The Amateur Amateur: My First Step Toward HF -- High on the RooF
By Gary Hoffman, KB0H
Contributing Editor
June 20, 2002
I am still in
the early stages of the HF game--still experimenting, still learning,
and still not sure I know what I'm doing.
Every new ham has
considered, at least briefly, working the high frequency (HF) bands.
I don't recall exactly when I decided I'd like to try it myself, but
even then I knew it wouldn't be like operating on 2 meters. All I
needed to operate on 2 meters was a hand-held transceiver. Working HF
would require... well, a bit more.
SWR meter: Just owning one of these things made me feel like a real ham.
[Photos by the author]
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I am still in the
early stages of the HF game--still experimenting, still learning, and
still not sure I know what I'm doing. Nevertheless I thought I'd
share my HF chronicles with you. Let me take you back to the
beginning: Setting up my first HF antenna.
They say that an
ideal HF antenna is a dipole suspended far above the ground. A very
long dipole suspended
way above the ground. I live in
the suburbs. My property is not all that large. My neighbors are
friendly enough, but I doubt any of them would allow me to erect tall
towers in their back yards. And then there is the matter of a major
international airport just a few miles away. What I'm trying to say
is that the perfect dipole antenna was simply not an option for me.
Since
putting up an ideal HF antenna is out of the question for
many
hams, a lot of compromise antennas have been developed. The variety
in the designs and costs of these antennas is overwhelming. Lesson
number one when you decide to operate on the HF bands is that you
will learn something about antennas--whether you
want
to or not.
I spent a long
time thinking about HF antennas. I read books on the subject, but
they assumed that I had a great deal of prior knowledge. I talked to
experienced hams, but the technical jargon they used went right over
my head. I consulted my Elmer, but even he gave me an answer that was
no help. "It depends on what you want to do," he said.
It seemed that
there was no one,
correct HF antenna. It all depended on an
infinite number of variables starting with "What are your
goals?" Well, being brand new to the HF bands, I didn't
have
any goals. I didn't
know what specific band would attract me.
I had no
idea which mode I would eventually use. Would I get
into DXing? Would I try CW? Would I enjoy contesting? I just didn't
know.
I eventually did
buy an HF antenna. I bought an MFJ-1796--a half-wave vertical--based on the
following criteria:
- I could afford it.
- It worked on several HF bands.
- Although tall, it didn't take up a huge amount of space.
- My wife Nancy and I might be able to erect it
without having to rent a crane.
Do the words "Some assembly required" strike terror in your heart?
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Some Assembly Required
When it arrived I
opened the box, read the instructions, said "Holy Cow!" and
put it back in the box. Do the words "Some assembly required"
strike terror in your heart? Okay, you get the picture. I mumbled and
groaned about it for months until Nancy told me to either put up the
antenna or shut up about it. I think she was hoping for "shut
up."
You see, it was
not just a matter of assembling the antenna--it had to be
tuned.
All antennas have a resonant frequency. An analogy is the phenomenon
observed when you rub the rim of a wine glass with your finger. At a
certain pressure and speed, the wine glass will hum. You have excited
its resonant
audio frequency. Antennas are like that. You have
to alter the antenna so that its resonant
radio frequency is
within some Amateur Radio band. And yes, Gary's First Law applies--
It
Takes a Special Tool.
Before assembling
the antenna, I had to buy the
Special Tool--a standing wave
ratio (SWR) meter. Just owning one of those things made me feel like
a real ham!
Although
assembling the antenna was labor-intensive, it wasn't complicated.
Tuning the antenna was another matter. The antenna had to be mounted
on a short mast and held in place by one person (Nancy) while a
second person (me) operated the SWR meter and wrote down readings.
The actual tuning consisted of calculating how far out-of-band the
antenna was, then laying it down and snipping off parts.
I told Nancy, "Of course ham spouses climb roofs." She took this
picture to prove she was up there.
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We spent an
afternoon doing this. Remember, it was a
multiband antenna,
and had to be tuned separately for
each band. The antenna was
an unwieldy affair, too, and raising and lowering it so many times
inevitably resulted in it being dropped--several times. I spent a lot
of time straightening bent parts.
Once the antenna
was assembled and tuned, we (yes, Nancy, too) climbed onto the roof
of our house and hauled the antenna up after us. We marched it over
to its stand, dropped it one more time for luck, attached the feed
line and raised it into position. A few minutes later it was in place
and fastened. Other than getting down from the roof in one piece, the
hard labor was over. It was a strange and exotic-looking antenna--and
if you looked at it with a pair of binoculars, you could still see
the bent parts.
Although the
heavy labor was over, there was more to do. You see, once the antenna
was mounted on the roof its resonances changed. Now it was
out
of tune for a couple of bands. Well, it was going to stay right where
it was. We were not going to mess with it again unless someone
volunteered the services of a helicopter. There were various things
that could be done to compensate for the antenna's poor tuning, but
that would be a job for the future.
After all, I
didn't even own an HF radio yet. (The "HF Chronicles" will
continue.)
Editor's
note: ARRL member Gary Hoffman, KB0H, lives in Florissant,
Missouri. He's been a ham since 1995. Hoffman says his column's
name--"The Amateur Amateur"--suggests the explorations of a
rank amateur, not those of an experienced or knowledgeable ham. His
wife, Nancy, is N0NJ. Hoffman has a ham-related Web page. Readers are invited to
contact the author via e-mail,
[email protected].
© 2002 American Radio Relay League