fm transmitter and hum and RDS

[intwoit2002]

I am using the FM transmitter that is made in Africa, can't remember the name, but it has the RDS chip included.

It had been working and still does except the RDS features. Can anyone give me the setup on the miniRDS software?

Secondly I have noticed some people complaining about hum with this unit. I have found that from the factory somtimes the case is not electrically connected to the grounds on the PC board. I removed a little of the paint so the mounting screws can make a good connection. The result was that some of the hum was reduced.

Still requires a loop of ferrite on the power supply wires.

Thanks,
Al

[N7XG]

Sounds like you need a good filtered power supply and not a wall wart.

[IdunBenhad]

Hi:
I assume that the power supply is 12 vdc. If so, try running the transmitter on a battery and see if the hum goes away.

I run my Vastelec FM02 on a converted PC power supply and it has no hum at all. However, it does not have RDS.

Check your shields on your audio cables. Sometimes a "ground loop" will cause hum. Disconnect one end of the shield, but not both. Usually the transmitter end should be disconnected.

Another way is to isolate your power supply from ground at the AC plugin. Do this by using a 3 wire to 2 wire adapter. This is not really the way to run the power supply, as it is "ungrounded" and not the safest setup, but it will help prove where the hum is coming from. Another consideration is that many power supplies and devices are 2 wire and not 3 wire. This means the 2 wire devices are not "safety" grounded, but they work OK anyway. (I will get some comments on this!)

Also, check your audio levels. Keep them as low as possible. Set your audio level to the FM transmitter by listening to a commercial station and then adjust your audio so the transmitter sounds about the same. Overdriving the audio can result in hum and distortion.

[budude]

I am using the FM transmitter that is made in Africa, can't remember the name, but it has the RDS chip included.

Sounds like EDM (http://www.edmdesign.com/) - have you contacted them for any advice?