Tim,
Time for a question. Regarding the dump power operation, are all the
elements connected to the 4-square box or is it done one element at a time?
Not that I have a 4-square but inquiring minds want to know. A 4-square is
in my future plans however.
Ken K5RG
------------------------------
Message: 3
Date: Tue, 1 Oct 2024 10:34:53 -0400
From: "Tim Duffy" <k3lr@k3lr.com>
To: "'Arthur Caswell'" <acaswell4238@charter.net>,
<towertalk@contesting.com>
Subject: Re: [TowerTalk] 40 Meter 4sq element tuning freq.
Message-ID: <006b01db140f$14b60620$3e221260$@k3lr.com>
Content-Type: text/plain; charset="us-ascii"
Hello Skip;
I have lots of experience with tuning four squares for best performance.
All of the elements must be on the exact same frequency. This has to be done
by floating three elements while working on one. Floating means
disconnecting the coax (RG-11) at the vertical feedpoints.
Put a wattmeter on the output of the dummy load port (4 square box) and look
at the power going into the dump load. Very the frequency until you see the
minimum dump power. Then determine the "shift" you need to lengthen or
shorten the elements to bring the "dump load" power to minimum in the middle
of your desired "band of operation". With 100 watts into the box, you should
have less than a watt in the dump load at the lowest point.
On my 40 meter four square here at K3LR, My elements are tuned so the
minimum dump power is at 7.100 for best DX performance of 7.000 to 7.200
MHz. Operation above 7.200 is also just fine.
My elements are individually tuned (all on the same frequency) at 6.880 MHz
to give minimum dump power at 7.100 MHz. Your elements might be lower of
higher than mine, it depends on the diameter of your elements.
Lots of good information is here:
https://www.dxengineering.com/parts/com-acb-40#documentation
Rod, K8RR can also help with questions - 800-777-0703
73
Tim K3LR
CEO DX Engineering
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Arthur Caswell
Sent: Tuesday, October 1, 2024 10:02 AM
To: towertalk@contesting.com
Subject: [TowerTalk] 40 Meter 4sq element tuning freq.
I am having trouble tuning the elements and would like some help as I lost
my tuning notes. My question is; what freq should I tune each element for?
My set up is: I have a RigExpert for an antenna analyzer, telescoping AL
elements, phasing lines cut for 7130 MHz, DX Engineering 4sq controller
>From my limited memory, tuning 150 KC down from 7130 sticks in my mind.
Once all elements are tuned to the same freq, the resonant freq rises up.
Any help would be appreciated.
Thanks...........Skip Caswell KE9L
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