Skip to content

Ham Radio . Magnum Experimentum

Antennas, experiments, engineering and other articles of interest to radio folks.

  • Home
  • Radio Shorthand
    • Morse Abbreviations
    • Morse Code
    • Phonetic Alphabet
    • Q Signals
    • RST Signal Report
  • Tech Talk
    • Antenna Gain
    • Antenna Counterpoise
    • Digital
    • Logging Software
  • Amateur Radio, Why?
  • About
    • Privacy Policy
    • Terms and Conditions
    • Request Account
    • Contact
    • Sitemap
    • Advertise
  • Subjects
    • Activities
    • Antennas
    • contesting
    • Connectors
    • Digital Modes
    • EmComm
    • Installations
    • interfaces
    • Introspection
    • Lab Shootouts
    • Miscellaneous
    • mobile
    • NEC Shootouts
    • News
    • Operating Tips
    • power supply
    • Accessories
    • Promoting
    • Propagation
    • Public Service
    • Radios
    • Repair
    • Reviews
    • Safety
    • Software
    • station
    • Test Gear
    • Tomfoolery
    • Whackers
  • Home
  • Radio Shorthand
    • Morse Abbreviations
    • Morse Code
    • Phonetic Alphabet
    • Q Signals
    • RST Signal Report
  • Tech Talk
    • Antenna Gain
    • Antenna Counterpoise
    • Digital
    • Logging Software
  • Amateur Radio, Why?
  • About
    • Privacy Policy
    • Terms and Conditions
    • Request Account
    • Contact
    • Sitemap
    • Advertise
  • Subjects
    • Activities
    • Antennas
    • contesting
    • Connectors
    • Digital Modes
    • EmComm
    • Installations
    • interfaces
    • Introspection
    • Lab Shootouts
    • Miscellaneous
    • mobile
    • NEC Shootouts
    • News
    • Operating Tips
    • power supply
    • Accessories
    • Promoting
    • Propagation
    • Public Service
    • Radios
    • Repair
    • Reviews
    • Safety
    • Software
    • station
    • Test Gear
    • Tomfoolery
    • Whackers

end-fed

Articles about feeding an antenna at its high impedance point.

The J-Pole antenna is herewith fixed

January 1, 2021November 14, 2019

For what it’s worth, the myths surrounding the J antenna have been sorted out resulting in an improved version.

Categories Antennas Tags EFHW, end-fed, J-Pole, measurement

Adding 0.05 wavelength wire to EFHW antenna

August 28, 2019
Various dipoles vs. one with 0.05 wavelength wire.

I add a 0.05 wavelength wire to my previous end-fed vs. center-fed dipole tests and plot the results.

Categories Antennas Tags counterpoise, EFHW, end-fed

BOB, the battery operated “beacon” for APRS

August 4, 2019July 29, 2019

I built a prototype APRS beacon, dubbed Thor Hammer (big), to test back-packable APRS 2m beacon concepts.

Categories Portable Tags 2m, APRS, backpack, Byonics, dipole, EFHW, end-fed, hiking, Laird, Larsen, N, NMO, portable, PVC, SMA

Electrically isolated end-fed vs. center-fed dipole radiation

January 1, 2021June 3, 2019
Measured magnetic field in vicinity of no-feedline end-fed and center-fed 10 MHz dipoles.

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.

Categories Antennas Tags center-fed, dipole, EFHW, end-fed, half wave, measurement, raspberry pi

Not all mobile antennas are the same

May 18, 2019May 9, 2019

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.

Categories Antennas Tags 2m, B1322W, EFHW, end-fed, Laird, Larsen, NMO, NMOWB150B

Of end-feds and feed-lines

June 12, 2019March 3, 2019
Grounded EFHW feedline

Simulations suggest end-fed and center-fed half-wave dipoles share sensitivity to various feedline lengths, but in differing and manageable ways.

Categories Antennas Tags 4nec2, autotransformer, counterpoise, dipole, EFHW, end-fed, feedline, NEC, Simulation, transformer

EFHW transformer two ways

May 2, 2019February 12, 2019

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.

Categories Antennas Tags autotransformer, EFHW, end-fed, ferrite, transformer

Simulating the end-fed half-wave (EFHW) dipole antenna

April 2, 2019February 4, 2019
The end-fed halfway dipole antenna with blowup of transformer.

A NEC model that includes the transformer helix helps demystify the end-fed half-wave (EFHW) dipole antenna using the autotransformer as impedance converter.

Categories Antennas Tags 4nec2, autotransformer, dipole, EFHW, end-fed, EZNEC, NEC, Simulation, transformer

EFHW HT antenna functions without additional counterpoise

January 1, 2021September 14, 2018
EIRP measurement of laboratory reference dipole, FT1D stock antenna and MFJ-1714 antenna.

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.

Categories Antennas Tags 2m, dipole, EFHW, EIRP, end-fed, FDTD, FT1D, measurement, MFJ, MFJ-1714, Simulation, Tiger Tail, yaesu

Diamond NR770HBNMO vs. Comet M-24M

February 18, 2020May 10, 2018

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.

Categories Antennas Tags 2m, 440, 70cm, Comet, Diamond, EFHW, end-fed, Forester, K515, M-24M, measurement, mobile, NR770HBNMO, roof rack, Subaru, UHF, VHF

The dipole antenna, how industry defines it

July 8, 2019April 28, 2016
All dipole antennas... according to the IEEE

Is a dipole antenna defined by its behavior alone or also how one energizes it? The answer exists in IEEE and historical literature.

Categories Antennas Tags center-fed, dipole, EFHW, EIA-329, end-fed, half wave, IEEE, offset-fed, TIA-329

EFHW LNR Precision EF-10/20/40MKII Test Data

May 18, 2019April 16, 2012
SWR Measurements of LNR Precision EF-10/20/40 End Fed Antenna

Basic tests of the LNR Precision EF-10/20/40 multi-band portable HF EFHW antenna including S11, SWR and a bandwidth check of the match box.

Categories Antennas, Reviews Tags 10m, 20m, 40m, EFHW, end-fed, half wave, LNR Precision, measurement

EFHW LNR Precision EF-10/20/40MKII Examination

May 22, 2018April 15, 2012
Schematic of LNR Precision 10/20/40 Portable Antenna Matchbox

The background and details of the LNR (Par Electronics) EF-10/20/40 end fed half-wave multi-band portable HF antenna. Come see what’s inside the mysterious “black box.”

Categories Antennas, Reviews Tags 10m, 20m, 40m, EFHW, end-fed, half wave, LNR Precision, NEC, portable, QRP, Simulation

2 Meter, 5/4 Wave Antenna Revealed

November 3, 2018December 20, 2008

We remove the mystique surrounding the 5/4 wave antenna comparing center and end fed approaches. One conclusion is the end fed 5/4 wave antenna shows little promise as a vertical antenna for terrestrial use.

Categories Antennas Tags 2m, 5/4 wave, center-fed, end-fed, J-Pole

Help support this site

Become a Patron!
Antenna and repeater parts

Topics & Keywords

2m 6m 10m 15m 20m 40m 43 foot 70cm 80m AHVD APRS Baluns battery BigIR copper Diamond dipole DX-Eng. EFHW Elecraft end-fed EZNEC Field Day Golden Packet hexbeam J-Pole Kenwood kj4faj KX3 kx4o measurement mobile NEC NMO NVIS packet PL259 QRP sdr Simulation SteppIR UHF vertical dipole verticals VHF

Recently popular

  • Improving the Super-J
  • Airspy YouLoop LF/MF/HF Möbius Receive Antenna
  • Build this Vertical Portable HF Antenna
  • Slim Jim vs. Traditional J-pole Antenna
  • EFHW LNR Precision EF-10/20/40MKII Examination
  • Simulating the end-fed half-wave (EFHW) dipole antenna
  • The 43 foot vertical – The answer to ...
  • Small Loop HF Antenna
  • J-Pole Antenna – Should I ground it?
  • Mast Mountable J-Pole Antenna
© 2007-2023 John Scott Huggins and other authors and creators, All Rights Reserved.