Radio Amateurs Old Timers Club Australia Inc
Registered No A0042780C

VK3OTN Broadcast 

Technical Requirements

 

Call for broadcast relay volunteers

If you feel you may be able to help to transmit the broadcast on a more or less regular basis, from your location, then why not drop a note to   . One example would be to transmit the evening broadcast on HF on 80 metres, from a location in Brisbane, or the morning broadcast on 160 metres from a location in Sydney. With the current decline in solar activity, every little bit helps. Another example would be to transmit it over your local FM repeater, providing of course, that you have the repeater owner's permission. The audio is supplied as an mp3 file and is made available via email a few days before the broadcast date. In order to provide a positive experience (as opposed to negative!), here is a look at our Broadcast Technical Requirements.

Broadcast Technical Requirements

In order to maintain a somewhat professional quality to the monthly news broadcast here are some suggested guidelines. The RAOTC committee welcomes volunteers and members from all over Australia to disseminate the monthly news bulletin, on all bands, all modes, including local FM and in the near future, digital radio repeaters, which are a lot closer to many older amateurs than they perhaps realize. For example, digital radio modes allow an amateur in a retirement village or aged care facility to still 'work the world'. Whilst every offer of assistance is very much appreciated, consideration needs to be given to avoid the following situations;
  • If the frequency drifts up and down the band, necessitating the listener to constantly retune their receiver; or
  • There is some sort of RF feedback from the audio or, for want of a better description, the audio quality is absolutely dreadful; or
  • The transmitted audio quality sounds dreadful for some other reason - extreme treble, extreme bass, inappropriate audio processing, to name a few - this will lead to;
  • A frustrated listener only listening for a few minutes, and then simply turning off, or retuning and listening to something else. If it sounds dreadful, people simply won’t listen!
The RAOTC management committee may be able to assist in providing some technical guidance, and if no one knows, we'll try our best to assist in finding someone that does..

An interface for an older model radio would usually consist of something like a small enclosure, some connectors, a few components and perhaps a small audio coupling transformer to help prevent ground loops and thus hum. Also desirable would be a microphone switch instead of having to unplug the microphone and plug in the interface plug, etc. The materials for such an interface and microphone/interface switch, if not available from the junk box, should not cost much more than $10 to $20.

Many of the more modern radios have a USB socket and, when plugged into a computer, behave as an auxiliary soundcard to the computer. Gone are the days of 'one size fits all'. Hence, each station needs to examine its own requirements and consider a solution that suits them.

Here are some initial guidelines from one of our broadcast co-ordinators, Bruce VK3UV.
  • The relay operator MUST have direct audio facilities from her/his PC / iPad / Tape, etc recorder to the audio socket of the transmitter.
  • The relay operator MUST be a member of RAOTC.
  • On 20 metres, the relay operator preferably should be capable of running the maximum legal limit to a rotatable beam.
  • On 40, 80 and 160 metres, from 100 watts up to the legal limit into a dipole, etc would be quite sufficient.
The RAOTC broadcast team look forward to hearing from you, if you're able to assist.







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