Signature Wireless Group Icom iDAS Multitrunk (Northern CA)

[inigo88]

This is the first NXDN digital trunking system I've run across in California (though I know there are many more). NXDN is an FDMA 6.25 KHz narrowband digital protocol that was developed jointly by Kenwood and Icom for business users. NXDN is not supported by any scanner manufacturer, but can supposedly be decoded using the DSD program.

While they both use the NXDN protocol for voice, Icom and Kenwood made separate trunking system types, called iDAS and NEXEDGE respectively. This particular commercial system, owned by Signature Wireless Group, is the Icom iDAS variety. There is no control channel (unlike Kenwood NEXEDGE, which uses a control channel), and instead each voice frequency broadcasts a digital databurst every 5 seconds or so. This databurst sounds identical to the Kenwood NEXEDGE control channel data protocol, only it is a short one second burst of it, repeating every 5 seconds. For comparison, here is an audio sample of the NEXEDGE control channel: http://www.kb9ukd.com/digital/Nexedge478.6375control.wav

Signature Wireless Group has a website advertising the iDAS multitrunk system here: IDAS Multi Trunk Digital Wireless Network
And a coverage map of the system here: http://www.signaturewirelessgroup.com/images/all1.jpg

So far I've identified sites in the northern SF bay area on San Pedro Ridge, Big Rock Ridge and Grizzly Peak, and I've started an entry in the database here: Signature Wireless Group iDAS Multitrunk (Bay Area) Trunking System, San Rafael, California - Scanner Frequencies

Based on the coverage map, it looks like there are additional sites in San Mateo, San Francisco, Sonoma, Santa Clara, San Joaquin and Sacramento counties, along with possibly something up near Truckee.

Specifically, it looks like there are sites at:
Wolfback Ridge (Sausalito)
Twin Peaks (San Francisco)
Pine Hill (east of Sacramento)
Auburn Hill (Auburn)
Black Mountain? (San Mateo County)
Sonoma Mountain
Geyser Peak
etc...

I haven't been able to get DSD to decode NXDN yet, but the frequencies seem pretty active. SWG runs a lot of conventional LTR systems all over northern California, and as this system gains in popularity you'll likely see a lot of the analog LTR users make the switch. If anyone wants to take a stab at finding identifying the other sites on this system, please post here or make a database submission.

 

[mmckenna]

Some more info for ya'

Kenwood NexEdge is the name of the NXDN protocol, not just the trunking protocol.
Kenwood's NexEdge can operate in 6.25KHz (very narrow) or 12.5KHz (narrow) mode.
The current crop of Kenwood NexEdge radios will support LTR as well as analog and NexEdge. This makes it really easy for such service providers to do a gradual transition of their systems from pure LTR to NexEdge.
While Icom currently is only selling VHF and UHF IDAS radios, Kenwood is offering VHF, UHF, 800 as well as 900MHz NexEdge radios, so it would be worth looking for NXDN signals up in that range.

I run the 800MHz NexEdge trunked system for the University of California Santa Cruz. We have plans to expand our system over to the south bay area with a site on top of Mt. Hamilton. Still in the planning stages, might take a year or so to actually happen.

Glad to see NXDN is catching on. My conversations with the local Kenwood factory representative have suggested that there are more than a few local companies looking at this option. I'm quite happy with our system and the Kenwood radios. One of the really nice options they offer is an over the air programming system. That has been one handy tool to have.

Thanks for posting this stuff.

 

[mikewazowski]

I haven't been able to get DSD to decode NXDN yet,

Pretty sure you won't. From what I understand, DSD doesn't handle the trunked voice frames properly.

 

[inigo88]

Pretty sure you won't. From what I understand, DSD doesn't handle the trunked voice frames properly.

Thanks for the info, I thought there must have been something like that. With the progress we have made with DMRDecode now following both TRBO trunking varieties, I was surprised to see how little progress has been made on NXDN (it seems everyone on the NXDN forums just buys the commercial radios). I believe the NXDN Forum was planning on releasing the standard, so hopefully that will assist some anonymous programmer smarter than I in cracking the trunked voice frames. I'd love to have a program that dumps NEXEDGE/iDAS control channel data as well so we can start mapping out these systems. Hopefully we'll get to that point!

 

[kma371]

You must be home for the holidays and VERY bored

 

[inigo88]

You must be home for the holidays and VERY bored

For anyone interested in some "light" reading, here are the published NXDN technical standards:
NXDN™ Forum: How to Obtain the NXDN™ Open Standards | Instructions | NXDN Forum Website