[Antennas] Cap Hat and L & C/ARRL Lightning Calculator

2002年4月28日 11:19:02 -0500

Tom,
I've sent an email to K1RO, Mark Wilson, publisher of QST and a couple of
other people at ARRL for info on when the ARRL Lightning Calculator was
last produced and whether the copyright has expired. My copy says
"Published by The American Radio Relay League, Inc., West Hartford, Conn.
 Under Copyright 1932 W.P. Koechel, Price One Dollar Postpaid." Mr
Koechel was the apparent mathmatician who designed it and sold (or gave?)
rights to ARRL.
Anyhow, the beauty of the circular calculator is that it not only does
L, C and F from 400kC to 150Mc, but also Wavelength and coil
calculations, turns per inch, diameter, length, vs: inductance. Very
easy to see equivalent inductance coils going to different diameters,
turns per inch, etc. Also different L and C combinations quickly for the
same frequency. Two moving scales rotate about fixed scales on a single
single center pin or rivet. The outer fixed scale contains the coil
diameter and turns per inch figures. The device really does not need an
index pointer, unless you want to be precise about wavelength vs.
frequency or have an interest in single or double cotton covered enamaled
wire. Hopefully, this tool can be copied and reproduced again. 
I would bet none of the other below mentioned LC calculators or "slip
sticks" can do what the above circular does.
Mike, ac5p
On 2002年4月22日 00:41:00 -0400 "Tom Bates" <[email protected]> writes:
> Thanks all for the many helpful responses to both querries.
>> Synopsis of the answers for those interested.....
>> I guess my crux was not considering I had to add the initial L to a 
> capacitive
> appearing short vertical to get to resonance. After arriving at 
> that point,
> increasing C requires decreasing L to remain at resonance. Boy, 
> that slide rule
> calculator would have shown that nicely.
>> And, the slide rule LC calculators.... It appears there were three 
> popular versions.
> One by Allied Radio, one by Shure, and a circular one by ARRL. Once 
> I get assurance
> that copyrights will not be violated, there may be a site where JPEG 
> files of the
> sleeves and sliders of these two rectangular calculators could be 
> downloaded. Then,
> one could print and mfg their own calculator. I'll post more info 
> as soon as I
> know.
>> Thank you all 73, Tom AA1NZ
>> - - - 
>> Your moderator for this list is:
> Larry Wilson KE1HZ [email protected]
> _______________________________________________
> Antennas mailing list
> [email protected]
> http://mailman.qth.net/mailman/listinfo/antennas