From: peterk@polari.online.com
Subject: Re: Random Wire Tuner with Sony 2010
Organization: Seattle Online Public Access Unix (206) 328-4944
Distribution: na
Date: Thu, 13 Aug 1992 21:10:26 GMT

In article
<Charles.R.Hohenstein.1-110892175059@hesmac29.hesburgh.lab.nd.edu.>
Charles.R.Hohenstein.1@nd.edu (Charles R. Hohenstein) writes:

>I use a Sony 2010 for my shortwave listening activities, sometimes with the
>Sony AN-1 active antenna, and sometimes with a random wire. The random wire
>is about 50 feet in length, about 25 feet off the ground, and runs from a
>tree to one of my windows, where it is end-fed with RG-8X coax. 
    {stuff deleted}
>good results when I connect the random wire to the external antenna jack on my 
>radio, and assumed that I would have achieve even greater success by adding 
>an MFJ random wire tuner to my system. But, as a matter of fact, the 
>results are better without the random wire tuner than with it. 

To really use it as a random wire, you should skip the coax and simply
plug one end of the antenna wire into the "antenna" terminal on the
tuner (a banana plug works nicely). By using coax, you are actually
turning the wire into a non-resonant end-fed Zepp fed with lossy coax
instead feed of open wire line (like TV twinlead). Use coax only
between the tuner and the radio.

Also, you may need to reverse the antenna/transmitter connections on the
lowest frequency bands to get the most out of the antenna tuner. It has
to do with whether the antenna is longer or shorter and 1/4 wavelength
at the operating frequency. Also, you should have a good ground
connection--as short as possible a wire between the tuner chassis and a
cold water pipe or ground stake.

I have the MFJ tuner you mention, and I haven't used it in years with
any of 3 radios I have owned: a old tube-type Hallicrafters SX-122A, an
ICOM ham transceiver and a Sony 2010. For a random wire, it just
doesn't help enough to be worth it. I just connect the random wire to
the antenna rod of the 2010 with an alligator clip, and disconnect it
whenever I'm not using it (2010s are prone to burning out the front end
due to static, nearby lightening, etc.).

I use a 66 foot (40 meter ham band) center-fed dipole fed with TV
twinlead for my ham work. Here, a more elaborate ham-type antenna tuner
*does* help a lot when using the antenna for SWLing. Signals are
sometimes slightly stronger than with the simple random wire, but the
main benefit is noise reduction. The tuned, balanced feeline picks up
less electrical noise from the house/area than does a simple random
wire that goes beside/into the house. 

But there's a trade-off: one of the main benefits of the 2010 is that
you can quickly switch between several frequencies to see which is
best. If you have to constantly adjust a tuner, you've just negated one
of the best reasons for owning a keypad-entry radio. As a result, I find
myself using the tuner only for weak signals, marginal conditions, or
noisy conditions.

In summary, I rarely find a random wire tuner to be worth using. Also,
the MFJ unit is not meant for coax feed, even though it has coax
connectors on the back (they're meant to facilitate reversing the
connections). In fact, simple wire antennas with coax feed are
generally single band devices, and an antenna tuner just isn't going to
change that. When you're off frequency, the coax loss is what kills
you, not the antenna/radio mismatch. Your coax may be too short to
create much loss when connected directly to the radio, but it's adding
a random amount of capacitance. Plus, you're using the tuner in a way
for which it wasn't designed.

On the other hand, a center-fed dipole fed with balanced twinlead and a
$100-150 ham tuner is an ideal multi-band antenna--I've used the one
described above on all HF ham bands for years. But unless noise is a
problem, my advice is to just use a plain 'ol random wire for all but
the most critical weak signal SWL work.

-- 
--Peter (Peter A. Klein)
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