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[QUOTE="Stellasstillarat, post: 526277, member: 42401"
Going to the choke. I believe it is 5 1/4 or 5 1/2 turns on a 4 inch diameter. for 27 mhz,
Anything close will do per say ( let the bashing begin).

Because of how narrow the bandwidth is on an air wound choke it needs to be spot on. Going from 5 turns of RG213 on a 4.25 inch core to 7 turns will move where it works from 26-28MHz down to 17-18MHz. Two turns and you have an almost 10MHz drop in the frequency it works on so half a turn can see you move the peak choking to above or below the 11m band quite easily.

Using ferrite rings and coax to make the choke, the peak choking bandwidth is 15-20MHz wide so getting it wrong by half a turn or so is not as critical as with an air wound.

[/QUOTE]

[QUOTE="M0GVZ, post: 526298, member: 22312"] [QUOTE="Stellasstillarat, post: 526277, member: 42401" Going to the choke. I believe it is 5 1/4 or 5 1/2 turns on a 4 inch diameter. for 27 mhz, Anything close will do per say ( let the bashing begin). [/QUOTE] Because of how narrow the bandwidth is on an air wound choke it needs to be spot on. Going from 5 turns of RG213 on a 4.25 inch core to 7 turns will move where it works from 26-28MHz down to 17-18MHz. Two turns and you have an almost 10MHz drop in the frequency it works on so half a turn can see you move the peak choking to above or below the 11m band quite easily. Using ferrite rings and coax to make the choke, the peak choking bandwidth is 15-20MHz wide so getting it wrong by half a turn or so is not as critical as with an air wound. [/QUOTE]

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