PPM Installation

[RadeoEngineer]

I'm about to do the world's simplest PPM installation on a stand alone FM. Question for you guys that have done these; should there be some kind of pre-processing in front of the encoders to help them during low level audio passages? Something like a Compellor? The stations audio chain consists of an 8100 working alone. Console levels are all over the place (noncommercial all volunteer staff).

 

[WNTIRadio]

You definitely need something in front of the PPM encoder. It needs a minimum level, and a fairly consistent one to encode the secret tones we can't hear. If the level goes below a certain threshold, the red light will come on and it won't encode. On the flip side, if the levels are hot, the A/D-D/A converters can overload in the PPM encoder. A compellor would be good to tame the levels going into the PPM and it will also have the effect of making the station sound quite a bit better on the dial.

If the budget affords it, I would recommend the Ariane (and no, I have no affiliation with TransLanTech nor am I paid for this message. I just really like their AGC). There's also a pair of used Prisms on eBay for about a grand.

 

[level42]

Agreed, you will need something. I highly recommend this box:

http://inovon.com/?a=2&s=1&i=32


Great AGC and Limiter...plus a built in audio loss alarm closure, analog and digital ins and outs. Wins over a Compellor hands down and can be had for a few bucks cheaper.

Good luck. Has anyone had multiple power supply failure problems on the PPM encoders?

 

[bossbill]

And Behringer makes a very inexpensive leveling product. Point already made and I concur, is you need to install the encoder(s) after the AGC and before the stereo generator.