June 6, 2019 Club Meeting
Thursday, June 6, 2019 at 7:00 PM Medford Police Department Community Room, 219 S. Ivy St., Medford, OR
Program: DMR Digital Mobile Radio, Pat Cunningham, KD7MPA
DMR (Digital Mobile Radio), is an open digital radio standard. DMR radios are capable of two transmissions on a single frequency (Slot 1 & Slot 2), and include features like text messaging and paging/alerting. They are very popular among hams because many (especially handheld) radios are available quite inexpensively. The is a large network of DMR radios developing around the world, and inexpensive hotspots can be purchased readily. Pat will talk about DMR, and demonstrate a hotspot.
Biography: Pat Cunningham, KD7MPA lives in Medford, and is involved in computer software and platform design for InVisionApp. He is active in the Rogue Hack Lab, and the Rogue Valley microwave mesh network.
Field Day planning session at the meeting, please plan on attending.
Announced in the June 2019 issue of The Repeater.
Meeting Notes
From the September 2019 issue of The Repeater.
2019-06-06 RVARC Meeting Minutes
Tonight’s presentation will be on DMR (Digital Mobile Radio), presented by Pat Cunningham, KD7MPA.
7:06pm Acting President, Scott, NA7OM, called the meeting to order. There was no Treasurer’s Report this month.
Work is continuing to get the club call sign changed to K7MFR.
The expenses for 7QP amounted to $117.50
Since upcoming Field Day expenses might exceed $300, Mike, WB6FFC, made a motion that the club authorize expenses to exceed $300. Tom, N5EG, seconded. In discussion, Raoul, KG6DKA, mentioned that last year’s FD expenses were about $375, but this year we are saved a $75 porta-potty expense due to the Agate Lake location. Voting was a unanimous YEA for the authorization.
The club website, W7DTA.org, is operating again, with new backups going to N5EG’s Google Drive.
Bill, N7EU, said the CARE club will help with Field Day and Mike, WB6FFC, said that he has improved his tower for easier setup. Field Day setup will be Friday, June 21, starting around Noon at the East side of Agate Lake.The Dry Creek Road will be used for wide separation of towers, where there will be about 1000 feet spacing available. The club has at least 200 feet of 99213 low-loss coax.
Scott, NA7OM, and Dan, N6WN, discussed the idea of giving first-test-Extras a chance at a free year-membership for checking out the club.
Some new attendees / visitors were:
- Nick, KJ7GHP
- Leroy, KJ7GFR
- Dave, KJ7GFS
- Fred, KF7UNF
- Forest, KH6EAL.
Welcome!
7:32pm Scott called for new business. The next club meeting will be in October, with the club swap meet in late August, or early September, usually the weekend before Labor Day. This year that weekend falls on the 24th of August, since Labor Day is on Sep. 2nd. Mike, WB6FFC, volunteered for the swap meet committee, and will help find a location.
John Laybourne, AC7S, needs to sign up for next year’s club meeting time-slots at the Medford PD Community Room.
7:37pm Break for snacks, and visiting.
—–Secretary had to leave at this point, Tom took over from here.
About 8:10 PM, Pat Cunningham, KD7MPA presented on Digital Mobile Radio (DMR).
DMR is an ETSI (European Telecommunications Standards Institute) standard. A Motorola specific version is called Mototurbo.
Some low cost radios available include: Anytone, TYT, and BTech.
There are three Tiers of DMR uses:
- Tier I : Unlicensed Simplex (used mainly in Europe)
- Tier II : Amateur, repeaters, and higher power
- Tier III : Trunked Radio (commercial).
DMR uses 4800 baud, 4FSK modulation in a 12.5 kHz bandwidth (basically a modified FM radio).
There are 2 independent timeslots during a transmission.
DMR supports talkgroups (of which there are thousands).
You need to get a DMR ID# before you can operate your radio. Website: RadioID.net— to register your callsign and receive a DMR ID#. The site receives about 3,000 registrations a month, and there are about 160,000 people registered at the current time.
DMR-MARC and Brandmeister are networks of linked Internet DMR reflectors. They provide access to the talkgroups, and provide the Internet linking of DMR repeaters and hotspots. Some reflectors can transcode between DSTAR or Fusion to DMR.
Website: hose.brandmeister.network is a network activity monitor that allows you to listen to DMR talkgroups with just your computer (no radio needed).
Each radio needs a “codeplug” which is a software configuration that defines the Zones, Channels, Frequencies, ID’s, color (like PL tone) for each channel. They can be complicated to program.
In the Rogue Valley there are no DMR repeaters currently, so operation is through personal hotspots (very short range) tied to a computer to access the worldwide DMR network.
DMR provides APRS support, both analog and over the Brandmeister network.
DMR also provides SMS (short test message) support.
Pat demonstrated his Anytone AT-878UV radio connected to his hotspot (which he brought along to the meeting). The hotspot is a small Chinese-made radio connected to a Raspberry Pi and is very inexpensive.
Pat made a call through the echo test service so he could have it record his audio then play it back. The audio quality was very good.
The meeting ended at 9:10, but discussions with the presenter continued for a long time afterwards.
(Editor—My experience is that the Internet based no-radio-needed monitors sometimes have poor audio quality, but the radios themselves, and internet-to-radio links sound quite good).
—73
