Wire Antenna
 

I have a simple scanner/shortwave receiver and have recently installed a
wire antenna. I have been able to pick up stations over 500 miles away.
However, it seems as though the stations are grouped in very narrow bands.
Is there a way to make the antenna "look" longer or shorter electronically
so that I have a greater range of frequencies? Thanks your help in advance.
Matthew



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On Wed, 10 Mar 2004 01:34:31 GMT, "Matthew&Wendy"
wrote:

I have a simple scanner/shortwave receiver and have recently installed a
wire antenna. I have been able to pick up stations over 500 miles away.
However, it seems as though the stations are grouped in very narrow bands.
Is there a way to make the antenna "look" longer or shorter electronically
so that I have a greater range of frequencies? Thanks your help in advance.
Matthew

Hi Matthew,

There is a certain amount of vagueness in your description. Is a 500
mile range unexpectedly good, or bad? Over what band of frequencies?
How long is the wire? How high is it? Put a tuner between the two
and you kill the scanning ability to some degree, however a tuner may
be necessary for good Shortwave.

For instance, in the Shortwave region, that is not particularly good,
but for VHF that would be gang-busters.

As for the grouping of active signals. What frequencies? It would be
a common observation anywhere across a lot of frequencies, but if you
were worried about Shortwave being deaf from 9.5 to 10 MHz, you would
have a complaint; bump it down between 9 and 9.5 and that would be no
surprise.

73's
Richard Clark, KB7QHC

OK, Sorry if I was unspecific. The antenna is about thirty feet long, with
one leg at twenty feet. The entire antenna is twenty feet off the ground.
The Five hundered mile range is great, but it was an AM station out of North
Carolina. The BBC broadcast on 5975 came in great too. But about 100
kilohertz on either side, and I can only pick up locals, within 200 miles. I
saw a vertical antenna that with a switch, the operator could change
something and make the antenna resonant on different frequencies. Is this
possible with a wire antenna?



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On Wed, 10 Mar 2004 02:00:02 GMT, "Matthew&Wendy"
wrote:

OK, Sorry if I was unspecific. The antenna is about thirty feet long, with
one leg at twenty feet. The entire antenna is twenty feet off the ground.
The Five hundered mile range is great, but it was an AM station out of North
Carolina. The BBC broadcast on 5975 came in great too. But about 100
kilohertz on either side, and I can only pick up locals, within 200 miles. I
saw a vertical antenna that with a switch, the operator could change
something and make the antenna resonant on different frequencies. Is this
possible with a wire antenna?


Hi Matthew,

That would have been either a preselector, or a tuner. Such a device
will restrict your scanning capacity by removing signals outside of a
band of frequencies (this is both an asset and downside if you want to
scan VHF/UHF through the tuner). The chief asset, especially when
wire antennas are added to portable radios for shortwave, is that it
will kill local AM stations that will desensitize your receiver
without you knowing it (complex explanation will be skipped here).
Get a tuner (cheapest ham one will do just fine, spend $20 - $30; skip
any that offer meters, you can't use them anyway). This does not mean
it will kill AM stations if you choose to listen to them, you just
need to adjust the tuner to accomplish it.

The antenna sounds fine, and is far better than using a whip. It is
unlikely that there were local signals in the 49 Meter band unless
they were the bible thumpers. If you are new to shortwave, keep in
mind that the same band that is dead now, may be kicking up a storm in
4 hours.

73's
Richard Clark, KB7QHC

First off, for frequencies less than about 5 MHz, 30 feet is really too
short. Try to at least double that, and try to get it as high as possible.

The stations will be bunched. that is how they are allocated. International
broadcast stations will be bunched around 6 MHz (49 meters),7 Mhz (39
meters), 9 Mhz (31 meters), 11 MHz (25 meters), and up around 16 Mhz.

Keep in mind that which band will work at any given time will depend on the
time of day. You will only hear long distance stations on 7 MHz and below
after dark. The higher frequency stations might come in all day long, or
only during the day. Afternoon is usually good. Long distance on the AM band
is strictly after dark. With a short antenna you will have the best luck on
stations above 1300 KHz, or so. The biggest problem will be hearing distant
stations that are close in frequency to a local stations. Tune for "clear
channel" stations (unfortunately, mostly on lower frequencies, like WABC and
WCBS NY, WJR Detroit. WLW Cincinnati, WLS New Orleans, etc. 1000 miles is
not a big deal.

Above all, you need a radio with good selectivity. A high end audiophile
receiver is absolutely the worst thing; old car radios work well.

Tam/WB2TT
"Matthew&Wendy" wrote in message
...
I have a simple scanner/shortwave receiver and have recently installed a
wire antenna. I have been able to pick up stations over 500 miles away.
However, it seems as though the stations are grouped in very narrow bands.
Is there a way to make the antenna "look" longer or shorter electronically
so that I have a greater range of frequencies? Thanks your help in
advance.
Matthew



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Thanks for the explanations and the help. I really appreciate it. And
hopefully, I can get my hands on a better SW radio soon.

Matthew



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