Wow. Thank you for these concise and clear directions. One thing though, I
really don't *think* I am overloading the set. Only problem I have is
digging the weak (but desired) signals our of the background noise
surrounding them. In another post I mentioned Voice of Korea's Central and
South American broadcast as the point of interest. It is just at the same
level as the background noise that doesn't interfere with other broadcasts
like the BBC on 5975 kHz or Radio Havana, Cuba on 9820 kHz (or Radio China
International, originally from Taiwan and rebroadcast through some place in
Florida, which frequency I can't remember at the moment.) It is only the
weak signals I am having trouble with. If I tune into WWV our of Ft.
Collins CO I can barely make out some out-of-band signals coming in, but
they are so weak as to be vanishing. Does this still sound like
overloading? Because the troublesom signals are also very weak, I am
thinking that a preselector will probably take care of my problems. (I am
still tempted to abandon my random wire and install your suggested antenna
just because it sounds so much more sophisticated. Will let you know.)

Thanks for the feedback.

Dave


"RHF" wrote in message
om...
DAVE,

So you have a Sangean ATS -505 and your 'problems' are Antenna
Overload and Noise Levels.
* Consider a 'smaller' shorter Antenna will reduce the overload problems.
* Consider a Low Noise Antenna Design will reduce the noise problems.
{LOW NOISE SWL ANTENNA - popularized by John Doty}
http://groups.yahoo.com/group/Shortw...enna/message/2
http://www.anarc.org/naswa/badx/ante...e_antenna.html

For a simple 'external' Shortwave Antenna to use with the Sangean
ATS-505 'portable' Shortwave Radio, using the 1/8" Mono-Jack
External Shortwave Antenna Input. Consider a Random Wire
Antenna using a Matching Transformer and Ground for Low Noise
and Wide Range Frequency Coverage.

PARTS: Here is a simple SWL Antenna Idea using a few common
RadioShack TV Antenna type parts:
Catalog #: 15-1174 = 25~50 Foot 300 Ohm (Flat) TV Twin-Lead
Catalog #: 15-1230 = 75 to 300 Ohm Matching Transformer (2 Ea.)
Catalog #: 274-286 = 1/8" Mono (Phone) Plug
Catalog #: Catalog #: 15-1579 = 25~50 Foot Coax Cable with F Connectors

NOTE: This is an 'improved' Random Wire SWL Antenna using "TV"
Parts for 'reducing' Man Made Noise (RFI EMF) that is generated in
or near most modern homes/buildings.

EXTERNAL "OUTSIDE" SWL ANTENNA:

The Antenna [Loop] Element is Stretched outside Horizontally or
in the shape of an Inverted "L". The Antenna [Loop] Element is
formed by connecting the two ends of the Far-End of the 300 Ohm
TV Twin Lead. This forms a continuous single skinny horizontal
flat loop going out and back. This also represents a Balance
300 Ohm Load to match-up with the 300 Ohm Matching Transformer.
The 300 Ohm Leads of the Matching Transformer connects to the
Near-Ends of the Loop Antenna Element. The 75 Ohm F Connector
of the Matching Transformer is connected to the 75 Ohm Coax Cable.
The 75 Ohm Coax Cable acts as the Lead-In from the Outside to
inside the house to the radio shack. The other end of the 75
Ohm Coax Cable is connected to the 75 Ohm F Connector of the
Matching Transformer. The Radio-End of the Coax Cable F Connector
would connect to a 75 to 300 Ohm Matching Transformer; and then
into a 1/8" Mono-Plug to plug into the Radio.
NOTE: Using the 300 Ohm TV Twin Lead in a Skinny Flat Loop
Antenna should balance-cancel-reduce most man made noise and be
Omni-Directional.

GROUND: Find a Grounding Point within/about your dwelling.
Secure a good Grounding Point for your Radio and Antenna.
Run a Heavy & Short Ground Wire to your Radio. Locate the
Ground Terminal on your Radio. Attach/Secure the Ground Wire
to the Coax Cable and/or the Radio's Ground Terminal.

FWIW: This Antenna using common TV Antenna type parts should
be effective as SWL Antennas above 5MHz and beyond 30MHz.


iane ~ RHF
.
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortw...na/message/502
I BELIEVE: On A Clear Night...
You Can Hear Forever and Beyond - The Beyond !
.
.
= = = "Dave" wrote in message
= = = ...
I recently hooked up a thirty-six foot (plus or minus a couple of feet)
piece of four-stranded wire with alligator clip to the internal "whip"
antenna of my portable shortwave receiver, for the extra performance
such a
device offered. It works so well that I now cannot usually use my "DX"
setting because of all the background noise (sounds like hundreds of
other
broadcasts vying for attention.) I don't know the frequency source of
all
this background noise, but would like to filter out as much of it as I
can.
One manufacturer of a similar "wind-up" antenna adds a capacitor to the
wire
in order to lower the resonance frequency of the wire. If I were going
to
try something similar (adding a capacitor, in series) in an attempt to
bring
the resonance of the wire down into the 30 MHz range, what size
(roughly)
capacitor should I use? Should I just try a few with different ranges,
or
does anyone here have any suggestions?

TIA

Cross-posted between sci.electronics.basics and rec.radio.shortwave


Dave


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