One of the many misconceptions about the D-STAR digital amateur radio protocol is that it is closed and will prevent tinkering by hobbyists. This turns out to be far from the truth indeed. Last year at the Dayton Hamvention there were several exhibits by D-STAR enthusiasts which included an entirely home brewed D-STAR radio and a home brewed D-STAR repeater controller. Well now someone has built a DV interface adapter which can provide a D-STAR digital voice interface on many existing transceivers. Of course some functionality is missing as there is no ability to change various DV settings from the minimal interface but it proves yet again that there is the possibility for much experimentation with this new digital mode.

On other fronts the OpenDSTAR group has released several software tools which build on existing commercially available repeaters and Internet gateways to extend functionality. Still in the pipe from that group is a USB dongle called the DV Dongle which will allow end users to encode audio in the AMBE format used by D-STAR digital voice for later playback through the repeater or, ostensibly, for live PC to repeater communications. Indeed the home brew spirit of amateur radio is alive and well in the world of digital communications, it just looks different than it has in the past.

I recently found the USRepeaters.com website which contains a listing of many of the amateur radio repeaters in the United States. I actually had a plan at one point to develop a similar PHP/MySQL driven site but simply have way too many other projects going to take on another. That said I do have a few issues with the US Repaters site. First, the site is a mess graphically and navigation leaves a lot ot be desired. The lack of an interface for owners of repaters and/or coordination bodies to make changes, users to search, etc. is also unfortuante. Secondly, the data is copyright instead of being open and freely available. As inexpensive as webhosting is these days and seeing that ham radio has a long tradition of sharing knowledge I am disappointed to see someone attempting to assert control over this factual data. I think a simple ad supported site (not the ads all over approach US Repeaters takes) would be sufficient to support such a directory. If someone out there is interested in working on an open PHP/MySQL repeater directory I would be more than happy to provide web space, bandwidth and my ideas. Contact me if interested.

Many towns, counties and states still using analog based radio communications systems for public safety use Motorola MDC systems which emit a short "chirp" at the beginning or end of a radio transmission. If this is the case in your area you might be interested in the open source WinMDCD software. This software allows you to decode that chirp with a Windows based PC and see data such as date, time, unit ID or whatever else they're transmitting. Note that if you're interested in Motorola radio technology a great resource is BatLabs, in particular the BatBoard which has a great number of people who are extremely knowledgeable about Motorola radios.

In a followup to an earlier article about the Cisco IPICS system I have received some additional information that seems to indicate my preliminary analysis was correct. If you remember when Cisco launched their IPICS 'emergency communications system' I suggested it was really more of a way to tie existing communications systems together than a new system itself.

It seems that Cisco has been looking into this for a while and ostensibly created this product to fill an internal company need for connecting disparate communications systems. This case study explains how Cisco created a Land Mobile Radio (LMR) over IP product to fill a need to communicate with their own security personnel. The end product is described in this Cisco whitepaper entitled "Cisco Land Mobile Radio over IP Solution Reference Network Design".

The LMR over IP product is a card which can be installed in any of the voice capable Cisco routers and provides an interface that connects full-duplex VoIP datastreams to speaker, mic, push-to-talk (PTT) half-duplex devices. Signaling is via standard H.323 and the card uses RTP audio with a variety of codecs. The card used is called a VIC Ear and Mic (E&M) interface and was originally used to connect VoIP to some legacy PBX hardware. Technical information about the E&M interface can be found in this technical publication. If your LMR equipment supports a half-duplex T1 that can be used as a trunk interface instead.

As a friend pointed out the existence of support for this type of configuration presents some interesting ideas for amateur radio VoIP projects. Without going into too much detail the current preferred methods of connecting amateur radio stations with VoIP is to use either the Echolink or IRLP project. Both of these have a significant number of problems, one of which is that they require a computer to be attached to the radio. It would be much nicer to attach a (more stable) router to the radio instead. This merits some more research. Once you got a radio attached to a VoIP phone system such as Asterisk there's all kinds of interesting possibilities.

While it's prohibtively expensive to build the Equinox radio scanner probably represents the pinnacle of radio scanning equipment today. A fully remote controllable PC based radio (RF) scanner this is truly the Cadillac monitor.

From its home in the Seattle, Washington area, the Equinox receiver provides continuous, remotely-accessible coverage of the DC-1 GHz spectrum on a 24-hour basis.

While it would be a bit much for individual hobbiests to build one of these it would be cool to see scanning clubs such as Minnesota based ScanFan get together and buid one for community use. The internet provides a great way of participating in this increasingly expensive hobby (as more systems go digital) if we could allow for some remote control and data from the reciever(s).