Electronics > RF, Microwave, Ham Radio

Feed line choke windings - coax or wire?

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JHNC:
As far as which mix toroid to use for CMCs: from what I have discerned from the linked articles in this post and a couple of other sources:

For 80m thru 10m, use type FT-240-43           [RFI Suppression 5 - 500 MHz];
 
For 160m, 80m & 40m use type FT-240-31     [RFI Suppression 1 - 500 MHz].

As far as power handling goes;  [per W1JR] RG-58 will work for a few hundred watts.
For higher power, using thin Teflon coax, such as RG-142 should be good for 4KW @ 10MHz ;
2KW @ 30MHz  *** estimated *** .


A.Z.:

--- Quote from: JHNC on December 10, 2021, 11:53:48 pm ---As far as which mix toroid to use for CMCs: from what I have discerned from the linked articles in this post and a couple of other sources:

For 80m thru 10m, use type FT-240-43           [RFI Suppression 5 - 500 MHz];
 
For 160m, 80m & 40m use type FT-240-31     [RFI Suppression 1 - 500 MHz].

As far as power handling goes;  [per W1JR] RG-58 will work for a few hundred watts.
For higher power, using thin Teflon coax, such as RG-142 should be good for 4KW @ 10MHz ;
2KW @ 30MHz  *** estimated *** .

--- End quote ---

correct, willing to go up with power just stack a pair of FT240 toroids one over the other and wind the choke; in my own experience 17 or 18 turns of RG142 around a #43 toroid will serve you pretty well on all HF bands down to 80, if you want to go down to 160 add a second choke wound on #31; if you want to go for a "belt and suspender" approach, place the chokes in three points, one at the antenna end of the coax, another at half length and a third one at the point where the coax enters the building/shack, at that point you may also want to add a gas discharging device

HTH


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