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Small QRP antenna

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Rick Dwight

Small QRP antenna

For about 50 years my usual portable antenna was a linked dipole, coax fed, and usually rigged as an inverted V for 40, 30, and 20 meters. Performance was usually very good especially if the apex was at least something like 25 feet. However, this was heavy, took too much time to set up, and often there was not enough room in a park or campground. Often the set up was just not worth the trouble after a long day of backpacking, etc. However about 12 years ago when I got my KX1 with internal tuner, I found out I could make many good QSO’s on 40, 30 and 20 meters with a simple 26 ft. wire in a tree, bush, vertical, sloped, or whatever and a 17 ft. wire or two laying on the ground. Many more QSO’s since set up was so easy, however not nearly as good as the inverted V. Now when I travel I usually just take a 26 ft piece of wire, two 17 ft counterpoise wires, and about an 8 ft. long wire with a big clip on the end. Sometimes counterpoise wires are not convenient to lay out, so I just clip onto a metal picnic table frame, chain link fence, or whatever for a ground (counterpoise) and it seems to be acceptable. At other times I extend my 26 ft wire or counterpoise with the 8 ft wire for a better tune or performance on 40 meters, especially if the counterpoise wires are elevated even slightly. If space and supports are limited, I have thrown one 17 ft wire up over short trees or bushes of only perhaps 10 ft in height, and this inverted u antenna has even worked some DX on 20 meters (the other 17 ft wire is a counterpoise). I usually I like two counterpoise wires since models show a slight null if only one counterpoise wire is used.
There are better portable antennas than the 26 ft wire, however it seems to be a winner when you consider weight, ease of set up, cost, and performance. This is usually the only antenna I carry when I go to Europe or the UK where millions of folks live within a few hundred miles. However when I operate portable from Alaska or other very remote locations, or especially in a contest, then sometimes better antennas are worth the effort and weight even for this old backpacker. Do investigate end fed half wave antennas…many portable QRP operators go this route. Your rig runs much more power than my kx1 and has a better antenna tuner, so you should have even more success than I have had with my 2 watts.
Cheers, Rick KL7CW

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k6dgw

Re: Small QRP antenna

The Summits On The Air crowd, at least one of whom "runs" up mountains,
has had very good luck with end-fed half-waves. The transformer weighs
next to nothing, and the rest is just wire. Requires no counterpoise,
very ground insensitive since it's fed at a voltage node. Also because
of that, you need no coax, just an adapter between rig and transformer.
The higher you can get the middle [current node] the better, but it will
work very well with just about any elevation on the far end.

For 40, it's about 67 ft of wire, and is a full-wave on 20 and will work
well there. My KX1, when I still had it, had no problem finding a
match. My HOA-Stealth here at home is an 80-10 EFHW strung about 6 ft
high along the top of a wooden fence. Works surprisingly well.

Fred K6DGW
Sparks NV DM09dn
Washoe County

--Northern California Contest Club
--CU in the Cal QSO Party
--7-8 Oct 2017

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K9MA

Re: Small QRP antenna

I've had good luck with the end fed 40 M half wave, too. I use it with
the KX1 to do CWT's on bicycle tours (in warmer weather). While the
transformer and ATU apparently works, I wanted a really good match to
maximize output power, so I built a small QRP tuner for it:

http://sdellington.us/hr/EFHW_Tuner2.pdf

Most of the parts come from the Pacific Antenna BLT+ kit, which they
were willing to sell me without the case.

73,

Scott K9MA

On 12/28/2016 14:56, Fred Jensen wrote:

> The Summits On The Air crowd, at least one of whom "runs" up
> mountains, has had very good luck with end-fed half-waves. The
> transformer weighs next to nothing, and the rest is just wire.
> Requires no counterpoise, very ground insensitive since it's fed at a
> voltage node. Also because of that, you need no coax, just an adapter
> between rig and transformer. The higher you can get the middle
> [current node] the better, but it will work very well with just about
> any elevation on the far end.
>
> For 40, it's about 67 ft of wire, and is a full-wave on 20 and will
> work well there. My KX1, when I still had it, had no problem finding
> a match. My HOA-Stealth here at home is an 80-10 EFHW strung about 6
> ft high along the top of a wooden fence. Works surprisingly well.
>
> Fred K6DGW
> Sparks NV DM09dn
> Washoe County
>
> --Northern California Contest Club
> --CU in the Cal QSO Party
> --7-8 Oct 2017
>
> ______________________________________________________________
> 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]

Chris Tate - N6WM

Re: Small QRP antenna

I just ordered a number of options from SotaBeams in the UK to compliment my KX2.

http://www.sotabeams.co.uk/antennas-hf/

Small and sometimes conveniently packed options make taking the fully qrv ready rig to the Caribbean very easy.

Even as a big gun contester I am having alot of fun with the little feature packed KX2 and its portable potential. they also sell a telescopic 30 ft fiberglass mast that breaks down to 26". amazing what you can fit in a backpack these days ;-).

Chris
N6WM

________________________________________
From: Elecraft [[hidden email]] on behalf of K9MA [[hidden email]]
Sent: Wednesday, December 28, 2016 1:32 PM
To: [hidden email]
Subject: Re: [Elecraft] Small QRP antenna

I've had good luck with the end fed 40 M half wave, too. I use it with
the KX1 to do CWT's on bicycle tours (in warmer weather). While the
transformer and ATU apparently works, I wanted a really good match to
maximize output power, so I built a small QRP tuner for it:

http://sdellington.us/hr/EFHW_Tuner2.pdf

Most of the parts come from the Pacific Antenna BLT+ kit, which they
were willing to sell me without the case.

73,

Scott K9MA

On 12/28/2016 14:56, Fred Jensen wrote:

--
Scott K9MA

[hidden email]

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K9MA

Re: Small QRP antenna

If you're willing to spend a little more for less weight, this outfit
has carbon-fiber fishing poles of various lengths:

allfishingbuy.com

The one I have extends to 38 feet, weighs about 500 grams, and collapses
to 34 inches. The tip is pretty floppy, but it holds up my AWG 26
wire. Stiffer ones are available, but they're heavier, though sometimes
cheaper. You do have to keep the wire away from the pole, as it's
conductive.

Never, ever lay it on the ground when some klutz can step on it, though.

73,

Scott K9MA

On 12/28/2016 15:47, Chris Tate - N6WM wrote:

> I just ordered a number of options from SotaBeams in the UK to compliment my KX2.
>
> http://www.sotabeams.co.uk/antennas-hf/
>
> Small and sometimes conveniently packed options make taking the fully qrv ready rig to the Caribbean very easy.
>
> Even as a big gun contester I am having alot of fun with the little feature packed KX2 and its portable potential. they also sell a telescopic 30 ft fiberglass mast that breaks down to 26". amazing what you can fit in a backpack these days ;-).
>
> Chris
> N6WM
>
>
> ________________________________________
> From: Elecraft [[hidden email]] on behalf of K9MA [[hidden email]]
> Sent: Wednesday, December 28, 2016 1:32 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Small QRP antenna
>
> I've had good luck with the end fed 40 M half wave, too. I use it with
> the KX1 to do CWT's on bicycle tours (in warmer weather). While the
> transformer and ATU apparently works, I wanted a really good match to
> maximize output power, so I built a small QRP tuner for it:
>
> http://sdellington.us/hr/EFHW_Tuner2.pdf
>
> Most of the parts come from the Pacific Antenna BLT+ kit, which they
> were willing to sell me without the case.
>
> 73,
>
> Scott K9MA
>
>
>
> On 12/28/2016 14:56, Fred Jensen wrote:
>> The Summits On The Air crowd, at least one of whom "runs" up
>> mountains, has had very good luck with end-fed half-waves. The
>> transformer weighs next to nothing, and the rest is just wire.
>> Requires no counterpoise, very ground insensitive since it's fed at a
>> voltage node. Also because of that, you need no coax, just an adapter
>> between rig and transformer. The higher you can get the middle
>> [current node] the better, but it will work very well with just about
>> any elevation on the far end.
>>
>> For 40, it's about 67 ft of wire, and is a full-wave on 20 and will
>> work well there. My KX1, when I still had it, had no problem finding
>> a match. My HOA-Stealth here at home is an 80-10 EFHW strung about 6
>> ft high along the top of a wooden fence. Works surprisingly well.
>>
>> Fred K6DGW
>> Sparks NV DM09dn
>> Washoe County
>>
>> --Northern California Contest Club
>> --CU in the Cal QSO Party
>> --7-8 Oct 2017
>>
>> ______________________________________________________________
>> 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]
>
> --
> Scott K9MA
>
> [hidden email]
>
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k6dgw

Re: Small QRP antenna

In reply to this post by k6dgw

Ron is correct ... however my experience is that the rig, headphone
cable, power cable from the battery, and me [holding the KX1] is more
than sufficient. For mine at home, it is fed with about 25 ft of coax,
the shield of which serves that purpose.

If you attempt to model it with NEC-2, and all you care about are the
radiation patterns, you don't need a counterpoise in the model. While
NEC-2 *really* doesn't like a source connected to the end of a wire, it
only affects the source impedance values. If you want those to be
reasonably accurate and real, a short wire is necessary ... anything
over a few feet seems to work just fine and is in no way critical.

Fred K6DGW
Sparks NV DM09dn
Washoe County

On 12/28/2016 3:43 PM, Ron D'Eau Claire wrote:

> While the efficiency as a radiator of a half wave end fed wire is relatively
> unaffected by the "ground" return, some sort of "ground" is needed to keep
> the whole rig from floating up to the RF potential at the end of the
> antenna. Often a hunk of wire roughly 1/4 wave long thrown on the ground is
> adequate.
>
> I too have had excellent results with them.
>
> 73 Ron AC7AC
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Fred
> Jensen
> Sent: Wednesday, December 28, 2016 12:57 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Small QRP antenna
>
> The Summits On The Air crowd, at least one of whom "runs" up mountains, has
> had very good luck with end-fed half-waves. The transformer weighs next to
> nothing, and the rest is just wire. Requires no counterpoise, very ground
> insensitive since it's fed at a voltage node. Also because of that, you
> need no coax, just an adapter between rig and transformer.
> The higher you can get the middle [current node] the better, but it will
> work very well with just about any elevation on the far end.
>
> For 40, it's about 67 ft of wire, and is a full-wave on 20 and will work
> well there. My KX1, when I still had it, had no problem finding a match.
> My HOA-Stealth here at home is an 80-10 EFHW strung about 6 ft high along
> the top of a wooden fence. Works surprisingly well.
>
> Fred K6DGW
> Sparks NV DM09dn
> Washoe County
>
> --Northern California Contest Club
> --CU in the Cal QSO Party
> --7-8 Oct 2017
>
> ______________________________________________________________
> 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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>
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>
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K9MA

Re: Small QRP antenna

The counterpoise for an end fed half wave (or multiple) really doesn't
have to be anywhere near a quarter wave long. The feedpoint impedance
is something over 2000 Ohms. I use a single wire about 8 feet long,
which seems to work fine. NEC agrees. My simple test is to get it
perfectly matched, then put my hand on the tuner box. If the SWR
doesn't change, the counterpoise is adequate.

I did recently try the 40 M half wave on 80, with two quarter wave
radials. There was, of course, some "rf in the shack", but it didn't
cause any problems, and the antenna seemed to work fairly well,
especially considering that it was in the bottom of Death Valley.

73,

Scott K9MA

On 12/28/2016 18:14, Fred Jensen wrote:

> Ron is correct ... however my experience is that the rig, headphone
> cable, power cable from the battery, and me [holding the KX1] is more
> than sufficient. For mine at home, it is fed with about 25 ft of
> coax, the shield of which serves that purpose.
>
> If you attempt to model it with NEC-2, and all you care about are the
> radiation patterns, you don't need a counterpoise in the model. While
> NEC-2 *really* doesn't like a source connected to the end of a wire,
> it only affects the source impedance values. If you want those to be
> reasonably accurate and real, a short wire is necessary ... anything
> over a few feet seems to work just fine and is in no way critical.
>
> Fred K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 12/28/2016 3:43 PM, Ron D'Eau Claire wrote:
>> While the efficiency as a radiator of a half wave end fed wire is
>> relatively
>> unaffected by the "ground" return, some sort of "ground" is needed to
>> keep
>> the whole rig from floating up to the RF potential at the end of the
>> antenna. Often a hunk of wire roughly 1/4 wave long thrown on the
>> ground is
>> adequate.
>>
>> I too have had excellent results with them.
>>
>> 73 Ron AC7AC
>>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Fred
>> Jensen
>> Sent: Wednesday, December 28, 2016 12:57 PM
>> To: [hidden email]
>> Subject: Re: [Elecraft] Small QRP antenna
>>
>> The Summits On The Air crowd, at least one of whom "runs" up
>> mountains, has
>> had very good luck with end-fed half-waves. The transformer weighs
>> next to
>> nothing, and the rest is just wire. Requires no counterpoise, very
>> ground
>> insensitive since it's fed at a voltage node. Also because of that, you
>> need no coax, just an adapter between rig and transformer.
>> The higher you can get the middle [current node] the better, but it will
>> work very well with just about any elevation on the far end.
>>
>> For 40, it's about 67 ft of wire, and is a full-wave on 20 and will work
>> well there. My KX1, when I still had it, had no problem finding a
>> match.
>> My HOA-Stealth here at home is an 80-10 EFHW strung about 6 ft high
>> along
>> the top of a wooden fence. Works surprisingly well.
>>
>> Fred K6DGW
>> Sparks NV DM09dn
>> Washoe County
>>
>> --Northern California Contest Club
>> --CU in the Cal QSO Party
>> --7-8 Oct 2017
>>
>> ______________________________________________________________
>> 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]
>>

Don Wilhelm

Re: Small QRP antenna

Scott,

If the radiator is not a half wave long, it is not a "half wave".
Yes, a random length wire may work, but please do not call a random
length a half wave - the length of a half wave is quite specific.
Similarly, a quarter wavelength is a specific length at a particular
frequency.

73,
Don W3FPR

On 12/28/2016 11:20 PM, K9MA wrote:
> The counterpoise for an end fed half wave (or multiple) really doesn't
> have to be anywhere near a quarter wave long.
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Fred Moore-2

Re: Small QRP antenna

Don,

Thank you very much, for pointing out a very common issue that gets
mixed up into discussions. Your point is so valid the random wire
always seems to get mixed into the 1/2 wave discussion for some
reason.. and should never be mixed together. you are absolutely
correct.. thanks again regards.. Fred

On 12/29/16 12:33 AM, Don Wilhelm wrote:

> Scott,
>
> If the radiator is not a half wave long, it is not a "half wave".
> Yes, a random length wire may work, but please do not call a random
> length a half wave - the length of a half wave is quite specific.
> Similarly, a quarter wavelength is a specific length at a particular
> frequency.
>
> 73,
> Don W3FPR
>
> On 12/28/2016 11:20 PM, K9MA wrote:
>> The counterpoise for an end fed half wave (or multiple) really doesn't
>> have to be anywhere near a quarter wave long.
> ______________________________________________________________
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>

mjisted

Re: Small QRP antenna

In reply to this post by Rick Dwight

Looking at your text message on the elecraft board. About a half wave length ...here is a question for you. I'm going to put up a half wavelength of wire for the 5 mhz band. ..hyendfed can I use a quarter wave length of counter point as a radiator ground plane. ..
The. ..G0MVP.

[hidden email]

Sent from Samsung Mobile

<div>-------- Original message --------</div><div>From: Fred Moore <[hidden email]> </div><div>Date:29/12/2016 13:04 (GMT+00:00) </div><div>To: [hidden email] </div><div>Subject: Re: [Elecraft] Small QRP antenna </div><div>
</div>Don,

Thank you very much, for pointing out a very common issue that gets
mixed up into discussions. Your point is so valid the random wire
always seems to get mixed into the 1/2 wave discussion for some
reason.. and should never be mixed together. you are absolutely
correct.. thanks again regards.. Fred

On 12/29/16 12:33 AM, Don Wilhelm wrote:

--
Fred Moore
email: [hidden email]
[hidden email]
phone: 321-217-8699

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Fred Moore-2

Re: Small QRP antenna

With an end fed 1/4 wave you only need a counterpoise that is about .05
wave length. it can be the coax or another counterpoise. Although a
counterpoise has some effect on radiation pattern of a quarter wave
radiator, it is minimal. You won't see much improvement in performance
by going above .05 wave length.. it's not worth the trouble to increase
the counterpoise length.. Fred

On 12/29/16 9:01 AM, mjisted wrote:

> Looking at your text message on the elecraft board. About a half wave
> length ...here is a question for you. I'm going to put up a half
> wavelength of wire for the 5 mhz band. ..hyendfed can I use a quarter
> wave length of counter point as a radiator ground plane. ..
> The. ..G0MVP.
>
> [hidden email]
>
>
> Sent from Samsung Mobile
>
>
> -------- Original message --------
> From: Fred Moore
> Date:29/12/2016 13:04 (GMT+00:00)
> To: [hidden email]
> Subject: Re: [Elecraft] Small QRP antenna
>
> Don,
>
> Thank you very much, for pointing out a very common issue that gets
> mixed up into discussions. Your point is so valid the random wire
> always seems to get mixed into the 1/2 wave discussion for some
> reason.. and should never be mixed together. you are absolutely
> correct.. thanks again regards.. Fred
>
>
> On 12/29/16 12:33 AM, Don Wilhelm wrote:
> > Scott,
> >
> > If the radiator is not a half wave long, it is not a "half wave".
> > Yes, a random length wire may work, but please do not call a random
> > length a half wave - the length of a half wave is quite specific.
> > Similarly, a quarter wavelength is a specific length at a particular
> > frequency.
> >
> > 73,
> > Don W3FPR
> >
> > On 12/28/2016 11:20 PM, K9MA wrote:
> >> The counterpoise for an end fed half wave (or multiple) really doesn't
> >> have to be anywhere near a quarter wave long.
> > ______________________________________________________________
> > 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]
> >
>
> --
> Fred Moore
> email: [hidden email]
> [hidden email]
> phone: 321-217-8699
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
> --
> This message has been scanned for viruses and
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> believed to be clean.

K9MA

Re: Small QRP antenna

I think Fred meant an end fed 1/2 wave, NOT 1/4 wave.

73,

Scott K9MA

----------

Scott Ellington

--- via iPad

> On Dec 29, 2016, at 9:30 AM, Fred Moore <[hidden email]> wrote:
>
> With an end fed 1/4 wave you only need a counterpoise that is about .05
> wave length. it can be the coax or another counterpoise. Although a
> counterpoise has some effect on radiation pattern of a quarter wave
> radiator, it is minimal. You won't see much improvement in performance
> by going above .05 wave length.. it's not worth the trouble to increase
> the counterpoise length.. Fred
>
>
>> On 12/29/16 9:01 AM, mjisted wrote:
>> Looking at your text message on the elecraft board. About a half wave
>> length ...here is a question for you. I'm going to put up a half
>> wavelength of wire for the 5 mhz band. ..hyendfed can I use a quarter
>> wave length of counter point as a radiator ground plane. ..
>> The. ..G0MVP.
>>
>> [hidden email]
>>
>>
>> Sent from Samsung Mobile
>>
>>
>> -------- Original message --------
>> From: Fred Moore
>> Date:29/12/2016 13:04 (GMT+00:00)
>> To: [hidden email]
>> Subject: Re: [Elecraft] Small QRP antenna
>>
>> Don,
>>
>> Thank you very much, for pointing out a very common issue that gets
>> mixed up into discussions. Your point is so valid the random wire
>> always seems to get mixed into the 1/2 wave discussion for some
>> reason.. and should never be mixed together. you are absolutely
>> correct.. thanks again regards.. Fred
>>
>>
>>> On 12/29/16 12:33 AM, Don Wilhelm wrote:
>>> Scott,
>>>
>>> If the radiator is not a half wave long, it is not a "half wave".
>>> Yes, a random length wire may work, but please do not call a random
>>> length a half wave - the length of a half wave is quite specific.
>>> Similarly, a quarter wavelength is a specific length at a particular
>>> frequency.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>>> On 12/28/2016 11:20 PM, K9MA wrote:
>>>> The counterpoise for an end fed half wave (or multiple) really doesn't
>>>> have to be anywhere near a quarter wave long.
>>> ______________________________________________________________
>>> 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]
>>>
>>
>> --
>> Fred Moore
>> email: [hidden email]
>> [hidden email]
>> phone: 321-217-8699
>>
>> ______________________________________________________________
>> 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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>> Message delivered to [hidden email]
>>
>> --
>> This message has been scanned for viruses and
>> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is
>> believed to be clean.
>
> --
> Fred Moore
> email: [hidden email]
> [hidden email]
> phone: 321-217-8699
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Don Wilhelm

Re: Small QRP antenna

In reply to this post by Fred Moore-2

I think this is mixing up 1/2 wave radiators and 1/4 wave radiators.
To be resonant, a 1/4 wave wire needs another 1/4 wave "counterpoise" -
think of a center fed dipole - it has 1/4 wave on each side whether one
side is a monopole (vertical) and the other 1/4 wave is an elevated
radial or buried radials of indeterminate length, or whether it is a
dipole with the center in the air.

A 1/2 wave radiator fed at the end theoretically does not need any
counterpoise, but in practice it does - but only needs to be about 0.05
wavelength long.

Refer to some antenna books (the ARRL has a good one) or the ARRL
Handbook for good information about basic antennas.

73,
Don W3FPR

On 12/29/2016 10:30 AM, Fred Moore wrote:

> With an end fed 1/4 wave you only need a counterpoise that is about .05
> wave length. it can be the coax or another counterpoise. Although a
> counterpoise has some effect on radiation pattern of a quarter wave
> radiator, it is minimal. You won't see much improvement in performance
> by going above .05 wave length.. it's not worth the trouble to increase
> the counterpoise length.. Fred
>
>
> On 12/29/16 9:01 AM, mjisted wrote:
>> Looking at your text message on the elecraft board. About a half wave
>> length ...here is a question for you. I'm going to put up a half
>> wavelength of wire for the 5 mhz band. ..hyendfed can I use a quarter
>> wave length of counter point as a radiator ground plane. ..
>> The. ..G0MVP.
>>
>> [hidden email]
>>
>>
>> Sent from Samsung Mobile
>>
>>
>> -------- Original message --------
>> From: Fred Moore
>> Date:29/12/2016 13:04 (GMT+00:00)
>> To: [hidden email]
>> Subject: Re: [Elecraft] Small QRP antenna
>>
>> Don,
>>
>> Thank you very much, for pointing out a very common issue that gets
>> mixed up into discussions. Your point is so valid the random wire
>> always seems to get mixed into the 1/2 wave discussion for some
>> reason.. and should never be mixed together. you are absolutely
>> correct.. thanks again regards.. Fred
>>
>>
>> On 12/29/16 12:33 AM, Don Wilhelm wrote:
>>> Scott,
>>>
>>> If the radiator is not a half wave long, it is not a "half wave".
>>> Yes, a random length wire may work, but please do not call a random
>>> length a half wave - the length of a half wave is quite specific.
>>> Similarly, a quarter wavelength is a specific length at a particular
>>> frequency.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> On 12/28/2016 11:20 PM, K9MA wrote:
>>>> The counterpoise for an end fed half wave (or multiple) really doesn't
>>>> have to be anywhere near a quarter wave long.
>>> ______________________________________________________________
>>> 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]
>>>
>>
>> --
>> Fred Moore
>> email: [hidden email]
>> [hidden email]
>> phone: 321-217-8699
>>
>> ______________________________________________________________
>> 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]
>>
>> --
>> This message has been scanned for viruses and
>> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is
>> believed to be clean.
>

Richard Fjeld-2

Re: Small QRP antenna

With reference to below, I have a question please. I put up a quarter
wave inverted-L for 160 meters. My only counterpoise is the ground rods
at the base of the tower. I wasn't expecting much, but it does so well
I'd like to add a decent counterpoise.

If I bury a quarter wave wire, would it be best to put it under the
Ariel wire, or opposite from it?
Thanks in advance,
Dick, n0ce

On 12/29/2016 10:16 AM, Don Wilhelm wrote:

> I think this is mixing up 1/2 wave radiators and 1/4 wave radiators.
> To be resonant, a 1/4 wave wire needs another 1/4 wave "counterpoise"
> - think of a center fed dipole - it has 1/4 wave on each side whether
> one side is a monopole (vertical) and the other 1/4 wave is an
> elevated radial or buried radials of indeterminate length, or whether
> it is a dipole with the center in the air.
>
> A 1/2 wave radiator fed at the end theoretically does not need any
> counterpoise, but in practice it does - but only needs to be about
> 0.05 wavelength long.
>
> Refer to some antenna books (the ARRL has a good one) or the ARRL
> Handbook for good information about basic antennas.
>
> 73,
> Don W3FPR
>
> On 12/29/2016 10:30 AM, Fred Moore wrote:
>> With an end fed 1/4 wave you only need a counterpoise that is about .05
>> wave length. it can be the coax or another counterpoise. Although a
>> counterpoise has some effect on radiation pattern of a quarter wave
>> radiator, it is minimal. You won't see much improvement in performance
>> by going above .05 wave length.. it's not worth the trouble to increase
>> the counterpoise length.. Fred
>>
>>
>> On 12/29/16 9:01 AM, mjisted wrote:
>>> Looking at your text message on the elecraft board. About a half wave
>>> length ...here is a question for you. I'm going to put up a half
>>> wavelength of wire for the 5 mhz band. ..hyendfed can I use a quarter
>>> wave length of counter point as a radiator ground plane. ..
>>> The. ..G0MVP.
>>>
>>> [hidden email]
>>>
>>>
>>> Sent from Samsung Mobile
>>>
>>>
>>> -------- Original message --------
>>> From: Fred Moore
>>> Date:29/12/2016 13:04 (GMT+00:00)
>>> To: [hidden email]
>>> Subject: Re: [Elecraft] Small QRP antenna
>>>
>>> Don,
>>>
>>> Thank you very much, for pointing out a very common issue that gets
>>> mixed up into discussions. Your point is so valid the random wire
>>> always seems to get mixed into the 1/2 wave discussion for some
>>> reason.. and should never be mixed together. you are absolutely
>>> correct.. thanks again regards.. Fred
>>>
>>>
>>> On 12/29/16 12:33 AM, Don Wilhelm wrote:
>>>> Scott,
>>>>
>>>> If the radiator is not a half wave long, it is not a "half wave".
>>>> Yes, a random length wire may work, but please do not call a random
>>>> length a half wave - the length of a half wave is quite specific.
>>>> Similarly, a quarter wavelength is a specific length at a particular
>>>> frequency.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> On 12/28/2016 11:20 PM, K9MA wrote:
>>>>> The counterpoise for an end fed half wave (or multiple) really
>>>>> doesn't
>>>>> have to be anywhere near a quarter wave long.
>>>> ______________________________________________________________
>>>> 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]
>>>>
>>>
>>> --
>>> Fred Moore
>>> email: [hidden email]
>>> [hidden email]
>>> phone: 321-217-8699
>>>
>>> ______________________________________________________________
>>> 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]
>>>
>>> --
>>> This message has been scanned for viruses and
>>> dangerous content by *MailScanner* <http://www.mailscanner.info/>,
>>> and is
>>> believed to be clean.
>>
> ______________________________________________________________
> 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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Don Wilhelm

Re: Small QRP antenna

Dick,

With buried radials, they do not have to be 1/4 wave long, and a single
one will probably not make much difference over your ground rod.
What you want to accomplish is a "ground screen", which means many short
(about 1/8 wavelength) close to the base of the radiator and a few
extending out further (to 1/4 or 1/2 wavelength).

Ground conductivity plays a great part in buried radials, and what you
are trying to accomplish is to increase the ground conductivity in the
area at the base of the antenna.

If you were instead using elevated radials, they would have to be
resonant - think of the various "ground plane" antennas that have been
published - 1/4 wave radiator plus 2 or 4 1/4 wave radials.
Buried radials do not have to be resonant, elevated radials must be
resonant. The ground effects will alter the resonance of buried radials
while radials in the air are a part of the total antenna resonance.

73,
Don W3FPR

On 12/29/2016 11:49 AM, Richard Fjeld wrote:
> With reference to below, I have a question please. I put up a quarter
> wave inverted-L for 160 meters. My only counterpoise is the ground rods
> at the base of the tower. I wasn't expecting much, but it does so well
> I'd like to add a decent counterpoise.
>
> If I bury a quarter wave wire, would it be best to put it under the
> Ariel wire, or opposite from it?
> Thanks in advance,
______________________________________________________________
Elecraft mailing list
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Mike Morrow-3

Re: Small QRP antenna

In reply to this post by Rick Dwight

Don wrote:

> A 1/2 wave radiator fed at the end theoretically does not need
> any counterpoise, but in practice it does - but only needs to
> be about 0.05 wavelength long.
>
> Refer to some antenna books (the ARRL has a good one) or the ARRL
> Handbook for good information about basic antennas.

The concise clarity of Don's input to this thread is refreshing. Such seem to occur rarely in ham discussions about antennas.

With respect to classical end-fed half-wave antennas, I think of the end-fed Zepp[elin] and the common VHF J-poles.

Mike / KK5F
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Elecraft mailing list

Re: Small QRP antenna

In reply to this post by Don Wilhelm

One thing I will add that has not been commented on, is the way of feeding a 1/2 wl wire with a 1/4 wl twin lead. Where one side of the twin lead at the top is connected to the 1/2 wl wire. You can feed the twin lead at the bottom with a 1:1 choke and you don't need a ground. Then for the upper bands, tie the twin lead together and feed it against your counterpoise. The twin lead does not have to be completely vertical either.

Mel, K6KBE

From: Don Wilhelm <[hidden email]>
To: Richard Fjeld <[hidden email]>; "[hidden email]" <[hidden email]>
Sent: Thursday, December 29, 2016 9:05 AM
Subject: Re: [Elecraft] Small QRP antenna

Dick,

With buried radials, they do not have to be 1/4 wave long, and a single
one will probably not make much difference over your ground rod.
What you want to accomplish is a "ground screen", which means many short
(about 1/8 wavelength) close to the base of the radiator and a few
extending out further (to 1/4 or 1/2 wavelength).

Ground conductivity plays a great part in buried radials, and what you
are trying to accomplish is to increase the ground conductivity in the
area at the base of the antenna.

If you were instead using elevated radials, they would have to be
resonant - think of the various "ground plane" antennas that have been
published - 1/4 wave radiator plus 2 or 4 1/4 wave radials.
Buried radials do not have to be resonant, elevated radials must be
resonant. The ground effects will alter the resonance of buried radials
while radials in the air are a part of the total antenna resonance.

73,
Don W3FPR

On 12/29/2016 11:49 AM, Richard Fjeld wrote:
> With reference to below, I have a question please. I put up a quarter
> wave inverted-L for 160 meters. My only counterpoise is the ground rods
> at the base of the tower. I wasn't expecting much, but it does so well
> I'd like to add a decent counterpoise.
>
> If I bury a quarter wave wire, would it be best to put it under the
> Ariel wire, or opposite from it?
> Thanks in advance,
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Message delivered to [hidden email]

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Jim Brown-10

Re: Small QRP antenna

In reply to this post by Fred Moore-2

Nothing in this post is true. Optimum length for a counterpoise is a
quarter wave. Radials are a form of counterpoise, and their optimum
length is also a quarter wave. More radials reduce ground losses.
Failing to provide an adequate counterpoise will cause the antenna's
return current to flow on your coax, which makes the rig hot with RF.
That's not much of a problem with 5W, but it can be a very big deal with
100W or more.

Of course, it does depend on what you mean by "much" and "minimal."
Inadequate counterpoise or radial systems can easily reduce you signal
by 6 dB. That's an S-unit, and it reduces your 5W signal to 1.25W. I
wouldn't call that minimal or "not much."

73, Jim K9YC

On Thu,12/29/2016 7:30 AM, Fred Moore wrote:
> With an end fed 1/4 wave you only need a counterpoise that is about .05
> wave length. it can be the coax or another counterpoise. Although a
> counterpoise has some effect on radiation pattern of a quarter wave
> radiator, it is minimal. You won't see much improvement in performance
> by going above .05 wave length.. it's not worth the trouble to increase
> the counterpoise length..

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Jim Brown-10

Re: Small QRP antenna

In reply to this post by Richard Fjeld-2

This slides for a talk I've done at Pacificon and for several ham clubs
will tell you everything you need to know about it!

http://audiosystemsgroup.com/160MPacificon.pdf

73, Jim K9YC

On Thu,12/29/2016 8:49 AM, Richard Fjeld wrote:
> With reference to below, I have a question please. I put up a quarter
> wave inverted-L for 160 meters. My only counterpoise is the ground rods
> at the base of the tower. I wasn't expecting much, but it does so well
> I'd like to add a decent counterpoise.

______________________________________________________________
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Post: mailto:[hidden email]

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Richard Fjeld-2

Re: Small QRP antenna

In reply to this post by Don Wilhelm

Thanks Charlie and Don, that helps. This is the first time I have gone
with an antenna that needs radials/ground poise.

Dick, n0ce

On 12/29/2016 11:05 AM, Don Wilhelm wrote:

> Dick,
>
> With buried radials, they do not have to be 1/4 wave long, and a
> single one will probably not make much difference over your ground rod.
> What you want to accomplish is a "ground screen", which means many
> short (about 1/8 wavelength) close to the base of the radiator and a
> few extending out further (to 1/4 or 1/2 wavelength).
>
> Ground conductivity plays a great part in buried radials, and what you
> are trying to accomplish is to increase the ground conductivity in the
> area at the base of the antenna.
>
> If you were instead using elevated radials, they would have to be
> resonant - think of the various "ground plane" antennas that have been
> published - 1/4 wave radiator plus 2 or 4 1/4 wave radials.
> Buried radials do not have to be resonant, elevated radials must be
> resonant. The ground effects will alter the resonance of buried
> radials while radials in the air are a part of the total antenna
> resonance.
>
> 73,
> Don W3FPR