The Experimentors Corner


My latest experiment was to build my very own DMR hot spot. When I was at Pacificon, I saw the Open Spot but with availability on back order and order fulfillment being delayed, this option wasn't for me. I travel to areas that are not RF friendly on several occasions. For example: Hotels, Starbucks and building(s) that make it difficult to get a signal out of with a rubber duck. As you can imagine the options to do such could be the following: Have a mobile repeater costing over $2500.00, or waiting for the open spot to come after a two month process of first paying for it then waiting approximately 2 months sometimes longer. However, after speaking with my good friend and DMR radio aficionado Don Webber KA7QQV the idea of building a Raspberry Pi III model B with the DV Mega board came up.

I was amazed how easy it was to source the required parts and get the station up and running. I went to Amazon procured the Pi, Case for the Pi, and DVMega all for under $250.00. Don was a tremendous help as he built the image and configured it for me. When all the parts came, it was simply plugs and play I logged into the box ran the updates set the hot spot up on all my wireless networks and like clock work after about a minute of boot up the system is up and running on the network.

The many benefits I have seen thus far are if you are limited to an HT and repeaters are hard to reach you can run this device in your vehicle teather it to you cellular device in the hot spot mode and use a HT to talk to the device, the device then takes your received signal transports it over the 3G and LTE networks to the Brandmeister server and then out to the repeater network.

Yesterday while traveling, there are no repeaters that cover the Pacheco Pass gap between Los Banos and Gilroy, Ca. With this little device I was able to communicate and communicate well as if I were sitting right next to my very own repeater.

This is exactly what amateur radio is all about, building experimenting and enjoying. My next project will be to build my very own home-brew DMR repeater using a Pair of Motorola CDM 1250 radios and a MMDVM board with DV MEGA. This solution has two possibilities that are cool one can run a repeater in Analog as Well as DMR in a true mixed mode application with network connectivity. Please stay tuned for more information to come.


Costs for the Pi DVMEGA Hot Spot are as follows:

Raspberry Pi III Model B with Case : $52.00
DVMEGA UHF Board: $129.00
SMA Antenna : $10.00
Shipping $10.00
Tax: $18.99
Total Cost $219.99

you will need to pick up a 16gb micro SD card at CVS, Walmart, Target, or eBay or even amazon to get the system to work as its the hard drive for the device.