The second phase or revision of D-Star is out there. Both Icom and Kenwood are selling radios for it, it's general name is NXDN - FDMA.. It's know as Icom IDAS (Icom Digital Advanced System) and Kendwood calls it NEXEDGE.
NXDN Forum Announces its Formal Establishment
This is a brand-new digital format was co-designed by Kenwood & Icom that is geared towards the business sector. It is designed for those that want to meet the up-coming FCC mandate for 6.25 KHz channel spacing, but that can't (or don't) want to move to the APCO P25 Phase-II equipment that will soon come to market. The format is based on the AMBE+2 voice codec (similar to ICOM's D-STAR), but uses a 4-level FSK modulation (FDMA). The radios are capable of narrowband analog, along with 12.5 KHz & 6.25 KHz digital emissions. Kenwood is offering the system under the name NEXEDGE, and the radios are capable of both conventional & trunking operation. The attached sound file contains all of the formats the system is capable of producing, including the raw data streams of both digital formats.
D-Star, developed by ICOM, is the forerunner to the commercial counterpart of the technology we now know as IDAS (ICOM Digital Advanced System).
IDAS, also known as FDMA is the system generally best suited for commercial use since it meets all FCC technical standards through 2018 and is backwards compatible with 25 kHz, 12.5 kHz analog systems plus capable of operating in the digital mode on 25, 12.5, and 6.25 kHz channel spacing.
We have been to be Icom's lab rat for their rollout of commercial P-25 Phase-2 products. It's nice to know that the AMBE codec that was chosen for D-Star is slated to replace the IMBE codec in Phase 2 of APCO 25. For once it puts us as ham radio operators into state-of-the-art in communications for the first time in about 10 years. It's so nice to say that.
Audio sample
It uses AMBE+2 codec and 4FSK (4 level FSK) / FDMA (frequency-division multiple access scheme) digital modulation. AMBE+2 codec is compatible with IMBE used by P25 phase I.
NexEdge/IDAS was built off D-Star. Unlike D-Star, the NXDN repeaters can repeat analog or digital so you can have a smooth user migration.
It supports unit ID auto-roaming/registration much like how D-Star works.
Looks like the pricing to get going with NXDN will be about half the cost of D-STAR implementation. NXDN is like MOTOTRBO in that it can support mixed mode, but whats nice unlike MOTOTRBO & D-Star is more than one manufacture making radios & costs less on both accounts.
An ID-RP2C Repeater Controller for D-Star runs about $1500. You need to add an band specific RF voice module such as the ID-RP2000V for 2 meters which is another $1400
Where as the Icom IC-FR5000 Series VHF and UHF Repeaters run about $1500. This NXDN route also provides the analog/digital mixed mode backwards compatibility that D-Star doesn't.
The user end radios between D-Star and NXDN appear to be very similar in price.
The best overview I have found:
http://www.mygmrs.com/nxdn/index.php
I'd like to think that now since Kenwood is making AMBE Digital voice radios for their Nexedge, that one might see a Kenwood D-Star radio here in the US in the not to distant future.
If they do this, I hope they can improved upon the current Icom line.
Not sure where you have been, but they have: it is called the NX700 for Hi-Band and the NX800 for UHF, they have up loadable radio "firmware" id currently Ver 4.0 and the audio in digital will knock your socks off! 512 channels, and are about half the price (on eBay) of a DStar Radio (New), be it made by Kenwood or Icom... Be well, Wilmajean KD7HP
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