Welcome to the Rio Amateur Radio Club Web
Site!
Ham radio has been sparking curiosity and building connections for more than a century—from local chats to worldwide contacts. At Rio ARC, we combine hands-on radio fun with a friendly, supportive community. Whether you’re a seasoned operator or just radio-curious, there’s a place for you here.
Based in Harlingen, Texas, we serve the entire Rio Grande Valley—from McAllen to Starbase. Our members explore every corner of the hobby: antennas, Parks on the Air, pico balloons, digital and analog modes, DXing, contesting, and more.
By joining Rio ARC, you’ll not only share in the fun but also have a voice in guiding the direction of the club. We host the Valley’s only Hamfest each year and take part in both ARRL Field Day and Winter Field Day. Along the way, we enjoy informal meetups where we learn, experiment, and share our knowledge with one another.
Curious to meet us? Drop by one of our laid-back breakfast gatherings—no pressure, just good food, good stories, and great company. You’re also welcome at our monthly evening meetings, where we talk radio, plan activities, and keep the club moving forward.
At Rio ARC, everyone is welcome. Whether you’ve held your license for decades or you’re just beginning to explore amateur radio, you’ll find a home here.
73
Rio ARC Serial # 11 Launched
09/01/2025
Last Report 09/05/2025
K5RGV Balloon #11 Flight Last Report
It appears that Balloon #11 was lost the evening of Sep 5 or Sep 6 early morning.
One likely cause is nighttime cooling. Because this was not a super-pressure design, the envelope cooled after sunset, reducing lift and causing a descent. Over lower terrain, the balloon could ride this out until sunrise, but in this case the track carried it into western Guatemala, where elevations are significantly higher.
That region includes Volcán Tajumulco (~4,200 m / 13,800 ft) and the Sierra de los Cuchumatanes, with peaks over 3,800 m. We had already seen the balloon drop below those altitudes on previous nights. If the same descent occurred again, it’s very possible that #11 descended into the mountains and was lost on a hillside or ridge.
73
— K5RGV Rio Amateur Radio Club
To track Serial 11's total global path, we now have three different sites for you to pick from.
Traquito balloon-specific telemetry decoding
wsprtv.com global map of who hears the balloon (good propagation visualization)
WSPR.spot raw WSPR reception reports (good for DIY analysis or feeding trackers)
Future Events
Breakfast Every Wednesday at 8:00 am
Los Leones in La Feria , 109 N Main St, La Feria, TX 78559-5004
Breakfast Every Saturday at 8:00 am
Tejano Grill in Harlingen, 803 S 77 Sunshine Strip
Harlingen, TX 78550
Monthly Club Meeting, 5:30 pm to 6:30 pm 2nd Tuesday of each month, except December.
Meeting Schedule:
September 9, 2025
October 14, 2025
November 11, 2025
No Meeting for December
Harlingen Irrigation District, 301 E. Pierce Ave., Harlingen, TX . 78550
Barry's Corner
Barry A. Boothe, W9UCW
"Over the coming months on this venue, I plan to present a variety of technical pieces and stories from nearly 70 years as an active ham."
There are now thirteen articles by Barry—some handwritten, some typed, and a few even featuring pictures! Just head to the menu and click on Barry’s Corner for some informative and entertaining reading.
What is an Unun?
Question 1:
What is the primary purpose of an unun in an antenna system, and how does it differ from a balun?
A) An unun converts balanced signals to unbalanced signals, while a balun converts unbalanced to unbalanced.
B) An unun matches impedance between two unbalanced systems, while a balun matches between balanced and unbalanced systems.
C) An unun balances antenna currents, while a balun matches impedance only.
D) An unun is only used with coaxial cables, while a balun is only used with ladder line.
Question 2:
Why is a 9:1 unun commonly used with long-wire or end-fed antennas?
A) Because it balances the antenna currents for symmetrical radiation.
B) Because it steps down high antenna impedance to closer to 50 ohms for easier matching.
C) Because it eliminates the need for a coax feed line.
D) Because it converts an unbalanced load to a balanced one.
An unun is a type of transformer used in radio and antenna systems. The word comes from “unbalanced to unbalanced.”
Here’s the breakdown:
Unbalanced: A signal that uses one conductor for the signal and another (often ground or shield) as the return. Coaxial cable is unbalanced.
Unun: Connects one unbalanced source (like your coax feedline) to another unbalanced load (like a random wire antenna).
What an unun does
It’s a transformer that changes the impedance between the coax and the antenna.
For example, a 9:1 unun is common for long-wire or end-fed antennas. It steps down a high impedance (like 450–600 ohms from a wire) to something closer to 50–75 ohms that your radio and coax expect.
It does not balance currents (that’s what a balun—balanced to unbalanced—is for).
Typical uses
Feeding a long wire antenna (random wire, end-fed, inverted-L, etc.).
Helping the radio’s tuner match the impedance more easily.
Reducing losses and improving efficiency when using coax with high-impedance antennas.
In short: An unun is a matching transformer that helps coax-fed radios work with unbalanced antennas that don’t naturally sit near 50 ohms.
Answers:
Question 1:
Correct Answer: B
Explanation: An unun connects unbalanced-to-unbalanced systems (like coax to a random wire) and provides impedance transformation, while a balun connects balanced-to-unbalanced systems (like coax to a dipole).
Question 2:
Correct Answer: B
Explanation: Long-wire and end-fed antennas often have impedances in the hundreds of ohms. A 9:1 unun steps that down to near 50 ohms, which is what radios and coax feed lines are designed to work with.
