March RMHAM-U Impedance, Reflections and Transformation

03/18/2017

March 18, 2017, Chris Hamilton AE5IT did a very hands on presentation on Impedance, Reflections and Transformation relating to antennas and feedlines.  It was a very good description of how antennas, feedlines and SWR is related.  It was a great demonstration with lots of real-world demonstrations on how antennas and feedline matching relates to power and antennas.

If you ever wanted to see SWR visually, you’d love this presentation.  Look for it at an event in the near future.

We know it’s going to be at an upcoming Denver Radio Club meeting!

 


The Swapfest 2017 Edition!

02/28/2017

Once again the Aurora Repeater Association, Cherry Creek Young Amateur Radio Club and Rocky Mountain Ham Radio put on one heck of a show. Sunday February 19th was a beautiful day with temperatures not too hot or not too cold, no threats of snow and no icy roads.  The attendees came from near and far, well over 500 in attendance with over 120 vendor tables filled with everything from soup to nuts and trash to treasure. Highlights of the Swapfest were displays of the RM Ham Communications Trailer and their QRV2 rover vehicle.

Rocky Mountain Ham Radio unveiled its 2017 Pledge Drive. In order to continue the maintenance and expansion of the DMR repeater system RM Ham is asking the amateur radio community to chip in what they can so that we can continue to offer this premiere system and expand it throughout the region. Here are the details of the Pledge Drive.

We want to extend a BIG THANK YOU to all those who volunteered to help put on the Swapfest and to all those who came out and attended the event! Mark your calendars for February 18, 2018 for 2018’s Swapfest


Jack McComb W0JMC SK

02/24/2017

It is with great sadness that we report the passing of Jack McComb, W0JMC on February 23, 2017. Jack was a dedicated member of Rocky Mountain Ham Radio, as well as former EC of Arapahoe County ARES (ACARES) and a tireless supporter of amateur radio and its causes. Jack was a former over the road truck driver, a board member of Owner/Operator Trucking Association.  Jack and his family used to own an ambulance company in Denver.  Jack was a paramedic and owned a company that supplied emergency medical services to the film and television industry. Many of us were able to visit with Jack at the January Northern Colorado Amateur Radio Club hamfest in Loveland last month where we were able to share many memories with Jack, he indicated he had had suspended the aggressive treatment of his cancer in favor of enjoying the time he had left with his family and friends.

His widow, Jocelyn KD0ZVA, indicated that they weren’t going to have a formal service, but maybe a graveside when the weather isn’t as cold. More information will be forthcoming.

We will surely miss him.


RMHAM is an ARRL Affiliated Club

  • 11/23/2017TURKEY DAY 5K
  • 11/23/2017ARES DEC DMR NET 8:30-9PM
  • 11/30/2017ARES DEC DMR NET 8:30-9PM
  • 12/02/2017 7:00 pmRMHAM DMR Tech Net
AEC v1.0.4

RMHR Donates UHF Repeater to TARA

02/12/2017

Tech Amateur Radio Association (TARA) is a university amateur radio club at the New Mexico Institute of Mining & Technology located in Socorro, New Mexico.  TARA is currently being led by a familiar face, Skyler Fennell KDØWHB of Denver), who is a freshman studying electrical engineering.

One of TARA’s current projects is the construction and operation of a UHF repeater to rally their members on the air, to provide teaching opportunities using their test gear, and to attract other New Mexico Tech students to amateur radio.

On behalf of Rocky Mountain Ham Radio, a few members (Alan N5BGC, Dave KB5YIW, Ed KA8JMW, Brian N5ZGT) attended TARA’s monthly meeting to present a Yaesu VXR-5000 UHF repeater and duplexer that RMHAM has donated towards TARA’s repeater project.  We look forward to these young hams to do great things with the system (they had it unpacked and on their air in a temporary configuration before the meeting ended!).

Ed, in his capacity as New Mexico Section Manager, also presented TARA’s membership with an ARRL Handbook and General Class study manual.  Jim Lommen KC7QY, president of Socorro Amateur Radio Association was also on hand for the repeater presentation.

The ambition these young hams are showing, under Skyler’s leadership, is as impressive as it is rare within amateur radio, and it’s a treat to have them emerging within New Mexico’s amateur radio community.

For more information about TARA, visit http://infohost.nmt.edu/~tara

 


George Bartling, WA9TCD SK

02/08/2017

It is with deep sadness that we must announce that another key has gone silent. Our very own George Bartling WA9TCD died suddenly this week leaving many of us in shock and wondering why.  Those of us that had the pleasure of knowing George, know that he gave of himself selflessly. Need him to cover the EOC, no problem, need him to teach a class, no problem, need him to solder a connector he was there every time.

George was an active member of Rocky Mountain Ham Radio for many years. In addition to RMHAM, George was also very active in Arapahoe County ARES, O.M.E.G.A. Responders, as a teacher, and Volunteer Examiner where he is responsible for bringing many new hams to the ranks. George’s upbeat and positive attitude made him enjoyable to be around and helped make learning fun and interesting. George is survived by his wife and two sons. An informal memorial service is scheduled for 2PM Saturday, January 11, Beck Recreation Center, 800 Telluride Street, Aurora, CO. Rest in peace my friend.

 


Baofeng DM-5R and Radioddity GD-55 test results

01/03/2017

(Updated Apr 3 2017 to include the Radioddity GD-55.)

Rocky Mountain Ham Radio continues to investigate alarming problems with recently released low-cost DMR Tier II radios. This article focuses on the Baofeng DM-5R Plus, Baofeng DM-5R with Tier II firmware update, and the Radioddity GD-55  (a rebranded Tytera MD-398).

Performance of several DMR Tier II radios compared. From left to right: Tytera MD-380, Baofeng DM-5R, Motorola XPR 6550. The Baofeng has the Tier II update applied, making it equivalent to a DM-5R Plus. Not shown: Radioddity GD-55.

Our tests find that the Baofeng DM-5R Plus and Radioddity GD-55 are unfit for DMR use and degrade the repeater network. We will continue to forbid the use of these units on our systems.

Here are our findings.

Read more →


RMHam U – Microwave Transmission

12/17/2016

Sub-zero temperatures and upwards of 12-14″ of snow in some areas of the Denver Metro area didn’t stop the December edition of Rocky Mountain Ham University. Instructors Doug Sharp, K2AD and John Maxwell, W0VG conducted a lab in which 16 students set up, configured and put point-to-point microwave radio links in service.   Attendees learned about the pros and cons of several different vendors, networking options and many “do’s and don’ts”.


Problems with New Baofeng DM-5R, TYT MD-398 and Radioddity GD-55 Models

11/25/2016

During 2016 we have noted some new and good DMR radios, and unfortunately we have also seen some radios which cause concern. The radios in question are the Baofeng DM-5R, TYT MD-398 and the Radioddity GD-55.

At this time Rocky Mountain Ham Radio is requesting that amateur operators refrain from using the Baofeng DM-5R, TYT MD-398, the Radioddity GD-55 radios on the RMHAM or DMR-MARC Repeater Systems. This request also includes clones of the above radios such as Pofung, Retevis, Chierda, VITAI, Juentai, SAMCOM, Zastone, HYDX, etc.

Early tests show serious problems with these radios which will jam other users and severely degrade the repeater system. Further tests are planned and we will keep our members and users informed of the results on the www.rmham.org web site. This request does NOT pertain to the new firmware release of the TYT MD-380 and MD-390 and the use of these radios remains acceptable. We do strongly recommend updating to the most recent firmware for these units.  In addition you can find a list of radios known to properly interoperate with our system here DMR Radios, as well as sample code plug to program your radios Code Plug Samples.

In a nutshell here is what is being observed with these radios. When these radios transmit on Time Slot 1, Rocky Mountain Wide on most of the RMHam repeaters, they will actually transmit for a significant amount of time within Time Slot 2, which on the RMHam system are usually North, South or Denver. The net result? These radios are, in effect, jamming Time Slot 2 or at the very least causing harmful interference to any potential user in Time Slot 2. The user of the Baofeng DM-5R, TYT MD-398, Radioddity GD-55 radios or their clones will be able to use Time Slot 1 and will have no idea they are producing harmful interference to other users.

If you already own one of these radios all is not lost. You do have some options. These radios appear to function normally in FM Analog and DMR Simplex modes. If you purchased your radio from Radioddity or their Amazon affiliate they are honoring the 30-day 100% satisfaction guarantee. The manufacturers and importers are not currently considering this a product flaw. The radios and upgraded firmware are advertised as Time Slot 1 only. They are not currently addressing the jamming issue. For the details concerning the protocols and more technical details See Technical Information