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Inovonics INOmini 636 NOAA Weather Radio

One thing has always been a critical part of the broadcast operation

Generally speaking, a radio broadcast engineer is responsible for multiple moving parts around the facility. And as radio continues to evolve, we find ourselves more responsible for items such as network reliability, and less responsible for demagnetizing reel heads.

One thing, however, has always been a critical part of the broadcast operation: The emergency alert system. With that in mind, the EAS encoder/decoder must be able to reliably and intelligibly receive emergency alerts when dangerous conditions arise outside. The INOmini 636 NOAA Weather Radio from Inovonics provides certainty that radio listeners will stay informed and safe.


When the wind kicks up and dark clouds roll in, EAS alerts are expected. Proper National Weather Service repeater monitoring not only has compliance implications, but it is also a matter of thoughtful service to the listening audience.

A NOAA weather receiver that introduces considerable noise floor problems and poor reception and output levels is at risk of creating unintelligible alerts that could be exacerbated by downstream monitoring stations. An LP-1, for example, is a critical link in the EAS process and originating clean EAS alerts is extremely important.

The breakdown of this process was exemplified during the national EAS (EAN) test conducted in November 2011. Many stations reported having retransmitted garbled, imperceptible audio. Many of the messages had degraded to the point that header and EOM information could not be decoded. The INOmini 636 is built with �automatic intelligibility enhancement� that greatly improves weather station audio and ensures that no extra noise is added to the signal chain.


The INOmini 636 front panel is loaded with an easy-to-read monochromatic screen and one push/turn selector knob. The screen displays alarms, menus and all functions and settings. The INOmini 636 will tune to the seven U.S. and Canadian weather radio frequencies. The tuned frequency, as well as carrier strength, audio loss alarm, audio levels, signal-to-noise ratio and �weather alarm� are conveniently displayed. The carrier strength display and SNR display allow for proper optimization of reception and antenna placement. The front panel also includes a 3.5 mm headphone jack for convenient monitoring.


The chassis for the INOmini 636 takes up one-third of one rack space, allowing for several units to be rack-mounted efficiently. There are two parallel 12-volt power connectors that allow for �daisy-chaining� up to three units using one power supply. An F-connector accommodates a 75-ohm antenna line. Analog and digital AES outputs are available on XLR connectors. Interestingly, even though the weather radio material is monaural, analog output is available on left and right XLR connectors. This eliminates the need to split or bridge a single output. The digital AES output has a 44.1 kHz fixed sampling rate. The INOmini 636 has three alarm relays that will close in the event of carrier loss, audio loss and during the 1050 Hz alert tone. This is a perfect solution for using the INOmini 636 to trigger other alerting devices during weather events.


Using critical-listening monitors, the INOmini 636 performs excellently. The attention to audio quality and reception is immediately noticeable. �Perfect Paul� sounds clean and well processed. The noise floor is virtually unnoticeable and the overall sound of the weather station is full.

Improving the limited audio bandwidth made available on weather stations is not feasible. Improving noise floor, however, and providing the tools to diagnose reception and tuning guarantee that no impurities are added to the weather station audio.

For stations that want to provide a quality weather alerting service to their audience, the Inovonics INOmini 636 is a must.

Wygal is the operations manager for The Journey Radio Network in Lynchburg, Va.