Dave,
Yes. In other words, just as we would wind in sequence around a toroid.
It limits the number of useful turns that can be wound to one side of
the clamp. Once I realized that, I no longer recommend the clamp-on for
TX chokes, only for RFI suppression.
73, Jim K9YC
On 12/21/2021 6:47
Jim,
When you said “turns must go through the core in sequence”, does that mean
that each turn must rest next to the last one, rather than overlapping one
or more previous turns? I suspect that’s what “in sequence “ means- just
want to make sure.
On Mon, Dec 20, 2021 at 10:40 PM Jim Brown
On 12/20/2021 7:50 PM, Buck K4IA wrote:
More turns is better until we get to very large chokes where the
inter-coil capacitance lowers the impedance.
No. See my post in this thread about resonance.
BTW -- I strongly agree that clamp-ons should be secured with a ty-wrap.
And something I
On 12/20/2021 6:21 PM, Pete Smith N4ZR wrote:
Others can speak more authoritatively about this, but I thought those
clamp-on cores, where they go right on the existing run of coax, offered
too little inductance to be of much use below VHF. Experts?
That's right, sort of. But it misses the
The impedance increases with the square of the turns. 2 turns = 4 times
the impedance. It would take 4 chokes in series to equal one choke with
2 turns. A "turn" is one pass through the middle. More turns is better
until we get to very large chokes where the inter-coil capacitance
lowers
Pete,
Yes. You either have to have lots of them, or you need to get bigger ones and
run multiple turns through them. Also get the right “mix” for the frequency
range in question. Type 31 is pretty good for HF.
Not an expert, but studied http://k9yc.com/RFI-Ham.pdf
I wire tie mine closed once in place...
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 12/20/21 17:02, Bob McGraw wrote:
For those using the clamp-on ferrite devices, when
Others can speak more authoritatively about this, but I thought those
clamp-on cores, where they go right on the existing run of coax, offered
too little inductance to be of much use below VHF. Experts?
73, Pete N4ZR
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Even when properly sized, as an added insurance policy, I run a zip tie around
the perimeter of the clamp-on and cinch it down tight to ensure that the two
halves are in solid contact with each other. It may not be a problem, but just
in case there is any play or give in the plastic snap and
For those using the clamp-on ferrite devices, when installing them, be
sure part A closes completely and solidly contacts part B. Otherwise,
there is no flux path and the device is ineffective. If it is closed
and loose on the cable, then that's good. If it is closed or difficult
to
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