Projects

Simplex DMR/Analog Emergency Portable Repeater

I started exploring the world of DMR around Christmas 2018 and the further into the subject I got the more I wanted to try it out... With no DMR repeaters or even people in my area with Handhelds to converse with I came up with the idea to build my own repeater! So the project started out as more of an experiment but soon exploded into a full-on portable DMR/Analog repeater solution. I chose a simplex repeater setup for ease of setup, portability, and on the fly change of Frequency if needed in the future.

Here is a basic run down of components I used for the project:

*HT's (users and repeater) - Radioddity GD-77 (https://www.radioddity.com/products/radioddity-gd-77-dmr-two-way-radio)

*50Watt UHF (DRM compatible) RF Amp- Btech U25D (https://baofengtech.com/amp-u25d)

*Simplex Repeater Controller and cable for HT (Kenwood style) - Argent Data Systems ADS-SR1 (https://www.argentdata.com/catalog/product_info.php?products_id=98)

*Waterproof Case

*Generic PWM Solar Charge Controller

*DC Voltage Display

*18650 cells and battery holders (to replace HT's battery for longer use)

*Lots of wire, switches, buses, connectors!

The system also includes a 100watt solar panel, deep cycle 12volt battery, and dual band base station antenna with coax feed-line (all not pictured)

I chose the GD-77 because at the time it was about the most reasonably priced, dual band/dual mode, DMR hand held on the market that fit my needs and budget. However this project could be done with about hand HT or mobile DMR rig of your choosing!

The biggest challenge of the project was actually choosing a simplex repeater that would work with DMR reliably! I tried out several Chinese made simplex controller and they would work great on Analog but were spotty at best when it came to repeating a DMR voice transmission! Without the versatility of the Argent Data System Simplex Controller this build wouldn't have been possible!! I cannot say enough about this very cool product and highly recommend it!!