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Showing posts from August, 2020

Ham Radio EMP Kits-The Tactical Trash Can

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This is post 2344 in a continuing series of simple ham radio antennas.

One of the great dangers facing radio amateurs these days is the damage done by EMP (electromagnetic pulse).  Whether the cause is natural (storms and solar flares) or human-made (detonation of nuclear weapons in the upper atmosphere), EMP can destroy much of today's solid-state equipment and wreck havoc with power generators and even the internet.

In this well-paced video from Josh Nass ("Ham Radio Crash Course"), we learn how to protect our equipment and continue to function after an EMP event.

Here are some of Josh's observations:

Many believe the worst threat to our electronics is being damaged by an Electromagnetic Pulse. Today I show you how to prevent that damage and what I place in my EMP trash can to be ready for what may come. The trick is useing a metal trash…

Vertical Antennas-Ground Radials

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This is post 2343 in a continuing series of simple ham radio antennas.

In this well-paced, informal discussion of vertical antennas, Callum (M0MCX) examines the number of radial wires needed to make a 1/4 wave vertical more efficient.

When I first went on the air as a "novice" licensee (1977) the general advice was lay "as many radials as possible for each band used." Depending on soil and moisture conditions, you could have anywhere between 4 and 100+ radials to raise the efficiency of the vertical antenna.

Nowadays, the advice is tempered by the use of elevated radials, sophisticated counterpoise systems, and vertical antenna systems requiring few or no radials (1/2 wavelength verticals).

In this video, Callum considers both theoretical and practical aspects of the ongoing radial debate.  Here are some of his observations:

Ground Radial…

How high should a dipole antenna be?

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This is post 2342 in a continuing series of simple ham radio antennas.

Thanks to David Casler (KE0OG) for this excellent, well-paced look at dipole antenna performance.

Customary wisdom says HF dipole antennas should be at least 1/2 wavelength above ground for best performance.  Dave use a variety of methods to answer this question.

The tutorial is informative and easy to understand.  Here are some additional comments from Dave:

How high should a dipole be? What happens if it's too low or too high? We turn to EZNEC antenna modeling software to see that the old rule of thumb of one half wavelength is correct. But there are lots of things going on! Learn about modeling and dipoles in this video. Subscribe: https://youtube.com/davidcasler. Ask Dave Playlist: https://goo.gl/inaQeB. Tip Jar: http://ke0og.net/tip-jar To learn more about me, visit: http://www.…

Slot Antenna

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This is post 2341 in a continuing series of simple ham radio antennas.

According to John Portune (W6NBC), an old satellite dish can be "repurposed" into a stealthy VHF/UHF amateur radio antenna with a few alterations.

In this videocast from "Ham Nation", John shows us how to make a surplus piece of equipment become a new 2 m/70 cm antenna.  All you need are a few basic tools and a few hours of your time to make an old "dish" a new antenna.
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For the latest Amateur/Ham Radio news and information, please visit these websites:

http://www.HawaiiARRL.info.
http://www.arrl.org.
http://www.hamradioupdate.com
http://www.southgatearc.org.
https://www.blubrry.com/arrlaudionews/
https://oahuarrlnews.wordpress.com.
https://hamradiohawaii.wordpress.com.
https://bigislandarrlnews.com.
https://eham.net.
https://paper.li/f-1576465810 (breaking Amateu…

My 2020 HF Radio Portable Field Kit

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This is post 2340 in a continuing series of simple ham radio antennas.

Thanks to Michael Martens (KB9VBR) for this enlightening introduction to portable radio operations.

As you can see, Michael has packed a full HF ham station into three easily-carried bags.  The bags contain his antennas, power supply adaptions, rig, tools, and spare parts.

Please assemble your own "Go-Kit" before emergencies occur.
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Here are some general observations from MichaelL
What do I carry with me when I hit the road for a Parks on the Air of some other kind of portable radio activity. In this video I break down the contents of my portable HF radio kit: Products/Items mentioned: Tactical Sling Bag: https://amzn.to/323gb5G Yaesu FT-891 Portable Transceiver: https://www.hamradio.com/detail.cfm?p... Domke Padded Wrap: https://amzn.to/317Ztmm LDG Z-11 Pro II Auto Tuner: h…

HF Portable-Choosing the right antenna

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This is post 2339 in a continuing series of simple ham radio antennas.

Thanks to the UK-based Watersstanton company for this informative and helpful tutorial on portable antennas. As the video explains, the end fed halfwave HF antenna is an excellent option for both home and portable use.

Here are some general comments from author:

Some antennas are more suitable than others. To have fun with HF QRP you need to stack the odds in your favour! LOW COST END FED HALF-WAVE MATCHING TRANSFORMER. https://www.youtube.com/watch?v=4PHyg...
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For the latest Amateur/Ham Radio news and information, please visit these websites:

http://www.HawaiiARRL.info.
http://www.arrl.org.
http://www.hamradioupdate.com.
http://www.southgatearc.org.
https://www.blubrry.com/arrlaudionews/
https://oahuarrlnews.wordpress.com.
https://hamradiohawaii.wordpress.com.
https://bigislandarrlnews.com…

How to build an inverted L for low bands.

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This is post 2338 in a continuing series of simple ham radio antennas.

If you enjoy working the low bands (80m/160m), then you know how difficult it can be to place a decent antennas for these frequencies on a small urban lot.

In this video from Callum (M0MCX) we learn how to build inverted L antennas to cover these bands.  Callum does an excellent job of explaining the theory, construction practices, and testing behind these HF antennas.

Here are some of his remarks:

I finally made my first Inverted L in summer 2017 to enter the IOTA contest for 80m band. I loved it. Small footprint and the best of both worlds, some DX capability on the one hand and some "local" ability too. See what you think. My name is Callum, callsign M0MCX. The whole DX Commander brand was a bit of an "accident" since I already have 2 x day-jobs (I own a couple of …