I had to check the publication month printed on the cover of the latest
Nuts & Volts magazine when I ran across
this article last night. It is labeled "August 2015" and not "April 2015," but take a look at the photo below
that accompanied an article titled "Build
a 50 MHz Dipole out of Crutches" (p25). Author and amateur radio operator
Bob Fischer (WB8BEL), aka "The Antenna Sculptor," actually fashioned a working 50 MHz
dipole out of a pair of metal-framed crutches. The ones featured in the article were purchased new, but he advises
suitable crutches can be bought second-hand for a couple bucks. Admittedly, he says, "I'm certain this novel antenna
would never survive high winds or ice loads, but it was not built with permanent installation in mind. I think the
best uses for these crutches are teaching antenna resonance, getting attention at Hamfests, and starting conversations
about emergency communications at public venues promoting ham radio." It is known that larger diameter antenna elements
result in a wider operational bandwidth, so I wonder whether those crutches have a measurably
higher bandwidth than a traditional wire element dipole? A simulator model of the radiation
pattern with az-el
gain would be interesting.
50 MHz Crutches Dipole Antenna
(Aug 2015
Nuts & Volts magazine)
Of course what really caught my attention was the license plate on the host truck. The Internet is full of photos
of contraptions that reinforce the stereotype - deserved or not - associated with West Virginia, like the
Hillbilly Hot Tub. WV folks, for
the record, are some of the best people around. In fact, I have such high regard for them that I married a West
Virginian (Melanie is from
New Martinsville,
and is a WVU alumnus). Note to West Virginians: If you
decide to build this antenna, be sure to use metal crutches and not wood, plastic, or fiberglass ;-)
Mr. Fischer, by the way, is a licensed professional engineer, and owner of
Fischer Technical Services, located in Huntington,
West Virginia. Per his website, "Fischer Technical Services is a small engineering firm that has been providing
cost effective plant maintenance and electrical & instrumentation consulting since 1979. If your company
has reliability issues, technicians that need to improve their troubleshooting skills or inexperienced engineers,
give us a call to discuss how Fischer Technical Services can help. We have an engineer who lives 'where the
rubber meets the road.'"
August 10, 2015 update from none other than Mr. Fischer himself himself:
I made a presentation on the development & construction of my crutches antenna at the
Huntington, WV Hamfest yesterday.
One of the attendees told me he was going to post a picture of him standing with the antenna to his
Facebook page.
I was looking for it this afternoon when I came across your article. Thanks for your kind remarks.
The antenna I built has a <1.2:1 bandwidth of more than 1 MHz.
I was interested in the fact that the dipole needed to be shortened to around 98 inches for 50.5 MHz
resonance (As opposed to something in the neighborhood of 108-110 inches.).
I believe that is due to the relatively large "apparent diameter" of the dipole elements. The crutch
parallel conductors are roughly 5.5 inches wide. I think that makes the "apparent ratio" of antenna
length to conductor diameter on the order of 20/1. Most antennas have ratios on the order of thousands
to tens of thousands.
I have worked OK, TX, FL, MO and a lot of New England sitting in my WV driveway with the antenna on the
back of the pickup.
Please give my regards to your hillbilly wife.
You have a nice website.
Bob Fischer
WB8BEL
Posted on July 23, 2015
