Antennas, experiments, engineering and other articles of interest to radio folks.
The Airspy YouLoop is a no tune, broadband, small footprint, affordable LF to HF receive antenna that works indoors. Its modular construction facilitates experiments to understand where the Möbius inspired electrical design provides benefit.
Aviation LF/MF beacons provide the opportunity to admire electrically-small antenna design on a macroscopic scale.
Today’s new SDR options and compatible software provide new ways to demonstrate radio technology to the next generation of STEM students.
Thule roof rails increased my VHF antenna mounting options on my Subaru Forester.
Quick demonstration of Time Difference of Arrival (TDoA) technique to correlate a common transmitted signal on multiple receivers to find the transmitter’s location.
Months of research prove the notion compressed data over ARQ modem techniques is anything, but effective encryption.
Much has been said about the electrical disadvantages of using a magnetic mount for your VHF/UHF mobile needs. Measurements compare the magmount to a thru-hole NMO mount.
Promoting amateur radio means to first promote technology and this American morse demo does just that.
One example of a PolyPhaser through panel protector makes one wonder if I have a counterfeit or has QC taken a turn for the worse.
For what it’s worth, the myths surrounding the J antenna have been sorted out resulting in an improved version.
Data from W4GO’s Virginia QSO Party operation confirms how well NVIS works from his SUV.
I add a 0.05 wavelength wire to my previous end-fed vs. center-fed dipole tests and plot the results.
I built a prototype APRS beacon, dubbed Thor Hammer (big), to test back-packable APRS 2m beacon concepts.
Add amateur radio to your beach trip keeping in mind family life balance.
Testing confirms an end-fed dipole can energize the radiator nearly as well as a center-fed without need of additional counterpoise or other extraneous conductors.
Win a Bridgecom System repeater system.
Some APRS beacon tests provide data directly comparing the energy performance of Energizer alkaline and lithium AA cells.
Mobile antennas have been around for decades, but assuming they perform the same is, sadly, a poor assumption as this comparison of Laird and Larsen VHF NMO EFHW aerials reveals.
Use this 2 second rule to measure when your driving is distracted enough to be of concern to you and others. Holding a microphone is fine, but other aspects of our mobile radios deserve scrutiny.
A simple S21 test reveals conductive shields do not change the behavior or ability of a ferrite to perform the role of common-mode rf current choke.
Careful selection of quality probes joined with the Raspberry Pi offerings yields a wireless E and H field sensor for accurate antenna analysis.
The Raspberry Pi Zero brings nearly off the shelf gear to the task of generating an RF test signal from a completely wireless, small, self powered device about the size of a D cell.
Simulations suggest end-fed and center-fed half-wave dipoles share sensitivity to various feedline lengths, but in differing and manageable ways.
I take a moment to document observed differences between end-fed antenna transformer topologies with and without ferrite core materials with a focus on the reactance compensation.