Inovonics 730 Manual

[Griselda Hamiter]

December 2016] Given the expense of a mod monitor that is read infrequently, some stations have opted to use only the meter in the processsor or a selection on the transmitter multimeter. Yet, the modulation monitor is a key diagnostic tool for any station, whether AM or FM. Here, Richard Rudman looks at the latest FM monitor from Inovonics.

I decided to start my evaluation of the 531N at a new FM transmitter I was building for a client at a remote mountaintop site in Eastern California, not far from where classic Route 66 crosses into Arizona.

My first challenge for new equipment was the answer to that eternal question: can I bypass the manual (yes, Inovonics still prints one out and includes it in the box) and go straight to productive use?

One built-in setup feature I especially like turns out to be the easiest way that I have seen thus far in a GUI to set a device up for dynamic DNS while dealing with IP connections that can block emails from going out.

If you are off-site, clicking on the speaker icon located in the common GUI header lets you listen to what is on the air provided you have an IP connection to the site with sufficient capacity. The pull-down menu to the left of the speaker icon lets you select several audio data rates up to 128 kilobits per second (kbps).

Although not an HD monitor itself, I have learned from Inovonics that the 531N is designed to operate among neighboring HD stations. They advise there is a known and fixed 4% higher reading in the presence of an HD signal at -20 dBc which could be eliminated with tighter filters, but would in turn compromise accurate measuring of modulation over the entirety of the 100 kHz FM baseband.

After conducting these tests, I brought the 531N test drive to several other sites for evaluation to see if it could pick out low-level signals at nearby sites in the presence of high power transmitters.

When I tried this monitor on several strong local stations in Santa Paula, California I found this statement is accurate as long as long as you also assure that is no multipath indicated on the instrument as the manual clearly states. In fact, I was able to get an accurate reading for the 57 kHz RDS subcarrier for the station I was monitoring with only a 2-foot wire antenna.

In our current FM world when most stations are using advanced audio processing to compete, as well as RDS or other subcarrier products, you should give serious consideration to the 531N to assure yourself that your facilities are in compliance with all Part 73 FM Rules.

A regular contributor to The BDR and a core member of the Broadcast Warning Working Group (BWWG), Richard Rudman is the owner of Remote Possibilities in Santa Paula, CA. He has extensive experience from small to major markets. Contact Richard at ra...@mac.com

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