What, then, is the point of the L matching network in these types of end fed antennas?
It provides a match in a small space that doesn't require a separate tuner. That's
the convenience factor: plug in your coax and operate. You can build your own and
it will work just as well, even if it doesn't have the high quality of workmanship.
But why wouldn't this work better than just a random wire of the same length?
If the wire is the same length, then it isn't actually random
, is it?
The wires are specifically chosen to be a half wavelength long because that
presents a high impedance (which many auto-tuners won't match because
of the high voltage it puts across the relays). That reduces the need for a
good ground system, as would be required for good efficiency with a quarter
Needless to say, such a wire is only 1/2 wavelength long on one band. Use
it with a tuner on any other band and it is no longer an end-fed half wave
(though it will still have the high input impedance on harmonics of the original
A half-wave wire will work about the same regardless of where or how you feed
it. And it happens to be a reasonably efficient antenna in many cases, though
not necessarily that much better than some other lengths.
It's hard to argue with the 5/5 rating of this antenna.
There are a lot of antennas with similar ratings that don't work particularly well. Remember
that most reviews are posted by those who bought an antenna, which rules out those who
didn't because they knew that any piece of wire would work as well. That's not to say that
end-fed half wave wire antennas can't work well, or that the LNR antennas aren't well built.
But looking at the reviews in general, they don't exactly represent a random sample of
hams. And to someone who has never used a full-sized HF antenna, the performance of such
a simple wire antenna can be pretty amazing.
I've made several homebrew dipoles for my setup, fed with ladder-line, coax, different types of crappy baluns, and have had varying success. I'm now planning on operating out of a shed in the corner of my property, so a traditional dipole isn't really an option. The biggest angle I could get on a dipole between the elements is about 60 degrees.
Personally, if I had a support high enough for a vertical half wave wire, I'd string up an
inverted vee from it instead, as it can be expected to provide better performance. I used to
use 130' end-fed wires for my portable operation, but now generally prefer dipoles instead.
(But that is a function of the bands I tend to use.) In your case, an end-fed wire with a
reasonable ground system may work as well as anything else if that is the best you can
While many autotuners won't match them, I happen to like using end-fed wires that are
a multiple of 1/2 wavelength (like the 130' length), and there is no reason why you couldn't
choose, say, 65' (half wave on 40m) as a wire length from your shack.