Topband: SAL antenna and proximity to ground
W3HKK at roadrunner.com
W3HKK at roadrunner.com
Fri Jan 7 13:40:55 EST 2022
Interesting commends by N4IV re: proximity of SAL to ground.
Over the years Ive read several emails/comments on here by uses and
the Array Solutions people regarding height above ground for the
SAL30.
These refer to elevating the SAL to prevent animals from damaging the
horizontal lower wire....deer etc. So while the antenna can be mounted
just 4 ft above ground level, many/most users raise it to 8 ft by
adding another 1.5" mil surplus mast section to the base.
The question was once posed to Array Solutions if 8 ft has any effect
on the antennas performance. As I recall, the answer was NO. So a
doubling of the antenna height ( from 4 to 8 ft) has no observable
difference in antenna performance. Id be curious what the most
reliable antenna evaluation software shows.
Bob, W3HKK
PS my SAL30 mast is mounted 4 ft above ground on land that slopes in
such a way that the lower exterior tips are: NE=3', SW=2', NW=3', SE=
1' above ground level.. While it performs quite well as is, Im curious
what others have observed with their SAL's above ground by varying
heights. rather than the ideal 4 ft all around?
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Today's Topics:
1. Radials on ground (Pete Smith N4ZR)
2. Re: Radials on ground (Bob Garrett)
3. Re: Radials on ground (Artek Manuals)
4. Re: K9AY Loop Questions (n4is at comcast.net)
5. Re: K9AY Loop Questions (n4is at comcast.net)
----------------------------------------------------------------------
Message: 1
Date: Fri, 7 Jan 2022 09:14:03 -0500
From: Pete Smith N4ZR
To: topband reflector
Subject: Topband: Radials on ground
Message-ID:
Content-Type: text/plain; charset=UTF-8; format=flowed
For the moment at least, I'm using on-the-ground radials for my 160M
inverted L. Discussion on the reflector triggered a thought - is the
size of wire used for on-the-ground radials - or elevated radials for
that matter - significant?? I ask this because I have a huge spool of
military-surplus, silver-plated (!) 18-gauge insulated copper wire.?
Currently using 16, +/- 1/8 wave on-the-ground radials made with the
stuff.?? Feedpoint resistance seems to be by the book, at least as
compared to feeding the antenna against a single ground rod.
--
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at.
For spots, please use your favorite
"retail" DX cluster.
------------------------------
Message: 2
Date: Fri, 7 Jan 2022 09:17:00 -0500
From: Bob Garrett
To: Pete Smith N4ZR
Cc: topband reflector
Subject: Re: Topband: Radials on ground
Message-ID:
Content-Type: text/plain; charset=utf-8
The size of the wire doesn?t matter one bit. Use what you have and
enjoy. Just remember, the more radios the better and if you only have
a choice of several long radios over multiple short ones go with the
short ones
Sent from my iPhone
> On Jan 7, 2022, at 9:14 AM, Pete Smith N4ZR wrote:
>
> ?For the moment at least, I'm using on-the-ground radials for my
160M inverted L. Discussion on the reflector triggered a thought - is
the size of wire used for on-the-ground radials - or elevated radials
for that matter - significant? I ask this because I have a huge spool
of military-surplus, silver-plated (!) 18-gauge insulated copper wire.
Currently using 16, +/- 1/8 wave on-the-ground radials made with the
stuff. Feedpoint resistance seems to be by the book, at least as
compared to feeding the antenna against a single ground rod.
>
> --
> 73, Pete N4ZR
> Check out the new Reverse Beacon Network
> web server at.
> For spots, please use your favorite
> "retail" DX cluster.
> _________________
> Searchable Archives: http://www.contesting.com/_topband [3] -
Topband Reflector
------------------------------
Message: 3
Date: Fri, 7 Jan 2022 09:47:13 -0500
From: Artek Manuals
To: topband at contesting.com
Subject: Re: Topband: Radials on ground
Message-ID:
Content-Type: text/plain; charset=UTF-8; format=flowed
Pete
I? was just? having this very discussion with some one else this
week.
We modeled a 100 ' tall T on 160 M with sixty-four 100' long radials
using NEC-4. with that many radials there was essentially no
discernible
difference between #22 wire radials and #14 radials on average earth
ground. If you want I'll run the analysis using NEC4 again against
your
smaller radial field later today. Give me the size of the vertical
radiator(L, T or straight Vertical)
Dave
NR1DX
On 1/7/2022 9:14 AM, Pete Smith N4ZR wrote:
> For the moment at least, I'm using on-the-ground radials for my
160M
> inverted L. Discussion on the reflector triggered a thought - is
the
> size of wire used for on-the-ground radials - or elevated radials
for
> that matter - significant?? I ask this because I have a huge spool
of
> military-surplus, silver-plated (!) 18-gauge insulated copper
wire.?
> Currently using 16, +/- 1/8 wave on-the-ground radials made with
the
> stuff.?? Feedpoint resistance seems to be by the book, at least as
> compared to feeding the antenna against a single ground rod.
>
--
Dave Manuals at ArtekManuals.com www.ArtekManuals.com
--
This email has been checked for viruses by Avast antivirus software.
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------------------------------
Message: 4
Date: Fri, 7 Jan 2022 10:07:16 -0500
From:
To: "'Andrew Ikin'" , "'Don Kirk'"
, "'W0MU Mike Fatchett'"
Cc: "'topband'"
Subject: Re: Topband: K9AY Loop Questions
Message-ID:
Content-Type: text/plain; charset="utf-8"
Hi Andrew
He concept is very simple, you can phase 2 verticals. 3 verticals or
4 vertical. See you got, two verticals in phase give you a cardioid
pattern, only one deep null on the back. Moving to 3 or 4 verticals
gives you two deep side nulls plus some front back.
The SAL does not have side lobe nulls. The feed system does no change
the fact that you have only two vertical wires as antenna, the
inclined wire can be describe as two vectors one vertical and another
horizontal. The two vertical vector and the center of the inclined
wire define the pattern.
See the case of a DHDL, invented by George AA7JV, the vertical wires
are far apart and the two inclined wires vertical vectors are half way
each other. The DHDL has 4 verticals as the Waller Flag with two
independent loops making 4 verticals as well, but the gain of the DHDL
is 1-2 db below the WF. Why? the reflection between the two loops and
the proximity of the two vertical vectors impact the DHDL pattern, as
well the two verticals wires on the SAL.
The SAL and the DHDL does not have side lobe nulls.
One Loaded loop or EWE, K9AY RDF is close to 9 db, the SAL and DHDL
are slighted better RDF 10 db on EZENEC, but again on practice,
measuring the diagram of irradiation the SAL never achieved the extra
1 db in RDF. Two loaded loops has side lobe nulls and RDF is close to
12 db, very similar to 3 element yagi azimuth diagram. Both antennas,
the SAL and the K9AY have impressive deep null on the back, giving you
a good front back. It is a null on the back , very different than
front rear, that take the 180 degree energy between the front and the
back.
You can find several stations using two DHDL in phase and it does
work, but you wont find any array of two SAL because the phase is so
critical that became impractical.
73's
JC
N4IS
73
Andrew Ikin
G8LUG
_________________
Searchable Archives: http://www.contesting.com/_topband [4] - Topband
Reflector
------------------------------
Message: 5
Date: Fri, 7 Jan 2022 10:27:16 -0500
From:
To: "'Don Kirk'"
Cc: "'W0MU Mike Fatchett'" , "'topband'"
Subject: Re: Topband: K9AY Loop Questions
Message-ID:
Content-Type: text/plain; charset="utf-8"
Hi Don
That's a very interesting question. The K9AY is ground dependent. The
reason is simple, the Loaded loop of flag has a resistor in one side
and the transformer on the other side. If you want to make it
reversible you need two relays, one on each end of the loop.
What K9AY did was genius, he created a transmission line between the
horizontal wire and the ground. Keeping the horizontal wire close to
the ground it does work as a transmission line and you can move the
resistor and transformer close at the center of the wire. With the
resistor and the transformer closed to the center you can use just one
relay to reverse direction. The switching for 4 direction became easy
to implement.
The horizontal wire must be close to the ground, is you raise the
ends of the K9AY the impedance of the transmission line also raise and
deteriorate the SWR on the loop, deteriorating the pattern as well.
Same on the SAL the ground is part of the antenna. Very different of
the Flag and WF that is ground independent. You can install a flag or
WF at 50 FT high and pattern will be the same , not the case of the
SAL or K9AY. Not because the loop, but because the transmission line
that allows you to move the resistor and the transformer close to the
center of the antenna.
The SAL is the same, the two transformers 1:X loaded the wire as a
resistor and a transformer, there is no magic about that, electrically
it is a resistor load and a transformer, changing the name of the
device does not change how it works. You cannot install the SAL far
from the ground, it does not work, the same way the K9AY does not work
far from the ground.
73's
JC
N4IS
-----Original Message-----
From: Topband On Behalf Of Don Kirk
Sent: Friday, January 7, 2022 12:15 AM
To: Jose_Carlos
Cc: W0MU Mike Fatchett ; topband
Subject: Re: Topband: K9AY Loop Questions
Hi Jose,
To keep things simple, I say the K9AY is not like a pennant or flag
since it has been demonstrated by many people to be more ground
dependent (sometimes needing added ground radials). Under certain
conditions the K9AY should be identical to a Flag or Pennant but since
ground radials have been shown to drastically impact the K9AY
performance depending on the ground conditions this sure does not
sound like this is always the case.
I won't debate the SAL (Shared Apex Loop), other than to say from a
construction standpoint it's definitely not the same as the K9AY or
other EWE type antenna (Flag, Pennants, etc.), and modeling the SAL
definitely yields a different pattern than a single pennant or flag
when used in the "in line direction" but as you said modeling does not
always reflect reality (your example was EZNEC not doing a good job
with loops close to ground). I have never used an SAL and therefore my
statements are only based on what modeling yields, but to say the SAL
is the same as a K9AY is hard to believe regardless if it performs
better or worse than the K9AY, just based on the design.
P.S. I believe there is a newer version of the SAL in which the two
halves of the SAL share the same center vertical conductor, but again
I'm not making any claims about the design. Also note I'm using 4NEC2
for my modeling, not that it necessarily impacts my above statements.
73,
Don (wd8dsb)
On Thu, Jan 6, 2022 at 10:27 PM Jose_Carlos wrote:
> Don
>
> I?m afraid your information is not accurate, SAL is the same as a
> K9AY, the two wires close to each other can be removed because they
> cancel each other. The remain wires works like two vertical in
phase,
> as the same in any flag, loaded loop or pennant. The cardioid
pattern is the same.
>
> The is no implementation of two SAL in phase because it does not
work,
> the phasing system is too complex to phase two SAL.
>
> If you know the people that actually tested the antenna, you know
that
> the claimed RDF was never achieved.
>
> The RDF of the K9AY is the same of the SAL, the EZENEC does a
horrible
> job with loops close to the ground.
>
> Saying that, both antennas are excellent receiver antennas if you
> don?t have anything else.
>
> 73?s
> JC
> N4IS
>
> Sent from Mail for Windows
>
> From: Don Kirk
> Sent: Thursday, January 6, 2022 7:19 PM
> To: W0MU Mike Fatchett
> Cc: topband
> Subject: Re: Topband: K9AY Loop Questions
>
> Hi Mike and gang,
>
> It has been a long time since I looked at the SAL in which I
modeled
> it with the help of the designer of the SAL (KB7GF). The SAL is
> actually different than the K9AY and other EWE types of RX antennas
> which have a typical RDF value of around 7.8 because the SAL
(Shared
> Apex Loop) antenna actively uses two of its loops which are "in
line"
> with each other for what you might call the primary direction
> (direction in line with the loops), and these two phased loops can
> provide an RDF value of around 9.2 depending on the coupler
locations.
> For the off axis directions (45 degrees to the
> loops) I believe all 4 loops of the SAL are active (phased
together)
> and they provide a pattern more like what you would expect from the
> K9AY or other EWEs with an RDF of approximately 7.8. Therefore in
the
> 4 primary directions of the SAL the SAL definitely has a better RDF
> than the K9AY or other types of EWE receiving antennas.
>
> When used "in line" the RDF of the SAL is around 9.2 as mentioned
> above which is similar to what you would obtain using two phased
> verticals with
> 1/8 wavelength spacing.
>
> Just FYI,
> Don (wd8dsb)
>
> On Wed, Jan 5, 2022 at 9:43 PM W0MU Mike Fatchett wrote:
>
> > The SAL is pretty much just an AY loop with a more functional
> > controller? I have had moderate success with a pennant at V31 as
well.
> >
> > W0MU
> >
> > On 1/5/2022 7:23 PM, john at kk9a.com wrote:
> > > I tried an AY loop decades ago, without the Array Solutions
> > > adjustable termination controller, and I do not remember it
being
> > > that useful for
> > RX.
> > > The antenna is ground dependant so perhaps it works better for
> > > some
> than
> > > others. Even a short Beverage may be a better choice. From my
P40A
> > station I
> > > used a Pennant with decent results. It was inexpensive to build
> > > and not ground dependant however it only covered one direction.
> > > The Array
> > Solutions
> > > Shared Apex Loop Array has great reviews and may be worth
> > > considering,
> > Pete.
> > >
> > > John KK9A
> > >
> > >
> > >
> > > Pete Smith N4ZR wrote:
> > >
> > > I recently installed a K9AY loop (with the Array Solutions
> > > controller), and have a couple of questions. Installation is
> > > pretty standard, with
> a
> > > fiberglass pole at the center, ground rod at its base, and on
the
> ground
> > > radials under each direction of the loop.
> > >
> > > The antenna is directional, as demonstrated by tuning in
broadcast
> > > stations at the high end of the AM band and separating stations
on
> > > the same frequency so that I can hear one or the other.
> > > Atmospheric noise is 1-2 S units more on my inverted L than on
the
> > > K9AY antenna, but signal strengths of stations in the favored
> > > direction of the loop seem about the same or a bit lower than
the
> > > inverted L. The Termination adjustment is working, to judge by
> > > the switching transients, but seems to make little or no
difference.
> > >
> > > How do these results compare with others' experience? I didn't
> > > expect
> a
> > > "magic bullet", but the K9AY loop seems a little bit
underwhelming.
> > >
> > _________________
> > Searchable Archives: http://www.contesting.com/_topband [5] -
Topband
> > Reflector
> >
> _________________
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>
> _________________
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>
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