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Reviewed by Pascal Villeneuve, VA2PV
In the past few years, VHF/UHF digital voice communication has been one of the fastest growing segments of Amateur Radio. D-STAR and System Fusion (C4FM) were specifically designed for Amateur Radio, but this is not the case with DMR — Digital Mobile Radio. It is an open standard, developed by the European Telecommunications Standards Institute (ETSI). As such, this technology is available to any company willing to build a digital radio, such as the BridgeCom Systems D-500 (by TEKK) reviewed this month. Introduction to DMR There are three types of DMR — Tier I, Tier II, and Tier III. To learn more about DMR, I strongly suggest that you read “Introduction to Digital Mobile Radio (DMR)” by John S. Burningham, W2XAB, in the October 2015 issue of QST. In this review, we will concentrate on the widespread Tier II DMR network. You will need to understand a bit about this technology to program your DMR radio. As DMR was not developed specifically for Amateur Radio, the terms are different from what we are used to. Tier II DMR uses TDMA (Time Division Multiple Access), which is a frequency-sharing protocol. You can have two conversations on the same frequency without interfering with each other. This is very efficient, as Tier II TDMA uses a 12.5 kHz bandwidth with two time slots. The switching is very fast, thus allowing for two simultaneous contacts on the same frequency, using this time-sharing method.
From Hoosier DMR Facebook page: https://www.facebook.com/HoosierDMR/posts/1472842543034680?notif_t=page_tag As we sit back and relish where Hoosier DMR has come from since its inception and the struggles we have endured, I am overwhelmed by the growth we have seen in just under a year....
Here are some thoughts and pictures from our visit to Ham-Com 2015 in Irving, TX.
Ron and I left the Kansas City, MO area on Thursday morning and it was 80+ degrees. When we got to TX it was 90+ degrees, so summer is officially here.
Driving from MO to TX without the radio on leaves for a lot of random conversation, good, but random. Ron and I discussed our thoughts and expectations for Ham-Com. We expected to have a good booth location, plenty of foot traffic, and generate a positive buzz surrounding BridgeCom Systems and our products. We packed with us three repeaters (BCR-50V, BCR-220, BCR-40U), the new BCM-220 mobile, and our MV-DMR server in a 2U chassis, plus the assorted banners and spec sheets.
We arrived in TX about 3:30p Thursday and went straight to the Irving Convention Center to unload and set up. The people of TX are very nice, lots of yes sir, no sir. We got set up pretty quickly, we like to keep the booth small with just a few products and brochures. I'm not a fan of the table across the entire front of the booth, but it seemed to work well this time giving us some shelter from the masses. However, I should have put the banners out front on the corners where people could have seen them better.
Author: John S. Burningham, W2XAB What is DMR? Digital Mobile Radio (DMR) was developed by the European Telecommunications Standards Institute (ETSI) and is used worldwide by professional mobile radio users. [http://www.dmrassociation.org] DMR is divided into three tiers. Tier I is a...
ROIP Radio over Internet Protocol (RoIP) is a two-way communication method which involves trans-reception of radio communication signals over internet protocol (IP). Cost effective and power efficient, RoIP essentially leverages the same communication principles as that of VoIP but requires...