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Updated October 5, 2018

President’s Corner

September 2018

     Ah, Fall is in the air! Well, OK, maybe the air isn’t crisp and clear yet, but it’s time for all those great second-half and end-of-year events!

     We’ll be doing more with the USB software defined radios at Play Day. We’ll be having an open-to-the-public event at Mary Heads Carter Park in Carrollton and we’ve invited the four-city fire department leadership to discuss Amateur Radio. There are community service events to support: LifeWalk® (see the Dallas Amateur Radio Club website; Tech Net on the Hill; our Christmas Party; Outdoor Warning Siren tests and, WOW! I just get breathless at everything that’s going on.

     EchoLink® is working on the 442.650 machine. Dave Lane, N5GDL, has opened it up so a bunch of people can get on it at the same time. Try it out! Soon he’ll be moving it to the 145.210. When that happens, it will open up our primary repeater for more on-the-air nets. What would you like to see? Swap nets? Technical nets? Non-radio-related nets? Club meetings on the air? Let your club officers know, and we’ll help you get started.

     We’ll be meeting at the Farmers Branch Fire Department training room again this month, and October and November. It’s very nice of them to let us use their facility. Please remember, they are allowing us to use it because we support them through our SKYWARN® and our Outdoor Warning Siren (OWS) volunteer work.

     Steve Darrah, KD5YPB, is getting ready to demonstrate AREDN™ at the public event in October. If you haven’t put up an AREDN node please contact Steve KD5YPB, Mike W5MDB, Andy KE5KOF or any of a dozen or so club members who have experimented with the 2.4GHz (3cm) ham band. We need more nodes on the air to truly build a mesh network for our area.

     Speaking of cool new projects, we need to pull together some teams to put up our Winlink digital gateway node and our AREDN nodes using money from the Irving Amateur Radio Club grant. I am tentatively calling an organizational meeting at 6:30 PM on September 13 (the night of the club meeting) at the Farmers Branch Fire Administration building. We can continue after the club meeting if needed. If you are interested in helping to build, install, help with or learn about these technologies please plan to attend.

     I’ll see you at the meeting(s)!

     73 Kevin N5KRG

Musings from the Vice President

September 2018

     This month we’re featuring the second of our three-part series on repeaters. In Part One we learned the parts of a repeater system:

     1. Power Supply—Used to power the system, normally 12 VDC.

     2. Repeater—Used to extend the range of other radios.

     3. Duplexer—A repeater with a duplexer can transmit and receive simultaneously and allows the use of one antenna instead of two.

     4. Feed Line—Used to carry the signals to the antenna. As you’ll see in part three, not all feed lines are suitable for use in a repeater system.

     5. Antenna— The antenna is where the signals go in and out. Using duplexers enables the use of only one antenna and feed line. You can now mount the antenna at the top of the tower, enabling maximum coverage.

     Another item to consider about antennas not covered in Part One is to use an all-metal antenna. Fiberglass can fail in high wind and become brittle when exposed to sunlight and temperature extremes.

     Now on to Part Two. This month Ron Kochanowicz, KC0QVT, considers the five most important items to consider when buying a repeater system. In summary they are:

     1. Good receiver—less than 0.25 µV at 12 dB SINAD

     2. Solid, consistent transmit power with adequate cooling

     3. Built-in power supply with built-in battery charger

     4. Built-in controller

     5. Accessory port/expansion

Please go now to read or download the complete article.

73 Andy, KE5KOF

Analyze This!

     At the September 15 MARS Play Day, we will be using the amazing RTL-SDR dongles as an antenna analyzer. Yes, really!

     We’ll have a brief lecture about how antenna analyzers actually measure VSWR (they don’t) and how to add an inexpensive noise source and RF bridge to calculate VSWR up to 2 GHz. For those of us who do not have an analyzer for such high frequencies, this will allow you to measure VHF, 220, UHF, 900, 1.2 GHz, or (maybe) even 2.3 GHz antennas.

     We’ve created a complete analyzer package upgrade for your RTL-SDR for $45.00 that you can order using the SDR order sheet. Or you can order the parts yourself from eBay and Amazon Smile if you prefer. Please note that the noise source may not be available by Play Day time, but we will have extra sources there for you to use.

     To get ready for Play Day, go ahead and download the free RTL-SDR scanner software at Ear to Ear Oak.

     Play Day will be at the Carrollton Josey Ranch Lake Library on Keller Springs starting at 10:00 AM. If you have any questions, please send an email to Andy, KE5KOF.

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