EFHW

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EFHW

Dan Presley
Wanted to get some thoughts from folks about pros and cons of an end fed half wave for portable/SOTA use, as opposed to just using a random length wire with a counterpoise connected directly to either the KX2 or 3.(I think Eric recommended somewhere around 28’ depending on the band coverage).Is there any particular gain advantage? To me the only obvious advantage is not having to deploy a counterpoise-with the end fed usually the length of coax will act for this, and of course the need for a suitable Un-Un,usually 9:1. My preferred antennas these days are lightweight resonant dipoles, which is fine assuming you have room to erect them, and second is a magnetic loop which I’ve had good luck with. I use the Alexloop-very light and easy to set up;ground and height independent generally. But-since you never quite know what will work best I try to be ready for whatever comes up. I have a variety of lightweight poles to use with wires.  I’ve had pretty good luck with throwing a random length in a tree or pole with a counterpoise, usually elevated if possible.The auto tuners in the elecraft rigs are excellent in my book. I think over the years I’ve used a bunch of portable antennas except the EFHW-just curious what the advantages might be.

Dan Presley  N7CQR
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Re: EFHW

k6dgw
I suspect you're going to get a lot of opinions on your question
[end-fed half waves], and a lot more on subjects well removed from your
questions ... such is the behavior of lists. [:-)

Any half-wave wire fed at the end will present a very high impedance
[multiple K-ohms] and will require some transformation to a value that
the Elecraft ATU can handle.  Transformers in the 9:1 [turns ratio]
range will take 4K down to 50 ohms.  For QRP [i.e. SOTA], they're
commonly autotransformers wound on small, light ferrite toroids.  The
high current portion [where most of the radiation occurs] is in the
center, and a single pole will get it elevated and the antenna can serve
as two guys for it.  There is little electrical value in elevating
either end although often, hanging it from a tall tree is physically
easiest.  A half-wave wire is a resonant dipole and radiates like any
other resonant dipole ... more or less broadside like a donut with the
wire through the center.  They are quite popular with the North American
SOTA folk.

I use a 41.5 meter wire on our wood fence here at home.  It works
surprisingly well, and is invisible to the HOA.  I run 100 watts, I
decided more might cause problems with the neighbors and I've sold the
KPA500 and KAT500.  It is NVIS on lower bands [only 2 meters high], and
the pattern is somewhat complex on the higher bands but I make a lot of
Q's with it on CW.  I too use an Alexloop in the field.

Possibly the biggest advantage to an EFHW is that there's usually no
transmission line involved for field operation and they're thus very
light and stow compactly.  There is an NA-SOTA Yahoo group you might
join, lots of discussion about field antennas.

73,

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

On 2/8/2017 2:41 PM, Dan Presley wrote:

> Wanted to get some thoughts from folks about pros and cons of an end fed half wave for portable/SOTA use, as opposed to just using a random length wire with a counterpoise connected directly to either the KX2 or 3.(I think Eric recommended somewhere around 28’ depending on the band coverage).Is there any particular gain advantage? To me the only obvious advantage is not having to deploy a counterpoise-with the end fed usually the length of coax will act for this, and of course the need for a suitable Un-Un,usually 9:1. My preferred antennas these days are lightweight resonant dipoles, which is fine assuming you have room to erect them, and second is a magnetic loop which I’ve had good luck with. I use the Alexloop-very light and easy to set up;ground and height independent generally. But-since you never quite know what will work best I try to be ready for whatever comes up. I have a variety of lightweight poles to use with wires.  I’ve had pretty good luck with throwing a random length in a tree or pole with a counterpoise, usually elevated if possible.The auto tuners in the elecraft rigs are excellent in my book. I think over the years I’ve used a bunch of portable antennas except the EFHW-just curious what the advantages might be.
>
> Dan Presley  N7CQR
> [hidden email]
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Re: EFHW

K9MA
In reply to this post by Dan Presley
Two distinct advantages of the EFHW: It's high feedpoint impedance means
a minimal counterpoise is required and very little power is wasted into
the ground system. Second, the high current part of the wire, which does
most of the radiating, is a quarter wave from the feedpoint, which can
usually be much higher than the feedpoint.

The EFHW can be used on harmonics.

The down side is that the high impedance is beyond the range of most
autotuners, so a transformer or external tuner is required.

I've been using a 40 meter EFHW for portable operations, mostly on 40
and 20 meters.  I support it with a single 11.5 meter pole about 1/4 the
way from the far end, like a lopsided inverted V. It seems to work quite
well.  I have a homebrew QRP tuner, but I use a commercial one for
higher power.  I've used the same antenna on 15 meters and, with a
couple longer radials, on 80.  (It's a quarter wave on 80, so there's
some "RF in the shack", but it hasn't been a problem as long as I keep
my fingers of the metal parts when I'm transmitting.)

I'll gladly share the design of the QRP tuner.

73,

Scott  K9MA

On 2/8/2017 16:41, Dan Presley wrote:

> Wanted to get some thoughts from folks about pros and cons of an end fed half wave for portable/SOTA use, as opposed to just using a random length wire with a counterpoise connected directly to either the KX2 or 3.(I think Eric recommended somewhere around 28’ depending on the band coverage).Is there any particular gain advantage? To me the only obvious advantage is not having to deploy a counterpoise-with the end fed usually the length of coax will act for this, and of course the need for a suitable Un-Un,usually 9:1. My preferred antennas these days are lightweight resonant dipoles, which is fine assuming you have room to erect them, and second is a magnetic loop which I’ve had good luck with. I use the Alexloop-very light and easy to set up;ground and height independent generally. But-since you never quite know what will work best I try to be ready for whatever comes up. I have a variety of lightweight poles to use with wires.  I’ve had pretty good luck with throwing a random length in a tree or pole with a counterpoise, usually elevated if possible.The auto tuners in the elecraft rigs are excellent in my book. I think over the years I’ve used a bunch of portable antennas except the EFHW-just curious what the advantages might be.
>
> Dan Presley  N7CQR
> [hidden email]
>
>
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--
Scott  K9MA

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Re: EFHW

Doug Person-4
In reply to this post by Dan Presley
I have two EFHW antennas. One covering 40 and 20; the other 17. They are
mounted at about 40 feet and perform equal to regular dipoles.  Feeding
them is therefore much simpler for portable ops since only one side
needs to be elevated.  For portable use I feed them with about 20 feet
of RG/58a, although they can be attached directly to the radio.  I find,
however, that a bit of coax causes them to be a lot less finicky.  They
have been my field day and SOTA portable goto antennas for many years.  
Transformers are not difficult to construct and there are some good
quality assembled products that are excellent.

Doug -- K0DXV


On 2/8/2017 3:41 PM, Dan Presley wrote:

> Wanted to get some thoughts from folks about pros and cons of an end fed half wave for portable/SOTA use, as opposed to just using a random length wire with a counterpoise connected directly to either the KX2 or 3.(I think Eric recommended somewhere around 28’ depending on the band coverage).Is there any particular gain advantage? To me the only obvious advantage is not having to deploy a counterpoise-with the end fed usually the length of coax will act for this, and of course the need for a suitable Un-Un,usually 9:1. My preferred antennas these days are lightweight resonant dipoles, which is fine assuming you have room to erect them, and second is a magnetic loop which I’ve had good luck with. I use the Alexloop-very light and easy to set up;ground and height independent generally. But-since you never quite know what will work best I try to be ready for whatever comes up. I have a variety of lightweight poles to use with wires.  I’ve had pretty good luck with throwing a random length in a tree or pole with a counterpoise, usually elevated if possible.The auto tuners in the elecraft rigs are excellent in my book. I think over the years I’ve used a bunch of portable antennas except the EFHW-just curious what the advantages might be.
>
> Dan Presley  N7CQR
> [hidden email]
>
>
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Re: EFHW

Brian Hunt
In reply to this post by k6dgw
The classic way to feed a EFHW is to use a tuned tank circuit. The top of it goes to the antenna and the bottom goes to a short counterpoise or the coax shield. You can either tap the coil X turns from the bottom to match 50 ohms or use a link coupling with the appropriate number of turns.

I use such a system to match a tri-band EFHW on 20, 30, and 40.  Yes, each an electrical half wave using tapped loading coils. The link is 6 turns, tapped every turn. YMMV

73,
Brian, K0DTJ
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Re: EFHW

ae5ka
In reply to this post by Dan Presley
No need to spend much money on an end-fed half-wave antenna. The EARCHI
 matchbox design is cheap if you do it yourself, and reasonable if you buy
the kit or pre-built from them. If you want it to be a true half-wave,
choose the wire length accordingly.

http://www.earchi.org/92011endfedfiles/Endfed6_40.pdf

Chip
AE5KA

On Wed, Feb 8, 2017 at 5:41 PM, Dan Presley <[hidden email]> wrote:

> Wanted to get some thoughts from folks about pros and cons of an end fed
> half wave for portable/SOTA use, as opposed to just using a random length
> wire with a counterpoise connected directly to either the KX2 or 3.(I think
> Eric recommended somewhere around 28’ depending on the band coverage).Is
> there any particular gain advantage? To me the only obvious advantage is
> not having to deploy a counterpoise-with the end fed usually the length of
> coax will act for this, and of course the need for a suitable Un-Un,usually
> 9:1. My preferred antennas these days are lightweight resonant dipoles,
> which is fine assuming you have room to erect them, and second is a
> magnetic loop which I’ve had good luck with. I use the Alexloop-very light
> and easy to set up;ground and height independent generally. But-since you
> never quite know what will work best I try to be ready for whatever comes
> up. I have a variety of lightweight poles to use with wires.  I’ve had
> pretty good luck with throwing a random length in a tree or pole with a
> counterpoise, usually elevated if possible.The auto tuners in the elecraft
> rigs are excellent in my book. I think over the years I’ve used a bunch of
> portable antennas except the EFHW-just curious what the advantages might be.
>
> Dan Presley  N7CQR
> [hidden email]
>
>
> ______________________________________________________________
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> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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Re: EFHW

Bill Leonard N0CU
In reply to this post by Doug Person-4
The reason your antenna was a lot less finicky with a bit of coax is that the EFHW antenna requires a return path for the RF field. Theoretically, without a return path, the antenna won't radiate at all. The recommended setup for this antenna is for a .05 wavelength counterpoised to be used. EZNEC models indicate that there is little benefit to going much longer than .05 wavelengths, and a quarter wavelength is actually less effective than the shorter lengths.  If no counterpoise is used, then coax shield becomes the counterpoise by default.

Bill  N0CU
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Re: EFHW

Elecraft mailing list
In reply to this post by ae5ka
Here I am using one with a 19ft wire:
(It might take a while for the video to upload, check later if not there
yet)

https://www.youtube.com/watch?v=8_Axs2ut7sE

Gil.

Chip Stratton wrote:
> No need to spend much money on an end-fed half-wave antenna. The EARCHI
>  matchbox design is cheap if you do it yourself, and reasonable if you buy
> the kit or pre-built from them. If you want it to be a true half-wave,
> choose the wire length accordingly.
>
> http://www.earchi.org/92011endfedfiles/Endfed6_40.pdf
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Re: EFHW

K9MA
In reply to this post by Bill Leonard N0CU
Well said, Bill!

73,

Scott  K9MA

On 2/9/2017 10:39, Bill Leonard N0CU wrote:

> The reason your antenna was a lot less finicky with a bit of coax is that the
> EFHW antenna requires a return path for the RF field. Theoretically, without
> a return path, the antenna won't radiate at all. The recommended setup for
> this antenna is for a .05 wavelength counterpoised to be used. EZNEC models
> indicate that there is little benefit to going much longer than .05
> wavelengths, and a quarter wavelength is actually less effective than the
> shorter lengths.  If no counterpoise is used, then coax shield becomes the
> counterpoise by default.
>
> Bill  N0CU
>
>
>
>


--
Scott  K9MA

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Re: EFHW

Doug Person-4
I am feeding my end-feds with over 100 feet of coax and they work just fine.

Doug - K0DXV


On 2/9/2017 1:21 PM, K9MA wrote:

> Well said, Bill!
>
> 73,
>
> Scott  K9MA
>
> On 2/9/2017 10:39, Bill Leonard N0CU wrote:
>> The reason your antenna was a lot less finicky with a bit of coax is
>> that the
>> EFHW antenna requires a return path for the RF field. Theoretically,
>> without
>> a return path, the antenna won't radiate at all. The recommended
>> setup for
>> this antenna is for a .05 wavelength counterpoised to be used. EZNEC
>> models
>> indicate that there is little benefit to going much longer than .05
>> wavelengths, and a quarter wavelength is actually less effective than
>> the
>> shorter lengths.  If no counterpoise is used, then coax shield
>> becomes the
>> counterpoise by default.
>>
>> Bill  N0CU
>>
>>
>>
>>
>
>

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Re: EFHW

Kevin - K4VD
I work portable with about 1 ft of coax to my end-fed. Never really had a
problem making contacts. Guess I could do a lot better with a longer coax
or with a counterpoise?

Kev - K4VD

On Thu, Feb 9, 2017 at 5:22 PM, Doug Person <[hidden email]> wrote:

> I am feeding my end-feds with over 100 feet of coax and they work just
> fine.
>
> Doug - K0DXV
>
>
> On 2/9/2017 1:21 PM, K9MA wrote:
>
>> Well said, Bill!
>>
>> 73,
>>
>> Scott  K9MA
>>
>> On 2/9/2017 10:39, Bill Leonard N0CU wrote:
>>
>>> The reason your antenna was a lot less finicky with a bit of coax is
>>> that the
>>> EFHW antenna requires a return path for the RF field. Theoretically,
>>> without
>>> a return path, the antenna won't radiate at all. The recommended setup
>>> for
>>> this antenna is for a .05 wavelength counterpoised to be used. EZNEC
>>> models
>>> indicate that there is little benefit to going much longer than .05
>>> wavelengths, and a quarter wavelength is actually less effective than the
>>> shorter lengths.  If no counterpoise is used, then coax shield becomes
>>> the
>>> counterpoise by default.
>>>
>>> Bill  N0CU
>>>
>>>
>>>
>>>
>>>
>>
>>
> ______________________________________________________________
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>
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Re: EFHW

K9MA
In reply to this post by Doug Person-4
On 2/9/2017 16:22, Doug Person wrote:
> I am feeding my end-feds with over 100 feet of coax and they work just
> fine.
>
> Doug - K0DXV

If they are end-fed half wave multiples without matching at the
feedpoints, there has to be a lot of loss in the coax.  Even if there
are 9:1 transformers at the feedpoints, there still could be quite a bit
of loss, as the SWR is very likely over 3:1.

73,

Scott  K9MA

--
Scott  K9MA

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Re: EFHW

Elecraft mailing list
In reply to this post by Doug Person-4
Do yourself a favor sometime and measure the 2:1 SWR bandwidth and use the tutorial to calculate how much loss you really have.  Just for grins.....  It gives you a bench mark.....

Mel, K6KBE


      From: Doug Person <[hidden email]>
 To: [hidden email]
 Sent: Thursday, February 9, 2017 2:22 PM
 Subject: Re: [Elecraft] EFHW
   
I am feeding my end-feds with over 100 feet of coax and they work just fine.

Doug - K0DXV


On 2/9/2017 1:21 PM, K9MA wrote:

> Well said, Bill!
>
> 73,
>
> Scott  K9MA
>
> On 2/9/2017 10:39, Bill Leonard N0CU wrote:
>> The reason your antenna was a lot less finicky with a bit of coax is
>> that the
>> EFHW antenna requires a return path for the RF field. Theoretically,
>> without
>> a return path, the antenna won't radiate at all. The recommended
>> setup for
>> this antenna is for a .05 wavelength counterpoised to be used. EZNEC
>> models
>> indicate that there is little benefit to going much longer than .05
>> wavelengths, and a quarter wavelength is actually less effective than
>> the
>> shorter lengths.  If no counterpoise is used, then coax shield
>> becomes the
>> counterpoise by default.
>>
>> Bill  N0CU
>>
>>
>>
>>
>
>

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Re: EFHW

K9MA
In reply to this post by Kevin - K4VD
On 2/9/2017 16:28, Kevin - K4VD wrote:
> I work portable with about 1 ft of coax to my end-fed. Never really had a
> problem making contacts. Guess I could do a lot better with a longer coax
> or with a counterpoise?
>
> Kev - K4VD
It wouldn't hurt to add a counterpoise of 6-8 feet, just a single wire
on the ground opposite the antenna, but it may not make much
difference.  (I'm assuming EFHW, not random or quarter wave wire.) That
short coax, the radio, the headphone cable, etc. is probably serving as
an adequate counterpoise.  You definitely do NOT want a longer coax,
unless there's a matching network at the feedpoint to keep the SWR low.  
Even then, the long coax would only be advantageous if it allows you to
place the antenna in a more favorable location.

73,

Scott  K9MA


--
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Re: EFHW

Bill Frantz
In reply to this post by Dan Presley
PackTenna <http://packtenna.com/> has a end fed half wave
antenna with a 50:1 transformer called the PackTenna Mini:

"This compact wire antenna is ideal for SOTA activations,
camping, backpacking, and travel. The PackTenna Mini End-Fed
Half Wave Antenna combines a 50:1 UNUN, winder and antenna wire
in a compact unit that is quick to set up and take down. The
antenna comes with 40' of 26 AWG copper clad steel wire with a
great "silky" jacket to minimize wire tangle. You can cut the
wire to any band from 20 meters and up in frequency. You can add
additional wire for lower frequency bands as well. This is a
single band antenna and does *not* require a tuner."

73 Bill AE6JV

On 2/8/17 at 4:54 PM, [hidden email] (Ron D'Eau Claire) wrote:

>As others pointed out, to get any real benefit from the EFHW it
>needs to be a real half wave or very close to it, necessitating
>a transformer to shift the impedance into range of the ATU or a
>purpose-built matching network (tuner). Shifting the length
>from a half wave simply turns the wire into a "random wire".

---------------------------------------------------------------------------
Bill Frantz        | "I wish there was a knob on the TV to turn
up the
408-356-8506       | intelligence.  There's a knob called
"brightness", but
www.pwpconsult.com | it doesn't work. -- Gallagher

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Re: EFHW

k6dgw
George, KJ6VU, is a principle in the Pack-Tenna venture and a good
friend.  I don't have one but I've seen it.  It's a fairly slick package
for field work and it does not need an ATU which might put another 0.1
watt into the radiation resistance instead of heat in the ATU.

73,

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

On 2/9/2017 3:30 PM, Bill Frantz wrote:

> PackTenna <http://packtenna.com/> has a end fed half wave antenna with
> a 50:1 transformer called the PackTenna Mini:
>
> "This compact wire antenna is ideal for SOTA activations, camping,
> backpacking, and travel. The PackTenna Mini End-Fed Half Wave Antenna
> combines a 50:1 UNUN, winder and antenna wire in a compact unit that
> is quick to set up and take down. The antenna comes with 40' of 26 AWG
> copper clad steel wire with a great "silky" jacket to minimize wire
> tangle. You can cut the wire to any band from 20 meters and up in
> frequency. You can add additional wire for lower frequency bands as
> well. This is a single band antenna and does *not* require a tuner."
>
> 73 Bill AE6JV
>
> On 2/8/17 at 4:54 PM, [hidden email] (Ron D'Eau Claire) wrote:
>
>> As others pointed out, to get any real benefit from the EFHW it needs
>> to be a real half wave or very close to it, necessitating a
>> transformer to shift the impedance into range of the ATU or a
>> purpose-built matching network (tuner). Shifting the length from a
>> half wave simply turns the wire into a "random wire".
>
> ---------------------------------------------------------------------------
>
> Bill Frantz        | "I wish there was a knob on the TV to turn up the
> 408-356-8506       | intelligence.  There's a knob called
> "brightness", but
> www.pwpconsult.com | it doesn't work. -- Gallagher
>
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>
> --
> This message has been scanned by E.F.A. Project and is believed to be
> clean.
>
>
>

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Re: EFHW

Kevin - K4VD
In reply to this post by K9MA
​Thanks Scott. I use the Par EndFedZ EF-10/20/40 and EF-20/40 depending on
what's in the bag at the moment. These are resonant and I'm assuming the
KX3 tuner is enough to keep the SWR low. The radio always seems happy.

I will add up to 8 feet of wire next time out and try some A/B tests.

During this thread there's been a couple of comments that kind of challenge
my way of thinking. I would never have thought a random wire would be
considered superior to a resonant antenna. I also don't equated high SWR
with high loss. My home antenna is comprised of a dipole fed with 600 ohm
ladder line through a 4:1 BALUN. It's about the best antenna setup I've
ever had and I use it on all bands 80 (where it is resonant) through 6. The
KX3 and the Flex tunes it nicely and the log fills up.

Threads like this get me questioning everything I thought I knew. That's
not a bad thing.

Kev K4VD​

On Thu, Feb 9, 2017 at 5:37 PM, K9MA <[hidden email]> wrote:

> On 2/9/2017 16:28, Kevin - K4VD wrote:
>
>> I work portable with about 1 ft of coax to my end-fed. Never really had a
>> problem making contacts. Guess I could do a lot better with a longer coax
>> or with a counterpoise?
>>
>> Kev - K4VD
>>
> It wouldn't hurt to add a counterpoise of 6-8 feet, just a single wire on
> the ground opposite the antenna, but it may not make much difference.  (I'm
> assuming EFHW, not random or quarter wave wire.) That short coax, the
> radio, the headphone cable, etc. is probably serving as an adequate
> counterpoise.  You definitely do NOT want a longer coax, unless there's a
> matching network at the feedpoint to keep the SWR low.  Even then, the long
> coax would only be advantageous if it allows you to place the antenna in a
> more favorable location.
>
> 73,
>
> Scott  K9MA
>
>
> --
> Scott  K9MA
>
> [hidden email]
>
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Re: EFHW

Dan Presley
I wanted to thank everyone who commented on this thread. I felt an obligation to wrap it up since I ‘poked the hornet’s nest’ :)) I did get some good information and some interesting comments. It’s always fascinating to see how things morph from the original post.One thing I did realize is that there still is some confusion over what is an end fed halfwave; a fair amount of folks conflate an end fed wire of any length with a resonant half wave. While it’s true that a resonant half wave may be a non resonant random wire at bands other than it was made, that’s not exactly a useful premise for my needs. So-in the interest of closure I’ll post the original question in the clearest fashion I can and ask that any thoughts on this please email me directly and if i get some good responses I’ll post to the list so we can all have that to enjoy.
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. I have a number of options I use already including resonant dipoles; verticals and loops, and I plan to continue to use these as conditions require. You never know what’s the best option until you’re actually at the site..One other option is either an end fed random wire with a counterpoise (length selected to avoid a resonant quarter or half wave-there’s charts out there to help select good lengths) or an end fed (resonant) halfwave cut to resonate at the desired band. Think say, 66 feet for 40M give or take. Now-when I use a non resonant random length wire I feed it directly off the radio (BNC-binding post adaptor). With a resonant halfwave I would (and have) used a 9:1 transformer, coax (variable length) and perhaps a common mode choke, and perhaps a short counterpoise. Between just those  two antennas is there any advantage to using the resonant halfwave over the random length wire? Is there more gain? Better takeoff angle? More lobes ? Would this justify packing the extra stuff for the resonant halfwave? I’m guessing a lot will depend on terrain/height,etc so may be hard to answer, but that’s the question, and that only. I imagine efficiency may be a factor, but if I can eliminate a transformer,feed line,and choke and feed directly to the radio that should help eliminate some losses.
So-it isn’t about how to build/buy an EFHW; what to use at a home station,etc. It’s just this one question. Like i said-I have a few good answers but curious if there’s something I’m missing about the EFHW over the random length antenna. Thanks everyone, and I hope we all can get out and enjoy our great rigs as much as possible. The KX 2 is the radio I’ve been dreaming about for a long.long time and now I have one...
Dan Presley  N7CQR
[hidden email]


> On Feb 9, 2017, at 4:03 PM, Kevin - K4VD <[hidden email]> wrote:
>
> ​Thanks Scott. I use the Par EndFedZ EF-10/20/40 and EF-20/40 depending on
> what's in the bag at the moment. These are resonant and I'm assuming the
> KX3 tuner is enough to keep the SWR low. The radio always seems happy.
>
> I will add up to 8 feet of wire next time out and try some A/B tests.
>
> During this thread there's been a couple of comments that kind of challenge
> my way of thinking. I would never have thought a random wire would be
> considered superior to a resonant antenna. I also don't equated high SWR
> with high loss. My home antenna is comprised of a dipole fed with 600 ohm
> ladder line through a 4:1 BALUN. It's about the best antenna setup I've
> ever had and I use it on all bands 80 (where it is resonant) through 6. The
> KX3 and the Flex tunes it nicely and the log fills up.
>
> Threads like this get me questioning everything I thought I knew. That's
> not a bad thing.
>
> Kev K4VD​
>
> On Thu, Feb 9, 2017 at 5:37 PM, K9MA <[hidden email] <mailto:[hidden email]>> wrote:
>
>> On 2/9/2017 16:28, Kevin - K4VD wrote:
>>
>>> I work portable with about 1 ft of coax to my end-fed. Never really had a
>>> problem making contacts. Guess I could do a lot better with a longer coax
>>> or with a counterpoise?
>>>
>>> Kev - K4VD
>>>
>> It wouldn't hurt to add a counterpoise of 6-8 feet, just a single wire on
>> the ground opposite the antenna, but it may not make much difference.  (I'm
>> assuming EFHW, not random or quarter wave wire.) That short coax, the
>> radio, the headphone cable, etc. is probably serving as an adequate
>> counterpoise.  You definitely do NOT want a longer coax, unless there's a
>> matching network at the feedpoint to keep the SWR low.  Even then, the long
>> coax would only be advantageous if it allows you to place the antenna in a
>> more favorable location.
>>
>> 73,
>>
>> Scott  K9MA
>>
>>
>> --
>> Scott  K9MA
>>
>> [hidden email]
>>
>> ______________________________________________________________
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Re: EFHW

ve3bwp
In reply to this post by Dan Presley
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.

Brian ve3bwp

Date: Wed, 8 Feb 2017 16:33:25 -0700
From: Doug Person <[hidden email]>
To: [hidden email]
Subject: Re: [Elecraft] EFHW
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=utf-8; format=flowed

I have two EFHW antennas. One covering 40 and 20; the other 17. They are
mounted at about 40 feet and perform equal to regular dipoles.  Feeding
them is therefore much simpler for portable ops since only one side
needs to be elevated.  For portable use I feed them with about 20 feet
of RG/58a, although they can be attached directly to the radio.  I find,
however, that a bit of coax causes them to be a lot less finicky.  They
have been my field day and SOTA portable goto antennas for many years.  
Transformers are not difficult to construct and there are some good
quality assembled products that are excellent.

Doug -- K0DXV
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Re: EFHW

Don Wilhelm
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.
>
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