally shown above is a personal message put up on Austext by my family in 1989.

    I have some interference problems with the circuit that I never repaired. I upgraded the unit with the IR-Remote kit and the additional tuner module. Alas, while testing the turner unit I accidentally shorted a pin and smoked the tuner and have never replaced it since.

    A teletext page is made up of 40 x 25 characters. It may contain simple block like graphics. Pages are in groups of 100 starting with 100 thru to 899. Pages may have a subpage id within a time format for changing pages. Teletext remotes have a reveal function to reveal text marked as initially hidden.

    Before the new digital tv services commenced in 2001, ABC and Channel 10 had test teletext services here in Melbourne. At the time of digital tv introduction these services were discontinued.

    Teletext has not taken off here in Australia however it serves one important service. The ABC, Channel 7, Channel 9, Channel 10 and SBS all transmit teletext subtitles for programming. With a teletext receiver set to page 801 on these channels you will receive overlay subtitles for hearing impaired viewers. This remains to be the main benefit of teletext here in Australia.

    Update September 2009

    The AUSTEXT service was discontinued on September 30 2009. Before it was turned off I captured a video of the closing pages using my DVB-T Set-Top-Box.


    DVB-T Teletext 2009.


    AM Radio

    During my childhood years I enjoyed listening to the AM radio stations from other cites during the night.

    Using a Ham It Up upconverter I am able to look at the Medium Wave spectrum using a rtl-sdr.

    Ham It Up Upconverter

    Ham It Up Upconverter

    Shown here is the Melbourne AM Radio spectrum upconverted to work in gqrx using a rtl-sdr dongle.

    Medium Wave radio from Melbourne

    Medium Wave radio from Melbourne


    Sky Wave Reception of Gippsland

    This video shows sky wave reception of Gippsland Digital TV received in Melbourne on February 8 2010. The main Gippsland channels are 5, 6 and 8.


    Sky wave reception of Gippsland TV.