Loop Antennas / minijack works-clips don't / impedence??
dan...@yahoo.com
and it came with a 3 conductor mini-jack to "two clips"
(antenna/ground) adapter. The antenna works fine with the minijack /
but not the clips. I tried the clips with my Edek Torus Tuner... the
clips don't seem to work with that either. The clips are making
electrical contact through, though. I tried the clips with two radios
(one radio doesn't have an antenna jack - hence the issue).
Important details:
The DE-31 has a 3 conductor mini-jack and the adapter ends with TWO
clips, one for antenna and one for ground. The radios don't have
"ground" connectors per-se, so I'm not sure the best place to connect
the ground wire and if that's causing an issue.
When I connect either antenna via the minijack, I can tune the antenna
just fine (I hear the "click" around the proper spot and then tune
slowly) and it makes a marked improvement.
When I connect the Torus Tuner via the clip adapter, I can hear the
"click" and fine tune, but it makes very little difference (on the same
frequencies I tested with the minijack). Remember that the Torus Tuner
has a 2 conductor plug and the adapter is 3 conductor - I don't know if
that makes a difference.
When I connect the DE-31 via the clip adapter, I can't hear the "click"
at all. The DE-31 has a pretty long minijacked wire to connect to the
loop. When I use the clip adapter, removing the wire from the loop,
gives the same reception as having the loop attached.
That is, it seems that on the DE-31 at least, when it's connected using
the clip adaptor, it's using the wire as a 'longwire' antenna, but it's
not interacting with the loop at the end of the longwire correctly (and
reception using the wire varies by frequency). Is this an impedence
mismatch? Could this have to do with not connecting the grounding wire?
Any other possibilities How can this be tested (I do have a
multimeter)/ corrected?
This thread has technical data regarding the insides of the DE-31 if it
can be of any help.
I have not moded the unit:
http://www.drmrx.org/forum/showthread.php?t=1210
Thanks for any insights!
Charly
Hello,
Can you connect both clips ? one to the antenna and one to a "ground" point ?
It does help to have the ground point...
Charly
dan...@yahoo.com
negative battery terminal... Besides being "sloppy" (maybe put a wire
around the battery door), will that do damage? Any other locations to
ground it, for a portable which doesn't have a ground (or antenna)
terminal?
If I don't use headphones, someone mentioned the headphone jack... Is
that ok? I guess I'd have to buy a minijack... which terminal would be
ground? Do I then not connect anything to the other terminal of the
jack?
Interestingly, at around 15 mHz, using the antenna via the clips, does
seem to work (I can tune the antenna and get sensitivity increase - I
don't know if it 100% matches the jack or not - but it's pretty good).
At around 9 mHz, using the antenna via the clips only seems to see the
wire and not the antenna at the end (tuning does nothing).
Does that show an impedence matching issue?
Thanks
Charly
> The question is, what can I use as a ground point? The seller said the
> negative battery terminal... Besides being "sloppy" (maybe put a wire
> around the battery door), will that do damage? Any other locations to
> ground it, for a portable which doesn't have a ground (or antenna)
> terminal?
>
> If I don't use headphones, someone mentioned the headphone jack... Is
> that ok? I guess I'd have to buy a minijack... which terminal would be
> ground? Do I then not connect anything to the other terminal of the
> jack?
Yes it can be ok. I did it. If your radio has a line-out jack, then you can use
it. You can also use the negative connection of the power jack if your radio got
one.
>
> Interestingly, at around 15 mHz, using the antenna via the clips, does
> seem to work (I can tune the antenna and get sensitivity increase - I
> don't know if it 100% matches the jack or not - but it's pretty good).
>
> At around 9 mHz, using the antenna via the clips only seems to see the
> wire and not the antenna at the end (tuning does nothing).
>
You must tune the antenna VERY SLOWLY ! The KA31 is very difficult to tune
sometime, and you can only see the difference on the S-meter sometime...
Using this antenna without an S-meter is quite difficult, I don't do it.
> Does that show an impedence matching issue?
Dunnow... What is your radio ? I did use it with a Sony SW100 and a Sangean ATS909.
>
> Thanks
You're most welcome...
Charly
RHF
DANR,
Most of the times with a 'portable' AM/FM Shortwave Radio
you are OK with 'assuming' that the Negative Battery Terminal
is Circuit Ground for the Radio and hence the RF Ground
for the Radio. - The Altenative is to check-out the Radio's
Circuit Diagram {Schematic} -or- Take the Radio 'appart'
and Eye-Ball the internal circuitry.
The Outer-Ring of the Headphone Jack can 'usually' be
used as a Circuit Ground connecting point that will function
as an RF Ground for the Radio.
Your one "Known" Antenna connection-point
{RF Signal Input} is the Radio's Whip Antrenna.
NOTE - Most Loop Antennas are considered LO-Z -and-
the Whip Antenna to Radio Ground is most likely HI-Z.
Go back to the beginning and attach a 20-30 Foot Random
Wire Antenna to the Whip Antenna and a Ground Wire to
the Negative Battery Connector -or- the Headphone Jack.
- - - If with this combination the Shortwave Radio reception
is much better - then move-on to more complicated Antenna
'connections' with your other Loop and Active Antennas.
hope this helps - iane ~ RHF
.
Shortwave Listener Antennas => http://tinyurl.com/ogvcf
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL Antenna Group => http://tinyurl.com/ogvcf
.
The Shortwave Listener's Blessing :
SWL BLESSING => http://tinyurl.com/s2bjm
May You Never Tire of Listening to the Radio and Always
have Strong Signals and Noise Free Reception ~ RHF {ibid}
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/9233
.
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dan...@yahoo.com
SW100 powers the antenna which comes with it -- so it outputs voltage
on the antenna jack... When I bought a Torus Tuner (Edek) loop, Ed
especially modified it (and future units) to work with the SW100, after
I requested it.
I actually tried it with the SW100 antenna jack and then reminded
myself that I probably shouldn't. I'm now testing it on the SW100 rod
antenna and the DE1105 rod antenna.
The DE1105 does have an S meter (I don't know what units they use).
My goal is to get the DE1105 with DE-31 to work and then sell my SW100
and Torus Tuner loop. The SW100 and Torus Tuner are both great... but
nowadays, I use shortwave mostly for travel and the SW100 is too
precious and the Torus Tuner is too big to bring along.
RHF
DANR,
Which Torus Tuner Loop Do You Have ?
Shortwave or AM/MW ?
Size / Inchs Diameter ?
Price ?
i want to know ~ RHF
.
.
. .
dan...@yahoo.com
SW100 or other radios which output voltage on the antenna jack), R/C
amp (seperate, optionally connected box), all with 3.5mm jacks. The
antenna tunes slightly above 19 mHz (Ed tested my antenna and told me
in an email before shipping it out - I don't tune to anything above 18
mHz).
I'm not selling the antenna at this second, until I do more testing
with the new antenna/radio and different connection methods. I may end
up placing the antenna and SW100 on ebay. Probably another few weeks.
cuh...@webtv.net
ago,all of those jacks are not alike.The article was about how to modify
certain kinds of jacks.Some jacks work two way,some jacks work three
way.
Arra,if you like to google, Radio jacks
cuhulin
dan...@yahoo.com
2003...
Would this be useful for connecting to the loop? Someone in another
group mentioned wrapping insulated wire around the antenna itself about
10 or so times... Is the PVC piping you mention just for convenience--
or is the extra isolation needed? What diameter PVC pipe? (Since the
antenna has a tuner, is there a point to doing the tuned version you
mentioned?)
* HOME MADE: Tune-A-Stick Whip Coupler for External Shortwave
Antenna.
1. One Piece of PVC Pipe about 8" to 12" long.
2. Wrap about 50 to 100 turns of 18 to 24 AWG Insulated Wire
uniformally around the PVC Pipe.
3. Tape the Coil End Windings to secure them.
4. Strip away one inch of wire insulation to allow for ground and
external antenna connections.
5. Position the radio's Whip Antenna to the Vertical (Up-Right) Do not
Extend the Whip Antenna.
6. Place the The PVC Pipe over the Whip Antenna.
7. Connect the Ground to the bottom coil end wire and External SW
Antenna to the top coil end wires.
This is the end of the construction of the simple version of the
Tune-A-Stick Whip Coupler.
RHF
> RHF- I see that you recommended this for antenna coupling, back in
> 2003...
>
> Would this be useful for connecting to the loop? Someone in another
> group mentioned wrapping insulated wire around the antenna itself about
> 10 or so times... Is the PVC piping you mention just for convenience--
> or is the extra isolation needed? What diameter PVC pipe? (Since the
> antenna has a tuner, is there a point to doing the tuned version you
> mentioned?)
>
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
* HOME MADE: Tune-A-Stick Whip Coupler
for External Shortwave Antenna.
1. One Piece of PVC Pipe about 8" to 12" long.
2. Wrap about 50 to 100 turns of 18 to 24 AWG
Insulated Wire uniformally around the PVC Pipe.
3. Tape the Coil End Windings to secure them.
4. Strip away one inch of wire insulation to allow
for ground and external antenna connections.
5. Position the radio's Whip Antenna to the Vertical
(Up-Right) Do not Extend the Whip Antenna.
6. Place the The PVC Pipe over the Whip Antenna.
7. Connect the Ground to the bottom coil end wire
and External SW Antenna to the top coil end wires.
This is the end of the construction of the simple
version of the Tune-A-Stick Whip Coupler.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
DANR,
1 - If you Wrap the Insulated Wire Directly on-to the
Whip Antenna : Then you have a Fixed {Permenant}
Installation on the one Radio.
2 - If you use a Coil Form {Tube} and wrap the Wire
around it : Then you have a Temporary {Slide-On
and Slide-Off} Installation.
IMHO - Most Shortwave Listener's (SWL) perfer the
greater utility of Method # 2 using the Coil Form -and-
The ability to Install and use it when you want -or-
The ability to Transfer it from Radio to Radio.
READ - Using the "Portable Wire Antenna" (PWA)
with your 'portable' AM/FM Shortwave Radio
http://groups.google.com/group/rec.radio.shortwave/msg/a789c8fd6fcb38f2
http://groups.google.com/group/rec.radio.shortwave/msg/4d918a519e2a7237
- - - Three Ways to Use the "Portable Wire Antenna" (PWA)
http://groups.yahoo.com/group/SWL-AM-FM-Antenna/message/306
http://groups.google.com/group/rec.radio.shortwave/msg/24c4c12c1284c635
http://groups.google.com/group/rec.radio.shortwave/msg/207605149d11a356
http://groups.google.com/group/rec.radio.shortwave/msg/20e52b5c47771d66
READ - Consider building and using the
"Portable Wire Antenna" (PWA) with your
'portable' AM/FM Shortwave Radio
http://groups.google.com/group/rec.radio.shortwave/msg/93990162f5b6eb0e
ABOUT - The "Portable Wire Antenna" (PWA)
that was created and written about by Tom Sevart [N2UHC].
PWA => http://www.geocities.com/n2uhc/portablewire.html
READ - Two Things that most 'portable' AM/FM
Shortwave Radios Could Use for "Improved"
Shortwave Radio Listening (SWL)
http://groups.google.com/group/rec.radio.shortwave/msg/423b6d9bcdb872a8
1. External Antenna Input Isolator
2. Moderate Size Low Noise Inverted "L" Antenna
once again more than you wanted to know - iane ~ RHF
dan...@yahoo.com
I was asking if the tubing made a difference, so that I could TEST
using insulated wire directly on the antenna... and then get some
tubing once I see that the wrapping works and how many wraps are
needed.
RHF
DANR - Yes - The Tubing will make a difference.
Since the Insulated Wire will be closer to the Metal
of the Whip Antenna and therefore coupling to it more
effectively. You will find that few turns are required
with the Direct-Wrap. More Turns when the Tubing is
used 'in-between' the Wire and the Whip Antenna.
TIP # 1 - Instead of Tubing for your first attempt. Try a
few wraps of Paper taped around the Whip Antenna as
a Thin Core to make the Coupling Coil more easier to
Put-On or Take-Off as needed.
TIP # 2 - With the Tubing the Coil Assembly can be
positioned {move} In-and-Out on the Whip Antenna
so that the Coupling Effect between the Whip and
Coil can be varried {adjusted} for the best reception.
hope this helps - iane ~ RHF
.
.
. .
dan...@yahoo.com
insulated wire), directly around the antenna. I extended the bottom
(thick) part of the antenna, just enough to fit the wraps (-the wraps
are NOT spaced out). I then attached antenna and ground wires of the
loop to the ends of the wire wrapped around the antenna.
Well, off of the rod by itself, I can hear CHU Canada, but it's below 1
on the S-Meter. Using the inductive connection (40 wraps), it gives a
signal of 4 -- but it's VERY noisy.
(I tried reversing the antenna/ground to no avail).
With the antenna clip directly to the top (thin part) of the rod
antenna (rest of rod not extended), I get signal of 6 but very noisy.
When I connect the ground clip to the battery, it get's MUCH quieter
(than without ground, or with inductive connection) and it stays at a
signal of 6. Direct connection of the antenna to a radio with an
antenna jack is still much better!
(I did a test with the clips to that radio - in order to make sure it's
an antenna connection issue).
So, as of now, the inductive connection isn't helping. Suggestions or
recommendations?
I emailed Universal about the AA-1, to ask if it's ok to use with
active antennas (it's also $60...which is a bit much, considering).
Thanks
RHF
DANR,
Seems like you have tried all the various combinations
and described your results fairly well.
Remember - Not everything words for everyboby.
Choose the one that works for you the best and stick with it.
- - - Until you try something better :o)
If increased 'noise' coming from the simple straight wire
Antenna is an issue. Then try a Horizontal [Flat] Loop
Antenna with either TV Twin Lead or Coax Cable as a
feed-in-line from the Antenna to the Radio.
READ - The Shortwave Listener's (SWL) "Random"
Horizontal [Flat] Loop Antenna
http://groups.google.com/group/rec.radio.shortwave/msg/c173213a11be0b83
READ - The In-the-Attic Horizontal [Flat] Loop Antenna
- - - Just may be the better choice to fill that . . .
empty space overhead {not in your head :o}.
http://groups.google.com/group/rec.radio.shortwave/msg/01f4e10e7df8249c
http://groups.google.com/group/rec.radio.shortwave/msg/8678920c10cb5cc9
Note - A simple Loop Antenna {Square / Triangle / Round}
with a 10 - 15 Foot Side or Diameter is really about a
40'-60' / 30'-45' / 31'-47' long piece of Wire; and that
is enough Wire-in-the-Air for most 'portable' AM/FM
Shortwave Radios.
something to think about - iane ~ RHF
.
.
. .
Telamon
dan...@yahoo.com wrote:
> RHF wrote:
> > dan...@yahoo.com wrote:
> > > Thanks.
> > >
> > > I was asking if the tubing made a difference, so that I could
> > > TEST using insulated wire directly on the antenna... and then get
> > > some tubing once I see that the wrapping works and how many wraps
> > > are needed.
> > >
> > > >1 - If you Wrap the Insulated Wire Directly on-to the Whip
> > > >Antenna : Then you have a Fixed {Permenant} Installation on the
> > > >one Radio.
> >
> > DANR - Yes - The Tubing will make a difference.
> >
> > Since the Insulated Wire will be closer to the Metal of the Whip
> > Antenna and therefore coupling to it more effectively. You will
> > find that few turns are required with the Direct-Wrap. More Turns
> > when the Tubing is used 'in-between' the Wire and the Whip Antenna.
> >
> > TIP # 1 - Instead of Tubing for your first attempt. Try a few wraps
> > of Paper taped around the Whip Antenna as a Thin Core to make the
> > Coupling Coil more easier to Put-On or Take-Off as needed.
> >
> > TIP # 2 - With the Tubing the Coil Assembly can be positioned
> > {move} In-and-Out on the Whip Antenna so that the Coupling Effect
> > between the Whip and Coil can be varried {adjusted} for the best
> > reception.
> >
> Well, I went from 10 wraps, to about 40 wraps (of the same 22 gauge
> insulated wire), directly around the antenna. I extended the bottom
> (thick) part of the antenna, just enough to fit the wraps (-the wraps
> are NOT spaced out). I then attached antenna and ground wires of the
> loop to the ends of the wire wrapped around the antenna.
>
> Well, off of the rod by itself, I can hear CHU Canada, but it's below
> 1 on the S-Meter. Using the inductive connection (40 wraps), it gives
> a signal of 4 -- but it's VERY noisy. (I tried reversing the
> antenna/ground to no avail).
>
> With the antenna clip directly to the top (thin part) of the rod
> antenna (rest of rod not extended), I get signal of 6 but very noisy.
> When I connect the ground clip to the battery, it get's MUCH quieter
> (than without ground, or with inductive connection) and it stays at a
> signal of 6. Direct connection of the antenna to a radio with an
> antenna jack is still much better! (I did a test with the clips to
> that radio - in order to make sure it's an antenna connection issue).
>
> So, as of now, the inductive connection isn't helping. Suggestions or
> recommendations?
>
> I emailed Universal about the AA-1, to ask if it's ok to use with
> active antennas (it's also $60...which is a bit much, considering).
The radio input is a differential mode input. This means it see a signal
relative to its internal ground. Most local noise is common mode so an
antenna setup that picks it up and presents it to the radio input causes
the radio to respond to it without a ground connection. Connecting an
antenna to just the antenna terminal causes any received station by the
antenna to look the same as any local noise it also picks up since both
are presented to the radio as a signal to ground. Connecting an antenna
to the radio antenna terminal and ground causes the received station to
appear differentially across the radio input so the radio responds to it
and the common mode locally picked up noise is the same on the antenna
and ground terminal so it is rejected as a common mode signal.
--
Telamon
Ventura, California
RHF
- The radio input is a differential mode input. This means
- it see a signal relative to its internal ground.
- Most local noise is common mode so an antenna setup
- that picks it up and presents it to the radio input causes
- the radio to respond to it without a ground connection.
- Connecting an antenna to just the antenna terminal causes
- any received station by the antenna to look the same as any
- local noise it also picks up since both are presented to the
- radio as a signal to ground.
- Connecting an antenna to the radio antenna terminal and
- ground causes the received station to appear differentially
- across the radio input so the radio responds to it and the
- common mode locally picked up noise is the same on the
- antenna and ground terminal so it is rejected as a common
- mode signal.
-
- --
- Telamon
> Ventura, California
El Telo Mundo - Translation Please ! ~ RHF
Is simply connecting an Antenna to the Radio's Whip
Antenna or Antenna Terminal :
- - - Good -or- Band for Reception ?
Is simply connecting a Ground to the Radio :
- - - Good -or- Band for Reception ?
Will doing both make Radio Listening Beter : Yes -or- No ?
.
.
. .
Telamon
"RHF" <rhf-new...@pacbell.net> wrote:
You are confused by the terms differential and common mode?
Common mode means that you have the same voltage or signal on both
antenna and ground. Imagine a sine wave time varying voltage in phase
on the antenna and ground lead. Even though it is varying since it is
the same signal on both terminals it will not induce a current through
the radio input because there is no potential difference between the
terminals but if the signal was only on one terminal (antenna) then
there would be a potential difference and current will flow through the
radio input.
Consider a dipole antenna with one leg connected to the antenna and the
other leg connected to the ground terminal. A local noise field will
cause the same time varying voltage to be generated by both legs of the
dipole and then the radio terminals so that the radio does not respond
to it. However, a distant station will cause a time varying voltage 180
degrees out of phase to be generated and when that time varying
potential difference appears at the radio terminals that will cause a
current to flow from the antenna terminal to ground terminal.
The result of using a balanced antenna helps the radio reject local
noise while responding to the distant radio signal in this way. If we
were discussing amplifiers we would call it common mode rejection.
--
Telamon
Ventura, California