Diamond Antenna NR770HBNMO with K515SNMO mobile antenna review
After three years of mobile operation, I review the Diamond Antenna NR770HBNMO with appropriate K515SNMO mount including pattern measurements.
measurement
Experiments confirmed via various real world measurements.
Anatomy of a low frequency aviation radio beacon
Aviation LF/MF beacons provide the opportunity to admire electrically-small antenna design on a macroscopic scale.
Roof-racking VHF antennas on SUV
Thule roof rails increased my VHF antenna mounting options on my Subaru Forester.
VHF magmount vs. hole-mount performance comparison
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.
Will the real PolyPhaser please stand up
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.
The J-Pole antenna is herewith fixed
For what it’s worth, the myths surrounding the J antenna have been sorted out resulting in an improved version.
Electrically isolated end-fed vs. center-fed dipole radiation
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.
Energizer lithium vs. alkaline batteries
Some APRS beacon tests provide data directly comparing the energy performance of Energizer alkaline and lithium AA cells.
Effect of shields on ferrites
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.
Wireless near-field sensor
Careful selection of quality probes joined with the Raspberry Pi offerings yields a wireless E and H field sensor for accurate antenna analysis.
When an N connector isn’t
You would think the world of RF connectors of the pedigree of the “N” would rigorously follow the dictates of the standards that define them. Thankfully most do, but exceptions arise and here is one such example of why it pays to “trust, but verify.”
HT Antenna Comparisons
Does one really need to upgrade the antenna that came with your HT? Presented are EIRP measurements of various aftermarket HT aerials to help understand the trade space.
Fair-Rite 2661480002 Type 61 Ferrite Slide-on Chokes
A closer look at type 61 ferrite material in various configurations for RG58 reveals the benefits and insufficiencies of chokes in series.
Finding facts of Fair-Rite Ferrites
Learning more about several ferrite compositions from the Fair-Rite manufacturer including where to buy them.
Where a choke chokes
I measure one example of a ferrite coax choke for response over frequency to understand its suitability for VHF and UHF.
EFHW HT antenna functions without additional counterpoise
EIRP measurements of the 2m end-fed half-wave HT antenna from MFJ aids understanding a dipole is a dipole no matter where you feed it.
When antenna tilt matters
We test a popular VHF/UHF dual band antenna at various angles to reveal antenna tilt on a vehicle matters only in certain circumstances.
Diamond NR770HBNMO vs. Comet M-24M
The Diamond Antenna NR770HBNMO paired with their K515S insulated luggage rack mount provides measurable and observable upgrade for my 2015 Subaru Forester 2m/440 mobile.
Radials mitigate feedline and mast currents, tests reveal
Antenna patterns from a Diamond X50NA reveal how radials of proper size mitigate current running down the feedline and mounting structure.
N9TAX 2m Slim Jim Antenna Review
Erroneous specs aside, the N9TAX VHF SlimJim antenna is an exemplary dipole.
Antenna pattern plots: Good intentions vs. good data
In the 21st century should we believe antenna graphical gain data based on hope and hearsay? J-pole antenna gain drawings are a common bad example.
SlimJIM and Antenna Gainflation
Understanding why SlimJIM antenna aficionados hype the gain in their marketing and discussions.
Aluminum RF power splitters under test
Two examples of square aluminum RF power splitters built from 1973 plans reveal a 15 MHz difference from the claimed design frequency.
Slim Jim vs. Traditional J-pole Antenna
Real measurements of a Slim Jim antenna and traditional j-pole antenna reveal the truth about their respective gain and pattern.