• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

COTHEN Questions

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BOBRR

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Hello,

Saw the new list in the new MT for COTHEN freq's.
Thought it would be fun to try to receive.

They show 13 of them, which means a lot of going back and forth trying to find something active.

Was wondering: are there any that are "most" active or most used ?

Also, have never played with ALE, which I guess all of these are.
Questions:

a. once the ALE controller establishes a link, is the freq pretty much set for the duration of the conversation ?

b. Is the determined freq. for both ends of the conversation, assuming it is two-way ?

c.Are they usually two-way ?

Much thanks, and regards,
Bob
 
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ALE can operate were all stations in the net periodically send out a "sounding" on each of the frequencies assigned to the net, other stations will "remember" the call and quality (LQA) of the sounding station. When a station call another they will attempt the connection on the best quality frequency that was last received from the called station. The connect call will be repeated several times over a period of a few minutes, this gives the called station time to scan through all net frequencies ( currently 5 ch/sec) one it hears the calling station it will handshake with the calling station, one this is complete the radios win unmute and can carry on a conversation. At the end of the conversation the protocol is the calling station will disconnct the call.

So yes once a call is established it will remain on the same channel until the call is terminated.

Having said that you may not know any conversation ever took place CBP and other agencies are implementing the Rockwall-Collins DVP-200 digital voice capable of 128 bit AES encryption. I recently attrended a demo of the system conducted by R-C. It sounded a lot like P25 on a VHF/UHF radio you can operate in a digital voice mode or AES mode, which sounds like noise on the channel with the exception of two quick soft beeps at the start of each transmission. This is remarkable because they are doing this in a standard HF channel with a bandwidth of 2700 Hz.

If you monitor for ALE you should hear periodic warbling tones which is what ALE sounds like while sounding or linking.
 

BOBRR

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Dec 15, 2004
Messages
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Location
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From OP:

Hi,

Just a quick thanks for info.

Sure is a lot to know with all the modes, methods, etc.
But, trying to learn.

Regards,
Bob
 
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