Ham Radio . Magnum Experimentum
Antennas, experiments, engineering and other articles of interest to radio folks.
Articles about VHF operating.
Thule roof rails increased my VHF antenna mounting options on my Subaru Forester.
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.
I measure one example of a ferrite coax choke for response over frequency to understand its suitability for VHF and UHF.
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.
Erroneous specs aside, the N9TAX VHF SlimJim antenna is an exemplary dipole.
Aluminum comes in varying grades and the Diamond Antenna CP22E demonstrates why not all aluminum is created equal.
Despite its age AX.25 can compete with the slick newer digital technologies. Let’s see where packet fits into the digital landscape.
The J-Pole antenna’s long and storied design history is due for one more chapter to mitigate the longstanding mast current and reliability issues.
2014 Appalachian Trail Golden Packet report from Hawksbill (aka Northern Virginia) Station #6
You need an antenna with energy at high take off angles to hit the hill top repeaters… right? Well, not likely. Let’s review the details and do the math to understand what’s needed for VHF terrestrial radio communication.
Doyt Hoverman’s 1960s TV antenna design placed over a simple reflector screen provides impressive performance for today’s UHF and VHF-HI television bands.
Will the KX4O version of the 20-10m Asymmetrical Hatted Vertical Dipole work on 6m? Yes, sort of.
The Baofeng UV-5R provides modest quality with a low price yielding high value. This HT can literally be a Christmas stocking stuffer.
My first journey to the mountains as SOTA activator was a success using minimalist VHF FM gear.
The traditional collinear J-Pole, aka Super-J, improves the basic J-Pole. Are further improvements possible? By replacing the phasing stub with a simple coil, the answer is yes. The result is the Collinear J-Pole.
Results from station 6 of the Appalachian Trail Golden Packet attempt from Stony Man mountain.
A reinforced Subaru through-hole NMO installation using silver epoxy and a metal plate stiffener accommodates the 62 inch Diamond SG7900A dual-band mobile antenna.
The Northern Virginia team of Ham Radio operators and companion hikers manned Hawksbill Mountain for the 2011 Appalachian Trail Golden Packet event. Gear included a Kenwood D710 with Green Light Lab GPS, 2m Collinear J-Pole and a 70cm collinear J-Pole.
My G3TXQ Hexbeam gets a new metal backbone to accommodate a VHF beam antenna. A byproduct is a much stronger antenna assembly than the common Hexbeam approach.
I have experimented with Radio Mobile for a few years. If you have not tried using it, you should. It is a free RF link analysis program that uses geographic elevation data to help you determine the obstacles between two radio stations.
The details of this program’s capabilities are too numerous to mention here so please visit the web site here…
This J-Pole, Monopole, Coaxial Dipole VHF EZNEC shootout addresses a comment made that no models exist for j-pole and coaxial dipole antenna simulation.
Can a 2 meter J-Pole antenna work well on a child’s playset? Read and find out.