Crime Stoppers

[415Tango]

removed.

[Phil]

hi 415Tango,

Fantastic info you have provided at the moment the Motorola Zeon Digital Network is unlistenable as it is a digitally encrypted trunked network although the lower frequencies you provided for example 468.25 is a Special Events channel which today is being used for the QPS at the Big Day Out not alot of chat but enough to know where they are coming from

[Comint]

hi 415Tango,

Fantastic info you have provided at the moment the Motorola Zeon Digital Network is unlistenable as it is a digitally encrypted trunked network although the lower frequencies you provided for example 468.25 is a Special Events channel which today is being used for the QPS at the Big Day Out not alot of chat but enough to know where they are coming from

The original poster said that the frequencies are between 505 and 515 MHz, so it is NOT the Motorola Zeon Digital Network (which is between 865.0125 and 869.9875 MHz). And while MOST Tetra networks are encrypted by default, it is apparently NOT a Mandatory requirement. However, having said that, it is true that there is currently NO scanner available that will monitor Tetra, encrypted, or otherwise.

FWIW: Frequencies between about 505.0000 and 509.5250 MHz are repeater output frequencies, with the inputs 10 MHz higher eg., 515.000 to 519.5250 MHz.

Also, it would be interesting to know the Brand/Model No. of the radios being used, as there aren't many models that will handle both Tetra and Conventional in the same unit.

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Comint

[Stretch]

So Comint, seeing as it isn't in the 800 range, are these listenable??

[Finch]

You can pop in the freqs but it's probably encrypted and you'll only get freqs not TGIDs and you'll miss bits of conversation if it isn't encrypted.

[415Tango]

Also, it would be interesting to know the Brand/Model No. of the radios being used, as there aren't many models that will handle both Tetra and Conventional in the same unit.

The radios being used are the Motorola MTP850, which is Motorola's most recent TETRA Portable Hand Held two way. It does say that they use the Zeon network, and I remember when I turned them on they would say "Zeon" on the screen with a blue circle. However, a mate of mine who was scanning during schoolies, said he heard me talking around the 505 MHz area, and these were the only radios we used the whole time.

[Comint]

So Comint, seeing as it isn't in the 800 range, are these listenable??

. . . However, having said that, it is true that there is currently NO scanner available that will monitor Tetra, encrypted, or otherwise.

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Comint

[Comint]

The radios being used are the Motorola MTP850, which is Motorola's most recent TETRA Portable Hand Held two way. It does say that they use the Zeon network, and I remember when I turned them on they would say "Zeon" on the screen with a blue circle. However, a mate of mine who was scanning during schoolies, said he heard me talking around the 505 MHz area, and these were the only radios we used the whole time.

Well, the plot thickens.

As far as I can tell, the MTP850 is only capable of operation on one Band, and in this case, as it was on the Motorola Zeon Digital Network, that would be the 800 MHz Band. Also, I can find no mention of it being able to operate as a Conventional analogue radio, so direct operation on QAS, QPS, etc, frequencies is not possible.

TETRA is 4 slot TDMA (Time Division Multiple Access) so monitoring with a conventional scanner would only receive 'raucous noise', and NO intelligible audio, irrespective of whether it is encrypted or un-encrypted, as it is still Digital. Each slot only transmits for 14.167 milliseconds (0.014167 of a second) at a time.

If your mate heard you on 505 Mhz, then the organisers were probably using a Bridge of some kind to link different systems together.

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Comint

[415Tango]

Wow. It amazes me how complicated these things are.

How would they have used a bridge to link systems together?

[Comint]

Wow. It amazes me how complicated these things are.

How would they have used a bridge to link systems together?

A Communications Bridge (also known by various other names), is basically some electronics that takes the received audio from one radio and feeds it to one or more other radios, and also has provision for keying the other radios.

It can be something as simple as a JPS ACU-M, or as complex as their ACU-1000, or Link-Comm's Tactical Communications Bridge.

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Comint