Saturday, February 15, 2020

Bridging modes

Mike, K9MLS recently posted to one of the Allstar lists I am on about creating a D-Star bridge.

dvswitch is a combined effort of Steve N4IRS, Cort N0MJS, and a few others.

Take a look at:

The software pieces are ASL (Allstar Link), Analog_Bridge, ircDDBgateway, MMDVM_Bridge.

It's possible to create multi-mode / cross-mode bridges with the software, between DMR, DSTAR, NXDN, YSF and P25.

With the DV3000 hardware AMBE vocoder dongle, DSTAR audio is quite good.

However a lot of folks use the MD380 emulator (which is the handy work of Travis, KK4VCZ's md380 reverse engineering project) to get around the hardware requirements of most systems that with otherwise require with dongles or boards.

Its also the preference for a virtual environment where you don't have physical access to the servers. Russell, KV4S did a good job documenting this with his blog entry titled "Hosting an AllStar Node and an AllStarDMR bridge in the cloud" 

Sadly that emulator doesn't support D-Star even though that is the mode completely out of patent.

In my opinion; For the price Mike would likely be investing in AMBE hardware, one should really think about soliciting the coding community and offering that money toward a solution that will benefit the community and move it forward.

Tuesday, February 11, 2020

Multiprotocol DV

Multiprotocol Digital Voice
Most of my ham radio "on the air" time has historically been mobile.  It’s a convenient way to enjoy the hobby when you'd otherwise not have the time to sit in front of a radio.  So that is VHF/UHF. Unfortunately we have a lack of standards adopted by the community so we have this digital fragmentation problem.  While repeater-to-repeater network layer cross mode solutions exist (like DVSwitch and XLXD), we still are waiting for a digital HT and or mobile radio that supports more than one digital mode.
But the problem is worse than that.  We don't even have a direct way to talk on the various modes over our smartphones, like you can with Echolink.  
A number of people seem convinced the AMBE patents are a part of the problem. Lets review:
Patents are protected for the longer of 17 years from issue date or 20 years from filing date.  Patents are still applicable for DMR, YSF (Yaesu Fusion), and NXDN. They should all expire by 2022, but sadly Patent 8,359,197B2 was filed on April 1, 2003. USPTO tardily granted it on January 22, 2013.  In compliance with legal guarantees, USPTO granted the patent a 5-year and 51-day extension. This patent would expire on May 22, 2028.
Open source advocate, Bruce Perens gave a talk a while back about possibly trying to invalidate it some years back. But since that costs money to pursue, and there are exceptions for non-commercial/ research usage of patented technology, that would really only benefit potential manufactures.
The AMBE patents aren't really the biggest problem. Solutions already exist. If you want better solutions those won't just come along when those patents expire anyway.
As an example, D-Star is already fully cleared of AMBE patents and has been since 2017A potential conflict, impeding software AMBE is the dplus person, AA4RC. The creator of the DV dongle. 
Software decoding (and encoding) tools exist. DSD, DSD+, op25, md380 emulator, etc. And a couple of those are open source. I'd say it’s just a matter of finding coders.
In my opinion, Max, KA1RBI and Doug, AD8DP should have a large fan base, as they are the unsung heros trying their best to move things forward, with zero monetary interest.... true hams!
I suspect another part of the problem why we don't have chipless AMBE access over the internet to at least the D-Star networks is because our current architecture relies on hardware AMBE for authentication/access.  If software AMBE apps were easily and readily available then this would open a can of worms as there is no current way to restrict access to just hams.
So this is something that needs thought by the US Trust (REF) and truthfully is more likely to be supported by some of the other splinter reflector network operators, like XRF, DCS, XLX..
And Brandmeister, Marc and other DMR network operators also need to get together and do some thinking too and come to a consensus on a new network protocol that actually has end user protocol level authentication, ie, password/ auth token.
As software AMBE becomes easier to install, presently I don't see anything that prevents someone from streaming AMBE audio at an IP address/UDP port and having it coming out over a repeater or group of repeaters.
If you are interested in ever seeing a cheap HT that can do more than one digital voice mode, then I suggest promoting and starting to learn about the above mentioned open source Digital Voice projects.  It's fairly clear to me after waiting years for things like the CS7000, DV4mobile and the “HT of the Future” to materialize, we (the hams) need to repeat the steps of the how the TNC (for packet radio) came to be readily available from commercial suppliers.
So let’s look back at how that came to be:
If you recall the TNC was started by Vancouver Area Digital Communications Group (VADCG) and it started as kits. Kantronics and Paccomm came later to offer it commercially. That is how it is supposed to work. We the hams innovate, and commercial guys can pick it up if they see it as something there is a business model for.
The Vancouver guys (especially Doug Lockhart) were the real pioneers, but it was a small experimentally-minded group that wasn't really thinking about mass-marketing yet.
A couple of Arizona hams with a vision took things to the next level. They designed their own TNC and formed Tucson Amateur Packet Radio (TAPR) to market it as a kit. The TNC-2 (their second version) eventually became a huge hit. But TAPR was (and still is) a volunteer organization, and volunteers can only go so far in making hardware. Even if you're a nonprofit, somebody has to sink a lot of money into a parts inventory. You need boards made. You need somebody to take the orders, package up the kits, and ship them. For volunteers, that eventually gets old though I'm amazed at how dedicated some of them still are.
So TAPR approached ham manufacturers and gave them the complete TNC-2 design for free. Yet TAPR still had to plead and beg them to build and sell it. TAPR wasn't trying to make a profit, they were simply trying to get packet radio into the ham mainstream and they couldn't do it alone.
Ham manufacturers are a fairly conservative bunch. They don't want to invest in anything unless they know it's going to sell. And that's hard for the kind of radical innovations that technically oriented hams like to work on just for fun. To coin a phrase, there's a real impedance mismatch between the two groups. Fortunately, much of the innovation now is purely in the form of software, which is much easier to mass-produce than hardware. So all you need the manufacturers for is to make general purpose SDR hardware, which is an easier sell than some new special mode.
The purpose of this article isn't just to bring awareness, it’s to hopefully attract some dormant hams with software coding skills to join forces and to help propel the projects and move ham radio forward.