What happens when: Multiple DMR signals & SDRangel

The below video shows native DMR decoding with SDRangel software. On 427.505 MHz is an OpenSpot V1 and on 427.565 MHz is a duplex "China" Spot. 

It is very easy to leave the SDR, in this case the inexpensive NooElec Nano3 tuned to 427.565 and then toggle in the channel down to 427.505 MHz.  Both hotspots were tuned to the same talk group of 31630 during the Tuesday evening Northstar Digital Net.

One thing to notice is that the carrier time keys up quicker and also "hangs" when a discussion drops compared to the quicker times on the duplex "China" Spot.

With SDRangel, you can "run" multiple decoders for different (or the same modes) at the same time. 

You would leave SDRangel "tuned" to one frequency and you can then tune up or down from that frequency in each decoder. This will work within the SDR's capable bandwidth. In the case of the NooElec Nano3, this is 2.8 MHz. 

Also, you can "run" multiple decoders (Analog FM Narrow, DSD for digital voice, Channel Analyzer, etc) all at the same time on the same frequency to just "hear" for example the buzzzz sound of DMR via the analog FM Narrow decoder PLUS the actual DMR demodulated audio AT the same time.

There is A LOT of capability with SDRangel. Give it a try. You will like it and the ability to customize the layout to your liking for certain tasks.

Why Update To Pi-Star Update 3.14.3?

Most of the folks involved with HVDN agree that DMR is the digital voice mode that is spurring on massive growth in the hobby compared to Yaesu Fusion (C4FM) and Icom D-Star (GFSK) digital modes.

This HVDN article talks about Pi-Star
version 3.14.3 and its new cross mode features

Other digital voice modes that amateur radio operators are experimenting with include NXDN and P25.  While Fusion and D-Star were developed just for amateur radio use, DMR, NXDN and P25 all started life as commercial standards.  DMR was the first to see "ham grade" equipment for sale and truly sparked the digital growth we see today.

DMR is an open standard and many new vendors took advantage of this and started to offer radios at budget price points to spur experimentation with radios marketed directly towards the amateur radio community.   Traditional "ham equipment manufacturers" such as Yaesu and Icom pretty much missed the boat by continuing to push closed standards, with Icom having a very high licensing rate of its D-Star technology built by the Japanese Amateur Radio League almost 20 years ago. The only vendor who paid to get on board with Icom's D-Star is Kenwood with its 2016/2017 released $500+ TH-D74 radio.  Limited options and expensive equipment has kept many away from D-Star as a result.  Yaesu has fared a little better, but really not by much until recently with new affordable equipment.

All These Acronyms...

There is a comparison of the different modes mentioned above at the bottom of the "Basics of DMR" page on HVDN for those interested in more details as it gets confusing quickly for some people.

Because of all these different digital modes, different radios can not communicate with each other and take advantage of benefits and featured offered by digital technology compared to analog FM or NFM. Analog FM equipment is what has been the dominant amateur choice of non-HF radio for at least 40 years and digital migration is kicking and screaming its way into the amateur radio community. A universal digital standard is needed to truly replace FM.

Your very own repeater? Sort of...

The SharkRF OpenSpot was the first "hot spot" type device to provide cross digital mode support.  What this meant was a DMR based radio could talk on the D-Star network to other users with D-Star radios.  It also provided the ability for a Fusion radio user to talk on parts of the DMR network.

SharkRF Openspot was the first cross mode capable hot spot
device to see mass adoption by amateur radio operators

With DMR radios such as the TYT MD-380 or Radioddity GD-77 costing less than $100, it gave many amateurs a taste of what 80,000+ individual users already registered to use and also be able to talk to those with just Yaesu Fusion or Icom D-Star Equipment to see if they are missing anything.

Converting analog FM repeaters is not always the best option for those looking to add digital repeater capabilities to a specific area, so "hot spots" have found a unique niche to fill the gaps while owners of great sites for repeaters decide what to do when thinking about what digital modes to support for wide area coverage to eventually replace much of the FM based repeater infrastructure.

One of the latest "hot spot" devices provided by a community of developers. This MMDVM board
provides simultaneous transmit and receive or "full duplex" operation. It is like a "mini repeater" 

Pi-Star & 3.14.3

Another "hot spot" type of device based on open source design is sometimes known as the ZUMspot, JumboSPOT, ChinaSPOT and a number of others.  The team behind Pi-Star took somewhat more "scary" command line interfaces and made things easier by way of nice visual interfaces. These all mostly run a user interface called Pi-Star and the latest revision does something very interesting.

Version 3.14.3 allows anyone with a Yaesu Fusion radio to also communicate over DMR, NXDN and P25 now. This is pretty monumental where now that Yaesu has some lower priced new Fusion radios such as the dual band hand held FT-70DR or higher powered mobile FTM-7250DR, users an now use the inexpensive Pi-Star driven hot spots to connect with users of NXDN and P25 plus of course those on DMR. It also lets someone who may have purchased surplus commercial NXDN or P25 radios communicate over DMR or Fusion.

Turn in 1000 Feet: Excitement Ahead

Could these largely community and developer driven efforts be just what some of the more well known amateur vendors need to take advantage of?  Notably absent is any form of Icom D-Star anything in this latest revision.  Kenwood sells commercial NXDN equipment as well as P25.  Icom also sells commercial P25 equipment.  Yaesu's sister brand, Vertex, also has P25 equipment on the market.

One great example of a community member working with a commercial vendor is Ty,  KG5RKI who has alternate firmware available to increase features in certain radios.  Retevis partnered with him to officially support his work.  Will we see Icom, Yaesu, Kenwood or even Alinco take a similar approach?

Could DMR just be the entrance ramp towards a NXDN or P25 amateur future?

All these digital modes also do much more than just transmit voice. They can also be used to share GPS location and text messages in the same narrow frequency bandwidth used, some at the same time as voice communication.

From just May of 2017 to today,  by May of 2019 it should be interesting what else continues to see development and what commercially made equipment comes to market.

Updating to the latest 3.14.3 release is as easy as logging into your pi-star interface, going to "expert" mode and then to the SSH function.  After providing username "pi-star" and your password or default "raspberry",  type in "sudo pistar-update" and then after that completes, run "sudo pistar-upgrade"

Please note that you may need to modify certain hot spot boards to allow firmware upgrades, but you should find no shortage of those with knowledge to help you along the way.

Sample Resources

• Live Discussion: Have a look at the HVDN Net & Activity page 

• Social Media:  Facebook has a number of users groups such as JumboSpot, MMDVM & Digital 

• Local Discussion:  Local Hudson Valley DMR repeater directory (always under construction)

• In Person:  HVDN will start having in person meetings in Rhinebeck, NY later this summer once the location completes construction.

Join HVDN for FREE for the first year. Details here.

Using a JumboSPOT via bridged Wi-Fi

On a recent business trip, I left my trusty GL i.Net GL-AR150 at home by accident and could not use my new JumboSPOT unless I used my mobile hot spot feature on my mobile phone to give it the internet access it needs.

JumboSPOT running Pi-Star in DMR only mode

The GL-AR150 is a travel Wi-Fi router which I have plugged in to the ethernet port on my laptop to share its internet connection and create a wi-fi hotspot. This setup essentially lets me take hotel wi-fi and then rebroadcast it so that other devices could use the internet. The laptop essentially acts as a router of sorts in this configuration taking wireless hotel internet, translating it to wired internet and then turning it back into wireless internet.  Make sense?

GL-AR150 multi purpose travel router

Since its always annoying to keep my mobile phone charged up while traveling, I figured it would be a good experiment to see what range too expect from a 10mW DMR hotspot from the 39th  floor of the hotel and out into the city of  Atlanta.  Not having the AR150 with me prevented me from trying this, so I had to find another solution instead of setting up my mobile phone hotspot function, which worked great to make a contact via TG 31368 the previous evening.



Connectify to the rescue!

I found this application named Connectify to do what the hardware I left behind but via software and it works great! It took the hotel Wi-Fi SSID and creates a new access point using the laptop wi-fi to then rebroadcast to the SSID I set up and had in place on the JumboSPOT.

    

   

I would highly recommend the Connectify application to be used in a  travel situation much like I describe above in order to get on DMR with a JumboSPOT.   This is slightly more elegant than the DV4MINI I have used before with my laptop or the GL-AR150 and OpenSPOT combination when traveling. 

Connectify is currently running a 70% coupon on top of it, so get it while you can. You will need the MAX version, not the LITE one. This application will find many more uses aside from just using it to connect the JumboSPOT, which is now my go to device for travel along with the MD-380 for DMR operation. This trip proved a benefit that came out of an annoyance afterall.

An optional, but recommended addition is to also use the "Speedify" VPN application to provide a secure connection and the ability to monitor latency and loss in addition to the upload and download speed reported in the "Connectify" application. Speedify is free for up to 1GB of data transfer a month which seems more than enough if only using this for use with the JumboSPOT.

After about an hour of listening in to a few talk groups with active discussion, only used 3MB of download and all traffic was less than 30ms latency.

http://www.connectify.me/