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

Dave wrote:

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?

What receiver? It sounds like it's being overloaded.

"N8KDV" wrote in message
...


Dave wrote:

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?

What receiver? It sounds like it's being overloaded.



Sorry, forgot to include that information. I am using a DX-402 (aka Sangean
ATS-505). I honestly wondered about that, but hesitated to shorten the wire
because I would (obvioiusly) lose some sensitivity, and really like being
able to pick up VOK's English broadcasts to Central America. Only problem
is the noise that makes it difficult to single out.

Thanks,

Dave

DAVE,

Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI]
http://www.radiointel.com/review-ats505.htm
Two points made by the reviewer we
* "An external antenna jack is provided, but it only works
for SW (not AM/MW)."
* "This receiver is quite sensitive on SW and I found that
using an external antenna overloaded it."

iane ~ RHF
..
..
= = = "Dave" wrote in message
= = = ...

- - - - - S N I P - - - - -

Sorry, forgot to include that information. I am using a DX-402
(aka Sangean ATS-505).

I honestly wondered about that, but hesitated to shorten the
wire because I would (obvioiusly) lose some sensitivity, and
really like being able to pick up VOK's English broadcasts to
Central America. Only problem is the noise that makes it
difficult to single out.

Thanks,

Dave

Hmmm. Others have suggested I was overloading it, but I don't *think* that
is the case. It's just hard to dig weak signals out of the hash and trash
surrounding them (like Voice of Korea's broadcast to Central and South
America.) I am planning on building a preselector anyway, and will post
updates on the effects of that addition.

Dave


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

Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI]
http://www.radiointel.com/review-ats505.htm
Two points made by the reviewer we
* "An external antenna jack is provided, but it only works
for SW (not AM/MW)."
* "This receiver is quite sensitive on SW and I found that
using an external antenna overloaded it."

iane ~ RHF
.
.
= = = "Dave" wrote in message
= = = ...

- - - - - S N I P - - - - -

Sorry, forgot to include that information. I am using a DX-402
(aka Sangean ATS-505).

I honestly wondered about that, but hesitated to shorten the
wire because I would (obvioiusly) lose some sensitivity, and
really like being able to pick up VOK's English broadcasts to
Central America. Only problem is the noise that makes it
difficult to single out.

Thanks,

Dave

Sorry, all, for the repeated posts. It's not me, my ISP has been doing
something funny, and disconnecting me without warning. Every time I
reconnect to do something else it reposts whatever is left in the job it
never finished. Think it may be fixed now though.

Dave


"Dave" wrote in message
...
Hmmm. Others have suggested I was overloading it, but I don't *think*
that
is the case. It's just hard to dig weak signals out of the hash and trash
surrounding them (like Voice of Korea's broadcast to Central and South
America.) I am planning on building a preselector anyway, and will post
updates on the effects of that addition.

Dave


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

Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI]
http://www.radiointel.com/review-ats505.htm
Two points made by the reviewer we
* "An external antenna jack is provided, but it only works
for SW (not AM/MW)."
* "This receiver is quite sensitive on SW and I found that
using an external antenna overloaded it."

iane ~ RHF
.
.
= = = "Dave" wrote in message
= = = ...

- - - - - S N I P - - - - -

Sorry, forgot to include that information. I am using a DX-402
(aka Sangean ATS-505).

I honestly wondered about that, but hesitated to shorten the
wire because I would (obvioiusly) lose some sensitivity, and
really like being able to pick up VOK's English broadcasts to
Central America. Only problem is the noise that makes it
difficult to single out.

Thanks,

Dave

"Dave" ) writes:
Hmmm. Others have suggested I was overloading it, but I don't *think* that
is the case. It's just hard to dig weak signals out of the hash and trash
surrounding them (like Voice of Korea's broadcast to Central and South
America.) I am planning on building a preselector anyway, and will post
updates on the effects of that addition.

Dave


But if it's really just adjacent signals, and I doubt it, nothing done
at the antenna will fix the problem, unless you go to a directional
antenna so you can null out the unwanted signals.

You can't get enough selectivity at shortwave frequencies with
coil and capacitor filters to knock out stations adjacent in
frequency to what you want to hear. Well, a crystal filter at
the signal frequency would work, but that gets complicated, and
it's only good for one frequency. That's the whole point of the superhet
receiver, to convert to a fixed frequency where a good filter can
be built.


Michael

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

Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI]
http://www.radiointel.com/review-ats505.htm
Two points made by the reviewer we
* "An external antenna jack is provided, but it only works
for SW (not AM/MW)."
* "This receiver is quite sensitive on SW and I found that
using an external antenna overloaded it."

iane ~ RHF
.
.
= = = "Dave" wrote in message
= = = ...

- - - - - S N I P - - - - -

Sorry, forgot to include that information. I am using a DX-402
(aka Sangean ATS-505).

I honestly wondered about that, but hesitated to shorten the
wire because I would (obvioiusly) lose some sensitivity, and
really like being able to pick up VOK's English broadcasts to
Central America. Only problem is the noise that makes it
difficult to single out.

Thanks,

Dave

Hmmm. Others have suggested I was overloading it, but I don't *think* that
is the case. It's just hard to dig weak signals out of the hash and trash
surrounding them (like Voice of Korea's broadcast to Central and South
America.) I am planning on building a preselector anyway, and will post
updates on the effects of that addition.

Dave


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

Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI]
http://www.radiointel.com/review-ats505.htm
Two points made by the reviewer we
* "An external antenna jack is provided, but it only works
for SW (not AM/MW)."
* "This receiver is quite sensitive on SW and I found that
using an external antenna overloaded it."

iane ~ RHF
.
.
= = = "Dave" wrote in message
= = = ...

- - - - - S N I P - - - - -

Sorry, forgot to include that information. I am using a DX-402
(aka Sangean ATS-505).

I honestly wondered about that, but hesitated to shorten the
wire because I would (obvioiusly) lose some sensitivity, and
really like being able to pick up VOK's English broadcasts to
Central America. Only problem is the noise that makes it
difficult to single out.

Thanks,

Dave

Hmmm. Others have suggested I was overloading it, but I don't *think* that
is the case. It's just hard to dig weak signals out of the hash and trash
surrounding them (like Voice of Korea's broadcast to Central and South
America.) I am planning on building a preselector anyway, and will post
updates on the effects of that addition.

Dave


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

Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI]
http://www.radiointel.com/review-ats505.htm
Two points made by the reviewer we
* "An external antenna jack is provided, but it only works
for SW (not AM/MW)."
* "This receiver is quite sensitive on SW and I found that
using an external antenna overloaded it."

iane ~ RHF
.
.
= = = "Dave" wrote in message
= = = ...

- - - - - S N I P - - - - -

Sorry, forgot to include that information. I am using a DX-402
(aka Sangean ATS-505).

I honestly wondered about that, but hesitated to shorten the
wire because I would (obvioiusly) lose some sensitivity, and
really like being able to pick up VOK's English broadcasts to
Central America. Only problem is the noise that makes it
difficult to single out.

Thanks,

Dave

Is it ALL frequencies that have the " overload" or just a few??

- try Unclipping the antenna wire & moving it 1/4 inch away from the antenna
( use a string to move it around)

& see if that helps..

Dan


In article , "Dave"
writes:

Subject: Shortwave random-wire antenna question
From: "Dave"
Date: Sat, 3 Apr 2004 13:41:21 -0600

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