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I was first introduced to DMR while in Florida in late 2016 by Jim Blocker (KF5IW) Jim is the owner/sysop of the KF5IW repeater based in Ft. Myers Florida in Lee County. The repeater is linked to others up and down the southwest coast of Florida and provides excellent coverage for local communications along with worldwide connectivity via the K4USD network.

Since early 2016, I have owned and used three TYT-MD-380's, a TYT MD-2017 and Anytone D868uv radios. Since I like to keep in touch with the guys down in Ft. Myers over the summer, I needed a way to do that, so I started building hotspots that took advantage of the Brandmeister network. Below is a sampling of what I have built. Both of the hotspots can be used portable/mobile with the appropriate power packs I have available and are configured to connect to any of my wi-fi connections at home or in my vehicle. Since there are no usable repeaters in the Rochester area with access to Brandmeister talkgroups, this method has allowed me to have reliable local and WW connectivity at home and on the road. No need for a costly mobile radio or antenna on the car!

 

Recent changes and upgrades to the Hotspot lineup (June 2018)

Anytone D868uv - Zumspot on RPi3B+ w/Nextion - Zumspot on RPi ZeroW

2.4" Nextion TFT Screen in "Idle Mode"

Zumspot on a RPi 3B+

5V cooling fan for the RPi3B+ and 90 deg. connector for antenna

Zumspot receiving my incoming signal showing RSSI and BER

Rear of Nextion Screen

 

The completed DMR Hotspot boards with cases ( January 2018)

Top: Shark RF Openspot - Zumspot on a Rpi3B+  Bottom: JumboSpot - Zumspot on a RpiZeroW

The acrylic cases are from C4 Labs - excellent laser cut parts form a beautiful and protective case

 

JumboSpot Project 01/2018

 

After searching for a wi-fi enabled, low cost alternative to the Shark RF Openspot, I was informed of a kit in the form of the popular Zumspot. It is available from AliExpress in China. Mine was purchased with the 1" OLED display which adds to the functionality of the unit. Upon arrival, a quick inspection of the parts indicated that they were of good quality and required only the header pins, OLED display and antenna connector to be mounted and soldered to the board. Only took about 15 minutes to complete the soldering of the parts and once put together and powered-up, an issue arose. No display! An inspection revealed that one of the header pins on the OLED was just long enough to make contact with the interior of the aluminum case when the antenna was tightened down. After resolving that problem, and a small configuration issue, it came to life!

Be sure to know that this board is used in conjunction with a Raspberry Pi Zero/W (wi-fi enabled) board that has the Pi-Star image loaded and operational so the JumboSpot can be configured. After going through the required configuration steps, and tethered to my cellphone hotspot, we're on DMR!

 

Parts included in the kit from AliExpress

 

 

JumboSpot mounted to the Raspberry Pi Zero/W and ready for configuration

 

Configured, in the case and ready to go on DMR!

 

Interested in building one of these?

Here are links to the basic parts needed to build and configure your own!

JumboSpot from AliExpress

Raspberry Pi Zero W

Configuration instructions **

** The above configuration document is based on the ZumSpot board **

All parameters are the same except under "General Configuration" - the Radio/Modem type should be set to:

MMDVM_HS_HAT (DB9MAT & DF2ET) for Pi (GPIO)

Refer to page 21 of the document

If your JS board is labeled with TX & RX offsets, be sure to make the changes in the Pi-Star configuration

From Pi-Star Dashboard. go to: (Admin - Configuration - Expert - MMDVM Host)

 


 

Portable DMR Go-Box for your TYT & Anytone handheld radios

in conjunction with an iPhone 6 / 7 as the "Hotspot"

 

Now that DMR is taking it's place among the newest digital modes, why not take your handheld with you as you travel and not be reliant on your local DMR repeater. With this article, you can construct a travel Go-box that will allow you to stay in touch with your friends back home and around the world! Consisting of a few items obtained from Amazon and easily assembled, you'll be on the air when and wherever you travel.

 

After researching many interesting approaches, I settled on the design seen below. It along with my iPhone 6 or 7 as a "hotspot" provides excellent DMR communications.

 

 

Components I used in the construction are as follows:

 

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Construction is straightforward. Place your components in the case to best serve your needs. There are a lot of different amperage levels and physical sizes for the power packs so select one that will power the router, Shark RF Openspot and even your iPhone. I chose the Rav Power model because of good reviews and I did not need 3 outlets. Once constructed, you'll need to configure the Shark Openspot, TP-Link Router and enable the "hotspot" on your phone.

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Not that familiar with the whole DMR thing? See the following link for a complete explanation of the workings of DMR  courtesy of Jim - KF5IW  Introduction to DMR 2017

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