• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

RDS Detector

C

Chuck

About a year ago, someone was selling a box that detected the presence of RDS on a station’s carrier. It had a relay which could be used to set off an alarm or shut off a translator’s xmiter if the RDS signal was lost.

I haven’t seen it advertised for some time. Does anyone remember who it was? Did it actually work? It shouldn’t be too hard to detect the presence of the RDS sub-carrier if you have access to the composite output of a tuner. Does anyone have a better idea for modifying a receiver to detect the presence of RDS?
 
That unit works great. I use it on a client's FM translator to avoid rebroadcasting a co-channel if/when the primary station would go off-air. Also, this translator is in the very fringe area of recpetion of the primary signal, so I use it to alert me when RDS is lost so we can shut the TX off (when it says RDS lost, the sound is usually horrible).

You simply set the PI code into the unit and (software adjustable) a relay will either open/close to alert you to the loss. Also, you can get lots of good into about your RDS signal.

Feel free to contact me if you have any other questions with the unit.
 
Chuck,

Just curious, where did you order this device? This seems like a neat backup alarm system for remote monitoring, as opposed to waiting for the transmitter to scroll through the dial out list. Is there also some type of system that will trip if the Stereo carrier is lost?

Thanks,

R
 
Robert Bass said:
Chuck,

Just curious, where did you order this device? This seems like a neat backup alarm system for remote monitoring, as opposed to waiting for the transmitter to scroll through the dial out list. Is there also some type of system that will trip if the Stereo carrier is lost?

Thanks,

R
Click to expand...

I ordered them from Broadcaster's General Store in Florida. You can buy them directly from the manufacturer, but they are about $10-15 more and they are not equipped to take a credit card.

These devices look for your station's unique RDS information. If that identifier goes away, the relay trips. That is fairly fail-safe, since it takes into account that any interfering signal might also have RDS present as well. If it does not match your unique identifiers, the box will decide that there is no signal present and pull in the relay. My observation is about the time you lose the RDS lock, your audio is so bad that it really needs to be turned off.

I don't think these folks make a stereo failure alarm, but you should be able to find a reasonably priced FM tuner that has an LED stereo indicator. If there is enough current present to light the LED, it might be sufficient to pull in a small relay. If nothing else, you could use the LED current to drive a transistor that pulled in the relay. Henry Engineering and (I think) RDL make stand alone relay boxes that can be triggered by low voltages such as would be present at the stereo indicator. Of course, some off-air and modulation monitors have alarm contacts, expressly for that purpose. You might check with Dayton Industrial. I think it is an optional feature on their tuners, which aren’t too expensive.
 
Thanks Chuck!

R
 
I said I would report on the Via Radio RDS detectors, so here goes. Mine just arrived today. I have not installed it yet, so consider this preliminary information. It is a very compact little box that seems to have origins in Germany. It is really intended to interface electronic sign displays with a station’s RDS signal. It does have a relay output, which is what I need to dump the translator input if RDS is lost. You can program the contacts to be normally open or normally closed. It comes with a full array of interconnecting cables.

Interestingly, there is both a composite input and a full-blown RF input. You can either connect it to antenna or run it off of the composite output of a translator's receiver. There is a software defined FM radio inside the box. The setup for it is very simple. In fact, it was almost fun to do. I don't know how sensitive or selective the built in receiver is, but using the headphone monitor jack, this thing sounds really good through my Sony 7506 headphones. I was VERY surprised.

All in all, it looks like an elegant solution to a nagging problem. There is no instruction book included, but each unit comes with a CD that has full documentation and all the software needed to set it up. Unlike lots of things I've tried recently, the set-up software was simple and easy to use. I wish everything worked this well.

I guess the acid test is at the translator site. At least, it works great in the shop.
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom