Antennas And The Alinco EDX2
Dave
antenna, or can the EDX2 be used with other antennas, e.g the G5RV, the
information sheets dont come with much information at all...
Thanks..
Dave
KA9CAR
The tuner is an unbalanced L network tuner, that can change its
configuration for high or low impedance.
I never used it to feed an end fed wire, which is what it is sold for.
I used it to feed 300 ohm balanced line to a dipole, and a loop. I did NOT
use my home brew 1:1 Balun as I found it just added losses.
In one configuration I found I had some ground currents, so I used a few
ferrite tube chokes on the control line and the feed line to control that.
In an A/ B comparison, I found that my Johnson Matchbox was noticeably
better in received signal strength on one band, I don't recall which one.
This was probably due to losses in the tuner at some matching
configurations.
For "straight through" you power down the radio, then power it back up, with
out using the tune feature. This often works better for out ob band
listening than trying to tune the nearest Amateur band.
Dave <hei...@btconnect.com> wrote in message
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Owen Duffy
Although the information supplied with mine is scant, it does show its
application for end feeding a vertical or wire (including advice on
selection of radiator length). It does not show how to feed a balanced
line.
You could use a balun to transition from the unbalanced EDX2 to a
balanced load, but given that the EDX2 is designed to match a very wide
range of impedances, the design of a balun that is not unduly lossy and
does not restrict the impedance and frequency range of the tuner would
be a challenge.
If you look at the circuit diagram, you might reasonably form the
opinion that the earth terminal is meant to be earthed rather than
connected to one side of a balanced load. Nevertheless, you will find
plenty of OMs who will assure you that it (and others like the AHx and
SGCxxxx) works just fine used on balanced loads, and that some have had
to eliminate RF conducted into the shack on the feedline and control
cable. I would not operate it in that way.
In my experience, the lack of information on the EDX2, especially
alignment information, and the patent lack of interest in support of
Alinco products by Alinco and their dealers is the worst aspect of the
tuner. When I properly calibrated the detectors in mine, and rebuilt in
in a new box when the original enclosure cracked up within a few months
of purchase ( http://u01.owenduffy.com.au/~owen/edx201.jpg ), it works
real well.
I use it frequently in a portable situation and it almost always
achieves a match better than 1.2 (enabling full output power from the
DX70TH) on any HF band on a 26m sloper that is 15m above ground at the
high end and ground level at the EDX2 end. Whilst the sloper loads up on
any band, it lacks the low angle radiation that is generally desired for
20m and up, but the high angle radiation is just what is needed for
local contacts on 160, 80 and 40m. The 26m was chosen to not be within
5% of an odd or even quarter wave resonance on any HF band so as to
avoid very high voltages impressed on the tuner at even multiples, or
excessive influence of earth system loss at odd multiples.
Owen
>
> Thanks..
>
> Dave
KA9CAR
Although I ran the tuner into several different "Balanced" loads, I ALWAYS
grounded the ground terminal. No point in letting stray RF toast the CPU in
the tuner. If the antenna is not designed to work against ground, there
should be no ground currents to upset the balance.
KA9CAR
Owen Duffy <ow...@oda.com.au> wrote in message
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