[TowerTalk] TowerTalk Digest, Vol 216, Issue 16
Steve Davis | Davis RF
sdavis at davisrf.com
Mon Dec 21 13:54:29 EST 2020
Hi Charlie,
I agree completely with Tim's suggestions. And where you mention testing the phasing lines, yes. Be sure to totally disconnect them from the system and test on an appropriate analyzer to be sure all are in sync.
Let us know what the solution is, good luck.
73 Steve K1PEK DAVIS RF Co
Message: 5
Date: Sun, 20 Dec 2020 22:34:37 -0500
From: "Tim Duffy" <k3lr at k3lr.com>
To: "'Charles Morrison'" <junkcmp at gmail.com>, "'TOWERTALK at contesting.
com'" <towertalk at contesting.com>
Subject: Re: [TowerTalk] Isolating adjacent 4-Squares
Message-ID: <014801d6d74a$3629d030$a27d7090$@k3lr.com>
Content-Type: text/plain; charset="us-ascii"
Hello Charlie:
This is going to be tough with all of these wires so close together - to
make both bands work right. Elevated radials further complicates the
problem..1/4 wave shorted stubs on the 160 elements is not going to help 160
- it might help 80 (it did here).
You might try disconnecting the 80 meter feedlines at the feed points of the
80 meter elements and see if 160 comes to life. If not, remove the 80
completely and see if 160 works. If not, you will need to detune the towers.
With elevated radials - everything is in play and you have bigtime coupling
between the two antenna systems.
Having high CMI chokes at the feedpoints of all elements is needed to keep
the feedlines out of the picture.
You will need to experiment - trying one thing at a time.
Good Luck, Merry Christmas and 73
Tim K3LR
________________________________
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Sent: Monday, December 21, 2020 12:00 PM
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Subject: TowerTalk Digest, Vol 216, Issue 16
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Today's Topics:
1. Isolating adjacent 4-Squares (Charles Morrison)
2. Re: Isolating adjacent 4-Squares (Mpridesti)
3. Re: Isolating adjacent 4-Squares (K9MA)
4. Re: Isolating adjacent 4-Squares (Mike Smith VE9AA)
5. Re: Isolating adjacent 4-Squares (Tim Duffy)
6. Re: Isolating adjacent 4-Squares (john at kk9a.com)
7. Re: Isolating adjacent 4-Squares (K9MA)
----------------------------------------------------------------------
Message: 1
Date: Sun, 20 Dec 2020 12:22:54 -0500
From: Charles Morrison <junkcmp at gmail.com>
To: "TOWERTALK at contesting. com" <towertalk at contesting.com>
Subject: [TowerTalk] Isolating adjacent 4-Squares
Message-ID:
<CAHEjY+TYYs9K48eo0ik8vxt3iV_dZ1qpwDWaHeKnaQOqtDx9oA at mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
I have an 80M wire 4-square around tower #1. (90ft with two big 10M & 15M
monobanders) Each vertical has 12 above ground radials and is tuned to
3535. All guys are broken with insulators.
This array works well.
My second version of a 160M wire 4-square around tower #1 was raised last
week. They are Inverted L's to a 120ft tower. It already has two Cushcraft
40-2CD's and a big homebrew 20M6L OWA yagi. All guys are broken with
insulators. Each Inverted L has 20 on-ground radials and is tuned to 1725.
The closest 80M element is 40 feet from a 160M element.
The 160 is not working well. I will be testing the phasing lines once this
snow melts. ###
I want to apply a passive device to further isolate these systems. I'm
thinking of a 1/4 wave 50 ohm shorted coaxial stub on each feedpoint. My
first guess is the 160 elements.... ?
Alternatives are to move one of the arrays.... but I'd rather explore
making them work where they are.
-Charlie N1RR
------------------------------
Message: 2
Date: Sun, 20 Dec 2020 14:21:44 -0500
From: Mpridesti <mpridesti at yahoo.com>
To: Charles Morrison <junkcmp at gmail.com>
Cc: "TOWERTALK at contesting. com" <towertalk at contesting.com>
Subject: Re: [TowerTalk] Isolating adjacent 4-Squares
Message-ID: <E45B52A2-71F7-47AB-A949-833A315FC351 at yahoo.com>
Content-Type: text/plain; charset=utf-8
Charlie
Thought I had a similar challenge and built a box with 4 spst relays mounted right at Comtek box that when powered, would short out all 4 elements of the 80 m 4 sq At the end of the 1/4 wave lines. Effectively creating an open circuit connection at each feed point.
Unfortunately it did not work for me, but does so at places like K3LR.
Regards,
Mark, K1RX
> On Dec 20, 2020, at 12:23 PM, Charles Morrison <junkcmp at gmail.com> wrote:
>
> ?I have an 80M wire 4-square around tower #1. (90ft with two big 10M & 15M
> monobanders) Each vertical has 12 above ground radials and is tuned to
> 3535. All guys are broken with insulators.
> This array works well.
>
> My second version of a 160M wire 4-square around tower #1 was raised last
> week. They are Inverted L's to a 120ft tower. It already has two Cushcraft
> 40-2CD's and a big homebrew 20M6L OWA yagi. All guys are broken with
> insulators. Each Inverted L has 20 on-ground radials and is tuned to 1725.
>
> The closest 80M element is 40 feet from a 160M element.
> The 160 is not working well. I will be testing the phasing lines once this
> snow melts. ###
>
> I want to apply a passive device to further isolate these systems. I'm
> thinking of a 1/4 wave 50 ohm shorted coaxial stub on each feedpoint. My
> first guess is the 160 elements.... ?
>
> Alternatives are to move one of the arrays.... but I'd rather explore
> making them work where they are.
> -Charlie N1RR
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 3
Date: Sun, 20 Dec 2020 15:08:15 -0600
From: K9MA <k9ma at sdellington.us>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Isolating adjacent 4-Squares
Message-ID: <45105690-c2f1-f592-06e7-e47dcec5df65 at sdellington.us>
Content-Type: text/plain; charset=utf-8; format=flowed
Charlie,
Are you sure it is not the tower itself that is degrading the
performance of the 4-square?? If so, you may be able to detune the tower
with a gamma match. That worked on 160 for me with a 70 foot tower and
an array of loops. It did not work on 80, apparently because the tower
was just too big.
73,
Scott K9MA
On 12/20/2020 1:21 PM, Mpridesti via TowerTalk wrote:
> Charlie
>
> Thought I had a similar challenge and built a box with 4 spst relays mounted right at Comtek box that when powered, would short out all 4 elements of the 80 m 4 sq At the end of the 1/4 wave lines. Effectively creating an open circuit connection at each feed point.
>
> Unfortunately it did not work for me, but does so at places like K3LR.
>
> Regards,
>
> Mark, K1RX
>
>
>> On Dec 20, 2020, at 12:23 PM, Charles Morrison <junkcmp at gmail.com> wrote:
>>
>> ?I have an 80M wire 4-square around tower #1. (90ft with two big 10M & 15M
>> monobanders) Each vertical has 12 above ground radials and is tuned to
>> 3535. All guys are broken with insulators.
>> This array works well.
>>
>> My second version of a 160M wire 4-square around tower #1 was raised last
>> week. They are Inverted L's to a 120ft tower. It already has two Cushcraft
>> 40-2CD's and a big homebrew 20M6L OWA yagi. All guys are broken with
>> insulators. Each Inverted L has 20 on-ground radials and is tuned to 1725.
>>
>> The closest 80M element is 40 feet from a 160M element.
>> The 160 is not working well. I will be testing the phasing lines once this
>> snow melts. ###
>>
>> I want to apply a passive device to further isolate these systems. I'm
>> thinking of a 1/4 wave 50 ohm shorted coaxial stub on each feedpoint. My
>> first guess is the 160 elements.... ?
>>
>> Alternatives are to move one of the arrays.... but I'd rather explore
>> making them work where they are.
>> -Charlie N1RR
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
--
Scott K9MA
k9ma at sdellington.us
------------------------------
Message: 4
Date: Sun, 20 Dec 2020 18:49:48 -0400
From: "Mike Smith VE9AA" <ve9aa at nbnet.nb.ca>
To: <towertalk at contesting.com>
Subject: Re: [TowerTalk] Isolating adjacent 4-Squares
Message-ID: <009301d6d722$6c633830$4529a890$@nbnet.nb.ca>
Content-Type: text/plain; charset="us-ascii"
Charlie,
I am by no means any kind of authority on isolating 4-squares even though I
own a few.
I do note that on my 80m 4-square, my pattern and gain is "off" to my
Northwest. Coincidently(?), there is lots of conductive
"clutter" in that direction. Other, higher band 4-squares, other antennas,
shed full of 'stuff', separate metal greenhouse, the spot where we park
cars, xmas lights in trees mid Nov-Mid Jan etc.
If I just had to toss out one "guess", I'd suspect the tower.
VE9AA
Mike, Coreen & Corey
Keswick Ridge, NB
------------------------------
Message: 5
Date: Sun, 20 Dec 2020 22:34:37 -0500
From: "Tim Duffy" <k3lr at k3lr.com>
To: "'Charles Morrison'" <junkcmp at gmail.com>, "'TOWERTALK at contesting.
com'" <towertalk at contesting.com>
Subject: Re: [TowerTalk] Isolating adjacent 4-Squares
Message-ID: <014801d6d74a$3629d030$a27d7090$@k3lr.com>
Content-Type: text/plain; charset="us-ascii"
Hello Charlie:
This is going to be tough with all of these wires so close together - to
make both bands work right. Elevated radials further complicates the
problem..1/4 wave shorted stubs on the 160 elements is not going to help 160
- it might help 80 (it did here).
You might try disconnecting the 80 meter feedlines at the feed points of the
80 meter elements and see if 160 comes to life. If not, remove the 80
completely and see if 160 works. If not, you will need to detune the towers.
With elevated radials - everything is in play and you have bigtime coupling
between the two antenna systems.
Having high CMI chokes at the feedpoints of all elements is needed to keep
the feedlines out of the picture.
You will need to experiment - trying one thing at a time.
Good Luck, Merry Christmas and 73
Tim K3LR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
Charles Morrison
Sent: Sunday, December 20, 2020 12:23 PM
To: TOWERTALK at contesting. com
Subject: [TowerTalk] Isolating adjacent 4-Squares
I have an 80M wire 4-square around tower #1. (90ft with two big 10M & 15M
monobanders) Each vertical has 12 above ground radials and is tuned to
3535. All guys are broken with insulators.
This array works well.
My second version of a 160M wire 4-square around tower #1 was raised last
week. They are Inverted L's to a 120ft tower. It already has two Cushcraft
40-2CD's and a big homebrew 20M6L OWA yagi. All guys are broken with
insulators. Each Inverted L has 20 on-ground radials and is tuned to 1725.
The closest 80M element is 40 feet from a 160M element.
The 160 is not working well. I will be testing the phasing lines once this
snow melts. ###
I want to apply a passive device to further isolate these systems. I'm
thinking of a 1/4 wave 50 ohm shorted coaxial stub on each feedpoint. My
first guess is the 160 elements.... ?
Alternatives are to move one of the arrays.... but I'd rather explore
making them work where they are.
-Charlie N1RR
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 6
Date: Mon, 21 Dec 2020 07:05:34 -0600
From: john at kk9a.com
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Isolating adjacent 4-Squares
Message-ID:
<20201221070534.Horde.sO-xS7l4pRGrzNTS7AwCVsI at www11.qth.com>
Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes
Did you model this before building it? From the little bit of
vertical array modeling that I have done I found the patterns easily
skewed by other verticals and towers, even those pretty far way. You
may have been better off centering the 160m 4Sq around the 80m one.
John KK9A
Charles N1RR wrote:
I have an 80M wire 4-square around tower #1. (90ft with two big 10M & 15M
monobanders) Each vertical has 12 above ground radials and is tuned to
3535. All guys are broken with insulators.
This array works well.
My second version of a 160M wire 4-square around tower #1 was raised last
week. They are Inverted L's to a 120ft tower. It already has two Cushcraft
40-2CD's and a big homebrew 20M6L OWA yagi. All guys are broken with
insulators. Each Inverted L has 20 on-ground radials and is tuned to 1725.
The closest 80M element is 40 feet from a 160M element.
The 160 is not working well. I will be testing the phasing lines once this
snow melts. ###
I want to apply a passive device to further isolate these systems. I'm
thinking of a 1/4 wave 50 ohm shorted coaxial stub on each feedpoint. My
first guess is the 160 elements.... ?
Alternatives are to move one of the arrays.... but I'd rather explore
making them work where they are.
-Charlie N1RR
------------------------------
Message: 7
Date: Mon, 21 Dec 2020 10:33:05 -0600
From: K9MA <k9ma at sdellington.us>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Isolating adjacent 4-Squares
Message-ID: <7f6e03a2-e3db-8f60-e1f3-0f9ee06e14f3 at sdellington.us>
Content-Type: text/plain; charset=utf-8; format=flowed
The interactions, based on my modeling, usually affects the nulls in the
pattern much more than the forward gain. This is mainly a concern for
receiving.
73,
Scott K9MA
On 12/21/2020 7:05 AM, john at kk9a.com wrote:
> Did you model this before building it?? From the little bit of
> vertical array modeling that I have done I found the patterns easily
> skewed by other verticals and towers, even those pretty far way. You
> may have been better off centering the 160m 4Sq around the 80m one.
>
> John KK9A
>
>
> Charles N1RR wrote:
>
> I have an 80M wire 4-square around tower #1. (90ft with two big 10M & 15M
> monobanders) Each vertical has 12 above ground radials and is tuned to
> 3535. All guys are broken with insulators.
> This array works well.
>
> My second version of a 160M wire 4-square around tower #1 was raised last
> week. They are Inverted L's? to a 120ft tower. It already has two
> Cushcraft
> 40-2CD's and a big homebrew 20M6L OWA yagi. All guys are broken with
> insulators. Each Inverted L has 20 on-ground radials and is tuned to
> 1725.
>
> The closest 80M element is 40 feet from a 160M element.
> The 160 is not working well. I will be testing the phasing lines once
> this
> snow melts. ###
>
> I want to apply a passive device to further isolate these systems. I'm
> thinking of a 1/4 wave 50 ohm shorted coaxial stub on each feedpoint. My
> first guess is the 160 elements.... ?
>
> Alternatives are to move one of the arrays.... but I'd rather explore
> making them work where they are.
> -Charlie N1RR
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
--
Scott K9MA
k9ma at sdellington.us
------------------------------
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