September 2023 Lecture and Lab: build an active fox hunt attenuator

If you’ve ever tried to find a hidden radio transmitter, or if you’ve ever wanted to…or if you’ve ever wondered how close you could get to finding a “jammer,” this month’s Lecture and Lab is for you!

We’ll be building the KC9NON active attenuator kit, an easy-to-build device that lets you get up close and personal with the radio transmitter that you’re hunting. The kit cost is only $20.00, and the tools needed are simple: a soldering iron, solder, wire cutters, wire strippers, and a small screwdriver are all that you really need. A hot glue gun and a needle-nose pliers were enough for me to finish my build. You’ll also need a jumper cable with BNC connectors (it can be very short, 2 feet is plenty), and a BNC-equipped antenna and radio, or else a set of adapters.

We’ll be meeting at 10:00 AM on Saturday, September 23rd, in the 3rd-floor community room at the Dallas Medical Center, 7 Medical Parkway Dallas, TX 75234. There are 15 kits available, first-come-first-served.

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Lecture and Lab, August 2022

The QFH Antenna, courtesy of Eugene Ruperto, W3KH

The latest revision of the instruction sheet and information guide is now available. I’ve also added some information about on-line resources.

The August, 2022, Lecture and Lab will be held in-person at the Dallas Medical Center on Saturday, August 27th, at 10:00 am. We’ll have an antenna build and a presentation, too. The antenna we build will be a 137-MHz helicoidal loop antenna pair for receiving weather satellite images and aircraft radio voice transmissions. The presentation will discuss the best software tools for decoding satellite imagery for yourself. The antenna will be very easy to build, and the cost will be only $30.00. 20 kits will be available!

You’ll need to bring a soldering iron and some general hand tools such as a tape measure, a sharpie, and your favorite set of files. The club will provide the antenna parts, but not the receiver: you’ll want to have a device that can receive signals at about 137 MHz. Most ham radios can’t do that, so now’s the time to check on your scanner or even order an RTL-SDR dongle or one of its competitors like an Airspy or SDR-Play. You’ll also want an adapter from a PL-259 connector to whatever connector your receiver uses.

I hope to see you there!

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DARC Lecture and Lab August 2021

These are the easy-to-build cores of the 1:1 balun and 1:49 transformer you’ll be assembling.

Join the DARC for Lecture and Lab August 28th, 2021 from 11am until 2 pm Central Time virtually via Google Meet. (The virtual meeting ID/Link is always on the W5FC event calendar) You will get to build two easy kits: a 1:1 choke balun and a 49:1 impedance transformer. Both will be enclosed in waterproof PVC enclosures and neither kit will require precision soldering. The balun will be constructed to hang below the center of your dipole, and the transformer will be set up for use at one end of an end-fed half-wave antenna. To pick up your kit, you will need to come to the front parking lot of the Dallas Medical Center on August 21st, 2021 from 10:30 – 11:30 to pick up your kit from the Dallas Medical Center parking lot from Tony, NT5TM.

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DARC Lecture And Lab April 2021

DIY Custom Shack LED Lighting Controller

DIY WiFi LED Controller Kit

Join the DARC for Lecture and Lab April 24, 2021 from 11am until 2/3pm Central Time virtually via Google Meet. (The virtual meeting ID/Link is always on the W5FC event calendar) You will be assembling a 12 volt custom LED lighting controller for your HAM Shack based on the QuinLED board with a WiFi enable Wemos board programed with WLED. In this LnL you will solder and assemble a complete WiFi enabled LED controller – it even comes with a case and a length of LEDs. Like previous virtual LnL events, participants will need to come to the Dallas Medical Center Apr 17, 2021 from 10:30 – 11:30 to pick up their kits from the Dallas Medical Center parking lot from Bill KF5ZBL.

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DARC Lecture And Lab March 2021

Anderson Power Pole Workshop

Anderson Power Pole

Join the DARC for Lecture and Lab March 27, 2021 from 11am until 2pm virtually via Google Meet. This will be an Anderson Power Pole Workshop – This Workshop will give you a complete overview of Anderson Power Poles and how they are used in HAM Radio. Participants will have a choice of five different Power Pole accessory kits to purchase and build. Like previous virtual LnL events, participants will need to come to the Dallas Medical Center March 20, 2021 from 10:30 – 11:30 to pick up their kits from the Dallas Medical Center parking lot from Bill KF5ZBL.

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Lecture and Lab 7/27/2019: A UPS for your RPi!

raspberry pi FMV34K4JU31TTMJ.LARGEThis Saturday’s Lecture and Lab will focus on a DIY Mini UPS suitable for use with a Raspberry Pi or charging your phone. It has 5v and 12v outputs and uses only 1 18650 Battery.  The cost will be $10.  Bring your soldering iron, hot glue gun, clippers and screwdriver.  If you don’t have any of the above, we will have extra on site.

If you’ve got something else you need to work on, don’t worry! All the “regulars” will be bringing our tools, and we’ll do our best to help.

Lab And Lecture May 2019

Anderson Power Pole Workshop

Anderson Power Pole

Join the DARC for Lab and Lecture May 25, 2019 from 10am until 3pm at the Dallas Medical Center. This will be an Anderson Power Pole Workshop – This Workshop will give you a complete overview of Anderson Power Poles and how they are used in HAM Radio. Participants will have a choice of five different Power Pole accessories to purchase and build.

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Lecture and Lab Presentation 08-26-2018: Measuring Return Loss with the RTL-SDR

return loss plot_cropSeveral club members and guests have asked if I can share my presentation…so here it is!

Some links you might find helpful include:

The scanning and comparison software that we installed and practiced using, RTLSDR-Scanner: https://eartoearoak.com/software/rtlsdr-scanner

The “runner up” software that can, sometimes, display spectrum graphs in real time, Spektrum: https://github.com/pavels/spektrum/releases (be sure to use version 1.2)

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Lecture and Lab 08-25-2018: What to Bring

analyzer setup IMG_20180710_142419262This Saturday’s Lecture and Lab should be a fun one: we’re going to learn about different ways to turn our RTL-SDR USB dongles into antenna analyzers. Bring yourself and your curiosity. Bring $45.00! Bring your RTL-SDR dongle. Bring your favorite ideas about what to do with the RTL-SDR. We’ll have time to talk about them. Besides all those things, you should bring:

    1. A laptop computer. A Raspberry Pi might not have the horsepower, but if you’re stubborn, you can try.
    2. You’ll save time if you download and install the software we’ll be using. We’ll start by doing things the easy way, with the RTLSDR-Scanner. The installation is very easy for Windows, but a little more involved for Mac or Ubuntu. If you have a Windows or Linux laptop, you can also install version 1.2 of Spektrum, which we’ll discuss and experiment with.
    3. Bring your RTL-SDR Dongle! We will not have any for sale. If you’d like to support the club, your could order a dongle or a dongle with small dipoles through smile.amazon.com.
    4. A 12-14V power DC power supply for your noise source. It helps if it has a variety of barrel connectors so that you can be sure of having the right one. It can be very low power; only 0.2 amps are needed.
    5. Bring an antenna to measure. You can even bring more than one. (You can bring a lawn chair to analyze! Have Fun! —KE5ICX) We’re going to have plenty of time to measure antennas, experiment with the scanning software, and share our favorite tips and tricks for the RTL-SDR.

 

Lecture and Lab 08-26-2017: What to Bring

We will have several extra sets of parts at the August Lecture and Lab, so don’t panic if you forgot to pre-register. What should you bring with you to the build?

At the very least, you’ll want to bring your choice of feedline connector. For many hams this will be a panel-mount SO-239, but you might prefer a panel-mount N or BNC. You’ll also need to bring some electrical tape, and possibly some coax if you want to test your antenna. A soldering iron and some solder will help you make much stronger connections.

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