Topband: Fwd: Topband Digest -- RX Antenna Performance
GEORGE WALLNER
aa7jv at atlanticbb.net
Sat Dec 29 14:44:00 EST 2018
Mike,
N4IS (JC) does know what he is talking about.
His Waller Flag, however, can be vertical or horizontal. The Horizontal WF
(HWF) is certainly a class above all other loops, provided it is more than
100' up. But you can have a Vertical WF at any height -- in fact lower is
better. Not as good as HWF, but still a very good RX antenna.
JC makes a very crucial point: the WF does have a much narrower front lobe
and has minimal side lobes, because it has two elements. You can not get
this narrow pattern with a single loop. Any single element loop will have a
more-or-less cardioid radiation pattern, which translates to a RDF of 7 to
8 dB. To get a higher RDF, you need two elements.
On JC's recommendation, I built a phased array of two delta loops on a small
island and tested its "radiation" pattern. The video at
https://www.youtube.com/watch?v=JMujut_5FdY&t=71s was shot from a drone that
carried a small 1.8 MHz transmitter. The audio is from the receiver
connected to the antenna (the two vertical poles hold the apexes of the two
delta loops). The video starts in front of the antenna (maximum signal). At
90 degrees (the side of the antenna) the signal is almost zero. As the drone
moves towards the rear, there are two weak side lobes, and then almost no
signal from the rear. This pattern is consistent with the NEC model of the
same antenna. This antenna has a 150' foot-print, which is much smaller than
a Beverage with similar performance.
Another crucial point: I have built many RX antennas of various designs. I
have found that their performance varied a great deal based on the
environment. The same antenna would work great in one place and would be
terrible somewhere else. Local conditions (the ground, wires in the ground,
nearby antennas, etc.) can change the radiation pattern and can induce
noise, rendering an antenna that models great useless. If you build a well
established design, like a K9AY or SAL, and it does not perform according to
its specifications, see what is around it. These antennas have very low gain
and even a very small amount of noise can swamp the weak signals they
produce.
73,
George
AA7JV/C6AGU
On Fri, 28 Dec 2018 19:50:52 -0600
Mike Waters <mikewate at gmail.com> wrote:
> Hi Wes,
>
> I'm 95% certain that N4IS knows what he's talking about here. I've been
> reading the posts on this reflector for years, and there's a few experts
> that stand above and beyond the rest of us. ;-)
>
> He invented the Waller flag, IIRC; you might want to look into that. He has
> written much about it, both here and on his website. If I were a young man
> again, I would put one on a tower and rotor in a heartbeat. It's like
> having a one-wavelength Beverage that's rotatable.
>
> Now, the Waller is more critical than many other good RX antennas, but with
> your years of hands-on electronics experience I have no doubt that wouldn't
> be an issue for you.
>
> You might want to start with Dr. Gary Breed's (K9AY) improved design first.
> I forget the URL of his website.
>
> Just my $0.02 worth. ;-)
>
> 73, Mike
> www.w0btu.com <http://www.w0btu.com>
>
> ---------- Forwarded message ---------
>From: <n4is at n4is.com>
> Date: Fri, Dec 28, 2018 at 2:44 PM
> Subject: Re: Topband: Topband Digest, Vol 192, Issue 33
> To: Jay Terleski <jayt at arraysolutions.com>, <topband at contesting.com>
>
>
> Jay
>
> The SAL is only one electrical equivalent loop with 9 db RDF, the Waller
>Flag has 2 flags in phase with 11.5 db RDF.
>
> It is not on the same class. Sorry but I am been honest here, both antennas
> need the tower to be detuned to work.
>
> The invention of a BALUN just transfer the impedance replacing a resistor
> 1000 ohms to load the loop as any FLAG, the other BALUN you call a special
> name to patent, it is just a simple BALUN, it is just the feed line , the
> SAL does have one resistor and one feed point, the two vertical wires works
> like a very short transmission line. And it removed does not affect
> anything, You own engineer admitted that.
>
> To prove that it is no the same class, check the side null, two flags can
> provide a deep null on each side , 30 db , and 20 db F/B.
>
> Does your SAL provide side null, 82 degree front lob,. 11.5 db RDF and it is
> ground independent? NO.
>
> Can you elevate it and turn.it? NO
>
> The SAL is grounded dependent and can not be elevated and turned.. Sorry
> the SAL is identical a K9AY, build them side by side and you will see it.
>
> The HWF is at another level because cancel manmade noise and the increase on
> signal to noise ratio improvement is 20 db or better.
>
> You get what you pay for. I can tell you that the SAL is really a Snake Oil.
> Work 300 countries with a SAL and I will give you some credit.
>
> 73.
> JC
>
>
> -----Original Message-----
>From: Topband <topband-bounces at contesting.com> On Behalf Of Jay Terleski
> Sent: Friday, December 28, 2018 12:20 PM
> To: topband at contesting.com
> Subject: Re: Topband: Topband Digest, Vol 192, Issue 33
>
> JC said,
> The SAL is a good antenna, any directivity increases signal to noise ratio.
> The RDF is 2 to 3 bd better than the vertical antenna, it means the
> improvement on signal to noise ratio is about 6db. You can dig signals 6 db
> below noise with the SAL that you cannot hear with the inverted L.
>>
>> ..but the SAL has the same performance of a K9AY, or EWE or a single
>FLAG, The clamed 10 db RDF was never confirmed or measured, The SAL is the
> most complicated K9AY you can build. The separation in two loops does not
> change the directivity.
>>
>> You can phase 2 FLAGS to increase RDF to 11.5 DB, as well you can
>> phase
> two K9AY or 4 if you want, but the SAL phasing system is complicated and it
> is impractical to phase two SAL to increase RDF.
>>
>> 73
>> JC
>> N4IS
>
> JC the SAL is not in the class of the single terminated loops of the K9AY
> antenna, and you of all people should know this as it is in the same class
> as your waller loop in that it uses two loops do derive the pattern. in
> each of the 4 directions. And combines the loops to get the intermediate
> directivity in 8 directions. It is a fantastice ground independent antenna
> and we can't hardly keep them in stock. As to your claim that the RDF has
> not been confirmed is also wrong. It has been run on many simulation
> platforms and I am sure you have studied it well.
>
> We have a Yahoo group that you may join and get the NEC models and you may
> feel free to join it as well.
>
> The SAL is a fantastic antenna, and if one takes time to optimize it, it
> will give the performance you see on the videos on You Tube, etc. It
> doesn't suffer from huge low gain problems of the HWF you sell, and is much
> more cost effective for the small guys to get a good low band antenna
> working to share DXing on top band as well as others as it is very broad
> banded.
> Due to it's gain, we do not need exotic amplification the the HWF requires.
> And we publish the details so a customer may build their own successfully.
>
> Try the SAL-30/20/12 guys, I have two of them up now and plan to phase them,
> as one of my customers has done.
>
> Thanks for reading and Happy New Year to the group.
> Jay, WX0B
>
>
> Jay Terleski
> Array Solutions
> 214 954 7140
>
>
> On Fri, Dec 28, 2018 at 11:00 AM <topband-request at contesting.com> wrote:
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>> Today's Topics:
>>
>> 1. Re: Inverted L improvement question (Cecil Acuff)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Fri, 28 Dec 2018 10:31:56 -0600
>> From: Cecil Acuff <chacuff at cableone.net>
>> To: n4is at n4is.com
>> Cc: Wes Stewart <wes_n7ws at triconet.org>, Arthur Delibert
>> <radio75a3 at msn.com>, Jeff Woods <jmwooods at yahoo.com>, topband
>> <topband at contesting.com>
>> Subject: Re: Topband: Inverted L improvement question
>> Message-ID: <592429B6-A654-473E-88E6-62EBBF643031 at cableone.net>
>> Content-Type: text/plain; charset=utf-8
>>
>> I would have kept mine if I had seen that kind of performance. Either
>> I have a very low noise floor, I had degraded performance of the RX
>> antenna for some reason or I was doing something wrong.
>> When I saw a
>> difference in SNR it was very minor and wouldn?t have been the
>> deciding factor in making the contact. It had a bit less loss than my
>> K9AY but there was more wire in the air. Difficult to erect...wife
>> helped but fell once before we got it right.
>>
>> I don?t expect my experience was typical so not wanting to dissuade
>> others...the SAL antennas are good antennas....but I didn?t see the
>> performance displayed on the Array Solutions web site video at this
>> location.
>>
>> Cecil
>> K5DL
>>
>> Sent using recycled electrons.
>>
>> > On Dec 28, 2018, at 10:21 AM, <n4is at n4is.com> <n4is at n4is.com> wrote:
>> >
>> > Wes you're right
>> >
>> > The SAL is a good antenna, any directivity increases signal to noise
>> ratio. The RDF is 2 to 3 bd better than the vertical antenna, it means
>> the improvement on signal to noise ratio is about 6db.
>> You can dig
>> signals 6 db below noise with the SAL that you cannot hear with the
> inverted L.
>> >
>> > ..but the SAL has the same performance of a K9AY, or EWE or a
>> > single
>> FLAG, The clamed 10 db RDF was never confirmed or measured, The SAL
>> is the most complicated K9AY you can build. The separation in two
>> loops does not change the directivity.
>> >
>> > You can phase 2 FLAGS to increase RDF to 11.5 DB, as well you can
>> > phase
>> two K9AY or 4 if you want, but the SAL phasing system is complicated
>> and it is impractical to phase two SAL to increase RDF.
>> >
>> > 73
>> > JC
>> > N4IS
>> > -----Original Message-----
>> > From: Topband <topband-bounces at contesting.com> On Behalf Of Wes
>> > Stewart
>> > Sent: Friday, December 28, 2018 10:50 AM
>> > To: Arthur Delibert <radio75a3 at msn.com>; Jeff Woods
>> > <jmwooods at yahoo.com>
>> > Cc: topband <topband at contesting.com>
>> > Subject: Re: Topband: Inverted L improvement question
>> >
>> > I was an early participant in the SAL yahoo group and introduced
>> > Dan,
>> AC6LA, to the group. He has provided a lot of modeling tools.
>> >
>> > That said, I lost interest after feeling that the design was too
>> complicated, not well understood and suffered from a dizzying number
>> of changes. I could be totally wrong about this, but that was my
>> assessment some time ago and frankly I haven't kept up.
>> >
>> > Wes N7WS
>> >
>> >
>> >
>> >> On 12/27/2018 4:15 PM, Arthur Delibert wrote:
>> >> You may also want to check out the SAL-12, -20 or -30 antennas from
>> >> Array Solutions. My yard is pretty small, but I was able to put up
>> >> a SAL-12, and I love it. (I do mostly 49-, 60- and 90-meter SWBC
>> >> DX.) I can switch the antenna to any one of 8 different directions,
>> >> and I'm often surprised to find that the DX is coming from a
>> >> direction
>> different from what I would expect.
>> >> Often there's a very pronounced peak in the signal when the antenna
>> >> is pointed in the right direction, and I really would not have had
>> >> any copy if I couldn't point in that direction.
>> >>
>> >> The SAL-12 isn't especially good on 160, but is good from 3 MHz and
>> >> higher. The SAL-20 and -30 are reportedly very good on 160. If I
>> >> recall right, the
>> >> SAL-20 is directional up to 20 meters; the SAL-30 is good up to 40
>> >> meters. Check the Array Solutions website to confirm.
>> >>
>> >> These aren't as cheap as putting up your own pennant, but above 3
>> >> MHz, the
>> >> SAL-12 aimed NE almost always outperforms my pennant pointed in the
>> >> same direction.
>> >>
>> >> Regards,
>> >> Art Delibert, KB3FJO
>> >>
>> >> -------------------------------------------------------------------
>> >> ---
>> >> ----------
>> >
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>>
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>> End of Topband Digest, Vol 192, Issue 33
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