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Nautel NX series running C-Quam

X

xmtrland

Any one out there using a Nautel NX series transmitter running C-Quam Stereo? I see a setting in the NX menu tree that says Stereo C-Quam. Is it as easy as that? Was any other equipment or options needed like a C-Quam exciter or the Exgine board? Did you have to get a C-Quam modulation monitor.

Can you describe the process from beginning (Selecting Stereo C-Quam) in the menu and all the steps in between, what inputs did you use.

Kinda curious, Thanks
 
I believe you simply just select C-QUAM from the menu. You can only feed the transmitter with a stereo signal via AES audio.

The 1u rack mount Nautel AM IBOC exciters also have a C-QUAM function. Under the Audio Settings menu and AM Mode. So if you come across one of those not being used of HD anymore, give AM stereo a try.
 
I'm actually looking for some one that is or has run an NX series transmitter with C-Quam.

Because I don't own the stations that I help take care of that have NX transmitters, I'm not at liberty to give it a try. So far lots of views on this thread but no one has replied that they are actually running C-Quam with an NX and what was involved in the set up.

I have done HD AM with an NX50, even running MDCL with HD AM. I have also heard that with the Nautel Exporter you could do C--Quam. That leads me to think you need the external Exporter and Exgine installed in the transmitter. What if you don't have the Exporter and Exgine. Does the C-Quam setting allow interfacing an older C-quam stereo generator/Exciter. Next time I'm talking to Nautel I will have to ask.
 
I was curious myself so I asked an engineer who has set up C-QUAM on a NX series transmitter. He said It's built into the software and doesn't require any additional modules or hardware. You just need to feed the transmitter a stereo feed via AES audio. The analog audio input is mono only. There are no licensing fees to run C-QUAM these days. You do not have to get FCC approval or alert the FCC when enabling or disabling AM stereo on a station. If your tower setup is capable of running IBOC, it can run C-QUAM. Bandwidth requirements are not as critical with C-QUAM as it is with IBOC. There's a number of engineers who have setup C-QUAM on Nautel NX transmitters such as that currently used at 750 CKJH and 940 WYLD on the AM Stereo "C-QUAM" Facebook group, if you want to pick their brains some more.

As for the "why bother running AM stereo in 2025" argument that is likely to ensue... if it's available (as it is with these larger NX series xmitters), and you have or can easily/cheaply obtain a stereo feed to the transmitter, then why not enable it and use it? Those listening on mono radios won't be affected negatively by it. Radio nerds and those who are driving around older and classic cars (yes, 80s and early 90s cars are "classic" now) will be your AM stereo listeners. The stock 6 CD changer in my 2002 Ford Escape, and the similar single CD model in my 2000 Ford F-150 can decode AM stereo. They have automatic variable bandwidth and will open up wider when tuned to strong signals and stations running AM stereo. I believe Ford fitted these radios in their cars up until around 2005. Up until 2001-2002, many Chrylser radios could decode C-QUAM. You can decode C-QUAM using a software defined radio with sodiraSDR software. The currently manufactured plug and play web browser based 0-30MHz KiwiSDR and WEB-888 SDRs have a C-QUAM decoder built in. A handful of relatively older HD radio models can decode C-QUAM, none advertise it as a feature, and most don't have a stereo indicator (you have to use your ears). Except for the Directed model DMHD-1000 add-on AM/FM/HD tuner that will convert any FM car stereo to HD (and C-QUAM, unadvertised), I have yet to see anyone list any HD car radios that could do C-QUAM.
 
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