Ham Radio . Magnum Experimentum
Antennas, experiments, engineering and other articles of interest to radio folks.
John S. Huggins 
It’s time to replace my mag mount antenna and go “through hole” with my Mobile Antenna. NMO seems to be the way to go. Reviewed are some candidates from brand name to no name.
“Shocking” evidence our aerials collect electric charge plus an educational video on the topic of static electricity.
Magnetic Mount Antennas get a bum wrap it seems and for poor reasons and misunderstanding on how antennas work. Here is a way to see they are not so bad afterall… at least electrically.
Test results of the Coaxial Cable Balun and the Folded Balun (aka Pawsey Stub) reveal coax Velocity Factor applies to the former, but not the latter, unlike what many web sites would have you believe. Part 2 of 2.
Test results show coaxial cable velocity factor does not always enter into stub length calculations especially in the world of Baluns. Part 1 of 2.
FDTD reveals Hex Beam behavior with real movies of magnetic and electric fields in time.
By now I have posted several times about my new G3TXQ Broadband Hex Beam which came online in March 2010. I figure it is time to post a bit more on the materials I used for my version of the hex beam. Read more about the fine spreader kit from Max-Gain Systems.
This year our club ran 3A for the ARRL Field Day.
Radios included an Icom IC-756 Pro, TenTec Omni VII, Icom IC-746 (for the GOTA) and a Icom 7000 for VHF plus HF spare. All these radios performed quite well despite the high temperatures.
The 100 Watt Elecraft K2 stood above the others not necessarily on performance, but the elegant way the radio’s owner configured his K2, 100 Watt Amplifier and 100 Watt Matcher.
Hikers and Equipment needed for July 25th APRS Golden Packet event in West Virginia/Virginia.
The Field Day Broadband G3TXQ Hex Beam works Hawaii from Virginia during Field Day.
Well Field Day 2010 all started to come together pretty well. I put all the drinks and heavy items in the front to ensure good positive tongue weight. Pre-positioned the radio on that beautiful desk. Loaded up several antennas. Three masts plus stakes, etc. I even managed to figure out how to get my hex beam in there with a minimum of dis-assembly. It is quite a mess. I am sooo glad I selected that slinky wire that does not kink.
Here is a picture.
There is nothing like going to the beach.
Seafood, sand in everything you own, beach strolls, a time with family away from the usual distractions of life.
What better to do at the beach than visit the local lighthouse… especially a big coastal light station like Assateague Lighthouse on the Eastern Shore of Virginia.
Of course being a ham makes you notice things others miss with your “hammy eyes.”
Follow along in this picture tour of our visit to Assateague Lighthouse in 2007 and see the unusual thing we found within.
For quite a few years I have used the DX Engineering Maxi-Core Balun model number BAL050-H05-A.
I needed some quick deploy Baluns for the 80 Meter Turnstile Antenna covered earlier on Ham Help Desk.
Also purchased were two DXE-UWA8X-KIT products which provide hoisting points and strain relief for RG-8 size coax.
Here is a good web site on how to set up Packet Equipment for APRS.
In the never ending quest to improve our HF mobile ops for the Virginia QSO Party we finally decided to try a small loop.
There is nothing new about small loop antennas. They have been discussed in the literature for decades. The ARRL has some very old articles about them in the 1968 March and July editions.
Constantine A. Balanis’ book on Antenna Theory discusses and defines large vs. small loops. This book is an essential reference if you seek the details on how loops work. The loop described below fits into the “small loop” category where the currents along the conductor are, for all practical purposes, constant. This is unlike full size antennas where current reaches a minimum where voltage approaches maximum. Since this loop is electrically short with respect to wavelength, current does not change “much.”
A few years ago I installed lengths of LMR-400 Direct Burial coaxial cable in my back yard. I wanted good connectors for my investment. I seriously considered the superior N connectors, but my DX Engineering Coax Switch uses SO-239 connectors. While not the high quality choice, I succumbed to tradition and sought out suppliers for the PL-259.
Money was really no object since the connector is often the weak link in the system and deserves quality. I just made an investment in 240 feet of LMR-400 cable and wasn’t about to shortchange the connector.
Another possible Whacker runs afoul of the law.. or did he.
Anyone know and good and currently maintained APRS applications?
My latest ARRL renewal came with the usual free gift. This time I selected the “Emergency Communication Handbook.” I made a promise to the fifteen or so EmComm organizations that made an appearance during the Haiti tragedy to look at EmComm again with an open eye resulting in the ordering of this book.
Fair enough.
I was glad to order this book to see how EmComm might be done from a well organized perspective. I sat down one evening and opened it up. Here is the first sentence…
Many hams add power hungry radios to their vehicle power systems. A preferred way to obtain the power is directly from the battery terminals.
I have been adding various gadgets to my Ford Taurus to bring battery power into my passenger area so I can get rid of my cigarette lighter plug for my 2m/440 radio.
Adding a wire to my original battery posts was a problem so I used replacement posts from the car audio market. This turned out to be a mistake.
Running a fan on low voltage can keep your power supply much cooler without making a lot of noise.
The new antenna for 2010 at this QTH will be the popular G3TXQ Broadbeam Hex Beam. What follows is a look at the DX Engineering Hex Hub.
YouTube helps to document helpful Haiti EmComm.
Can the 10-20 meter five band HF G3TXQ broadband hex beam be used on 6 meters as is?