WA Radio Scanner Users' Group

Just had a thought. It might be a good idea to build a small remotely operable scanner with a 3G modem, battery, and a small solar panel in a case.

For things like the fires in Esperance, and other remote areas, all someone has to do is just turn it on and leave it on the roof or in a secure, sunny area. The 3G modem can provide frequency adjustments as well as send back streaming audio.

Interesting idea.

One problem will be getting the unit to the area and housing it somewhere where it won't get pinched. The other is the amount of data streams consume - the two I run push about a gig a day. Pricey on 3G.

Something that operates using the GSM codes or G729 may not use that much bandwidth. For example G729 has a base of 8kbps and overhead (RTp, UDP, IP and Ethernet) of 31.2kbps bringing it to 39.2kbps. So 17.2MB/hr or 412MB/day. Just under half a gig but still a sizeable amount for a single stream.

One issue I can see is network load at larger incidents. I have just gotten back from the Esperance fires and that network was under heavy load at times, especially at the beginning because 4 Telstra towers were wiped out (power not fire) and Telstra couldn't get in with gensets right away due to the emergency conditions. Not to mention the amount of people contacting family and friends. Telstra brought a CoW in in the end. We put in place the BGAN with phone/fax because of these issues. Regardless, you might find dropouts frequent on 3G/4G in these types of situations.

I think a Raspberry Pi with an SDR dongle would do nicely if you were to go ahead.

matth2004 wrote:
I think a Raspberry Pi with an SDR dongle would do nicely if you were to go ahead.

They have just released a very small variant that will run for a week off a 9v battery.

Yes the Pi Zero. Not sure if that will have enough grunt for what you need though, plus the SDR would pull a bit of power itself.