View Full Version : FM broadcasts
kaspaas
10-01-2005, 04:38 PM
Hi,
Does anybody know:
are there any provisions for broadcasting at low levels (say less than 200mWatt) within the FM spectrum without license?
I've seen some very low cost transmitters, and it could offer a very cost effective solution in some cases.
You are welcome to attend. Please bring your own FM receiver if you want sound... :-)
I saw a copy of the regulations a couple of years ago, maybe you can find out from ICASA (good luck...).
One thing I remember is that there were severe restrictions on unlicensed broadcasting in the FM band. 200mW is WAAYYY too much, it may have have been 1 mW EIRP if I'm not mistaken. I once transmitted a 100mW carrier signal on FM from a high building and could receive it in my car from approximately 3 km away.
Some cd shuttles use FM to link to the car radio and I've heard of some walkman's using a wireless FM headset.
Do you want to setup your own FM repeater, Kaspaas?
DFantom
11-01-2005, 07:28 AM
not sure if it helps you but www.internet.org.za, under the wireless section is all the information on what frequencys can be used. Not sure how it works with FM or even if i'm on the right idea here
kaspaas
12-01-2005, 08:06 AM
Do you want to setup your own FM repeater, Kaspaas?
It could solve lots of problems in old age homes. Hearing aids are not that great in a crowd. Actually, they are quite often not that great!
Many of them are quite hard of hearing and functions are nightmares because of this.
If you issue Headphones of some kind, they are not used to them and just can't get it right.
Using FM will enable them to get small FM receivers with headphones (which is quite cheap), practice with them beforehand and then be able to hear what is going on.
My dad is quite hard of hearing. We purchased him a set of cordless headphones and connected it to the TV. He can now follow the dialogue for the first time in many years. But this is quite expensive if you have to provide it to 50 odd people.
Sounds like a good idea, but the problem is how to get enough signal to every room, but not too much as to broadcast to the whole neighbourhood.
When I was at Varsity, a friend and I built our own FM repeater using an "open" frequency - we wanted to listen to our favourite FM radio station but it was just unreceivable inside due to all the interfering computers and electronics testing equipment, networks and so on. We started with 10 mW and ended up transmitting 100 mW into approximately 40 m of copper wire that we "installed" in obscure places all over our specific building. It worked well inside the building, yet outside the range was still about 200 m.
When we left Varsity, obviously we terminated our "broadcasts" to the dismay of some of the secretaries who were permanently tuned in to "us".