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Elecraft CW Net Announcement

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kevinr@coho.net

Elecraft CW Net Announcement

Good Evening,

    Another cool week but there was more sun, the undergrowth is filling
in the scars from the timber thinning operation. The deer and elk
trails are becoming more regular and easier to follow. Previously they
trended east to west but now there are a few north south paths. The
huckleberries are not ripe yet though the blackberries are starting.
The wild strawberry season is almost done.

    A real sunspot has popped up and lasted for more than a day. It is
from cycle 25 and should be visible projected through a telescope or
binoculars. It's a start.

    An antenna design is stuck in my head. It consists of three legs,
each 1/4 wavelength long. One leg is vertical while the two radials are
120 degrees below it. The two radials are connected electrically while
the vertical leg is fed separately. If it had more radials it would be
called a 1/4 wave vertical. But the one stuck in my head has elevated
radials and only two of them. I cannot remember what this antenna is
called. I know 'inverted Y antenna' doesn't work as a search term.
Does anyone know what this is usually called so I can use a better
search string? The low take off angle would be nice. It looks like a
20 or 40 meter version would be easy to build and raise.

Please join us on (or near):

14050 kHz at 2200z Sunday (3 PM PDT Sunday)
   7047 kHz at 0000z Monday (5 PM PDT Sunday)

    73,
       Kevin. KD5ONS

_

Antelope Freeway 1/128 mile

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k6dgw

Re: Elecraft CW Net Announcement

Ground Plane?

73,

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

On 7/25/2020 8:20 PM, kevinr wrote:

>
>
> An antenna design is stuck in my head. It consists of three legs,
> each 1/4 wavelength long. One leg is vertical while the two radials
> are 120 degrees below it. The two radials are connected electrically
> while the vertical leg is fed separately. If it had more radials it
> would be called a 1/4 wave vertical. But the one stuck in my head has
> elevated radials and only two of them. I cannot remember what this
> antenna is called. I know 'inverted Y antenna' doesn't work as a
> search term. Does anyone know what this is usually called so I can
> use a better search string? The low take off angle would be nice. It
> looks like a 20 or 40 meter version would be easy to build and raise.

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Don Wilhelm

Re: Elecraft CW Net Announcement

Fred,

That would be correct if they are oriented at 180 degrees from each
other so as to cancel the horizontal radiation. Elevated radials must
be tuned to be effective, but only 2 are needed. How much tuning will
depend on the height above ground.

73,
Don W3FPR

On 7/26/2020 2:36 PM, Fred Jensen wrote:

> Ground Plane?
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 7/25/2020 8:20 PM, kevinr wrote:
>>
>>
>> An antenna design is stuck in my head. It consists of three legs,
>> each 1/4 wavelength long. One leg is vertical while the two radials
>> are 120 degrees below it. The two radials are connected electrically
>> while the vertical leg is fed separately. If it had more radials it
>> would be called a 1/4 wave vertical. But the one stuck in my head has
>> elevated radials and only two of them. I cannot remember what this
>> antenna is called. I know 'inverted Y antenna' doesn't work as a
>> search term. Does anyone know what this is usually called so I can
>> use a better search string? The low take off angle would be nice. It
>> looks like a 20 or 40 meter version would be easy to build and raise.
>

Kidder, George

Re: Elecraft CW Net Announcement

In reply to this post by k6dgw

I use one just like this on 30M, and have always thought of it as a
ground plane. The drooping radials give a good match to 50 ohms.

73 - George, W3HBM

On 7/26/2020 2:36 PM, Fred Jensen wrote:

> [This message came from an external source. If suspicious, report to
> [hidden email]<mailto:[hidden email]>]
>
> Ground Plane?
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 7/25/2020 8:20 PM, kevinr wrote:
>>
>>
>> An antenna design is stuck in my head. It consists of three legs,
>> each 1/4 wavelength long. One leg is vertical while the two radials
>> are 120 degrees below it. The two radials are connected electrically
>> while the vertical leg is fed separately. If it had more radials it
>> would be called a 1/4 wave vertical. But the one stuck in my head has
>> elevated radials and only two of them. I cannot remember what this
>> antenna is called. I know 'inverted Y antenna' doesn't work as a
>> search term. Does anyone know what this is usually called so I can
>> use a better search string? The low take off angle would be nice. It
>> looks like a 20 or 40 meter version would be easy to build and raise.
>
> ______________________________________________________________
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Rick Bates, NK7I

Re: Elecraft CW Net Announcement

In reply to this post by Don Wilhelm

The reading I've done says only one radial is required; that the
'favoring' in the direction of the radial is not enough to be worried
about; that there is no cancellation from opposing (or just more)
radials. I have used a single radial ground plane and found this to be
true (at 6' over dirt on 80M). It favors a morning net 800 miles away,
yet worked DX in any other direction easily (then I moved to a rotating
dipole at 60' which beats it out). That ground plane easily beat out a
horizontal dipole I used before them all (fixed, in the 'wrong' angle
because of tree location).

Both the radiator and radial are tuned (equally), but the angle of
difference from dipole to the traditional 90 deg ground plane will cause
the resistance to vary (roughly 72 ohms as a dipole, dropping to ~50
ohms when at 90 degrees), So if another angle is chosen (inverted Y),
to match a 50 ohm feedline (to have a 1:1 SWR), the element lengths are
adjusted equally until that match is made; altering the resonance of the
wires (maximum transfer of energy). And inverted Y antenna would be
between that 50-72 ohm range, still acceptably low SWR to not mess with.

Which again, is not a significant variance, so put it up, try it out and
compare to other antennas. Wire is cheap enough to play with and try
things out.

Modeling will demonstrate the pattern and 'take off' angles quite
clearly; reality is often different because of local objects, ground
resistance, height...

Don't forget to add a common mode current choke at the feed.

73,
Rick NK7I

On 7/26/2020 11:57 AM, Don Wilhelm wrote:

> Fred,
>
> That would be correct if they are oriented at 180 degrees from each
> other so as to cancel the horizontal radiation. Elevated radials must
> be tuned to be effective, but only 2 are needed. How much tuning will
> depend on the height above ground.
>
> 73,
> Don W3FPR
>
> On 7/26/2020 2:36 PM, Fred Jensen wrote:
>> Ground Plane?
>>
>> 73,
>>
>> Fred ["Skip"] K6DGW
>> Sparks NV DM09dn
>> Washoe County
>>
>> On 7/25/2020 8:20 PM, kevinr wrote:
>>>
>>>
>>> An antenna design is stuck in my head. It consists of three
>>> legs, each 1/4 wavelength long. One leg is vertical while the two
>>> radials are 120 degrees below it. The two radials are connected
>>> electrically while the vertical leg is fed separately. If it had
>>> more radials it would be called a 1/4 wave vertical. But the one
>>> stuck in my head has elevated radials and only two of them. I
>>> cannot remember what this antenna is called. I know 'inverted Y
>>> antenna' doesn't work as a search term. Does anyone know what this
>>> is usually called so I can use a better search string? The low take
>>> off angle would be nice. It looks like a 20 or 40 meter version
>>> would be easy to build and raise.
>>
> ______________________________________________________________
> 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]

k6dgw

Re: Elecraft CW Net Announcement

It's a fairly simple antenna. Yes, one radial is all you really "need,"
a couple more help improve efficiency and increase the BW. In the olden
daze [50's], we'd use 3 or 4 and cut them just a little different. Also
increased the BW, especially on 10, and in the later 50's, 10 was open
28000 - 29700, 24/7. It's really a very forgiving antenna. The
radials, with rope extensions are often used as guys as well. The droop
angle will affect the main lobe elevation somewhat, but I'll bet I could
do a blind "taste" test with you and you'd never really know the
difference. That angle is more often used to adjust the impedance at
the feed point.

Make that angle 90 deg and you have a vertical half-wave dipole
center-fed out of phase. Make the elements 1/2 wave each, mechanically
easy on 10 and even 15, and cophase feed them in the center, and you
have a Franklin vertical [see KFBK, one of the last ones I know of].
Very versatile basic design, works great, lasts a long time.

73,

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

On 7/26/2020 3:38 PM, Rick NK7I wrote:

> The reading I've done says only one radial is required; that the
> 'favoring' in the direction of the radial is not enough to be worried
> about; that there is no cancellation from opposing (or just more)
> radials. I have used a single radial ground plane and found this to
> be true (at 6' over dirt on 80M). It favors a morning net 800 miles
> away, yet worked DX in any other direction easily (then I moved to a
> rotating dipole at 60' which beats it out). That ground plane easily
> beat out a horizontal dipole I used before them all (fixed, in the
> 'wrong' angle because of tree location).
>
> Both the radiator and radial are tuned (equally), but the angle of
> difference from dipole to the traditional 90 deg ground plane will
> cause the resistance to vary (roughly 72 ohms as a dipole, dropping to
> ~50 ohms when at 90 degrees), So if another angle is chosen (inverted
> Y), to match a 50 ohm feedline (to have a 1:1 SWR), the element
> lengths are adjusted equally until that match is made; altering the
> resonance of the wires (maximum transfer of energy). And inverted Y
> antenna would be between that 50-72 ohm range, still acceptably low
> SWR to not mess with.
>
> Which again, is not a significant variance, so put it up, try it out
> and compare to other antennas. Wire is cheap enough to play with and
> try things out.
>
> Modeling will demonstrate the pattern and 'take off' angles quite
> clearly; reality is often different because of local objects, ground
> resistance, height...
>
> Don't forget to add a common mode current choke at the feed.
>
> 73,
> Rick NK7I
>
>
>
> On 7/26/2020 11:57 AM, Don Wilhelm wrote:
>> Fred,
>>
>> That would be correct if they are oriented at 180 degrees from each
>> other so as to cancel the horizontal radiation. Elevated radials
>> must be tuned to be effective, but only 2 are needed. How much tuning
>> will depend on the height above ground.
>>
>> 73,
>> Don W3FPR
>>

Vic Rosenthal

Groundplane antennas (was: Re: Elecraft CW Net Announcement)

A symmetrical arrangement of radials (which implies more than one) will
reduce common mode current and high-angle radiation, which are usually
considered undesirable (although for local QSOs the high-angle radiation
can be useful).

If you have an unsymmetrical radial arrangement, it's best to put a
choke at the feedpoint to kill the common mode current. Almost in any
case there will be some imbalance caused by nearby objects, so a choke
is a good idea.

Two radials is slightly less efficient than three or four, but not that
much.

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/
.
On 27/07/2020 5:25, Fred Jensen wrote:

> It's a fairly simple antenna. Yes, one radial is all you really "need,"
> a couple more help improve efficiency and increase the BW. In the olden
> daze [50's], we'd use 3 or 4 and cut them just a little different. Also
> increased the BW, especially on 10, and in the later 50's, 10 was open
> 28000 - 29700, 24/7. It's really a very forgiving antenna. The
> radials, with rope extensions are often used as guys as well. The droop
> angle will affect the main lobe elevation somewhat, but I'll bet I could
> do a blind "taste" test with you and you'd never really know the
> difference. That angle is more often used to adjust the impedance at
> the feed point.
>
> Make that angle 90 deg and you have a vertical half-wave dipole
> center-fed out of phase. Make the elements 1/2 wave each, mechanically
> easy on 10 and even 15, and cophase feed them in the center, and you
> have a Franklin vertical [see KFBK, one of the last ones I know of].
> Very versatile basic design, works great, lasts a long time.
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 7/26/2020 3:38 PM, Rick NK7I wrote:
>> The reading I've done says only one radial is required; that the
>> 'favoring' in the direction of the radial is not enough to be worried
>> about; that there is no cancellation from opposing (or just more)
>> radials. I have used a single radial ground plane and found this to
>> be true (at 6' over dirt on 80M). It favors a morning net 800 miles
>> away, yet worked DX in any other direction easily (then I moved to a
>> rotating dipole at 60' which beats it out). That ground plane easily
>> beat out a horizontal dipole I used before them all (fixed, in the
>> 'wrong' angle because of tree location).
>>
>> Both the radiator and radial are tuned (equally), but the angle of
>> difference from dipole to the traditional 90 deg ground plane will
>> cause the resistance to vary (roughly 72 ohms as a dipole, dropping to
>> ~50 ohms when at 90 degrees), So if another angle is chosen (inverted
>> Y), to match a 50 ohm feedline (to have a 1:1 SWR), the element
>> lengths are adjusted equally until that match is made; altering the
>> resonance of the wires (maximum transfer of energy). And inverted Y
>> antenna would be between that 50-72 ohm range, still acceptably low
>> SWR to not mess with.
>>
>> Which again, is not a significant variance, so put it up, try it out
>> and compare to other antennas. Wire is cheap enough to play with and
>> try things out.
>>
>> Modeling will demonstrate the pattern and 'take off' angles quite
>> clearly; reality is often different because of local objects, ground
>> resistance, height...
>>
>> Don't forget to add a common mode current choke at the feed.
>>
>> 73,
>> Rick NK7I
>>
>>
>>
>> On 7/26/2020 11:57 AM, Don Wilhelm wrote:
>>> Fred,
>>>
>>> That would be correct if they are oriented at 180 degrees from each
>>> other so as to cancel the horizontal radiation. Elevated radials
>>> must be tuned to be effective, but only 2 are needed. How much tuning
>>> will depend on the height above ground.
>>>
>>> 73,
>>> Don W3FPR
>>>
>
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>
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Rick M0LEP-2

Re: Groundplane antennas (was: Re: Elecraft CW Net Announcement)

Fred K6DGW wrote:
> Yes, one radial is all you really "need,"

....and Victor 4X6GP wrote:
> Two radials is slightly less efficient than three or four,

With only one tuned radial you've pretty much got a dipole, just in a
slightly unconventional geometrical arrangement.

I've used three radials for SOTA-type activations, with the vertical
element supported by a fishing pole, but only on bands from 20 metres
up, and experience suggests the arrangement works best when set up in
the open. It certainly doesn't work as well when set up on a wooded
summit with lots of straight-trunked conifers all around...

--
73, Rick, M0LEP (KX3 #3281)

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Bill Frantz

Re: Groundplane antennas (was: Re: Elecraft CW Net Announcement)

On 7/30/20 at 3:43 AM, [hidden email] (Rick M0LEP) wrote:

>I've used three radials for SOTA-type activations, with the vertical
>element supported by a fishing pole, but only on bands from 20 metres
>up, and experience suggests the arrangement works best when set up in
>the open. It certainly doesn't work as well when set up on a wooded
>summit with lots of straight-trunked conifers all around...

Steve Stearns, K6OIK has a article in the latest QST about the
effect of trees on 160M vertical antennas. It reads like it is
the first in a series about the effect of trees on antenna performance.

It also mentions Jim, K9YC who has some direct experience,
living in a coast redwood forest.

73 Bill AE6JV

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Rick M0LEP-2

Re: Groundplane antennas (was: Re: Elecraft CW Net Announcement)

On Thu 30 Jul Bill Frantz wrote:
> Steve Stearns, K6OIK has a article in the latest QST about the
> effect of trees on 160M vertical antennas. It reads like it is
> the first in a series about the effect of trees on antenna performance.
>
> It also mentions Jim, K9YC who has some direct experience,
> living in a coast redwood forest.

I tried operating on a summit covered by a timber plantation; lots of
tall fairly straight trees fairly regularly spaced. A friend operating
at the same time from a short distance away near the edge of the
plantation, and using an 817 and a dipole, made rather more contacts
than I did...

--
73, Rick, M0LEP (KX3 #3281)

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