Would you like to be able to hear more stations on
both
AM and Short Wave with your old radio?
If so there are several possibilities. First you want
to decide if you want an Inside Antenna or an
Outside antenna. If an outside one.. be sure to make
provisions for unhooking and grounding the
antenna when not in use. Don't take a chance on a
lightning
strike blowing up your radio.
First a simple 20 foot wire attached
to your radio will
work and receive stations on
your old radio..
Adding
a ground wire to the radio will
usually improve the
signals and reduce some of the noise your hearing.
In this next section you will be able to see an inside antenna that works well.
If you can get
a long wire up in your attic... you can have
a nice inside antenna...
This is a grid type of antenna that is simply stapled up to the roof
rafters in your attic... wire size is not important...
a #20 stranded wire works well... simply take your staple gun and a
few hundred feet of wire up into your
attic and go back and forth as in the example picture above. Spacing
between wires of one to two feet is fine.
In the above illustration you see Impedance Transformers ... Your old
radio needs a high imedance antenna.. and a simple long single wire
is just that .. a high impedance antenna..... you can just drop one
end of the antenna down to your radio... Or if you have
a noise problem with all sorts of noise generators in your home...
perhaps you want to try to keep the antenna
away from the noise sources? If so, you can change the impedance of
the antenna over to low impedance
using a small transformer... then use a coaxial shielded cable to get
the antenna down into your radio... if you do this then
you have to put another transformer on the radio end of the coax to
get the impedance back up for the radio.
These transformers are available in pairs from a local Ham Radio friend
of mine who makes them up for
the Ham Radio guys who also use them ... we refer to them as Beverage
Transformers as they are used by
Hams to correctly feed a "Beverage Antenna" ... Whats that you ask?
.. well it isn't something you drink...
The antenna was invented by a guy named Dr. Harold Beverage ...
The antenna is simply a very long wire that is first of all close to
the ground.... yes they work best if
installed between 4 feet and 10 feet above ground... the idea behind
this antenna is that by keeping
it close to the ground and making it long enough... it will receive
long distance radio signals and NOT
receive the atmospheric noise .... all those crashes and bangs you
hear... they will be greatly
reduced in strength vs the desired signal your trying to listen to....
These antennas can be either a single
direction .... or bi-directional.... if you want a single direction....
then we put a carbon resistor of about 600
ohms at the far end of the antenna connected to a ground rod... if
the antenna is left Un-Terminated then it will
be Bi-Directional.... to be really effective on the AM radio band a
Beverage Antenna should be at least 500 feet
in length... and 1000 feet is a whole lot better... I have three of
these Beverage Antennas ... mine are about 400 feet
in length because thats where I ran out of room on my property.. they
run in three different directions... there are
times that I can listen to two different AM radio stations by simply
switching from one directional antenna to
one of the other directions... with both stations on the same
frequency.
Here is an illustration of a beverage
antenna....
By bringing the shielded coaxial cable in to the house you too will
no longer have to listen to all the
noise generators in your home.... Computers, Monitors, TV sets, VCR's,
Variable Speed Ceiling Fans, Light Dimmers
and a whole list of other devices we all have in our homes...
John k9uwa
Roll Your Own 9 to 1 Unbalanced to Unbalanced Transformer
You will need two of these ferrite Cores. Amidon number FT-114-43
http://www.amidoncorp.com/ft-114-43/
These cores are presently priced at $2.25 each plus postage. Maybe
order a few spares
Everything else you need to know to build these 9 to 1 Un-Un's is
shown in the picture below.
You can use whatever connectors you want on either end of the
transformers. Spade Lugs are best on the RADIO end.
If your antenna and therefore one of these transformers will be outside
in the weather then weatherproof it.
Weatherproofing could be in a weatherproof box or perhaps just encase
the whole works in a ball of 100% silicone caulk
Or spray the whole works with a few coats of Flex Seal just like
on TV yes the stuff works well. Just put one of these transformers on
each end of your RG6 coax. Then connect up the ANT and GND terminals on
your Antique Radio to one end and a ground rod
and your Long Wire Antenna to the other end.
John k9uwa