On Oct 4, 4:15*am, Wimpie wrote:
On 2 oct, wrote:

I'd like to try an external antenna, but one was not included with my
G5. What type ofwireshould I get (stranded, solid, gauge,
insulated...), and do I just solder it to the pos or neg lead of a
miniplug to go into the ext antenna receptacle?

Thanks....

Jim

Hello Jim,

Every type of metalwirewill work for you situation (solid, stranded,
plasticized galvanized washing line, etc).

Most modern SW receivers with internal antennas are very sensitive,
but cannot handle strong signals, so longer will not always be
better.

To reduce the interference from electronic equipment close to your SW
receiver, you may put a coaxial cable between the actual antenna and
the receiver. You can use any type of 75, 90 or 50 Ohms cable. The
center conductor goes to the center pin of the mini plug and the bread
goes to the ground of the mini plug.

The antenna side of the cable needs some clarification. The antennawiregoes to the center conductor of the cable, the braid should be
connected to ground outside your house (or at least far away from
where you expect or have interference).

What is "ground"? *When you live in an apartment, it can be the metal
fence or railing of the balcony. *You can use a ground rod or any
other large metallic structure outside your house. Connect the braid
of the cable directly to the ground structure. Do not insert a long
run ofwirebetween the metal structure and the braid of the coaxial
cable.

For some form of static / impulse protection you may add a 1… 3 uH
inductor between the center conductor and the braid. Note that this
inductor will attenuate AM broadcast band reception.

As others said, you have to experiment with the orientation of thewireto get best signal/noise ratio. When you are very limited in
space for thewire, you may use some 5..10 feet of chicken mesh as
reception antenna or use more wires in a fan shape.

Best regards,

Wim
PA3DJSwww.tetech.nl
please remove abc when using PM.

OK, sorry, I see I was confusing the antenna and radio sides of the
coax. The radio side: center of coax to center of mini, shield brain
to surround of mini. Antenna side: braid to ground post, center to
antenna wire. So I can have the run between outside ground post and
radio using coax.

But can I damage G5 with an external wire? If so I'll use the whip
inductor. Please advise....

thanks
Jim

On Sun, 11 Oct 2009 18:28:53 -0700, JimK wrote:


Thanks iane. What are the advantages of the balun, vs the long wire?

The balun drives co-ax cable. Terminate the random wire away from the
electrical noise near the receiver by using co-ax and the balun.

On Oct 11, 7:25*pm, dave wrote:
On Sun, 11 Oct 2009 18:28:53 -0700, JimK wrote:
Thanks iane. What are the advantages of the balun, vs the long wire?

- The balun drives co-ax cable.

First the Balun effectively 'couples' the Antenna
Wire to the Coax Cable {Impedance Matching}.
[Balun = RF Matching Transformer]

Note the Coax Cable [50 Ohms] is already
'Impedance Matched' to the Radio/Receivers
50 Ohm [LO-Z] Antenna Input.

-*Terminate the random wire away from the
- electrical noise near the receiver by using
- co-ax and the balun.

Generally a Balun works best along with a
good earthen Ground {connection}.

Hello Jim,

On 11 oct, 18:10, JimK wrote:
On Oct 4, 4:15*am, Wimpie wrote:



On 2 oct, wrote:

I'd like to try an external antenna, but one was not included with my
G5. What type ofwireshould I get (stranded, solid, gauge,
insulated...), and do I just solder it to the pos or neg lead of a
miniplug to go into the ext antenna receptacle?

Thanks....

Jim

Hello Jim,

Every type of metalwirewill work for you situation (solid, stranded,
plasticized galvanized washing line, etc).

Most modern SW receivers with internal antennas are very sensitive,
but cannot handle strong signals, so longer will not always be
better.

To reduce the interference from electronic equipment close to your SW
receiver, you may put a coaxial cable between the actual antenna and
the receiver. You can use any type of 75, 90 or 50 Ohms cable. The
center conductor goes to the center pin of the mini plug and the bread
goes to the ground of the mini plug.

The antenna side of the cable needs some clarification. The antennawiregoes to the center conductor of the cable, the braid should be
connected to ground outside your house (or at least far away from
where you expect or have interference).

What is "ground"? *When you live in an apartment, it can be the metal
fence or railing of the balcony. *You can use a ground rod or any
other large metallic structure outside your house. Connect the braid
of the cable directly to the ground structure. Do not insert a long
run ofwirebetween the metal structure and the braid of the coaxial
cable.

For some form of static / impulse protection you may add a 1… 3 uH
inductor between the center conductor and the braid. Note that this
inductor will attenuate AM broadcast band reception.

As others said, you have to experiment with the orientation of thewireto get best signal/noise ratio. When you are very limited in
space for thewire, you may use some 5..10 feet of chicken mesh as
reception antenna or use more wires in a fan shape.

Best regards,

Wim
PA3DJSwww.tetech.nl
please remove abc when using PM.

OK, sorry, I see I was confusing the antenna and radio sides of the
coax. The radio side: center of coax to center of mini, shield brain
to surround of mini. *

OK

Antenna side:
braid to ground post, center to
antenna wire. So I can have the run between outside ground post and
radio using coax.

OK, working this way avoids that the cable picks up interference from
domestic equipment.

But can I damage G5 with an external wire? If so I'll use the whip
inductor. Please advise....

Yes, you can, as most of these portable recievers do not have strong
input protection, nearby strikes can damage the input. Don't make
the wire longer then necessary and remove the mini plug from the radio
in case of natural photo flash. You might add the inductor or resistor
to lower the risk on damage because of built-up of static
electricity.

Using a special transformer as mentioned in other postings gives you
more signal output in case of short wires. So you can have a shorter
wire (for example when you have limited space). I do not share the
opinion that these transformers reduce interference significantly.

When you live in a residential area, you probably don't need this as
noise will be dominant with moderate wire lengths. More signal does
not always mean better reception as noise will raise also.

thanks
Jim

Best regards,

Wim
PA3DJS
www.tetech.nl

Thanks again, everyone.


But can I damage G5 with an external wire? If so I'll use the whip
inductor. Please advise....

Yes, you can, as most of these portable recievers do not have strong
input protection, *nearby strikes can damage the input. *Don't make
the wire longer then necessary and remove the mini plug from the radio
in case of natural photo flash. You might add the inductor or resistor
to lower the risk on damage because of built-up of static
electricity.


Wim (or anyone),

So, an early post stated "the longer the better" but you say not so
long. What is a good length to try? I assume I'll want to experiment
with longer and shorter. Bought 24 gauge speaker wire, 100 ft. for
$6.50 at Home Depot. But I'm nervous now, I don't want to do anything
until I understand.

I presume you mean, disconnect the antenna during storms with
lightening flashes. OK.

So, I'm thinking there are three kinds of potential damage from a long
wi static, lightening, and overload from a strong signal.

There are four ways to connect the antenna that I've encountered:
miniplug into antenna out, alligator clip to whip, bare wire wrapped
around whip, and inductive coupler (insulated wire wrapped around tube
placed over whip). (Leaving the balun out for the moment)

Am I right that too strong a radio signal (from too long a wire) can
hurt the radio? I presume this is true anytime too strong a signal
reaches the inside electronics. But my brother tells me the whip is
connected to an internal amplifier that the antenna input jack is not
connected to. So maybe the antenna input jack is safe in terms of
overloading signal from the long wire. And maybe the inductor can also
induce too strong a signal in the antenna which is then amplified,
causing damage, is this so? So, connecting the wire via the antenna
out jack and miniplug is safe with regard to overload, but inductive
coupler, alligator clip on whip, and bare wire wrapping around whip
(i.e., all connections to whip) are not. True?

As for lightening, it seems all connection methods are dangerous. For
static, all but the inductive coupler are dangerous. Right?



Using a special transformer as mentioned in other postings gives you
more signal output in case of short wires. So you can have a shorter
wire (for example when you have limited space). I do not share the
opinion that these transformers *reduce interference significantly.

When you live in a residential area, you probably don't need this as
noise will be dominant with moderate wire lengths. * More signal does
not always mean better reception as noise will raise also.




If I can figure out how to safely connect the antenna to the radio,
then is a good way to solve this noise issue to use a very long wire?
Or will it just pick up more residential EMG noise? I am in a
residential area, I have apartment buildings on two sides, 100+ feet
away, house on third side.

Maybe tuning to wavelengths is the only way to get a wire to elevate
signal above noise.

Thanks very much!

Jim

-*Terminate the random wire away from the
- electrical noise near the receiver by using
- co-ax and the balun.

Generally a Balun works best along with a
good earthen Ground {connection}.
*.

Dave and RHF, thanks. I'll read up on the balun. What is the purpose
of impedence (or RF?) matching between random wire and coax?

Thanks,
Jim

On Oct 17, 10:32*pm, JimK wrote:
-*Terminate the random wire away from the
- electrical noise near the receiver by using
- co-ax and the balun.

Generally a Balun works best along with a
good earthen Ground {connection}.
*.

Dave and RHF, thanks. I'll read up on the balun. What is the purpose
of impedence (or RF?) matching between random wire and coax?

Thanks,
Jim

JIM K - Here is a visualization explanation
that is not technically correct.

The Long Wire Matching Transformer {Balun/UnUn}
incorporates a HI-Z Winding and a LO-Z Winding
plus an effective {efficient} means of 'coupling'
{energy transfer} which is usually a Ferrite Core.
-coupling-
The 'nominal' Impedance of a long wire {random wire}
Antenna is 450~500 Ohms [HI-Z] and captures the
RF Signal {relative Higher Voltage and Lower Current}.
-to-
The 'nominal' Impedance of a Coax Cable is 50~75
Ohms [LO-Z] and conducts the RF Signal {relative
Lower Voltage and Higher Current}.

NOTE - The Balun/UnUn is an Matching Transformer
that is designed to work/operate at Radio Frequencies.

Consider the common wall-wart 120VAC to 6VDC
that is designed to work/operate at AC Power
{50~60 Hz} Low Frequency : It too is a Transformer.

For a more technical explanation of Baluns read :

Electrical Impedance
http://en.wikipedia.org/wiki/Electrical_impedance

Characteristic {Nominal} Impedance
http://en.wikipedia.org/wiki/Characteristic_impedance

Impedance Matching
http://en.wikipedia.org/wiki/Impedance_matching

Balun
http://en.wikipedia.org/wiki/Balun

Impedance Matching Transformers
http://www.bcae1.com/trnimpmt.htm
http://www.allaboutcircuits.com/vol_2/chpt_9/7.html

Impedance Matching Transformers for Receiving Antennas
http://www.dxing.info/equipment/impe...ing_bryant.pdf

How RF Transformers Work
http://www.minicircuits.com/pages/pdfs/howxfmerwork.pdf
* About RF Transformers
http://www.minicircuits.com/pages/pdfs/tran14-2.pdf

Wide Band RF Transformers
http://www.electronics-tutorials.com...ansformers.htm

Broadband Receiving Antenna Matching
http://www.qsl.net/wa1ion/bev/bb_antenna_matching.pdf

hope this helps - iane ~ RHF

JimK wrote:
- Terminate the random wire away from the
- electrical noise near the receiver by using
- co-ax and the balun.

Generally a Balun works best along with a
good earthen Ground {connection}.
.

Dave and RHF, thanks. I'll read up on the balun. What is the purpose
of impedence (or RF?) matching between random wire and coax?

Thanks,
Jim


Think of "impedance" as hose diameter. You can dump water from a skinny
hose (low Z) into a fat hose (Hi Z) but not the other way around (most
of the water is spilled).

The matching "Bal Un" is usually an autotransformer which converts the
450 Ohms (max Z of the random wire) to 50 Ohms (good match for RG-58,
RG-59, RG-6, RG-8X, etc.) Note that at resonance, the random wire is
already at 50 Ohms, so the transformer lowers it to ca. 6 Ohms, but it
works fine for receiving).

A second benefit is that the "BalUn" is DC grounded everywhere (provided
you ground the cable sheath where it enters your house per NEC). This
will keep static charges out of your radio. Your brother is right.
Whips are usually "active" antennas, with an extra transistor to convert
the Hi Z antenna to Low-Z, to match the EXT ANT input, which you should
use, if you have a proper coaxial deed.

Hello Jim, I put my comment between your text

On 18 oct, 07:26, JimK wrote:
Thanks again, everyone.

But can I damage G5 with an external wire? If so I'll use the whip
inductor. Please advise....

Yes, you can, as most of these portable recievers do not have strong
input protection, nearby strikes can damage the input. Don't make
the wire longer then necessary and remove the mini plug from the radio
in case of natural photo flash. You might add the inductor or resistor
to lower the risk on damage because of built-up of static
electricity.

Wim (or anyone),

So, an early post stated "the longer the better" but you say not so
long. What is a good length to try? I assume I'll want to experiment
with longer and shorter. Bought 24 gauge speaker wire, 100 ft. for
$6.50 at Home Depot. But I'm nervous now, I don't want to do anything
until I understand.

As you are in a residential area, start with about 20 ft. there may
be some bends in the wire (for example some part horizontally, some
vertically. I checked the I-manual. The receiver has a DX/LOC switch.
When you are listening to a weak station and the clearness doesn’t
reduce when switching from DX to LOC, your wire is long enough (maybe
somewhat to long for that particular frequency band).


I presume you mean, disconnect the antenna during storms with
lightening flashes. OK.

Correct.


So, I'm thinking there are three kinds of potential damage from a long
wi static, lightening, and overload from a strong signal.

OK, If there is no DC bath between the inner conductor and the shield
of the cable, you can have build-up of static charge that may damage
the input circuitry. Strong overload (due to strong stations) will
very likely not damage the input, but may result in bad reception of
signals at certain frequency bands.


There are four ways to connect the antenna that I've encountered:
miniplug into antenna out, alligator clip to whip, bare wire wrapped
around whip, and inductive coupler (insulated wire wrapped around tube
placed over whip). (Leaving the balun out for the moment).

In my opinion, the insulated wire wrapped around a tube place over the
whip, looks like inductive coupling, but is capacitive coupling (no
direct electrical connection between wire and whip). This method of
coupling reduces the coupling for low frequency. By varying the number
of turns you can figure out the best coupling to your receiver. That
means sufficient signal from the antenna to overcome the receiver
noise, but not too much to get intermodulation (overload) problems.


Am I right that too strong a radio signal (from too long a wire) can
hurt the radio?

I think not, see text above.

I presume this is true anytime too strong a signal
reaches the inside electronics. But my brother tells me the whip is
connected to an internal amplifier that the antenna input jack is not
connected to. So maybe the antenna input jack is safe in terms of
overloading signal from the long wire.

Depends on type of receiver, I don't know the inside of the G5.

And maybe the inductor can also
induce too strong a signal in the antenna which is then amplified,
causing damage, is this so? So, connecting the wire via the antenna
out jack and miniplug is safe with regard to overload, but inductive
coupler, alligator clip on whip, and bare wire wrapping around whip
(i.e., all connections to whip) are not. True?

Many portable receivers show overload problems when connecting long
wire (for example 100ft) directly to the whip (electrically
connected). By wrapping the insulated wire around the whip, you reduce
the coupling (especially for the low frequency ranges like AM and LW),
hence reducing change of overload.


As for lightening, it seems all connection methods are dangerous. For
static, all but the inductive coupler are dangerous. Right?

Depends. When the wire is insulated from the antenna (what you call
inductive coupling), static charge may build-up until it reaches the
ultimate strength of the insulation. When exceeded, your whip might be
subjected to static discharge.

You can bleed the static charge by providing a DC path to ground.
Mostly when the bare antenna wire touches the building construction
(wood, concrete, etc), static charge will not build-up.


Using a special transformer as mentioned in other postings gives you
more signal output in case of short wires. So you can have a shorter
wire (for example when you have limited space). I do not share the
opinion that these transformers reduce interference significantly.

When you live in a residential area, you probably don't need this as
noise will be dominant with moderate wire lengths. More signal does
not always mean better reception as noise will raise also.

If I can figure out how to safely connect the antenna to the radio,
then is a good way to solve this noise issue to use a very long wire?
Or will it just pick up more residential EMG noise? I am in a
residential area, I have apartment buildings on two sides, 100+ feet
away, house on third side.

You may try this. When you have a significant part of the wire
outside, away from electronics, that will improve reception, but be
aware of overload as mentioned earlier (so use the capacitive coupling
with the insulated wire wrapped around the whip). Note that this is
not my favorite solution (I prefer the coaxial feed and have all
antenna parts away from electronics).


Maybe tuning to wavelengths is the only way to get a wire to elevate
signal above noise.

Sorry Jim, I don't understand what you mean.

Thanks very much!

Jim

I hope my response is not too confusing.

Best regards,

Wim
PA3DJS
www.tetech.nl
without abc, you have a valid address.

Am I right that too strong a radio signal (from too long a wire) can
hurt the radio?


Depends on the radio. The input gain device may be adversely
affected by too strong a signal. Being driven into saturation can
result in failure of some devices. This was a problem with some Sony
radios. It was a problem on a few inexpensive radios. It was a
problem on a number of early solidstate radios.

Today, receivers have overload protection before the first active
device. Sony installed diodes before the front end of their affected
devices. And most input devices used today have sufficient headroom
in circuit to prevent front end overload in all but the most extreme
cases. Buffers, and IF amps will more quickly overload than many
front ends, today.

But if you're talking about SW, unless you're near Antigua, or
living in Western Europe, you're not likely to encounter signals
strong enough to cause overload problems. A few domestic SW players,
if you're close enough. But not nearly what it used to be.

So, depending on your location, your concern may be a non-issue.

That said, it's something that's worth bearing in mind.