cartoon Martian antennas: practical?
 

What about those antennas atop the heads of cartoon Martians: rabbit
ears shishkabobing hula hoops, i.e., spikes with rings floating along
them. What good might they be as antennas? Sorry no graphic handy.

"Dan Jacobson" wrote in message
...
What about those antennas atop the heads of cartoon Martians: rabbit
ears shishkabobing hula hoops, i.e., spikes with rings floating along
them. What good might they be as antennas? Sorry no graphic handy.

Outside of being cartoons, if you mount a vhf or above antenna on your hat
you will usually gain some range. If you put a HT on your belt the antenna
is against your body and use a speaker/mic most of the signal is abosrbed
you your body. By placing the antenna on your hat you gain height and don't
have your body in the way.

Ralph Mowery wrote:
Outside of being cartoons, if you mount a vhf or above antenna on your hat
you will usually gain some range. If you put a HT on your belt the antenna
is against your body and use a speaker/mic most of the signal is abosrbed
you your body. By placing the antenna on your hat you gain height and don't
have your body in the way.

I have an aluminum hard hat with a 1/4WL 2m antenna on top.
I've wondered how much RF my brain is getting.
--
73, Cecil http://www.qsl.net/w5dxp


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On 14/02/2005 11:18 PM, Cecil Moore wrote:
Ralph Mowery wrote:

Outside of being cartoons, if you mount a vhf or above antenna on your
hat
you will usually gain some range. If you put a HT on your belt the
antenna
is against your body and use a speaker/mic most of the signal is abosrbed
you your body. By placing the antenna on your hat you gain height and
don't
have your body in the way.


I have an aluminum hard hat with a 1/4WL 2m antenna on top.
I've wondered how much RF my brain is getting.

There has been a fair amount of research on this. In Canada, your Basic
Qualification test may, in fact, contain questions based on information
from Health Canada's /Limits of Human Exposure to Radiofrequency
Electromagnetic Fields in the Frequency Range from 3 kHz to 300 GHz,
Safety Code 6/
(http://www.hc-sc.gc.ca/hecs-sesc/ccrpb/publication/99ehd237/toc.htm.)
At least the parts of this document that pertain to the Amateur Bands
allocated to Amateurs in Canada.

I'm guessing there are similar government or private bodies around the
world which have the same sorts of documents available.

This seems to boil down (pun not intended) to:

"Although not a requirement of the Code, it is suggested that whenever
possible, the organ-averaged SAR for the eye not exceed 0.4 W/kg. As
stated in Appendix VII, this suggestion shall remain until sufficient
scientific information is available to accurately assess the health
effects of RF exposure on the eye."

Translation: when working with reasonable powered RF transmitting
devices, especially at higher frequencies, minimize exposure to your eyes.

Apparently, this is something they want amateurs to remember, because
this is directly related to a few of the questions in the Basic
Qualification question bank.

I read somewhere that some amateurs cringe when they see VHF/UHF
amateurs wandering around at ham events wearing head-mounted mobile
units, not unlike your hardhat rig. I suppose a QRP rig would be no
worse than a mobile phone.

Of course, I have been thinking about getting a headset for /that/.
--
clvrmnky

Heat up and unmunge email to reply.

Mainly I'm curious about effect of the rings, seen here in cross section:
Like a finger with several rings,
|
o | o
o | o
or with wider rings as one goes toward the base,
|
o | o
o | o

depends on the output of your radio ....i.e. 2 watts
divide by 1/4 =
multiply by the brain cells you have =
then find the square root =
then multiply by 3.14 (pi) =