"-=jd=-" wrote in message
...
On Sun 11 Apr 2004 01:39:04a, "Dave" wrote in message
:

She absolutely hates
having a piece of wife laying across the roof, and can't wait until I
fix it in place underneath the eaves.



There's a few different ways I could interpret that!!


-=jd=-
--

LOL! I meant to say "a piece of WIRE..." Guess I was thinking something
else.

Dave

"starman" wrote in message
...
Dave wrote:

"starman" wrote in message


It sounds like you need a passive preselector rather than an antenna
tuner, if your receiver can't handle the strong signals on the
antenna.
Are you hearing stations outside the bands where they are actually
located? Is there a lot of noise from many stations all over the
shortwave range.


I am picking up a few very weak signals out-of-band, and there is only
background noise on the DX setting. The RF choke seems to have done a
nice
job of cleaning up most of the hash and trash in the background. I
would
like to enhance the signal I am actually looking for, however. During
periods of good propogation I have ocassionally picked up Voice of Korea
transmissions aimed at Central and South America, and I would like to
load
the dice in my favor if I can.

I really think you should try a passive preselector. It will reject the
strong out of band signals which cause intermodulation products while
peaking the weak stations. The choke helps but it also reduces the
receivers sensitivity to the signals you want to hear. The preselector
does the opposite. I used a preselector with my Sony-2010 and an
inverted-L antenna. It worked great. Without the preselector the 2010
would overload and produce a lot of spurious signals throughout the
shortwave spectrum.

It's pretty easy to build a passive preselector that will cover the
range of 3-30 Mhz with two coils. The larger coil will tune the range of
about 3-7 Mhz and the smaller one 7-30 Mhz. It's best to use ferrite
cores in the coils for the best selectivity or 'Q'. Of course you'll
also need an air variable capacitor like 10-365/pf and a simple rotary
switch to select the coils. The circuit is a parallel (tank) design
which is connected between the antenna input of the radio and ground,
along with the antenna itself.

If you're not into building, you can buy a passive preselector at:

http://www.grove-ent.com/MFJ1046.html

Here's an interesting article on antenna tuners:

http://www.nyx.net/~dgrunber/tuner.ssi



Hmmm. A tank circuit between the antenna input and ground, to improve
reception? I believe you, but I don't understand how it works. Could you
enlighten me a little? Does it resonate at the selected frequency (chosen
by adjusting the variable cap) and thereby "select" that signal for the
input to the radio? (This is all I can figure.)

I could do that real easy. I have several variable caps of that general
size, and can pick up whatever size inductor I need. I even have the charts
and formulas for calculating the appropriate value of inductance, just have
to sit down with them. Thanks for the suggestion.

PS: Haven't checked out the links yet, but will do so asap.

Dave

Dave wrote:

"starman" wrote in message
...
Dave wrote:

"starman" wrote in message


It sounds like you need a passive preselector rather than an antenna
tuner, if your receiver can't handle the strong signals on the
antenna.
Are you hearing stations outside the bands where they are actually
located? Is there a lot of noise from many stations all over the
shortwave range.


I am picking up a few very weak signals out-of-band, and there is only
background noise on the DX setting. The RF choke seems to have done a
nice
job of cleaning up most of the hash and trash in the background. I
would
like to enhance the signal I am actually looking for, however. During
periods of good propogation I have ocassionally picked up Voice of Korea
transmissions aimed at Central and South America, and I would like to
load
the dice in my favor if I can.

I really think you should try a passive preselector. It will reject the
strong out of band signals which cause intermodulation products while
peaking the weak stations. The choke helps but it also reduces the
receivers sensitivity to the signals you want to hear. The preselector
does the opposite. I used a preselector with my Sony-2010 and an
inverted-L antenna. It worked great. Without the preselector the 2010
would overload and produce a lot of spurious signals throughout the
shortwave spectrum.

It's pretty easy to build a passive preselector that will cover the
range of 3-30 Mhz with two coils. The larger coil will tune the range of
about 3-7 Mhz and the smaller one 7-30 Mhz. It's best to use ferrite
cores in the coils for the best selectivity or 'Q'. Of course you'll
also need an air variable capacitor like 10-365/pf and a simple rotary
switch to select the coils. The circuit is a parallel (tank) design
which is connected between the antenna input of the radio and ground,
along with the antenna itself.

If you're not into building, you can buy a passive preselector at:

http://www.grove-ent.com/MFJ1046.html

Here's an interesting article on antenna tuners:

http://www.nyx.net/~dgrunber/tuner.ssi



Hmmm. A tank circuit between the antenna input and ground, to improve
reception? I believe you, but I don't understand how it works. Could you
enlighten me a little? Does it resonate at the selected frequency (chosen
by adjusting the variable cap) and thereby "select" that signal for the
input to the radio? (This is all I can figure.)

I could do that real easy. I have several variable caps of that general
size, and can pick up whatever size inductor I need. I even have the charts
and formulas for calculating the appropriate value of inductance, just have
to sit down with them. Thanks for the suggestion.

PS: Haven't checked out the links yet, but will do so asap.

Dave


The parallel tuned (tank) circuit causes all frequencies above and below
the tuned one, to be shunted to ground while passing the desired
frequency range to the radio's antenna input. It makes up for the lack
of good preselection in the receivers front-end. This is the main
problem when connecting a good antenna to a portable radio. Be sure to
use coils with ferrite cores for good selectivity.


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"starman" wrote in message
...
Dave wrote:

"starman" wrote in message
...
Dave wrote:

"starman" wrote in message


It sounds like you need a passive preselector rather than an
antenna
tuner, if your receiver can't handle the strong signals on the
antenna.
Are you hearing stations outside the bands where they are actually
located? Is there a lot of noise from many stations all over the
shortwave range.


I am picking up a few very weak signals out-of-band, and there is
only
background noise on the DX setting. The RF choke seems to have done
a
nice
job of cleaning up most of the hash and trash in the background. I
would
like to enhance the signal I am actually looking for, however.
During
periods of good propogation I have ocassionally picked up Voice of
Korea
transmissions aimed at Central and South America, and I would like
to
load
the dice in my favor if I can.

I really think you should try a passive preselector. It will reject
the
strong out of band signals which cause intermodulation products while
peaking the weak stations. The choke helps but it also reduces the
receivers sensitivity to the signals you want to hear. The preselector
does the opposite. I used a preselector with my Sony-2010 and an
inverted-L antenna. It worked great. Without the preselector the 2010
would overload and produce a lot of spurious signals throughout the
shortwave spectrum.

It's pretty easy to build a passive preselector that will cover the
range of 3-30 Mhz with two coils. The larger coil will tune the range
of
about 3-7 Mhz and the smaller one 7-30 Mhz. It's best to use ferrite
cores in the coils for the best selectivity or 'Q'. Of course you'll
also need an air variable capacitor like 10-365/pf and a simple rotary
switch to select the coils. The circuit is a parallel (tank) design
which is connected between the antenna input of the radio and ground,
along with the antenna itself.

If you're not into building, you can buy a passive preselector at:

http://www.grove-ent.com/MFJ1046.html

Here's an interesting article on antenna tuners:

http://www.nyx.net/~dgrunber/tuner.ssi



Hmmm. A tank circuit between the antenna input and ground, to improve
reception? I believe you, but I don't understand how it works. Could
you
enlighten me a little? Does it resonate at the selected frequency
(chosen
by adjusting the variable cap) and thereby "select" that signal for the
input to the radio? (This is all I can figure.)

I could do that real easy. I have several variable caps of that general
size, and can pick up whatever size inductor I need. I even have the
charts
and formulas for calculating the appropriate value of inductance, just
have
to sit down with them. Thanks for the suggestion.

PS: Haven't checked out the links yet, but will do so asap.

Dave


The parallel tuned (tank) circuit causes all frequencies above and below
the tuned one, to be shunted to ground while passing the desired
frequency range to the radio's antenna input. It makes up for the lack
of good preselection in the receivers front-end. This is the main
problem when connecting a good antenna to a portable radio. Be sure to
use coils with ferrite cores for good selectivity.




Gotcha. That was the only way I could figure it. I saw something almost
similar (is that like almost pregnant?) in my Practical Antenna Hanbook (Joe
Carr) last night, but suspect it is a printing error. It was an series
inductor following behind a capacitor shunt to ground. Only that would (I
think) choke off RF and shunt it to ground. (Am I wrong?) Have been trying
to figure that one out all day. Last night I fixed my big solder gun, and
can now solder a ground wire to the grounding rod outside my bedroom window.
Hope to do that tomorrow.

I am definetly going to set this up. Have already tested several of my
small capacitors, but they do not appear stable enough for anything serious.
Just to familiarize myself with the mathematics, I have already calculated
the inductors I would need for the first one I tested. Just finished
removing a better variable cap from an old junk shortwave radio (a Luke, I
think) and am going to try to use it. May have a problem with my meter
though. May have to take the variable cap to the shop and have it tested on
a known good LCR meter (gotta get one of those. I a currently using a DMM
with limited capacitance capability.) If I do that I'll take my calculator
and notepad with me, so I can figure out and write down the values of
inductance I need. Damn I'm having fun.

Thank you very much for this suggestion. It is much appreciated.

Dave

"Dave" wrote in message
...
What you saw in the antenna book was not a misprint. It was an L network
tuner. It is an impedance matcher, not a preselector.


Gotcha. That was the only way I could figure it. I saw something almost
similar (is that like almost pregnant?) in my Practical Antenna Hanbook
(Joe
Carr) last night, but suspect it is a printing error. It was an series
inductor following behind a capacitor shunt to ground. Only that would (I
think) choke off RF and shunt it to ground. (Am I wrong?) Have been
trying
to figure that one out all day. Last night I fixed my big solder gun, and
can now solder a ground wire to the grounding rod outside my bedroom
window.
Hope to do that tomorrow.

I am definetly going to set this up. Have already tested several of my
small capacitors, but they do not appear stable enough for anything
serious.
Just to familiarize myself with the mathematics, I have already calculated
the inductors I would need for the first one I tested. Just finished
removing a better variable cap from an old junk shortwave radio (a Luke, I
think) and am going to try to use it. May have a problem with my meter
though. May have to take the variable cap to the shop and have it tested
on
a known good LCR meter (gotta get one of those. I a currently using a DMM
with limited capacitance capability.) If I do that I'll take my
calculator
and notepad with me, so I can figure out and write down the values of
inductance I need. Damn I'm having fun.

Thank you very much for this suggestion. It is much appreciated.

Dave

Oh. An impedance matcher. Never was much good with those... Does this
match the impedance of the random wire to that of the radio input? That
would be good too... Yes, an L network, that was what it was called I
think. I marked it, to go back to it.

Thanks,

Dave


"CW" wrote in message
...

"Dave" wrote in message
...
What you saw in the antenna book was not a misprint. It was an L network
tuner. It is an impedance matcher, not a preselector.


Gotcha. That was the only way I could figure it. I saw something
almost
similar (is that like almost pregnant?) in my Practical Antenna Hanbook
(Joe
Carr) last night, but suspect it is a printing error. It was an series
inductor following behind a capacitor shunt to ground. Only that would
(I
think) choke off RF and shunt it to ground. (Am I wrong?) Have been
trying
to figure that one out all day. Last night I fixed my big solder gun,
and
can now solder a ground wire to the grounding rod outside my bedroom
window.
Hope to do that tomorrow.

I am definetly going to set this up. Have already tested several of my
small capacitors, but they do not appear stable enough for anything
serious.
Just to familiarize myself with the mathematics, I have already
calculated
the inductors I would need for the first one I tested. Just finished
removing a better variable cap from an old junk shortwave radio (a Luke,
I
think) and am going to try to use it. May have a problem with my meter
though. May have to take the variable cap to the shop and have it
tested
on
a known good LCR meter (gotta get one of those. I a currently using a
DMM
with limited capacitance capability.) If I do that I'll take my
calculator
and notepad with me, so I can figure out and write down the values of
inductance I need. Damn I'm having fun.

Thank you very much for this suggestion. It is much appreciated.

Dave

Thank you for this. I will check this out.

Dave


"CW" wrote in message
...
Take the batteries out. Put your (unconnected) plug into the socket. Check
for continuity between its outer contact (barrel) and the negative battery
terminal. Many radios have jacks with plastic external rings but there is
a
ground terminal inside.

"Dave" wrote in message
...
Just a quick note: it actually does have an external antenna input, I
just
don't know what type of plug to stick into it. Plastic ring with metal
contact inside, looks like 1/8" mono would do it, but how would I ground
it?
Negative battery term?

Thanks,

Dave

Impedance matching on a random wire antenna may or may not do much good. It
is considerably more helpful with short wires. The most useful impedance
match you are likely to get is that obtained with a 9:1 transformer at the
base of your antenna before the coax. Take a look at my website (long
overdue for an update).
www.kc7nod.20m.com

"Dave" wrote in message
...
Oh. An impedance matcher. Never was much good with those... Does this
match the impedance of the random wire to that of the radio input? That
would be good too... Yes, an L network, that was what it was called I
think. I marked it, to go back to it.

Thanks,

Dave


"CW" wrote in message
...

"Dave" wrote in message
...
What you saw in the antenna book was not a misprint. It was an L network
tuner. It is an impedance matcher, not a preselector.


Gotcha. That was the only way I could figure it. I saw something
almost
similar (is that like almost pregnant?) in my Practical Antenna
Hanbook
(Joe
Carr) last night, but suspect it is a printing error. It was an
series
inductor following behind a capacitor shunt to ground. Only that
would
(I
think) choke off RF and shunt it to ground. (Am I wrong?) Have been
trying
to figure that one out all day. Last night I fixed my big solder gun,
and
can now solder a ground wire to the grounding rod outside my bedroom
window.
Hope to do that tomorrow.

I am definetly going to set this up. Have already tested several of
my
small capacitors, but they do not appear stable enough for anything
serious.
Just to familiarize myself with the mathematics, I have already
calculated
the inductors I would need for the first one I tested. Just finished
removing a better variable cap from an old junk shortwave radio (a
Luke,
I
think) and am going to try to use it. May have a problem with my
meter
though. May have to take the variable cap to the shop and have it
tested
on
a known good LCR meter (gotta get one of those. I a currently using a
DMM
with limited capacitance capability.) If I do that I'll take my
calculator
and notepad with me, so I can figure out and write down the values of
inductance I need. Damn I'm having fun.

Thank you very much for this suggestion. It is much appreciated.

Dave

Dave wrote:

"starman" wrote in message

Hmmm. A tank circuit between the antenna input and ground, to improve
reception? I believe you, but I don't understand how it works. Could
you
enlighten me a little? Does it resonate at the selected frequency
(chosen
by adjusting the variable cap) and thereby "select" that signal for the
input to the radio? (This is all I can figure.)

I could do that real easy. I have several variable caps of that general
size, and can pick up whatever size inductor I need. I even have the
charts
and formulas for calculating the appropriate value of inductance, just
have
to sit down with them. Thanks for the suggestion.

PS: Haven't checked out the links yet, but will do so asap.

Dave


The parallel tuned (tank) circuit causes all frequencies above and below
the tuned one, to be shunted to ground while passing the desired
frequency range to the radio's antenna input. It makes up for the lack
of good preselection in the receivers front-end. This is the main
problem when connecting a good antenna to a portable radio. Be sure to
use coils with ferrite cores for good selectivity.



Gotcha. That was the only way I could figure it. I saw something almost
similar (is that like almost pregnant?) in my Practical Antenna Hanbook (Joe
Carr) last night, but suspect it is a printing error. It was an series
inductor following behind a capacitor shunt to ground. Only that would (I
think) choke off RF and shunt it to ground. (Am I wrong?) Have been trying
to figure that one out all day. Last night I fixed my big solder gun, and
can now solder a ground wire to the grounding rod outside my bedroom window.
Hope to do that tomorrow.

I am definetly going to set this up. Have already tested several of my
small capacitors, but they do not appear stable enough for anything serious.
Just to familiarize myself with the mathematics, I have already calculated
the inductors I would need for the first one I tested. Just finished
removing a better variable cap from an old junk shortwave radio (a Luke, I
think) and am going to try to use it. May have a problem with my meter
though. May have to take the variable cap to the shop and have it tested on
a known good LCR meter (gotta get one of those. I a currently using a DMM
with limited capacitance capability.) If I do that I'll take my calculator
and notepad with me, so I can figure out and write down the values of
inductance I need. Damn I'm having fun.

Thank you very much for this suggestion. It is much appreciated.

Dave


If you can find a large enough variable capacitor, like 10-600 pf, you
can tune the entire shortwave spectrum (3-30 Mhz) with one coil. One way
to do this is to connect the individual gangs of a multi ganged
capacitor together in parallel. However there is a practical limit to
this because the high end (fully opened) range of the cap' will also get
larger and this will prevent the circuit from tuning all the way up to
30-Mhz. That's why it's usually easier to use a standard capacitor like
10-365 pf with at least two coils and a switch. It's also best to use
coils with an adjustable ferrite core (slug) so you can fine tune the
circuit's tracking on the low end of the range. You can buy such coils
from suppliers like Amidon and Miller. They come either wound for a
particular value of inductance or without any windings, if you want to
wind your own. The ferrite core material should be the type made for HF
use, such as T-43. I used to get my coil forms from old televisions that
used vacuum tubes. These sets had several coils in the I.F. and chroma
circuits which worked well for shortwave purposes. I would remove the
windings and rewind them for the value I needed in the preselector. Let
us know how your project goes.


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Dave,

Here is the Radio Netherlands 'review' of the Sangean ATS-505.
http://www.rnw.nl/realradio/ats505.html

The Shortwave "External Antenna" Jack appears to be a 1/8"
Mono-Jack. The Outer-Barrel is Ground and the Tip-End is the
Antenna. Using a 1/8" Mono-Plug 'wire' the External Antenna to
the Tip-End of the plug and the Ground Wire 'connection' to
the Outer-Barrel of the plug.


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

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

Just a quick note: it actually does have an external antenna
input, I just don't know what type of plug to stick into it.
Plastic ring with metal contact inside, looks like 1/8" mono
would do it, but how would I ground it?

Negative battery term?

Thanks,

Dave


..