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Originally Posted by tripelo
The graphs of ferrite impedance look OK for your application.
They are a form of ceramic, if they bang against each other they crack and separate.
Merry is a good state.
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I will be merry when I get the results I want
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Looks like your UHF Fair-Rite's have somewhat more than about 400 Ohms impedance at 500 MHz. If you use four of them, that makes at least 1600 Ohms (from ferrite) to resist signal passage down the coax shield. Splitting locations, 2 at junction and two at 1/4 wave would likely increase the effective impedance to well above 1600 Ohms.
Four of them together at 1.126 inches length each would cover about 4.5 inches. Splitting for quarter wave leaves only a small space between.
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So at least for UHF, I will have four ferrite cores on the coax? OK so far so good. Will I be limited to the length on the coax?
And what about the VHF? That should be a longer 1/4 wave right?
How should I configure the ferrite on that coax?
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The signal can divide some portion to pass through the interior of the coax at 75 Ohms impedance, some to pass through 1600+ Ohms (plus the inherent impedance down a coax shield outer conductor).
The point is, the higher the impedance, the less signal passes on the outer shield. Signal on the outside of the shield is for practical purposes 'lost'.
There are practical limits, cost, weight, difficulty handling and securing a ferrite laden cable.
In some cases, two or three is about all a connection at a junction can handle.
Diminishing returns, revisited.
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Weight seems like the most important concern. No reason to put strain on my Kitz KT-200 F fitting. Or, the strain on the F connectors. Or the extra weight pulling on the Dipole, although I will be encasing the twin lead in CPVC tube to keep rain off and that should relieve the strain at the dipole end of the twin lead.
In my case, the cost is low so that's not an issue.
So, 2 or 3 is enough? 4 is OK, but wont do much? As in "diminishing returns"?...
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