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BL-2 Connection To An Unbalanced Wire Antenna

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Jack

BL-2 Connection To An Unbalanced Wire Antenna

Is there a way to connect a long wire to a BL-2?

I vaguely remember seeing a post re: this kind of setup used as a way to get
a wider range of matches without using a longer wire antenna.

My rig is a KX1 and where I am going to be backpacking makes it impractical
to use a balanced line setup.

I have a 28 foot fishing pole that makes great matches on the upper bands
with a 28 foot wire attached to the KX1.

I have searched the web and the archives but could not find anything
relevant.

Basically the question is to which two of the three output connections on
the BL-2 do I connect a long wire antenna and its counterpoise(s) too? A and
B, A and GND, B and GND or.... well you get the idea.

Jack, AE6GC

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Bob Nielsen-2

Re: BL-2 Connection To An Unbalanced Wire Antenna

Why not connect the wire directly to the KX-1 output? The KXAT1 will
handle a pretty wide range of load impedances.

On Mar 31, 2009, at 12:08 PM, Jack Regan wrote:

> Is there a way to connect a long wire to a BL-2?
>
>
>
> I vaguely remember seeing a post re: this kind of setup used as a
> way to get
> a wider range of matches without using a longer wire antenna.
>
>
>
> My rig is a KX1 and where I am going to be backpacking makes it
> impractical
> to use a balanced line setup.
>
>
>
> I have a 28 foot fishing pole that makes great matches on the upper
> bands
> with a 28 foot wire attached to the KX1.
>
>
>
> I have searched the web and the archives but could not find anything
> relevant.
>
>
>
> Basically the question is to which two of the three output
> connections on
> the BL-2 do I connect a long wire antenna and its counterpoise(s)
> too? A and
> B, A and GND, B and GND or.... well you get the idea.
>
>
>
> Jack, AE6GC
>
>
>
>
>
>
>
>
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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AC7AC

Re: BL-2 Connection To An Unbalanced Wire Antenna

In reply to this post by Jack

CONTENTS DELETED

The author has deleted this message.

Jim Brown-10

Re: BL-2 Connection To An Unbalanced Wire Antenna

On Tue, 31 Mar 2009 13:57:55 -0700, Ron D'Eau Claire wrote:

>The most important thing is to have an RF ground at the rig - especially
>when using a wire that's 1/4 wavelength or less long as we often must do
>when travelling light.

>For my KX1 I carry two 33 foot lengths of wire soldered to a BNC male
>connector. One goes to the "hot" center pin and the other connects to the
>shell of the ANT connector.

>If I can, I get both of wires "in the clear".

That's not an "RF ground," it's a counterpoise, it's radials, it's the other
half of the antenna. I agree that what you've described is very important to
make the antenna work, but it's NOT "RF ground."

73,

Jim Brown K9YC

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AC7AC

Re: BL-2 Connection To An Unbalanced Wire Antenna

CONTENTS DELETED

The author has deleted this message.

Jim Brown-10

Re: BL-2 Connection To An Unbalanced Wire Antenna

On Tue, 31 Mar 2009 18:43:39 -0700, Ron D'Eau Claire wrote:

>But it *IS* a ground for RF purposes

Nope! It has NO relationship with the earth, nor is one needed. This
use of the word "ground" is an ongoing source of confusion and
misunderstandings. Hams to go extremes to install ground rods,
thinking that it will improve the performance of their antennas or
make their radios quieter or fix RFI. A connection to earth does NOT
do any of those things. It IS critical for lightning protection.
That's all.

Radials are not GROUND in any sense. They are part of the antenna!
Indeed, their purpose is to intercept the fields produced by the
antenna and by providing a low resistance path for return currents,
prevent those fields from producing current in the lossy earth.
There is an excellent discussion of this by Rudy Severns, N6LF, both
in the ARRL Antenna Book and on his website.

73,

Jim Brown K9YC

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AC7AC

Re: BL-2 Connection To An Unbalanced Wire Antenna

CONTENTS DELETED

The author has deleted this message.

Jack Brindle

Re: BL-2 Connection To An Unbalanced Wire Antenna

In reply to this post by Jack

I have to agree with Jim on this one. Perhaps the biggest concept drilled into me by the RF engineers I worked with at Motorola (I was a digital/software/comm engineer) is that there is no such thing as RF ground. RF can, and is, conducted on any path that it wants. This is especially true for the so-called "ground" and "power" paths, which while appearing to be well bypassed, still will carry RF currents. The problem was really drilled home when I had to track down a problem with a 450 MHz handheld data transceiver being desensed. The cause was the 250th harmonic of the microcontroller main clock, which placed a 14 uV signal on the receiver input. The signal was being conducted on the system ground, including shielding, and into the receiver front-end. How do you solve it? Shift the crystal frequency when on problematic channels.

So, while the concept of a common ground which carries no signals may be an interesting one, in practice it simply does not exist.

- Jack Brindle, W6FB.

-----Original Message-----

>From: Ron D'Eau Claire <[hidden email]>
>Sent: Apr 1, 2009 2:00 PM
>To: [hidden email]
>Subject: Re: [Elecraft] BL-2 Connection To An Unbalanced Wire Antenna
>
>Jim, IMX it's a mistake to equate "RF ground" with an Earth connection.
>
>An RF "ground" is just a low-impedance, low-reactance current sink for RF.
>Of course it is an integral part of the antenna circuit.
>
>An RF "ground" would not be expected to radiate, and most "counterpoise" or
>"radial" setups don't radiate a significant amount of energy*:
>
>1) Counterpoises near the Earth and on-ground "radials" tend to couple all
>their energy into the lossy dielectric of the Earth, never to be seen again.
>This is how BCB stations achieve a good RF ground generally using 120 0.2
>wavelength radials around their towers to couple the RF into the Earth.
>
>2) Elevated radials will radiate a lot unless they are carefully balanced
>and symmetrical so "legs" produce RF fields that cancel each other outside
>of the immediate area of the antenna. Such radials, like any RF ground,
>*are* part of the antenna circuit but, when properly designed, they are a
>non-radiating "current sink". In the common "ground plane" designs, they
>also decouple the radiating element from the feed line, providing an RF
>"ground" not only for the radiator but also grounding the feed line at the
>antenna so RF currents don't flow down the outside of the coax shield.
>
>Ron AC7AC
>
>* Students have asked me what happens if they use only one radial with a 1/4
>wave antenna. I reply that if they make it 1/4 wave long, then elevate them
>both into the air and arrange them to run in opposite directions for maximum
>efficiency, one 'radial' works just fine. If they draw out the antenna I
>described on paper they'll recognize the common center fed dipole antenna.
>In that case, there's no problem with the "radial" radiating.
>
>
>-----Original Message-----
>
>On Tue, 31 Mar 2009 18:43:39 -0700, Ron D'Eau Claire wrote:
>
>>But it *IS* a ground for RF purposes
>
>Nope! It has NO relationship with the earth, nor is one needed. This
>use of the word "ground" is an ongoing source of confusion and
>misunderstandings. Hams to go extremes to install ground rods,
>thinking that it will improve the performance of their antennas or
>make their radios quieter or fix RFI. A connection to earth does NOT
>do any of those things. It IS critical for lightning protection.
>That's all.
>
>Radials are not GROUND in any sense. They are part of the antenna!
>Indeed, their purpose is to intercept the fields produced by the
>antenna and by providing a low resistance path for return currents,
>prevent those fields from producing current in the lossy earth.
>There is an excellent discussion of this by Rudy Severns, N6LF, both
>in the ARRL Antenna Book and on his website.
>
>73,
>
>Jim Brown K9YC
>
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

Don Wilhelm-4

Re: BL-2 Connection To An Unbalanced Wire Antenna

In reply to this post by AC7AC

Ron,

I have been preaching similar points in ham circles for years now - and
I find that many hams cannot visualize the difference between a
"ground" (meaning a return path for current) and Mother Earth.
Actually any point where the RF current crosses the zero voltage point
is a point of RF Ground (it is a potential, not a physical place), and
on a balanced antenna it should occur midway between the two sides of
the feedpoint - and a vertical with radials *is* a balanced antenna,
that is why a balun is needed even on a vertical.

The English do distinguish between "earthing" and "grounding", and I do
wish that sort of distinction were also in common use in the US, it
certainly would help.

BTW - elevated radials *do* radiate in the very near field, but when
arranged properly (pairs in opposing directions), the radiation is out
of phase and will cancel at a distance from the antenna. Your term
"current sink" is not a description I would use.

73,
Don W3FPR

Ron D'Eau Claire wrote:

> Jim, IMX it's a mistake to equate "RF ground" with an Earth connection.
>
> An RF "ground" is just a low-impedance, low-reactance current sink for RF.
> Of course it is an integral part of the antenna circuit.
>
> An RF "ground" would not be expected to radiate, and most "counterpoise" or
> "radial" setups don't radiate a significant amount of energy*:
>
> 1) Counterpoises near the Earth and on-ground "radials" tend to couple all
> their energy into the lossy dielectric of the Earth, never to be seen again.
> This is how BCB stations achieve a good RF ground generally using 120 0.2
> wavelength radials around their towers to couple the RF into the Earth.
>
> 2) Elevated radials will radiate a lot unless they are carefully balanced
> and symmetrical so "legs" produce RF fields that cancel each other outside
> of the immediate area of the antenna. Such radials, like any RF ground,
> *are* part of the antenna circuit but, when properly designed, they are a
> non-radiating "current sink". In the common "ground plane" designs, they
> also decouple the radiating element from the feed line, providing an RF
> "ground" not only for the radiator but also grounding the feed line at the
> antenna so RF currents don't flow down the outside of the coax shield.
>
> Ron AC7AC
>
>

Steve Ellington

Re: BL-2 Connection To An Unbalanced Wire Antenna

Don
I'm running a special on RF grounds today. I've carefully measured out some
1/2 wave wires, cut out 6" from the midpoint and offering these for $25.
This will totally eliminate the need for multiple radials.
Happy April 1.

Steve Ellington
[hidden email]
----- Original Message -----
From: "Don Wilhelm" <[hidden email]>
To: "Ron D'Eau Claire" <[hidden email]>
Cc: <[hidden email]>
Sent: Wednesday, April 01, 2009 6:12 PM
Subject: Re: [Elecraft] BL-2 Connection To An Unbalanced Wire Antenna

> Ron,
>
> I have been preaching similar points in ham circles for years now - and
> I find that many hams cannot visualize the difference between a
> "ground" (meaning a return path for current) and Mother Earth.
> Actually any point where the RF current crosses the zero voltage point
> is a point of RF Ground (it is a potential, not a physical place), and
> on a balanced antenna it should occur midway between the two sides of
> the feedpoint - and a vertical with radials *is* a balanced antenna,
> that is why a balun is needed even on a vertical.
>
> The English do distinguish between "earthing" and "grounding", and I do
> wish that sort of distinction were also in common use in the US, it
> certainly would help.
>
> BTW - elevated radials *do* radiate in the very near field, but when
> arranged properly (pairs in opposing directions), the radiation is out
> of phase and will cancel at a distance from the antenna. Your term
> "current sink" is not a description I would use.
>
> 73,
> Don W3FPR
>
> Ron D'Eau Claire wrote:
>> Jim, IMX it's a mistake to equate "RF ground" with an Earth connection.
>>
>> An RF "ground" is just a low-impedance, low-reactance current sink for
>> RF.
>> Of course it is an integral part of the antenna circuit.
>>
>> An RF "ground" would not be expected to radiate, and most "counterpoise"
>> or
>> "radial" setups don't radiate a significant amount of energy*:
>>
>> 1) Counterpoises near the Earth and on-ground "radials" tend to couple
>> all
>> their energy into the lossy dielectric of the Earth, never to be seen
>> again.
>> This is how BCB stations achieve a good RF ground generally using 120 0.2
>> wavelength radials around their towers to couple the RF into the Earth.
>>
>> 2) Elevated radials will radiate a lot unless they are carefully balanced
>> and symmetrical so "legs" produce RF fields that cancel each other
>> outside
>> of the immediate area of the antenna. Such radials, like any RF ground,
>> *are* part of the antenna circuit but, when properly designed, they are a
>> non-radiating "current sink". In the common "ground plane" designs, they
>> also decouple the radiating element from the feed line, providing an RF
>> "ground" not only for the radiator but also grounding the feed line at
>> the
>> antenna so RF currents don't flow down the outside of the coax shield.
>>
>> Ron AC7AC
>>
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Matt Palmer-4

Re: BL-2 Connection To An Unbalanced Wire Antenna

In reply to this post by Jack Brindle

Ahh now you are no longer talking about RF ground but the black art of
EMI. Its not to difficult to determine RF ground, you have to have
very good spatial visualization, the ability to hold the 3D model of
the board, chassis and housing in your head, and you need to think
like an electron. It takes practice, but being relatively
inexperienced i've gotten the hang of it after being involved in the
successful design of 2 radios, but then again I have fantastic mentors
and elmers. In the end everything is explained by Maxwell's equations
and if 1/10th of the ham population took the time to understand how
these fantastic formula work and what they mean, 99% of this confusion
and most of the half truths you see passed around as 'common
knowledge' would disappear.

Matt
W8ESE
Former KD8DAO
http://blog.MattIsKichigai.com

On Wed, Apr 1, 2009 at 6:04 PM, Jack Brindle <[hidden email]> wrote:

> I have to agree with Jim on this one. Perhaps the biggest concept drilled into me by the RF engineers I worked with at Motorola (I was a digital/software/comm engineer) is that there is no such thing as RF ground. RF can, and is, conducted on any path that it wants. This is especially true for the so-called "ground" and "power" paths, which while appearing to be well bypassed, still will carry RF currents. The problem was really drilled home when I had to track down a problem with a 450 MHz handheld data transceiver being desensed. The cause was the 250th harmonic of the microcontroller main clock, which placed a 14 uV signal on the receiver input. The signal was being conducted on the system ground, including shielding, and into the receiver front-end. How do you solve it? Shift the crystal frequency when on problematic channels.
>
> So, while the concept of a common ground which carries no signals may be an interesting one, in practice it simply does not exist.
>
> - Jack Brindle, W6FB.
>
> -----Original Message-----
>>From: Ron D'Eau Claire <[hidden email]>
>>Sent: Apr 1, 2009 2:00 PM
>>To: [hidden email]
>>Subject: Re: [Elecraft] BL-2 Connection To An Unbalanced Wire Antenna
>>
>>Jim, IMX it's a mistake to equate "RF ground" with an Earth connection.
>>
>>An RF "ground" is just a low-impedance, low-reactance current sink for RF.
>>Of course it is an integral part of the antenna circuit.
>>
>>An RF "ground" would not be expected to radiate, and most "counterpoise" or
>>"radial" setups don't radiate a significant amount of energy*:
>>
>>1) Counterpoises near the Earth and on-ground "radials" tend to couple all
>>their energy into the lossy dielectric of the Earth, never to be seen again.
>>This is how BCB stations achieve a good RF ground generally using 120 0.2
>>wavelength radials around their towers to couple the RF into the Earth.
>>
>>2) Elevated radials will radiate a lot unless they are carefully balanced
>>and symmetrical so "legs" produce RF fields that cancel each other outside
>>of the immediate area of the antenna. Such radials, like any RF ground,
>>*are* part of the antenna circuit but, when properly designed, they are a
>>non-radiating "current sink". In the common "ground plane" designs, they
>>also decouple the radiating element from the feed line, providing an RF
>>"ground" not only for the radiator but also grounding the feed line at the
>>antenna so RF currents don't flow down the outside of the coax shield.
>>
>>Ron AC7AC
>>
>>* Students have asked me what happens if they use only one radial with a 1/4
>>wave antenna. I reply that if they make it 1/4 wave long, then elevate them
>>both into the air and arrange them to run in opposite directions for maximum
>>efficiency, one 'radial' works just fine. If they draw out the antenna I
>>described on paper they'll recognize the common center fed dipole antenna.
>>In that case, there's no problem with the "radial" radiating.
>>
>>
>>-----Original Message-----
>>
>>On Tue, 31 Mar 2009 18:43:39 -0700, Ron D'Eau Claire wrote:
>>
>>>But it *IS* a ground for RF purposes
>>
>>Nope! It has NO relationship with the earth, nor is one needed. This
>>use of the word "ground" is an ongoing source of confusion and
>>misunderstandings. Hams to go extremes to install ground rods,
>>thinking that it will improve the performance of their antennas or
>>make their radios quieter or fix RFI. A connection to earth does NOT
>>do any of those things. It IS critical for lightning protection.
>>That's all.
>>
>>Radials are not GROUND in any sense. They are part of the antenna!
>>Indeed, their purpose is to intercept the fields produced by the
>>antenna and by providing a low resistance path for return currents,
>>prevent those fields from producing current in the lossy earth.
>>There is an excellent discussion of this by Rudy Severns, N6LF, both
>>in the ARRL Antenna Book and on his website.
>>
>>73,
>>
>>Jim Brown K9YC
>>
>>
>>______________________________________________________________
>>Elecraft mailing list
>>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>Help: http://mailman.qth.net/mmfaq.htm
>>Post: mailto:[hidden email]
>>
>>This list hosted by: http://www.qsl.net
>>Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Don Wilhelm-4

Re: BL-2 Connection To An Unbalanced Wire Antenna

Matt,

Many years ago, I had an EE professor who said it right - there are two
disciplines in EE that need to consider 4 dimensions - the 3 dimensions
of space as well as that position in time. One is 3 phase motor
analysis and the other is analysis of an RF wave in space (or on
antennas). I have found repeatably that his statement is quite true.
The added time element makes the subject complex and difficult to visualize.

The discussion of RF ground is related.

73,
Don W3FPR

Matt Palmer wrote:

> Ahh now you are no longer talking about RF ground but the black art of
> EMI. Its not to difficult to determine RF ground, you have to have
> very good spatial visualization, the ability to hold the 3D model of
> the board, chassis and housing in your head, and you need to think
> like an electron. It takes practice, but being relatively
> inexperienced i've gotten the hang of it after being involved in the
> successful design of 2 radios, but then again I have fantastic mentors
> and elmers. In the end everything is explained by Maxwell's equations
> and if 1/10th of the ham population took the time to understand how
> these fantastic formula work and what they mean, 99% of this confusion
> and most of the half truths you see passed around as 'common
> knowledge' would disappear.
>
>
>

David Woolley (E.L)

Re: BL-2 Connection To An Unbalanced Wire Antenna

In reply to this post by Jack

Jack Regan wrote:

> Basically the question is to which two of the three output connections on
> the BL-2 do I connect a long wire antenna and its counterpoise(s) too? A and
> B, A and GND, B and GND or.... well you get the idea.

Any apparent benefit you get from using anything other than A and B will
be false, as it will reflect matching the transmitter into the loss
resistance of the balun, rather than the antenna.

Even using A and B, you risk a similar effect, especially if the antenna
impedance is high. Even though the 4:1 setting may be better for
slightly high impedances, it is bad for very high impedances, because
that configuration effectively puts a short across the receiver terminals.

The main purpose of a balun in this configuration would be to force the
use of the counterpoise as the RF return path, rather than having the
transceiver case, or your body, act as the counterpoise.

--
David Woolley
"The Elecraft list is a forum for the discussion of topics related to
Elecraft products and more general topics related ham radio"
List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm>
______________________________________________________________
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Guy, K2AV

Re: BL-2 Connection To An Unbalanced Wire Antenna

In reply to this post by Don Wilhelm-4

I gave up on using "ground" for anything other than ground rods and lightning protection. For antennas where only one connection radiates to significant degree I refer to a "current sink" as the device one uses to accept the current from the opposite side of the feedline. This allows me to construct a sentence such as: "If you use a ground rod as a current sink for your all-band vertical, you can lose 10 db or more to losses in the dirt."

I can also have the discussion about whether the current sink contains more than one thinks, or whether part of what you consider to be the current sink is in fact radiating, and therefore receiving as well.

As to "RF ground", that term is so polluted and spread over so many fairly independent issues in common use, with some having vociferous emotional attachments to their favorite of the various meanings, I've given up. Even with specific intention to NOT step on feelings and stir up old controversies, the technical point gets lost in the resurrected hollering and confusion from honestly-held differing definitions.

The issue with RF in the shack is whether while transmitting one set of cabling in the shack has a disruptive RF voltage when measured against another set of cabling in the shack. While some techniques work decently often, I'm not aware of a silver bullet technique, as even point-of-entry grounding can sometimes have miscellaneous impedances which defeat the intent at RF.

73, Guy.

-------------- Original message ----------------------
From: Don Wilhelm <[hidden email]>

>
> Ron,
>
> I have been preaching similar points in ham circles for years now - and
> I find that many hams cannot visualize the difference between a
> "ground" (meaning a return path for current) and Mother Earth.
> Actually any point where the RF current crosses the zero voltage point
> is a point of RF Ground (it is a potential, not a physical place), and
> on a balanced antenna it should occur midway between the two sides of
> the feedpoint - and a vertical with radials *is* a balanced antenna,
> that is why a balun is needed even on a vertical.
>
> The English do distinguish between "earthing" and "grounding", and I do
> wish that sort of distinction were also in common use in the US, it
> certainly would help.
>
> BTW - elevated radials *do* radiate in the very near field, but when
> arranged properly (pairs in opposing directions), the radiation is out
> of phase and will cancel at a distance from the antenna. Your term
> "current sink" is not a description I would use.
>
> 73,
> Don W3FPR
>
> Ron D'Eau Claire wrote:
> > Jim, IMX it's a mistake to equate "RF ground" with an Earth connection.
> >
> > An RF "ground" is just a low-impedance, low-reactance current sink for RF.
> > Of course it is an integral part of the antenna circuit.
> >
> > An RF "ground" would not be expected to radiate, and most "counterpoise" or
> > "radial" setups don't radiate a significant amount of energy*:
> >
> > 1) Counterpoises near the Earth and on-ground "radials" tend to couple all
> > their energy into the lossy dielectric of the Earth, never to be seen again.
> > This is how BCB stations achieve a good RF ground generally using 120 0.2
> > wavelength radials around their towers to couple the RF into the Earth.
> >
> > 2) Elevated radials will radiate a lot unless they are carefully balanced
> > and symmetrical so "legs" produce RF fields that cancel each other outside
> > of the immediate area of the antenna. Such radials, like any RF ground,
> > *are* part of the antenna circuit but, when properly designed, they are a
> > non-radiating "current sink". In the common "ground plane" designs, they
> > also decouple the radiating element from the feed line, providing an RF
> > "ground" not only for the radiator but also grounding the feed line at the
> > antenna so RF currents don't flow down the outside of the coax shield.
> >
> > Ron AC7AC
> >
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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