KB6NU's Ham Radio Blog

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What are we doing wrong?

Posted: 26 May 2016 09:07 AM PDT
http://feedproxy.google.com/~r/kb6nu...m_medium=email


About ten years ago, one of the guys in my General Class course, called and
asked if Id like to see his new Buddipole, and oh, by the way, could I
bring over my antenna analyzer? When I got over there, he had the Buddipole
mounted on a tripod, much the same way as its mounted in the picture at
right. (Being in Michigan, however, we didnt have an ocean view and palm
trees swaying in the breeze.)

We connected up the antenna analyzer, but no matter what we did, we couldnt
get a good match on 20m. This was puzzling to me, as there are probably
hundreds, if not thousands, of hams out there that are very successful
using Buddipoles in this configuration.

I then suggested that we try one of the Buddipole elements in the vertical
position, and operate it against a full, quarter-wavelength counterpoise. I
had brought some wire along for just this purpose. We cut it, connected it,
and voila, we had a good match.

What brought this all back to mind was that on Monday, another friend
called me and asked if I could bring over my antenna analyzer to make some
measurements on a dipole that he was attempting to make using a couple of
MFJ 30m ham sticksÂ*that he bought at Dayton. Although the ham stick is
designed to be a vertical antenna, MFJ sells a bracket that supposedly
allows you to use two of their ham sticksÂ*as a dipole, much like the
Buddipole. He told me that no matter what he tried, he couldnt seem to get
the SWR down.

Before going over there, I found an item on reddit that I thought might
help him. I emailed this to him, but he replied that he tried all of the
suggestions, but still no luck.

So, last night, I went over to his house. He had disconnected one of the
ham sticks, Â*and when I connected the analyzer to it, I got a reading
between 2.5:1 and 3:1. I suggested that we try connecting a wire
counterpoise to it, but he was hot on getting the dipole configuration to
work, so we screwed in the other element. Whoa! The SWR jumped up Â*to 8.5:1.

We buzzed out the connections to make sure that there were no shorts and
that one of the ham sticks was connected to the center conductor of the
coax, and that the other ham stick was connected to the shield. We also
moved the mast away from the house. Neither of these had any affect on the
SWR.

At this point, he decided just to return the ham sticks to MFJ. Even so, it
bugs me a little that we couldnt get this to work. Im wondering if any of
you might give us a little insight as to what were doing wrong. It doesnt
seem like it should be so complicated, but as Ive said before, Im certainly
not an antenna expert.

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