EFHW

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Re: EFHW

K9MA
Here's the old trade-off between radiating efficiency and ease of
matching for an end fed wire. The EFHW is more efficient, because little
power goes into the ground system, but its high impedance is harder to
match.  A wire of a different length may be easier to match, but more
power goes into the ground system, where it doesn't radiate much.  Both
will work but, I believe, on average the EFHW will be a bit better.  Is
it worth the trouble?  Who knows?

Antenna discussions have long had a tendency to focus on SWR.  Low SWR
does not necessarily mean an antenna is effective.  There's an old
saying, "The SWR of a dummy load is 1:1."

73,

Scott  K9MA



On 2/10/2017 09:56, Don Wilhelm wrote:

> Brian,
>
> If your end fed antenna is actually a halfwave (which is what EFHW
> means), the answer is no.
>
> The solution for portable work is to use a length that is not a
> halfwave - 58 feet is known to work well for 40 thru 10 meters when
> used with a 13 foot counterpoise.  Double the lengths if you want 80
> meters.
>
> With that antenna and counterpoise length, dispense with the balun for
> portable operations, and use a BNC to Binding post adapter instead (no
> coax).
>
> If you need to use a short length of coax, you can put the balun at
> the end of the coax, and you can try both the 1:1 and 4:1 positions to
> see which provides the better match.
>
> 73,
> Don W3FPR
>
>
> On 2/10/2017 10:36 AM, Brian Pietrzyk wrote:
>> Speaking of baluns or un-un's... I'm about to assemble a BL2 which is
>> a 4:1. Will that be enough to bring an End Fed Half Wave (EFHW)
>> within tuning range of my KX3 ATU?
>>
>> I'm going to be ve3bwp/hi9 QRP week after next and hoping to try a
>> couple of different length end feds into one of the trees near the
>> beach. I'll be trying Phone and psk31/JT65/CW an afternoon or two
>> that week. Anyone interested in a sked email me direct.
>>
> _

--
Scott  K9MA

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Re: EFHW

Brendon Whateley
In reply to this post by Don Wilhelm
On occasion I've run into RF in my KX3 when using a coax to feed random
length antenna. The symptom was that the radio wouldn't transmit with
anything other than trivial power, even though the tuner matched easily. A
quick choke wound out of the coax helped a little, but the Elecraft BL2
stopped the problem.

Personally I don't worry too much about the match when the radio is close
to the "antenna" if the tuner matches.

- Brendon

On Fri, Feb 10, 2017 at 7:56 AM, Don Wilhelm <[hidden email]> wrote:

> Brian,
>
> If your end fed antenna is actually a halfwave (which is what EFHW means),
> the answer is no.
>
> The solution for portable work is to use a length that is not a halfwave -
> 58 feet is known to work well for 40 thru 10 meters when used with a 13
> foot counterpoise.  Double the lengths if you want 80 meters.
>
> With that antenna and counterpoise length, dispense with the balun for
> portable operations, and use a BNC to Binding post adapter instead (no
> coax).
>
> If you need to use a short length of coax, you can put the balun at the
> end of the coax, and you can try both the 1:1 and 4:1 positions to see
> which provides the better match.
>
> 73,
> Don W3FPR
>
>
> On 2/10/2017 10:36 AM, Brian Pietrzyk wrote:
>
>> Speaking of baluns or un-un's... I'm about to assemble a BL2 which is a
>> 4:1. Will that be enough to bring an End Fed Half Wave (EFHW) within tuning
>> range of my KX3 ATU?
>>
>> I'm going to be ve3bwp/hi9 QRP week after next and hoping to try a couple
>> of different length end feds into one of the trees near the beach. I'll be
>> trying Phone and psk31/JT65/CW an afternoon or two that week. Anyone
>> interested in a sked email me direct.
>>
>> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
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Re: EFHW

Lynn W. Taylor, WB6UUT
In reply to this post by Bill Leonard N0CU
Just a reminder, folks.

An End-Fed Half-Wave is a 1/2 wave antenna on the frequency of operation.

If it's not a half-wave, then it's a non-resonant wire.

Elecraft tuners do a great job tuning non-resonant wires.

They won't tune an End-Fed Half-Wave without some help, like a 9:1 un-un.

So, when someone says "EFHW" and then says "I just use an adapter and
binding posts" we know it isn't an EFHW.

Terminology matters.

73 -- Lynn
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Re: EFHW

Lynn W. Taylor, WB6UUT
In reply to this post by Dan Presley
What I'd do if I was carrying it all on my back is take about 3
different lengths of wire with banana plugs on end, and banana jacks on
the other.

Use one as a counterpoise if needed.  Use one or two as the radiator,
depending on how well it tunes.  You won't be using a resonant antenna
because the KX2/KX3 won't tune it.

53' gets mentioned a lot as a good "random" wire length for most bands.  
I think the other two could be 8' and 15' since one would be a
counterpoise, and the other would be used to change the overall length
of the antenna itself -- that'd give you two steps.

73 -- Lynn

On 2/9/2017 11:50 PM, Dan Presley wrote:
> I also want to keep it Elecraft related as best I can. ,Ok-here’s what I’m asking: Think about a SOTA (summits on the air) outing where I’m hiking to activate a summit
> and the goal is to travel light. ‘Ounces are pounds’ as the saying goes.Radios are either a KX 3 or KX 2 both with autotuners.

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Re: EFHW

Bill K9YEQ
In reply to this post by Lynn W. Taylor, WB6UUT
Perfect explanation to help clarify all the "end fed" confusion.  Random is not EFHW!  EFHW must be cut at/very near frequency to work with a "tuned" matching circuit.  There's so much misinformation, with vendors also making good bucks on EFHW intereset.  Lots of "stuff" works but is it efficient? Do you get better radiation?  The efficiency of the end feds is too often left out of the conversation.  This created headaches for me as I began to study....  Screw it, I have a bunch of antennas ready to go and this includes both tuned EFHW, Randoms and dipoles, yet this evening while sitting in my basement hooked up the~30" 20 meter whip with 11' counterpoise. Heard some signals on a relatively dead band on my full outdoor antennas. Just like Wayne has suggested, try anything, anywhere. My most rewarding contacts have been on a walk about with the short vertical with a trailing wire and working SSB on 20 and 17.  God bless the KX2!



-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Lynn W. Taylor, WB6UUT
Sent: Friday, February 10, 2017 12:13 PM
To: [hidden email]
Subject: Re: [Elecraft] EFHW

Just a reminder, folks.

An End-Fed Half-Wave is a 1/2 wave antenna on the frequency of operation.

If it's not a half-wave, then it's a non-resonant wire.

Elecraft tuners do a great job tuning non-resonant wires.

They won't tune an End-Fed Half-Wave without some help, like a 9:1 un-un.

So, when someone says "EFHW" and then says "I just use an adapter and binding posts" we know it isn't an EFHW.

Terminology matters.

73 -- Lynn
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Re: EFHW

ve3bwp
In reply to this post by Dan Presley
This thread has really given me things to try when earth tilt/absence of white rain is back in our favour. Great group of folks on this forum btw.

The many contributions to this thread have given me the confidence to try end feds (for the first time) on my up coming trip to HI9 land. I'm packing a few end fed lengths for whatever  the trees on the resort will support. I'll start with Wayne's 25ft radiator and 25 ft wire on the ground suggestion first. Again this untried for me.

Before getting my kx3 I used an FT817 and the ATAS25. Worked fine when 20 to 10m openings were easier to come by a few years ago. Now my thoughts are about the reactions I'll get throwing something at a tree or two on the resort near the beach. I've managed to strip my CrankIR down to 12lbs so I'm taking it anyway only because I've used it/know it. The goal is to no longer feel the need to cram it into charter flight size and weight constraints and keep it for car trips instead. I'm guessing throwing a half full water bottle will suffice. Corrections invited.

Now my thoughts are about permanent end fed resonant wires (vs dipoles) for the home shack. I currently have a home brew 80/40 centre fed dipole tied from the house to a tree in the woods. If that were instead an end fed resonant wire fed by a 9:1 at house end things could get much simpler (and less saggy) coax wise.

Now comes the fantasy thinking... What about making it an end fed multi band by either putting traps in the 80m end fed or better still adding on a couple of fan EFHW wires for 40 and 20? Anyone tried this? How would the efficiencies compare to their centre fed trap or fan dipole counterparts respectively?

Then there is that 160m antenna I'm think about putting up this summer...

Brian ve3bwp

Date: Fri, 10 Feb 2017 12:05:56 -0600
From: K9MA <[hidden email]>
To: [hidden email]
Subject: Re: [Elecraft] EFHW
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=windows-1252; format=flowed

Here's the old trade-off between radiating efficiency and ease of
matching for an end fed wire. The EFHW is more efficient, because little
power goes into the ground system, but its high impedance is harder to
match.  A wire of a different length may be easier to match, but more
power goes into the ground system, where it doesn't radiate much.  Both
will work but, I believe, on average the EFHW will be a bit better.  Is
it worth the trouble?  Who knows?

Antenna discussions have long had a tendency to focus on SWR.  Low SWR
does not necessarily mean an antenna is effective.  There's an old
saying, "The SWR of a dummy load is 1:1."

73,

Scott  K9MA

On 2/10/2017 09:56, Don Wilhelm wrote:

> Brian,
>
> If your end fed antenna is actually a halfwave (which is what EFHW
> means), the answer is no.
>
> The solution for portable work is to use a length that is not a
> halfwave - 58 feet is known to work well for 40 thru 10 meters when
> used with a 13 foot counterpoise.  Double the lengths if you want 80
> meters.
>
> With that antenna and counterpoise length, dispense with the balun for
> portable operations, and use a BNC to Binding post adapter instead (no
> coax).
>
> If you need to use a short length of coax, you can put the balun at
> the end of the coax, and you can try both the 1:1 and 4:1 positions to
> see which provides the better match.
>
> 73,
> Don W3FPR
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Re: EFHW

k6dgw
In reply to this post by Bill K9YEQ
Ummm ... A full-wavelength wire is not resonant?

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Lynn W. Taylor, WB6UUT
> Sent: Friday, February 10, 2017 12:13 PM
> To: [hidden email]
> Subject: Re: [Elecraft] EFHW
>
> Just a reminder, folks.
>
> If it's not a half-wave, then it's a non-resonant wire.
>
>

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Re: EFHW

Kevin - K4VD
In reply to this post by ve3bwp
Brian:

The end fed I use uses a stub for 20 meters. When I set it up I tuned the
antenna for 40 meters. Then I added the stub 1/2 down the antenna and
trimmed that for best SWR on 20 meters. Worked exactly as expected with an
antenna analyzer.

K


On Sat, Feb 11, 2017 at 2:03 PM, Brian Pietrzyk <[hidden email]> wrote:

> This thread has really given me things to try when earth tilt/absence of
> white rain is back in our favour. Great group of folks on this forum btw.
>
> The many contributions to this thread have given me the confidence to try
> end feds (for the first time) on my up coming trip to HI9 land. I'm packing
> a few end fed lengths for whatever  the trees on the resort will support.
> I'll start with Wayne's 25ft radiator and 25 ft wire on the ground
> suggestion first. Again this untried for me.
>
> Before getting my kx3 I used an FT817 and the ATAS25. Worked fine when 20
> to 10m openings were easier to come by a few years ago. Now my thoughts are
> about the reactions I'll get throwing something at a tree or two on the
> resort near the beach. I've managed to strip my CrankIR down to 12lbs so
> I'm taking it anyway only because I've used it/know it. The goal is to no
> longer feel the need to cram it into charter flight size and weight
> constraints and keep it for car trips instead. I'm guessing throwing a half
> full water bottle will suffice. Corrections invited.
>
> Now my thoughts are about permanent end fed resonant wires (vs dipoles)
> for the home shack. I currently have a home brew 80/40 centre fed dipole
> tied from the house to a tree in the woods. If that were instead an end fed
> resonant wire fed by a 9:1 at house end things could get much simpler (and
> less saggy) coax wise.
>
> Now comes the fantasy thinking... What about making it an end fed multi
> band by either putting traps in the 80m end fed or better still adding on a
> couple of fan EFHW wires for 40 and 20? Anyone tried this? How would the
> efficiencies compare to their centre fed trap or fan dipole counterparts
> respectively?
>
> Then there is that 160m antenna I'm think about putting up this summer...
>
> Brian ve3bwp
>
> Date: Fri, 10 Feb 2017 12:05:56 -0600
> From: K9MA <[hidden email]>
> To: [hidden email]
> Subject: Re: [Elecraft] EFHW
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> Here's the old trade-off between radiating efficiency and ease of
> matching for an end fed wire. The EFHW is more efficient, because little
> power goes into the ground system, but its high impedance is harder to
> match.  A wire of a different length may be easier to match, but more
> power goes into the ground system, where it doesn't radiate much.  Both
> will work but, I believe, on average the EFHW will be a bit better.  Is
> it worth the trouble?  Who knows?
>
> Antenna discussions have long had a tendency to focus on SWR.  Low SWR
> does not necessarily mean an antenna is effective.  There's an old
> saying, "The SWR of a dummy load is 1:1."
>
> 73,
>
> Scott  K9MA
>
> On 2/10/2017 09:56, Don Wilhelm wrote:
> > Brian,
> >
> > If your end fed antenna is actually a halfwave (which is what EFHW
> > means), the answer is no.
> >
> > The solution for portable work is to use a length that is not a
> > halfwave - 58 feet is known to work well for 40 thru 10 meters when
> > used with a 13 foot counterpoise.  Double the lengths if you want 80
> > meters.
> >
> > With that antenna and counterpoise length, dispense with the balun for
> > portable operations, and use a BNC to Binding post adapter instead (no
> > coax).
> >
> > If you need to use a short length of coax, you can put the balun at
> > the end of the coax, and you can try both the 1:1 and 4:1 positions to
> > see which provides the better match.
> >
> > 73,
> > Don W3FPR
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
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Re: EFHW

Charlie T, K3ICH
In reply to this post by k6dgw
Define "resonance".

Chas

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Fred
Jensen
Sent: Saturday, February 11, 2017 2:40 PM
To: [hidden email]
Subject: Re: [Elecraft] EFHW

Ummm ... A full-wavelength wire is not resonant?

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> Lynn W. Taylor, WB6UUT
> Sent: Friday, February 10, 2017 12:13 PM
> To: [hidden email]
> Subject: Re: [Elecraft] EFHW
>
> Just a reminder, folks.
>
> If it's not a half-wave, then it's a non-resonant wire.
>
>

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Re: EFHW

Wes Stewart-2
jX = 0

Sent from my iPhone

> On Feb 11, 2017, at 1:29 PM, Charlie T, K3ICH <[hidden email]> wrote:
>
> Define "resonance".
>
> Chas
>
> -----Original Message-----
> From: Elecraft [mailto:-[hidden email]] On Behalf Of Fred
> Jensen
> Sent: Saturday, February 11, 2017 2:40 PM
> To: [hidden email]
> Subject: Re: [Elecraft] EFHW
>
> Ummm ... A full-wavelength wire is not resonant?
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Lynn W. Taylor, WB6UUT
>> Sent: Friday, February 10, 2017 12:13 PM
>> To: [hidden email]
>> Subject: Re: [Elecraft] EFHW
>>
>> Just a reminder, folks.
>>
>> If it's not a half-wave, then it's a non-resonant wire.
>>
>>
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Re: EFHW

K9MA
In reply to this post by ve3bwp
On 2/11/2017 13:03, Brian Pietrzyk wrote:
> Now comes the fantasy thinking... What about making it an end fed
> multi band by either putting traps in the 80m end fed or better still
> adding on a couple of fan EFHW wires for 40 and 20? Anyone tried this?
> How would the efficiencies compare to their centre fed trap or fan
> dipole counterparts respectively?

That won't work, because the shorter wires will present a much lower
impedance, and essentially short out the half wave wire.  The whole idea
of the EFHW is that the high feedpoint impedance reduces ground system
current to practically zero.

A trap might work, but might not be compatible with keeping the antenna
very light.  A QRP trap could be pretty small, I suppose, but it still
might be hard to support the wire with the extra weight on it using a
lightweight pole.

However, an EFHW will work on harmonics, though the pattern changes.  A
40 meter half wave works quite well on 20, but I'm not sure an 80 meter
half wave would be all that great on 20, especially with a single
support.  The free space patterns of long wire antennas are shown in the
ARRL Antenna Book.  As frequency goes up, more lobes appear in the
pattern, and the main ones get closer to the axis of the wire.  For
example, a full wave antenna has a cloverleaf pattern, the lobes about
55 degrees from the wire axis, with nulls broadside.  For a 2 wavelength
wire, there are 8 lobes, the main ones 35 degrees from the wire axis.  
These patterns will, of course, be modified by the effects of ground and
the fact that the wire probably won't be straight, but the free space
patterns give some idea of how the antenna will radiate.  Modeling these
antennas is very easy, and gives much more accurate results.

Note that the pattern of an EFHW (full wave, etc.) is NOT the same as
that of a center fed dipole operated at even harmonics.

73,

Scott  K9MA


--
Scott  K9MA

[hidden email]

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Re: EFHW

Lynn W. Taylor, WB6UUT
In reply to this post by k6dgw
True, but that wasn't the point (and I think you understood that).

A wire that is approximately 67 feet long will be resonant on 20
meters.  The impedance at the ends will be very high.

A wire that is approximately 80 feet will not be resonant on 20 meters,
but an Elecraft tuner will be able to tune it pretty well.

My objection is calling any non-resonant length, fed from the end an
EFHW (End-Fed Half-Wave), just because it kinda looks like one.

73 -- Lynn

On 2/11/2017 11:40 AM, Fred Jensen wrote:

> Ummm ... A full-wavelength wire is not resonant?
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Lynn W. Taylor, WB6UUT
>> Sent: Friday, February 10, 2017 12:13 PM
>> To: [hidden email]
>> Subject: Re: [Elecraft] EFHW
>>
>> Just a reminder, folks.
>>
>> If it's not a half-wave, then it's a non-resonant wire.
>>
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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Re: EFHW

Don Wilhelm
In reply to this post by K9MA
Walt,

Which LNR End-Fedz are you using that has a trap.  I have never seen one
with a trap.

On 2/11/2017 4:22 PM, Walter Underwood wrote:
>
> The LNR End-Fedz antennas use traps. They appear to work just fine.
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Re: EFHW

Tony Estep
In reply to this post by Dan Presley
On Sat, Feb 11, 2017 at 3:46 PM, Don Wilhelm <[hidden email]> wrote:

A halfwave dipole is a halfwave dipole whether fed at the center or at an
> end or somewhere in between.
> The radiation pattern and efficiency is the same.
> ============

This is 100% correct. Two minutes spent with EZ-NEC will verify that the
radiation pattern of a dipole antenna is more or less independent of the
feedpoint location.The idea that an end-fed antenna is "less efficient" is
wrong. Antenna efficiency is a function of radiation resistance and ohmic
losses, not of feedpoint location.

The power has to go somewhere, and where it goes is into radiation. In the
days before most hams had an antenna simulator program, Cebik was a big
proponent of EFHW and had a nice analysis on his website. He made the
qualitative point that since the impedance at the end is high, there is
little current flowing in the unbalanced feedline at that point; if the
antenna is fed with open-wire line, the return current in the unterminated
leg is small and it's not hard to match. He followed this up with some
actual calculations. Although Mr. Cebik is no longer with us, nowadays
serious hams have antenna programs, so they can do their own analysis. The
role of folklore in antenna design has diminished considerably.

Tony KT0NY
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Re: EFHW

Wes Stewart-2
In reply to this post by Wes Stewart-2
It is with some reluctance that I smack this whole EFHW tarbaby, but here goes.  
Comments in no particular order:

1)  A resonant antenna (even one that is self-resonant), e.g. one with a
non-reactive feedpoint, isn't necessarily "efficient."  A quarter-wavelength
monopole over lossy earth leaps to mind.

2)  A non-resonant antenna isn't necessarily inefficient.  The ever popular G5RV
isn't resonant on the band of interest (20M) but when fed appropriately, was as
efficient as a resonant dipole.

3)  Consider a BC band 1/2 wavelength vertical antenna.  Does the station
designer say, "Well, this EFHW doesn't really doesn't need much of a
counterpoise, so I'll just throw a 100' long wire on the ground and call it good
enough?"  No, he install 120 radials that are even longer than the ones he would
use under a 1/4 wavelength monopole.  Devoldere in "Low-Band DXing, Chapter 9,
Section 4.3 says: "Here comes another surprise. A terrible misconception about
voltage-fed verticals is that they do not require either a good ground or an
extensive radial system.'"  Later in the same section he says, "Therefore it is
even more important to have a good radial system with a voltage-fed antenna such
as the voltage-fed T or a λ/2 vertical. These verticals require longer radials
to do their job efficiently compared to current-fed verticals."

3)  When you backpacking mountain goats say, "Hey my wire isn't a vertical, it's
mostly horizontal", I say, if your radio is sitting on a boulder or the ground,
it's a vertical and your wire-on-the-ground counterpoise proves it.

Wes  N7WS



On 2/11/2017 2:33 PM, Ron D'Eau Claire wrote:

> All efficient antenna systems are "resonant" (jX=0) but the shorthand often
> used is "resonant" to mean "self resonant". That is true of any 1/4
> wavelength long radiator (again our common shorthand is usually "1/4 wave
> wire") or any multiple thereof worked against ground. It is also true of any
> half wave length radiator or any multiple thereof. (Note that these are
> electrical lengths, taking into account any surroundings including the
> radiator itself.)
>
> While self-resonant antennas do not present a reactive load to the source of
> RF power, the value of R, the resistance, may vary widely. There is nothing
> magic about the 50 ohm load most of our transmitters are designed for.
>
> However, a half wave radiator fed at the center presents a resistive value
> near 50 ohms when fed at typical heights above ground (in free space it is
> 75 ohms). Half wave antennas became very popular after WWII because 50-ohm
> coaxial feed line became abundant and cheap on the "surplus" market and Hams
> were taking steps to deal with needing to avoid interfering with the rapidly
> growing number of TV sets in nearby homes, including the Ham's own living
> room.
>
> In the following decades, greater and greater demands on harmonic
> suppression have led to Ham transmitters with output filters specifically
> designed for a 50 ohm load instead of being able to match a wide range of
> load impedances.
>
> So we have now moved the wide-range output network that was in Grandpa's Ham
> transmitter out of the transmitter and into what we call an "Antenna Tuner".
> But, of course it does not "tune" an antenna at all. It's just a matching
> network to be sure the transmitter is delivering power to a load close to 50
> ohms and non-reactive.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Wes
> N7WS
> Sent: Saturday, February 11, 2017 12:44 PM
> To: Charlie T, K3ICH
> Cc:[hidden email]
> Subject: Re: [Elecraft] EFHW
>
> jX = 0
>
> Sent from my iPhone
>
>> On Feb 11, 2017, at 1:29 PM, Charlie T, K3ICH<[hidden email]>  wrote:
>>
>> Define "resonance".
>>
>> Chas
>>
>> -----Original Message-----
>> From: Elecraft [mailto:-[hidden email]] On Behalf Of Fred
>> Jensen
>> Sent: Saturday, February 11, 2017 2:40 PM
>> To:[hidden email]
>> Subject: Re: [Elecraft] EFHW
>>
>> Ummm ... A full-wavelength wire is not resonant?
>>
>> 73,
>>
>> Fred ["Skip"] K6DGW
>> Sparks NV DM09dn
>> Washoe County
>>> -----Original Message-----
>>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>>> Lynn W. Taylor, WB6UUT
>>> Sent: Friday, February 10, 2017 12:13 PM
>>> To:[hidden email]
>>> Subject: Re: [Elecraft] EFHW
>>>
>>> Just a reminder, folks.
>>>
>>> If it's not a half-wave, then it's a non-resonant wire.
>>>
>>>

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Re: EFHW

Kevin - K4VD
​So what we are saying here is that all the local and DX QSOs we make from
a picnic bench with an end fed or random wire thrown up in a tree and a
short or no counterpoise doesn't really happen or, at best, is a fluke. The
end fed is only 10% efficient (did I get that right) and most of our QRP
signals are going to heat worms. Pretty hopeless situation I guess. ​I
might have to just stick with the local repeater and Google Hangouts for
communications.

Or, for those of you that are thinking the situation isn't so hopeless,
grab your portable antenna, head out to the campsite, throw your wire up in
the tree and I'll catch you on the air. Let's warm up the worms.

73,
Kev


On Sat, Feb 11, 2017 at 11:54 PM, Ron D'Eau Claire <[hidden email]> wrote:

> Ha, ha!!! Well put Wes!
>
> Some mountain portables erect low "horizontal" antennas on the side of a
> steep mountain. The result is a very low angle of radiation because, even
> though the main lobe is "straight up" from the mountainside from the
> antenna, the slope puts that lobe at a fairly low angle relative to the
> earth.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Wes
> Stewart
> Sent: Saturday, February 11, 2017 8:02 PM
> Cc: [hidden email]
> Subject: Re: [Elecraft] EFHW
>
> It is with some reluctance that I smack this whole EFHW tarbaby, but here
> goes.
> Comments in no particular order:
>
> 1)  A resonant antenna (even one that is self-resonant), e.g. one with a
> non-reactive feedpoint, isn't necessarily "efficient."  A
> quarter-wavelength monopole over lossy earth leaps to mind.
>
> 2)  A non-resonant antenna isn't necessarily inefficient.  The ever
> popular G5RV isn't resonant on the band of interest (20M) but when fed
> appropriately, was as efficient as a resonant dipole.
>
> 3)  Consider a BC band 1/2 wavelength vertical antenna.  Does the station
> designer say, "Well, this EFHW doesn't really doesn't need much of a
> counterpoise, so I'll just throw a 100' long wire on the ground and call it
> good enough?"  No, he install 120 radials that are even longer than the
> ones he would use under a 1/4 wavelength monopole.  Devoldere in "Low-Band
> DXing, Chapter 9, Section 4.3 says: "Here comes another surprise. A
> terrible misconception about voltage-fed verticals is that they do not
> require either a good ground or an extensive radial system.'"  Later in the
> same section he says, "Therefore it is even more important to have a good
> radial system with a voltage-fed antenna such as the voltage-fed T or a λ/2
> vertical. These verticals require longer radials to do their job
> efficiently compared to current-fed verticals."
>
> 3)  When you backpacking mountain goats say, "Hey my wire isn't a
> vertical, it's mostly horizontal", I say, if your radio is sitting on a
> boulder or the ground, it's a vertical and your wire-on-the-ground
> counterpoise proves it.
>
> Wes  N7WS
>
>
>
> On 2/11/2017 2:33 PM, Ron D'Eau Claire wrote:
> > All efficient antenna systems are "resonant" (jX=0) but the shorthand
> > often used is "resonant" to mean "self resonant". That is true of any
> > 1/4 wavelength long radiator (again our common shorthand is usually
> > "1/4 wave
> > wire") or any multiple thereof worked against ground. It is also true
> > of any half wave length radiator or any multiple thereof. (Note that
> > these are electrical lengths, taking into account any surroundings
> > including the radiator itself.)
> >
> > While self-resonant antennas do not present a reactive load to the
> > source of RF power, the value of R, the resistance, may vary widely.
> > There is nothing magic about the 50 ohm load most of our transmitters
> are designed for.
> >
> > However, a half wave radiator fed at the center presents a resistive
> > value near 50 ohms when fed at typical heights above ground (in free
> > space it is
> > 75 ohms). Half wave antennas became very popular after WWII because
> > 50-ohm coaxial feed line became abundant and cheap on the "surplus"
> > market and Hams were taking steps to deal with needing to avoid
> > interfering with the rapidly growing number of TV sets in nearby
> > homes, including the Ham's own living room.
> >
> > In the following decades, greater and greater demands on harmonic
> > suppression have led to Ham transmitters with output filters
> > specifically designed for a 50 ohm load instead of being able to match
> > a wide range of load impedances.
> >
> > So we have now moved the wide-range output network that was in
> > Grandpa's Ham transmitter out of the transmitter and into what we call
> an "Antenna Tuner".
> > But, of course it does not "tune" an antenna at all. It's just a
> > matching network to be sure the transmitter is delivering power to a
> > load close to 50 ohms and non-reactive.
> >
> > 73, Ron AC7AC
> >
> > -----Original Message-----
> > From: Elecraft [mailto:[hidden email]] On Behalf Of
> > Wes N7WS
> > Sent: Saturday, February 11, 2017 12:44 PM
> > To: Charlie T, K3ICH
> > Cc:[hidden email]
> > Subject: Re: [Elecraft] EFHW
> >
> > jX = 0
> >
> > Sent from my iPhone
> >
> >> On Feb 11, 2017, at 1:29 PM, Charlie T, K3ICH<[hidden email]>  wrote:
> >>
> >> Define "resonance".
> >>
> >> Chas
> >>
> >> -----Original Message-----
> >> From: Elecraft [mailto:-[hidden email]] On Behalf Of Fred
> >> Jensen
> >> Sent: Saturday, February 11, 2017 2:40 PM To:[hidden email]
> >> Subject: Re: [Elecraft] EFHW
> >>
> >> Ummm ... A full-wavelength wire is not resonant?
> >>
> >> 73,
> >>
> >> Fred ["Skip"] K6DGW
> >> Sparks NV DM09dn
> >> Washoe County
> >>> -----Original Message-----
> >>> From: Elecraft [mailto:[hidden email]] On Behalf
> >>> Of Lynn W. Taylor, WB6UUT
> >>> Sent: Friday, February 10, 2017 12:13 PM To:[hidden email]
> >>> Subject: Re: [Elecraft] EFHW
> >>>
> >>> Just a reminder, folks.
> >>>
> >>> If it's not a half-wave, then it's a non-resonant wire.
> >>>
> >>>
>
> ______________________________________________________________
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> Message delivered to [hidden email]
>
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> Message delivered to [hidden email]
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Re: EFHW

Igor Sokolov-2
In reply to this post by K9MA
A certain inductance places at a correct place along the 80m HW will
make multy band EFHW. Here is the example
http://myantennas.com/wp/product/efhw-8010p/

73, Igor UA9CDC

12.02.2017 1:50, K9MA пишет:

> On 2/11/2017 13:03, Brian Pietrzyk wrote:
>> Now comes the fantasy thinking... What about making it an end fed
>> multi band by either putting traps in the 80m end fed or better still
>> adding on a couple of fan EFHW wires for 40 and 20? Anyone tried
>> this? How would the efficiencies compare to their centre fed trap or
>> fan dipole counterparts respectively?
>
> That won't work, because the shorter wires will present a much lower
> impedance, and essentially short out the half wave wire. The whole
> idea of the EFHW is that the high feedpoint impedance reduces ground
> system current to practically zero.
>
> A trap might work, but might not be compatible with keeping the
> antenna very light.  A QRP trap could be pretty small, I suppose, but
> it still might be hard to support the wire with the extra weight on it
> using a lightweight pole.
>
> However, an EFHW will work on harmonics, though the pattern changes.  
> A 40 meter half wave works quite well on 20, but I'm not sure an 80
> meter half wave would be all that great on 20, especially with a
> single support.  The free space patterns of long wire antennas are
> shown in the ARRL Antenna Book.  As frequency goes up, more lobes
> appear in the pattern, and the main ones get closer to the axis of the
> wire.  For example, a full wave antenna has a cloverleaf pattern, the
> lobes about 55 degrees from the wire axis, with nulls broadside.  For
> a 2 wavelength wire, there are 8 lobes, the main ones 35 degrees from
> the wire axis.  These patterns will, of course, be modified by the
> effects of ground and the fact that the wire probably won't be
> straight, but the free space patterns give some idea of how the
> antenna will radiate. Modeling these antennas is very easy, and gives
> much more accurate results.
>
> Note that the pattern of an EFHW (full wave, etc.) is NOT the same as
> that of a center fed dipole operated at even harmonics.
>
> 73,
>
> Scott  K9MA
>
>

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Re: EFHW

Wes Stewart-2
In reply to this post by Kevin - K4VD
I'm pretty sure the laws of physics are still in place.

What you describe isn't much different from my situation on 160 meters.  I have
an inverted vee dipole with the apex at 45' and the ends at 6 feet or less.  
With 500W I have worked about 60 counties.  But I am under no illusions that
this is an effective antenna; it is not.

Several years ago on a Field Day when the locals were all on mountain tops
calling CQ and not listening, I worked a JA using the same antenna, at that time
still fed with 200 feet of RG8 (now Heliax) and a barefoot K3 with no ATU. An
hour later I worked a second JA.  But do I recommend this setup for working 6
meter DX? Of course not.

So you make some contacts.  Good for you, maybe you're having fun.  However, I
submit that you (and I) would have more fun with better antennas.

Wes  N7WS

On 2/11/2017 10:19 PM, Kevin - K4VD wrote:

> ​So what we are saying here is that all the local and DX QSOs we make from
> a picnic bench with an end fed or random wire thrown up in a tree and a
> short or no counterpoise doesn't really happen or, at best, is a fluke. The
> end fed is only 10% efficient (did I get that right) and most of our QRP
> signals are going to heat worms. Pretty hopeless situation I guess. ​I
> might have to just stick with the local repeater and Google Hangouts for
> communications.
>
> Or, for those of you that are thinking the situation isn't so hopeless,
> grab your portable antenna, head out to the campsite, throw your wire up in
> the tree and I'll catch you on the air. Let's warm up the worms.
>
> 73,
> Kev
>

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Re: EFHW

Rick Dettinger-3
In reply to this post by Kevin - K4VD
10% efficient is for a “short” end fed antenna and a ground rod or similar.
Something near a quarter wave and a typical one or two wire counterpoise is much better.
It doesn’t take much effort to get to 50% efficient with a quarter wave or longer wire, and a few short radials.
After that, there are diminishing returns for a given amount of effort.  The BC 120 radial, half wave long ground systems are a good example.  
And, as QRP and mobile operators have shown, contacts with a 10% efficient antenna system do happen!
 
73,
Rick  K7MW

> On Feb 11, 2017, at 9:19 PM, Kevin - K4VD <[hidden email]> wrote:
>
> ​So what we are saying here is that all the local and DX QSOs we make from
> a picnic bench with an end fed or random wire thrown up in a tree and a
> short or no counterpoise doesn't really happen or, at best, is a fluke. The
> end fed is only 10% efficient (did I get that right) and most of our QRP
> signals are going to heat worms. Pretty hopeless situation I guess. ​I
> might have to just stick with the local repeater and Google Hangouts for
> communications.
>
> Or, for those of you that are thinking the situation isn't so hopeless,
> grab your portable antenna, head out to the campsite, throw your wire up in
> the tree and I'll catch you on the air. Let's warm up the worms.
>
> 73,
> Kev
>
>
> On Sat, Feb 11, 2017 at 11:54 PM, Ron D'Eau Claire <[hidden email]> wrote:
>
>> Ha, ha!!! Well put Wes!
>>
>> Some mountain portables erect low "horizontal" antennas on the side of a
>> steep mountain. The result is a very low angle of radiation because, even
>> though the main lobe is "straight up" from the mountainside from the
>> antenna, the slope puts that lobe at a fairly low angle relative to the
>> earth.
>>
>> 73, Ron AC7AC
>>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of Wes
>> Stewart
>> Sent: Saturday, February 11, 2017 8:02 PM
>> Cc: [hidden email]
>> Subject: Re: [Elecraft] EFHW
>>
>> It is with some reluctance that I smack this whole EFHW tarbaby, but here
>> goes.
>> Comments in no particular order:
>>
>> 1)  A resonant antenna (even one that is self-resonant), e.g. one with a
>> non-reactive feedpoint, isn't necessarily "efficient."  A
>> quarter-wavelength monopole over lossy earth leaps to mind.
>>
>> 2)  A non-resonant antenna isn't necessarily inefficient.  The ever
>> popular G5RV isn't resonant on the band of interest (20M) but when fed
>> appropriately, was as efficient as a resonant dipole.
>>
>> 3)  Consider a BC band 1/2 wavelength vertical antenna.  Does the station
>> designer say, "Well, this EFHW doesn't really doesn't need much of a
>> counterpoise, so I'll just throw a 100' long wire on the ground and call it
>> good enough?"  No, he install 120 radials that are even longer than the
>> ones he would use under a 1/4 wavelength monopole.  Devoldere in "Low-Band
>> DXing, Chapter 9, Section 4.3 says: "Here comes another surprise. A
>> terrible misconception about voltage-fed verticals is that they do not
>> require either a good ground or an extensive radial system.'"  Later in the
>> same section he says, "Therefore it is even more important to have a good
>> radial system with a voltage-fed antenna such as the voltage-fed T or a λ/2
>> vertical. These verticals require longer radials to do their job
>> efficiently compared to current-fed verticals."
>>
>> 3)  When you backpacking mountain goats say, "Hey my wire isn't a
>> vertical, it's mostly horizontal", I say, if your radio is sitting on a
>> boulder or the ground, it's a vertical and your wire-on-the-ground
>> counterpoise proves it.
>>
>> Wes  N7WS
>>
>>
>>
>> On 2/11/2017 2:33 PM, Ron D'Eau Claire wrote:
>>> All efficient antenna systems are "resonant" (jX=0) but the shorthand
>>> often used is "resonant" to mean "self resonant". That is true of any
>>> 1/4 wavelength long radiator (again our common shorthand is usually
>>> "1/4 wave
>>> wire") or any multiple thereof worked against ground. It is also true
>>> of any half wave length radiator or any multiple thereof. (Note that
>>> these are electrical lengths, taking into account any surroundings
>>> including the radiator itself.)
>>>
>>> While self-resonant antennas do not present a reactive load to the
>>> source of RF power, the value of R, the resistance, may vary widely.
>>> There is nothing magic about the 50 ohm load most of our transmitters
>> are designed for.
>>>
>>> However, a half wave radiator fed at the center presents a resistive
>>> value near 50 ohms when fed at typical heights above ground (in free
>>> space it is
>>> 75 ohms). Half wave antennas became very popular after WWII because
>>> 50-ohm coaxial feed line became abundant and cheap on the "surplus"
>>> market and Hams were taking steps to deal with needing to avoid
>>> interfering with the rapidly growing number of TV sets in nearby
>>> homes, including the Ham's own living room.
>>>
>>> In the following decades, greater and greater demands on harmonic
>>> suppression have led to Ham transmitters with output filters
>>> specifically designed for a 50 ohm load instead of being able to match
>>> a wide range of load impedances.
>>>
>>> So we have now moved the wide-range output network that was in
>>> Grandpa's Ham transmitter out of the transmitter and into what we call
>> an "Antenna Tuner".
>>> But, of course it does not "tune" an antenna at all. It's just a
>>> matching network to be sure the transmitter is delivering power to a
>>> load close to 50 ohms and non-reactive.
>>>
>>> 73, Ron AC7AC
>>>
>>> -----Original Message-----
>>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>>> Wes N7WS
>>> Sent: Saturday, February 11, 2017 12:44 PM
>>> To: Charlie T, K3ICH
>>> Cc:[hidden email]
>>> Subject: Re: [Elecraft] EFHW
>>>
>>> jX = 0
>>>
>>> Sent from my iPhone
>>>
>>>> On Feb 11, 2017, at 1:29 PM, Charlie T, K3ICH<[hidden email]>  wrote:
>>>>
>>>> Define "resonance".
>>>>
>>>> Chas
>>>>
>>>> -----Original Message-----
>>>> From: Elecraft [mailto:-[hidden email]] On Behalf Of Fred
>>>> Jensen
>>>> Sent: Saturday, February 11, 2017 2:40 PM To:[hidden email]
>>>> Subject: Re: [Elecraft] EFHW
>>>>
>>>> Ummm ... A full-wavelength wire is not resonant?
>>>>
>>>> 73,
>>>>
>>>> Fred ["Skip"] K6DGW
>>>> Sparks NV DM09dn
>>>> Washoe County
>>>>> -----Original Message-----
>>>>> From: Elecraft [mailto:[hidden email]] On Behalf
>>>>> Of Lynn W. Taylor, WB6UUT
>>>>> Sent: Friday, February 10, 2017 12:13 PM To:[hidden email]
>>>>> Subject: Re: [Elecraft] EFHW
>>>>>
>>>>> Just a reminder, folks.
>>>>>
>>>>> If it's not a half-wave, then it's a non-resonant wire.
>>>>>
>>>>>
>>
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>>
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>>
> ______________________________________________________________
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Re: EFHW

Jim Brown-10
In reply to this post by Wes Stewart-2
On Sat,2/11/2017 9:52 PM, Wes Stewart wrote:
> However, I submit that you (and I) would have more fun with better
> antennas.

Absolutely! I had fun as a kid with antennas at about 25 ft in the maple
trees at the front and back of our lot. I had fun with dipoles strung
between telephone pole in the alley and the front of my apartment in
Chicago, and somewhat better dipoles on a house I later owned in
Chicago. I've worked DX with 5W into a wire taped to a fiberglass pole
and jammed into a picnic bench, with a counterpoise laying on the
ground. I now have an antenna farm beyond my wildest dreams, and I'm
having even more fun. I can testify that better is better. :)

73, Jim K9YC

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