Cranbrook Institute of Science

[RayAir]

What is all the buzzing on 424.950MHz. This used to be Cranbrook security. I thought Cranbrook was going to the Open Sky system, but it appears 424.950MHz is still in use. However, there is no voice, but rather data sounds. I don't think the data sound is digital voice either, but rather some kind of control data. It isn't a constant signal. Did they go to something like TRBO and this is a "beacon signal" being sent out by the controller to determine what radios are in range, etc?

 

[freqs]

Cranbrook Campus WPLF942 ops 424.475 ops 424.850 sec 424.950 dont know if this will help. I know it dont help with open sky or TRBO question you had but this waht I have from a old RADIO INFOSYSTEMS book .It is a rather out dated book but still useful from time to time

 

[radioron231]

Cranbrook is not going to Opensky, so I don't know what the noise could be. Maybe some interference.

 

[RayAir]

OK, I have no idea what I am hearing then. I programmed in their security frequency on one of my radios and about a year ago I stopped hearing voice and now I just hear intermittent buzzing. Maybe they went to a digital radio system such as TRBO or NXDN. I guess I will have to listen and compare the signal to samples of TRBO or NXDN. Thanks.