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John KD5YI wrote:
I think any inductor with the same inductance, Q, and self-resonant frequency will give the same velocity factor and delay as your Bugcatcher. That may or may not be true - I don't have an opinion one way or another - and it is NOT part of my argument. My argument deals only with 75m Texas Bugcatcher coils and other large air- core loading coils used on 75m. My argument is that the velocity factor of a 75m Texas Bugcatcher coil is ~0.02, occupies ~41 electrical degrees on 4 MHz, and exhibits a delay of ~28 nS through the coil. That is my only argument. I am not interested in diversions from that argument. My argument also includes the 100 turn, 10 inch long, 2 inch diameter coil that w8ji used for his 3 nS delay "measurements". If he had used traveling wave current for the measurement, he would have measured approximately 25 nS. Maxwell's equations for slow-wave structures (like a 75m Texas Bugcatcher loading coil) are given in "Fields and Waves ...", by Ramo and Whinnery: pages 467-479 in the 2nd edition. This is one of the references in the Corum IEEE paper. What do you make of Roy's (w7el) statement at: http://www.w8ji.com/agreeing_measurements.htm "As described in my posting on rraa of November 11, the inductor 'replaces' about 33 electrical degrees of the antenna." -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
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