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Ham Radio . Magnum Experimentum

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

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  • 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
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Antennas

Simulations and testing are shown in these articles about ham radio, and a few other, antennas.

DX Engineering supports AHVD antenna

June 14, 2018June 14, 2018

DX Engineering supports the build of the Asymmetrical Hatted Vertical Dipole (AHVD) antenna with standard and two custom parts.

Categories Antennas Tags AHVD, dipole, DXE, vertical dipole

When antenna tilt matters

June 4, 2018June 3, 2018
Front view of UHF antenna patterns at various side to side tiles of the radiator.

We test a popular VHF/UHF dual band antenna at various angles to reveal antenna tilt on a vehicle matters only in certain circumstances.

Categories Antennas Tags 2m, 440, 70cm, Diamond, Forester, K515, measurement, NR770HBNMO, Subaru

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

Radials mitigate feedline and mast currents, tests reveal

January 1, 2021April 15, 2018
Radial Comparison Diamond Antenna X50NA

Antenna patterns from a Diamond X50NA reveal how radials of proper size mitigate current running down the feedline and mounting structure.

Categories Antennas Tags 2m, Comet, Diamond, GP-3, measurement, radials, X50NA

J antenna and variations thereof

February 22, 2018February 21, 2018
J antenna an variations thereof

There are many ways to morph the basic J antenna into useful forms.

Categories Antennas Tags collinear, J, J-Pole, Slim JIM, Super J

J Antenna Design Patent Grant

September 23, 2018October 10, 2017

USD798847S1 showcases one more incremental step towards a J antenna that works with masts and feedlines.

Categories Antennas Tags J-Pole, patent

Mast Mountable Antenna Patent Application

November 6, 2018July 22, 2017
Front view of Mast Mountable Antenna

The “mast mountable antenna” patent application is now available to review and critique.

Categories Antennas Tags J-Pole, patent

N9TAX 2m Slim Jim Antenna Review

January 1, 2021June 29, 2017

Erroneous specs aside, the N9TAX VHF SlimJim antenna is an exemplary dipole.

Categories Antennas Tags J-Pole, measurement, N9TAX, Slim JIM, VHF

The limits of aluminum antenna tubing

May 14, 2017May 6, 2017

Aluminum comes in varying grades and the Diamond Antenna CP22E demonstrates why not all aluminum is created equal.

Categories Antennas Tags 2m, Aluminum, CP22E, Diamond, VHF

Runt radials

March 24, 2017February 23, 2017

Antennas shipping with ineffective antenna decoupling are on the rise as manufacturers daringly advocate 1/12 wave radials work.

Categories Antennas Tags 2m, 70cm, Comet, decoupling, Diamond, GP-3, radials, X50

Diamond CP22E Antenna Review

October 10, 2018February 19, 2017

Despite some antenna gain hype, the Diamond Antenna CP22E 2m base station antenna is a remarkable design achieving 5 dBi directivity in a slim low-profile design.

Categories Antennas, Reviews Tags 2m, base, CP22E, Diamond

Decibel hell & the reign of antenna gain pain

March 6, 2017February 13, 2017

A short history of antenna gain terminology and some guidance to muddle your way through some of the nefarious alternative facts you may encounter.

Categories Antennas Tags bel, CP22E, dB, dBd, dBi, decibel, Diamond, directivity, gain, isotropic, LPFM, M2, neper, Slim JIM

Displacement Currents

September 17, 2018January 18, 2017
Kirchhoff's current law as boundaries.

Displacement current explains why the ends of dipole antennas have something more than zero current.

Categories Antennas Tags dipole, EFHW, half wave

Of fields and feedpoints

June 14, 2019December 31, 2016

Understanding how feed position along the half-wave dipole antenna affects the electric and magnetic fields around it.

Categories Antennas Tags AA5TB, Balanis, capacitance, dipole, E-field, EFHW, FDTD, Griffith, H-field, high impedance, Kirchhoff, link, link coupling, LNR, Simulation, Terman, voltage

Antenna pattern plots: Good intentions vs. good data

January 1, 2021May 31, 2016
Just say no to handcrafted data graphs

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.

Categories Antennas Tags G2BCX, J-Pole, measurement, Slim JIM

SlimJIM and Antenna Gainflation

June 21, 2018May 26, 2016
E-plane gain plots of J antenna variations

Understanding why SlimJIM antenna aficionados hype the gain in their marketing and discussions.

Categories Antennas Tags collinear, G2BCX, J-Pole, measurement, NEC, Simulation, Slim JIM

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

Ground effect

May 28, 2016April 27, 2016
40m monopole over various ground conditions

Ground conductivity, permittivity and the effects on vertical monopoles.

Categories Antennas Tags 40m, Ground, NEC, Simulation

Mast Mountable J Antenna Patent Pending

September 23, 2018January 14, 2016
Section View of Low Impedance Feed

A new j-pole patent? We will see.

Categories Antennas Tags J-Pole

Radials and their far field effects

May 28, 2016January 14, 2016
H-plane gain of monopole with 1, 2 and 3 radials

Radials are peculiar things worthy of some explanation.

Categories Antennas Tags far field, NEC, radials, Simulation, symmetry

Slim Jim vs. Traditional J-pole Antenna

February 27, 2022August 19, 2015
Measured gain of SlimJIM and J-Pole

Real measurements of a Slim Jim antenna and traditional j-pole antenna reveal the truth about their respective gain and pattern.

Categories Antennas Tags 5/8 wave, copper, dipole, HFSS, Hoverman, J-Pole, Lindenblad, measurement, NEC, Simulation, Slim JIM

Small Loop HF Antenna

July 4, 2021August 4, 2015

With components from a variety of vendors, custom machining and a bit of trial and error, another variant of a small loop HF antenna is born.

Categories Antennas Tags 40m, Aluminum, CAD, copper, DXE, Elecraft, gear-motor, HF, LMD18201, mast, microcontoller, NVIS, octagon, PicAxe, PX3, small loop, Solidworks, speaker stand, STL, toroid, transformer, type 43

NVIS Gain of Loop and Dipole vs. Height

March 17, 2017June 27, 2015

Observations from the Virginia QSO Party confirm simulation results concerning horizontal antennas and NVIS propagation.

Categories Antennas Tags 40m, dipole, horizontal, loop, NEC, NVIS, Simulation

Mast Mountable J-Pole Antenna

December 8, 2017June 17, 2015
Overview highlighting novel features of mast mountable j-pole antenna.

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.

Categories Antennas Tags inductance, J-Pole, Simulation, stub, UHF, VHF
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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
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