[Lowfer] Antenna Length Redux

[Mike Staines - WM1KE]

On Sat, 2010-01-30 at 22:14 -0600, JD wrote:
> Where do you draw the line?

Somehow, every time this subject comes up I find it impossible to my
mouth shut (or keep my fingers off the keyboard, as the case may be).

>From the rules:
§ 15.219   47 CFR Ch. I 
   (b) The total length of the transmission line, antenna, and ground
lead (if used) shall not exceed 15 meters.

Since the FCC does not appear to define "Length" anywhere let us look to
common usage.

Webster's ( http://www.merriam-webster.com/dictionary/length ) defines
length (in this context) as "The longer or longest dimension of an
object."

>From Dictionary.com: "The measure of the greatest dimension of a plane
or solid figure."

The FCC does not say that the "radiating element" or "the wire" must be
less than 15 meters in length. The ANTENNA must be less than that,
including feed line and ground lead. The "longest dimension" of my
ANTENNA is less than 15 meters. That's what the rules say and that is
how I "draw the line."

Out of curiosity, JD, if you were to come and look at my helical antenna
for satellite work, would you say that the antenna as 6 feet long (the
boom length) or would you measure the length of the helical radiating
element (20-something feet). I think you would agree that this antenna
is 10 feet in length (the "longest dimension") and that the length of
the radiating element is moot.

I choose to use wire in the shape of a square. And as far as I can tell,
the length of that antenna (greatest dimension or longest dimension) is
less than 15 meters. 

Until the FCC puts out a notice the says that "length" is something
different than common usage, I'll keep my antenna in place.

Now, to actually get it radiating again...

Regards,
Mike
WM1KE
TMO