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Don Sanders

Re: Less Than Perfect Antennas [was Flumoxed]

As Don has said, a good dipole as high as possible, even in an attic, fed
with balanced line will out perform most other compromise multiband
antennas.
While being retired in Ecuador I had the advantage to try several antennas.
The best over all was a fan dipole for 40, 30, 20,and 17 fed with RG6 up 80
feet AGL mounted on 30 foot bamboo poles at the top of a hill. Next was an
88 foot inverted L fed with 300 ohm line, then two RG6 coaxes, then
homemade open line. The horizontal sloped from the 33 foot peak to a 20
foot pvc mast. I noted no real difference with either feed line.

I also mounted the 88 footer with 66 feet in a slight vee from 33 feet peak
to 20 foot supports for the ends and 11 feet vertical at each end. This
also worked well all bands about as well as the inv L. I easily worked
Europe Asia, South Africa, eastern and asiatic Russia with QRP or 80 watts.
This was a test to see if an 80 meter ant could be installed in a limited
space as many homes in Ecuador have lots that are small.
While any antenna is better than no antenna, effort should be made to have
the best antenna possible. Wire antennas are simple, economical and easy
for most hams to iinstall.
Dr. Don W4BWS
EX-HC4/W4BWS

On Thu, Dec 6, 2018 at 9:58 AM Don Wilhelm <[hidden email]> wrote:

> That statement is true - however ---
> The problem is not radiation from the conductor, but how to get the RF
> current into the conductor and not in other unintended places.
>
> For those who want to build their own antennas, I suggest starting with
> a resonant dipole fed in the center. That provides a good match for 50
> ohm coax, and a good current mode choke (balun) at the feedpoint keeps
> RF from flowing back onto the outer shield of the coax which can create
> a lot of RF in the Shack.
>
> Off Center Fed, and End Fed antennas can be made to work with more care.
> The feedpoint impedance does not match coax, and special care must be
> used to keep the RF on the radiator rather than coming back into the shack.
> I realize that OCF and End-Fed non-resonant antennas are popular because
> they can be used on multiple bands, but there are problems feeding them
> while keeping the RF on the radiator and not in unintended places such
> as the shack.
>
> For those who want multiband operation, I still suggest a center fed
> radiator fed with open wire or ladder-line to a good current mode choke
> balun at transition point to coax is a better choice than OCF or end-fed
> antennas - keep the coax short and use a tuner that can match the
> resulting impedance.
> Make the length of the dipole approximately the length of a half-wave at
> the lowest operating frequency desired. It will be more "tame" for RF
> in the Shack than many OCF or End-fed antennas.
>
> 73,
> Don W3FPR
>
>
> On 12/6/2018 8:56 AM, ANDY DURBIN wrote:
> > "RF current into a conductor will radiate, even if it's at eye level."
> >
> ______________________________________________________________
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>

k6dgw

Re: Less Than Perfect Antennas [was Flumoxed]

The center-fed dipole fed with open wire balanced line may be the second
oldest antenna design, the first being the Marconi-T. Its only real
disadvantage is that today's solid state transceivers are all 50 ohm,
coax oriented and some form of balanced to unbalanced and possibly
impedance conversion is necessary. Solid state gear is also very
unforgiving of mis-matches, unlike an 807 PA with a link coupled tank
circuit. [Note how deftly I avoided using the dreaded word, "balun".
[:-)] Fan dipoles, where one coax transmission line feeds multiple
dipoles on different bands work very well ... if you can get them cut
correctly. There is a lot of interaction between them since all the
dipoles are directly fed.

The lesser known Coupled Resonator antenna is much more forgiving in the
tuning department. It consists of a center-fed dipole for the lowest
frequency normally fed with coax through an unbalanced-to-balanced
network. Close to it [like 1 - 1.5 inches max] are conductors cut for
each of the desired higher frequencies, but which are *not* connected to
the feed point. Trim the lowest frequency to desired resonance first,
then move up to the next in sequence. There is little if any
interaction with the previously trimmed conductors.

A convenient construction method is to use open wire or "window line"
for the conductors with the lowest frequency one also suspending the
assembly. Trim the other one for the next higher frequency. For 3
bands, bond another length to the longest conductor and trim the other
side for the the 3rd band.

I once saw a 5-band C-R with 5 conductors strung through the holes in
the crossed spreaders normally used to create "cage" antenna elements.
The fed conductor was larger wire through the center hole and used for
suspension, with the other four bands at the ends of the spreaders. You
can also feed the C-R with balanced line terminating at a transformer to
get to unbalanced, 50 ohm coax to keep your TX happy.

73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 12/7/2018 8:39 AM, Don Sanders wrote:
> As Don has said, a good dipole as high as possible, even in an attic, fed
> with balanced line will out perform most other compromise multiband
> antennas.
> While being retired in Ecuador I had the advantage to try several antennas.
> The best over all was a fan dipole for 40, 30, 20,and 17 fed with RG6 up 80
> feet AGL mounted on 30 foot bamboo poles at the top of a hill.

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Dick Dickinson

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by k6dgw

Why is there so much promotion of dipole antennas over inverted vee type antennas?

Kindly,

Dick – KA5KKT

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John Simmons

Re: Less Than Perfect Antennas [was Flumoxed]

An inverted vee IS a dipole.

-John NI0K

Dick Dickinson wrote on 12/7/2018 2:55 PM:

> Why is there so much promotion of dipole antennas over inverted vee type antennas?
>
>
>
>
>
> Kindly,
>
> Dick – KA5KKT
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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N4ZR

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by k6dgw

From forty till twenty or so years ago, I lived in a suburban
townhouse, with no antennas allowed. My solution then was a 40-meter
inverted vee with fanned 20 and 10-meter elements, and W9INN coils on
the end of the 40M elements to give me 80M. I was working on 5B DXCC in
those days, and eventually concluded the 80-meter side wasn't good
enough, so I threw a 280-foot vertical wire loop up in the trees out
back, fed through open wire line and a 4:1 balun. Finished the 80M part
in just a few months

When I moved here I had plenty of space, but not much time, so I threw
up a Carolina Windom antenna at only about 35 feet. Darned thing works
so well, despite a site that is in a river valley with higher terrain on
all sides, that I'm keeping it. Worked 92 countries during CQWW in about
6 hours on 40 meters, with ~900 watts

73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 12/5/2018 7:42 PM, Fred Jensen wrote:

> It seems these days that the "Amateur media," which includes all of us
> conversing on the air or via email lists, tends to dismiss LTPA [less
> than perfect antennas] which may be discouraging some Technicians from
> trying out their HF allocations on 10, 15, 40, and 80. Hard core
> DX'ers and contesters will scoff at a BWD-90 or my end-fed 80-10 at 6
> ft on the wooden fence, and I don't intend to make the Honor Roll with
> it, but antennas don't need to be perfect to work and even work well.
> I snagged VP6D on 40, 30, 20, and 17 CW with 100 W to my WOOF [Wire On
> Organic Fence] and it was easy. The SOTA folk don't buy a tower, they
> just hike up a mountain. I worked two DL's in a row on 15 CW a couple
> years ago from W5N/RO-015 in SE NM with 10 W from my K2 into an
> Alexloop over my head.
>
> If we want younger people to try out HF, we need to assure them that
> they don't have to spend a year's take-home pay to get on and have
> fun. Wayne has been relating some of his QRP-ish field adventures
> which is really great. Full Disclosure: I'm part of the W7RN crew and
> have remote access to the two remote K3/KPA1500 combos and 23 antenna
> selections [last count [:-) w7rn.com] including a 3-el 80 yagi at 175
> ft. Most of the time however, my K3/WOOF serves my needs which leaves
> the remotes to those on the crew who have no other option. RF current
> into a conductor will radiate, even if it's at eye level.
>
> 73,
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 12/5/2018 3:31 PM, Dave Cole (NK7Z) wrote:
>> I have one of the BWD-90 antennas up now, (at 25 feet), and use it
>> for local contacts on HF daily...
>>
>> DX is the vertical, soon to be a beam at 55 feet.... I also use the
>> BWD-90 for all the WARC bands, save 30, which is the vertical.
>>
>> I also have a new in the box BWD-90, (copper version, not the steel
>> version), as well...
>>
>> Works well with a K3, as the rig is atmospheric noise limited.
>>
>> 73s and thanks,
>> Dave (NK7Z/NNR0DC)
>> https://www.nk7z.net
>> ARRL Technical Specialist
>> ARRL Volunteer Examiner
>> ARRL OOC for Oregon
>
> ______________________________________________________________
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Dick Dickinson

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by k6dgw

Oh…I guess I tend to think of dipoles as being linear in configuration…such as horizontal dipole, etc.

Dick – KA5KKT

-------------------------------------------------------------------------------

An inverted vee IS a dipole.

-John NI0K

Dick Dickinson wrote on 12/7/2018 2:55 PM:

> Why is there so much promotion of dipole antennas over inverted vee type antennas?

>

>

>

>

>

> Kindly,

>

> Dick – KA5KKT

>

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k6dgw

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Dick Dickinson

A dipole is *anything* with two ends [poles]. A water molecule is a
dipole, as is a bar magnet, Inverted V, and Extended Double Zepp to
name a few.

73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 12/7/2018 12:55 PM, Dick Dickinson wrote:

> Why is there so much promotion of dipole antennas over inverted vee type antennas?
>
>
>
>
>
> Kindly,
>
> Dick – KA5KKT
>

K9MA

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Dick Dickinson

A flat dipole will have slightly more gain than an inverted V at the same height. The inverted V will also have to be a bit longer.

73,
Scott K9MA

----------

Scott Ellington. K9MA

--- via iPhone

> On Dec 7, 2018, at 2:24 PM, Dick Dickinson <[hidden email]> wrote:
>
> Oh…I guess I tend to think of dipoles as being linear in configuration…such as horizontal dipole, etc.
>
>
>
>
>
> Dick – KA5KKT
>
>
>
> -------------------------------------------------------------------------------
>
>
>
> An inverted vee IS a dipole.
>
>
>
> -John NI0K
>
>
>
> Dick Dickinson wrote on 12/7/2018 2:55 PM:
>
>> Why is there so much promotion of dipole antennas over inverted vee type antennas?
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> Kindly,
>
>>
>
>> Dick – KA5KKT
>
>>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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Bob McGraw - K4TAX

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Dick Dickinson

There is really little to no difference other than the manner to which
one is supported. Otherwise, it is relatively easy to steer the quasi
pattern of an Inverted V just by moving the ends around. The dipole,
well a bit more of a challenge to steer. Plus a dipole is the isotropic
standard to which most others are compared.

So the question ........ does A = B? If true, then B = A.

73

Bob, K4TAX

On 12/7/2018 2:55 PM, Dick Dickinson wrote:

Charlie T, K3ICH

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by K9MA

AND, A VEE will have a slightly more omni-directional pattern.
(That's where the gain of the horizontal dipole went !)

73, Charlie k3ICH

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of K9MA
Sent: Friday, December 07, 2018 4:44 PM
To: Dick Dickinson <[hidden email]>
Cc: [hidden email]
Subject: Re: [Elecraft] Less Than Perfect Antennas [was Flumoxed]

A flat dipole will have slightly more gain than an inverted V at the same height. The inverted V will also have to be a bit longer.

73,
Scott K9MA

----------

Scott Ellington. K9MA

--- via iPhone

> On Dec 7, 2018, at 2:24 PM, Dick Dickinson <[hidden email]> wrote:
>
> Oh…I guess I tend to think of dipoles as being linear in configuration…such as horizontal dipole, etc.
>
>
>
>
>
> Dick – KA5KKT
>
>
>
> ----------------------------------------------------------------------
> ---------
>
>
>
> An inverted vee IS a dipole.
>
>
>
> -John NI0K
>
>
>
> Dick Dickinson wrote on 12/7/2018 2:55 PM:
>
>> Why is there so much promotion of dipole antennas over inverted vee type antennas?
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> Kindly,
>
>>
>
>> Dick – KA5KKT
>
>>
>
>
>
> ______________________________________________________________
> 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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Jim Brown-10

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Dick Dickinson

On 12/7/2018 12:55 PM, Dick Dickinson wrote:
> Why is there so much promotion of dipole antennas over inverted vee type antennas?

As has been noted, an inverted vee is a compromise dipole -- the sort of
thing you can rig with a single support. A flat dipole with its center
at the same height as the inv vee will have a dB or two more gain, and
the directional pattern will be the classic "figure-eight" pattern with
broad peaks broadside to the wire and nulls off the ends. Inverted vees
tend to lose the nulls off their ends. All this stuff is in the ARRL
Handbook and Antenna Book which every ham should own and study as we
have time.

For rigging heights that are possible for most hams, horizontal antennas
for 160 or 80, and 40M over flat terrain produce more gain at greater
height. It is a fallacy that an antenna must be low to work short
distances. Low antennas radiate LESS signal at high angles than high
ones. I published a study of this several years ago. It's here.
http://k9yc.com/AntennaPlanning.pdf beginning on page 10. Field
strength at 70 degrees vertical elevation just starts to fall off as it
is raised to 1/3 wavelength. That's 45 ft on 40M, 90 ft on 80M, 180 ft
on 160M.

73, Jim K9YC

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Bob McGraw - K4TAX

Re: Less Than Perfect Antennas [was Flumoxed]

While I agree with Jim's information, I would point out the flat dipole
will have 3 dB more signal off of its broadside 0/180° as compared to
that of a inverted V dipole off of its broadside. At the same time, the
inverted V dipole will have about 4.5 db more signal off of its ends
90/270° as compared to that of a flat dipole off of its ends.

It appears what one loses with one antenna is made up with the other
antenna depending on azimuth and apex angle of the inverted V being
somewhat greater than 90°. In fact it appears that the Inverted V has
almost an omnidirectional pattern at an elevation angle of 25°. Fig 9.6

If a close match to 50 ohms is required, it is best to adjust the angle
for lowest SWR while maintaining resonance by adjustment of the length.

Reference: ARRL Antenna Book, 22nd Edition, 9.1.3 Inverted-V Dipole

73

Bob, K4TAX

On 12/7/2018 6:51 PM, Jim Brown wrote:

> On 12/7/2018 12:55 PM, Dick Dickinson wrote:
>> Why is there so much promotion of dipole antennas over inverted vee
>> type antennas?
>
> As has been noted, an inverted vee is a compromise dipole -- the sort
> of thing you can rig with a single support. A flat dipole with its
> center at the same height as the inv vee will have a dB or two more
> gain, and the directional pattern will be the classic "figure-eight"
> pattern with broad peaks broadside to the wire and nulls off the ends.
> Inverted vees tend to lose the nulls off their ends. All this stuff is
> in the ARRL Handbook and Antenna Book which every ham should own and
> study as we have time.
>
> For rigging heights that are possible for most hams, horizontal
> antennas for 160 or 80, and 40M over flat terrain produce more gain at
> greater height. It is a fallacy that an antenna must be low to work
> short distances. Low antennas radiate LESS signal at high angles than
> high ones. I published a study of this several years ago. It's here.
> http://k9yc.com/AntennaPlanning.pdf beginning on page 10. Field
> strength at 70 degrees vertical elevation just starts to fall off as
> it is raised to 1/3 wavelength. That's 45 ft on 40M, 90 ft on 80M, 180
> ft on 160M.
>
> 73, Jim K9YC
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> 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]

Charlie T, K3ICH

Re: Less Than Perfect Antennas [was Flumoxed]

I thought I said that.......
Oh wait I DID say that !

AND, A VEE will have a slightly more omni-directional pattern.
(That's where the gain of the horizontal dipole went !)

73, Charlie k3ICH

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Bob McGraw K4TAX
Sent: Friday, December 07, 2018 9:18 PM
To: [hidden email]
Subject: Re: [Elecraft] Less Than Perfect Antennas [was Flumoxed]

While I agree with Jim's information, I would point out the flat dipole will have 3 dB more signal off of its broadside 0/180° as compared to that of a inverted V dipole off of its broadside. At the same time, the inverted V dipole will have about 4.5 db more signal off of its ends 90/270° as compared to that of a flat dipole off of its ends.

It appears what one loses with one antenna is made up with the other antenna depending on azimuth and apex angle of the inverted V being somewhat greater than 90°. In fact it appears that the Inverted V has almost an omnidirectional pattern at an elevation angle of 25°. Fig 9.6

If a close match to 50 ohms is required, it is best to adjust the angle for lowest SWR while maintaining resonance by adjustment of the length.

Reference: ARRL Antenna Book, 22nd Edition, 9.1.3 Inverted-V Dipole

73

Bob, K4TAX

On 12/7/2018 6:51 PM, Jim Brown wrote:

> On 12/7/2018 12:55 PM, Dick Dickinson wrote:
>> Why is there so much promotion of dipole antennas over inverted vee
>> type antennas?
>
> As has been noted, an inverted vee is a compromise dipole -- the sort
> of thing you can rig with a single support. A flat dipole with its
> center at the same height as the inv vee will have a dB or two more
> gain, and the directional pattern will be the classic "figure-eight"
> pattern with broad peaks broadside to the wire and nulls off the ends.
> Inverted vees tend to lose the nulls off their ends. All this stuff is
> in the ARRL Handbook and Antenna Book which every ham should own and
> study as we have time.
>
> For rigging heights that are possible for most hams, horizontal
> antennas for 160 or 80, and 40M over flat terrain produce more gain at
> greater height. It is a fallacy that an antenna must be low to work
> short distances. Low antennas radiate LESS signal at high angles than
> high ones. I published a study of this several years ago. It's here.
> http://k9yc.com/AntennaPlanning.pdf beginning on page 10. Field
> strength at 70 degrees vertical elevation just starts to fall off as
> it is raised to 1/3 wavelength. That's 45 ft on 40M, 90 ft on 80M, 180
> ft on 160M.
>
> 73, Jim K9YC
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this email
> list: http://www.qsl.net/donate.html Message delivered to
> [hidden email]

RobertG

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Don Wilhelm

Ron...

Would such an antenna cut for 80m, fed with ladder-line, and used on
40m, be a better performer on either band than an 80-40m fan dipole fed
with 72ohm coax? Leaving all other extraneous but influencing parameters
aside. I have the second antenna; the weight of all that wire and the
coax with a ferrite balun results in a significant sag. I'm wondering if
the first antenna, lighter and higher in the air, would perform better?
Thanks.

...robert

On 12/6/2018 14:54, Don Wilhelm wrote:

> That statement is true - however ---
> The problem is not radiation from the conductor, but how to get the RF
> current into the conductor and not in other unintended places.
>
> For those who want to build their own antennas, I suggest starting with
> a resonant dipole fed in the center. That provides a good match for 50
> ohm coax, and a good current mode choke (balun) at the feedpoint keeps
> RF from flowing back onto the outer shield of the coax which can create
> a lot of RF in the Shack.
>
> Off Center Fed, and End Fed antennas can be made to work with more care.
> The feedpoint impedance does not match coax, and special care must be
> used to keep the RF on the radiator rather than coming back into the shack.
> I realize that OCF and End-Fed non-resonant antennas are popular because
> they can be used on multiple bands, but there are problems feeding them
> while keeping the RF on the radiator and not in unintended places such
> as the shack.
>
> For those who want multiband operation, I still suggest a center fed
> radiator fed with open wire or ladder-line to a good current mode choke
> balun at transition point to coax is a better choice than OCF or end-fed
> antennas - keep the coax short and use a tuner that can match the
> resulting impedance.
> Make the length of the dipole approximately the length of a half-wave at
> the lowest operating frequency desired. It will be more "tame" for RF
> in the Shack than many OCF or End-fed antennas.
>
> 73,
> Don W3FPR
>
>
> On 12/6/2018 8:56 AM, ANDY DURBIN wrote:
>> "RF current into a conductor will radiate, even if it's at eye level."
>>
> ______________________________________________________________
> Elecraft mailing list
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>

--
Robert G Strickland, PhD ABPH - KE2WY
[hidden email]
Syracuse, New York, USA
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Don Wilhelm

Re: Less Than Perfect Antennas [was Flumoxed]

Robert,

That depends on what you want to achieve. If it is more gain broadside
(perpendicular to the antenna) then the answer is yes. On 80 meters the
160 meter elements alone will be Two Halfwaves in Phase and will have 2
to 3 dB of gain broadside to the antenna.

Of course, that gain comes at a cost of radiation in other directions.
L.B. Cebik (SK) explained it best - if you visualize the radiation from
an isotropic antenna as a balloon, then squeeze that balloon so the
largest projection is in the direction(s) of the gain, you will see the
reduction of gain in other directions. In other words, there is no free
lunch. For the dipole, squeeze the balloon in the middle a bit, and for
2 half-waves in phase, squeeze it a bit harder.
If you want to achieve the maximum squeeze, change the length of each
half of the radiator to 5/8 wavelengths and you will have the greatest
broadside gain before the radiation pattern breaks into multiple lobes.

You can find that basic information in most any good antenna handbook.
It is the basis for all wire gain antennas.

For rotatable arrays or other directional switchable arrays, that
balloon effect is exactly what is desired, but for a fixed wire antenna,
that balloon effect may not be desirable if you want to work stations
that are off the ends of the antenna.

So the answer is -- it all depends. Do you want to orient your antenna
to favor certain locations, or do you want something more or less
omnidirectional. An Inverted Vee will be slightly more omnidirectional
than a horizontal dipole. A vertical is an omnidirectional antenna with
a circular pattern, but normally with a lower take-off angle than a
dipole at a modest height.

If you want to work nearby stations as well as those further away, use a
dipole - if you want to work DX (which usually comes in at low elevation
angles, use a vertical.

73,
Don W3FPR

On 12/8/2018 10:03 PM, Robert G Strickland wrote:
> Ron...
>
> Would such an antenna cut for 80m, fed with ladder-line, and used on
> 40m, be a better performer on either band than an 80-40m fan dipole fed
> with 72ohm coax? Leaving all other extraneous but influencing parameters
> aside. I have the second antenna; the weight of all that wire and the
> coax with a ferrite balun results in a significant sag. I'm wondering if
> the first antenna, lighter and higher in the air, would perform better?
> Thanks.
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Bob McGraw - K4TAX

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by RobertG

The 80 / 40 M fan dipole fed with 300 ohm transmitting line {The Wireman
#562} and then use the balun at the point where the feed line enters the
house would be preferable.   That configuration reduces the weight of
the balun on the antenna.   From the balun to the station, use a good
quality low loss coax.   The shorter length the better.

I bring my balanced line all the way to the operating position where the
balun is located and only about 18" from the tuner. There is no issue
running the insulated balanced 300 ohm line through windows, walls,
ceilings, floors and such.    Just maintain about 10" or so from any
metal gutters, metal duct work, AC wiring, phone lines, water lines and
such.

The question often arises about RF in the shack when using balanced
line.   If the line is reasonably well balanced the current in each side
of the line is equal but 180° difference in phase. The result is the
field cancels and there is no radiation into the shack.    Thus using a
balanced feed system on a center fed antenna is the optimum configuration.

73

Bob, K4TAX

On 12/8/2018 9:03 PM, Robert G Strickland wrote:

> Ron...
>
> Would such an antenna cut for 80m, fed with ladder-line, and used on
> 40m, be a better performer on either band than an 80-40m fan dipole
> fed with 72ohm coax? Leaving all other extraneous but influencing
> parameters aside. I have the second antenna; the weight of all that
> wire and the coax with a ferrite balun results in a significant sag.
> I'm wondering if the first antenna, lighter and higher in the air,
> would perform better? Thanks.
>
> ...robert
>
> On 12/6/2018 14:54, Don Wilhelm wrote:
>> That statement is true - however ---
>> The problem is not radiation from the conductor, but how to get the RF
>> current into the conductor and not in other unintended places.
>>
>> For those who want to build their own antennas, I suggest starting with
>> a resonant dipole fed in the center. That provides a good match for 50
>> ohm coax, and a good current mode choke (balun) at the feedpoint keeps
>> RF from flowing back onto the outer shield of the coax which can create
>> a lot of RF in the Shack.
>>
>> Off Center Fed, and End Fed antennas can be made to work with more care.
>> The feedpoint impedance does not match coax, and special care must be
>> used to keep the RF on the radiator rather than coming back into the
>> shack.
>> I realize that OCF and End-Fed non-resonant antennas are popular because
>> they can be used on multiple bands, but there are problems feeding them
>> while keeping the RF on the radiator and not in unintended places such
>> as the shack.
>>
>> For those who want multiband operation, I still suggest a center fed
>> radiator fed with open wire or ladder-line to a good current mode choke
>> balun at transition point to coax is a better choice than OCF or end-fed
>> antennas - keep the coax short and use a tuner that can match the
>> resulting impedance.
>> Make the length of the dipole approximately the length of a half-wave at
>> the lowest operating frequency desired. It will be more "tame" for RF
>> in the Shack than many OCF or End-fed antennas.
>>
>> 73,
>> Don W3FPR
>>
>>
>> On 12/6/2018 8:56 AM, ANDY DURBIN wrote:
>>> "RF current into a conductor will radiate, even if it's at eye level."
>>>
>> ______________________________________________________________
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>>
>

Jim Brown-10

Re: Less Than Perfect Antennas [was Flumoxed]

Several reasons why this is a bad idea. First, resonant dipoles are a
much closer match to 50 or 75 ohm coax than to 300 ohm line. Low dipoles
are closer to 50 ohms, higher ones closer to 75 ohms.

Second, the MOST important place for a choke is at the feedpoint. The
feedline is part of the antenna until it hits the first choke! If, for
example, the feedline is 60 ft long and the only choke is at the shack,
that 60 ft of feedline is picking up noise and can be de-tuning your
antenna. Additional chokes along the line can prevent the feedline from
interacting with nearby vertical antennas, and can further reduce
feedline noise.

Third, N6BV wrote an excellent piece for QST several years ago observing
that it's VERY easy to fry a common mode choke on a line with high
SWR. This happens when the choke is at a high current point on the
transmission line, overheating the line and the ferrite core.

I will soon publish a new Choke Cookbook for chokes wound on a single
#31 2.4-in o.d. core with RG400, a #12 teflon pair, and a #12 THHN pair.
I am no longer recommending chokes wound with RG8/11/213 size coax, for
reasons that will be detailed in the applications note that comes with
the "cookbook." I've been beta testing THHN and enameled pair chokes for
years; recent work shows that that RG400 and teflon #12 are the better
choice.

An 80/40 fan dipole will perform as well as separate 80 and 40 dipoles
at the same height -- the only compromise is that SWR bandwidth is
reduced by about half on 40M, but a fan dipole cut for the center of the
band is still below 2:1 at the band edges.

As to sag -- height IS a good thing. Modeling shows that horizontal
antennas, it takes a change of 5 ft on 40M for between 30 and 70 ft, and
10 ft on 80M for antennas twice that height to make a difference of 0.9
dB. That work is presented in this peer-reviewed paper.
http://k9yc.com/AntennaPlanning.pdf The discussion of rigging height
begins around page 10.

Yesterday in this thread someone questioned my statement that the
difference in field strength between a horizontal dipole and an inverted
Vee with it's apex at the same mounting height was in the range of 1-2
dB. For another project, I just modeled an inverted Vee for 80M with
it's apex at 46 ft and ends at 17 ft. The difference was about 1.5 dB as
compared to a horizontal antenna at 46 ft. Bringing the ends further
down will, of course, increase that difference. I didn't model it, but
3dB seems a reasonable number. But remember, with antennas, higher is
usually better. :) When we use Inv Vees for portable setups, we always
try to rig the ropes for the ends of the antenna as far away and as high
as possible.

73, Jim K9YC

On 12/8/2018 8:00 PM, Bob McGraw K4TAX wrote:
> The 80 / 40 M fan dipole fed with 300 ohm transmitting line {The
> Wireman #562} and then use the balun at the point where the feed line
> enters the house would be preferable.

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Bob McGraw - K4TAX

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Don Wilhelm

Balun Designs, both 1:1 and 4:1 for use with tuners. I have both because I also have a folded dipole that I feed direct.

I suggest you give the folks at Balun Designs a call and discuss your exact needs. Take their advice.
Also see the DJ0IP site for details on baluns. Just Google DJ0IP.

And I use the 8232 common mode choke from The Wireman.

73
Bob, K4TAX

Sent from my iPhone

> On Dec 8, 2018, at 9:35 PM, Don Wilhelm <[hidden email]> wrote:
>
> Robert,
>
> That depends on what you want to achieve. If it is more gain broadside (perpendicular to the antenna) then the answer is yes. On 80 meters the 160 meter elements alone will be Two Halfwaves in Phase and will have 2 to 3 dB of gain broadside to the antenna.
>
> Of course, that gain comes at a cost of radiation in other directions. L.B. Cebik (SK) explained it best - if you visualize the radiation from an isotropic antenna as a balloon, then squeeze that balloon so the largest projection is in the direction(s) of the gain, you will see the reduction of gain in other directions. In other words, there is no free lunch. For the dipole, squeeze the balloon in the middle a bit, and for 2 half-waves in phase, squeeze it a bit harder.
> If you want to achieve the maximum squeeze, change the length of each half of the radiator to 5/8 wavelengths and you will have the greatest broadside gain before the radiation pattern breaks into multiple lobes.
>
> You can find that basic information in most any good antenna handbook. It is the basis for all wire gain antennas.
>
> For rotatable arrays or other directional switchable arrays, that balloon effect is exactly what is desired, but for a fixed wire antenna, that balloon effect may not be desirable if you want to work stations that are off the ends of the antenna.
>
> So the answer is -- it all depends. Do you want to orient your antenna to favor certain locations, or do you want something more or less omnidirectional. An Inverted Vee will be slightly more omnidirectional than a horizontal dipole. A vertical is an omnidirectional antenna with a circular pattern, but normally with a lower take-off angle than a dipole at a modest height.
>
> If you want to work nearby stations as well as those further away, use a dipole - if you want to work DX (which usually comes in at low elevation angles, use a vertical.
>
> 73,
> Don W3FPR
>
>> On 12/8/2018 10:03 PM, Robert G Strickland wrote:
>> Ron...
>> Would such an antenna cut for 80m, fed with ladder-line, and used on 40m, be a better performer on either band than an 80-40m fan dipole fed with 72ohm coax? Leaving all other extraneous but influencing parameters aside. I have the second antenna; the weight of all that wire and the coax with a ferrite balun results in a significant sag. I'm wondering if the first antenna, lighter and higher in the air, would perform better? Thanks.
> ______________________________________________________________
> 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]
>

Dave Hachadorian-2

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Jim Brown-10

>I will soon publish a new Choke Cookbook for chokes wound on a
>single #31 2.4-in o.d. core with RG400, a #12 teflon pair, and a
>#12 THHN pair. I am no longer recommending chokes wound with
>RG8/11/213 size coax

Dang, I'm going to have a TON of spare 2.4" cores left over from
my old-style chokes!

Dave Hachadorian, K6LL
Yuma, AZ

.

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Jim Brown-10

Re: Less Than Perfect Antennas [was Flumoxed]

In reply to this post by Bob McGraw - K4TAX

I wonder if anyone using or recommending products like this have ever
measured them. They are not easy to measure. You can't measure them
accurately with a single-port antenna analyzer.

N6KT, a member of our contest club is building a station in the
Caribbean and asked me to measure a Balun Designs 1115T common mode
choke (often called a 1:1 current balun). It looks NOTHING like it's
data sheet, which shows an approximately flat high choking impedance
over the HF bands. It would be USELESS on 40, 80, and 160M! From what
I've seen them write about chokes, I don't believe that they understand
how common mode chokes work, and I certainly wouldn't suggest that
someone ask them for advice.

The Wireman 8232 is based on W2DU's excellent work from many years ago.
He built chokes with 50, 100, and 200 of the largest #73 Fair-Rite beads
that fit over RG142. This size bead of this material has the unique
property of relatively constant choking impedance in the HF spectrum,
but you have to a LOT of them. Only the 200-bead choke has sufficient
choking impedance to handle high power and kill receive noise, and
that's what he recommended, yet most products sold as a "W2DU balun"
have many fewer. The larger #31 cores are not useful at HF until you
wind multiple turns through them, but are often sold for use as a string
of beads on coax.

How many beads are in the 8232? Are they Fair-Rite #73?

73, Jim K9YC

On 12/9/2018 5:33 AM, Bob McGraw K4TAX wrote:
> Balun Designs, both 1:1 and 4:1 for use with tuners. I have both because I also have a folded dipole that I feed direct.
>
> I suggest you give the folks at Balun Designs a call and discuss your exact needs. Take their advice.
> Also see the DJ0IP site for details on baluns. Just Google DJ0IP.
>
> And I use the 8232 common mode choke from The Wireman.

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