On Tue, 5 Aug 2003 16:15:32 -0700, wrote:

Well, depends on HOW CLOSE to my flesh I held it! (according to the
inverse -square law, temperature decreases at a rate of 1/4 , for every 1/2
of an increment it is removed from you)!
Jim NN7K

Richard wrote:
This 0.1dB in the wrong hands is clearly an example of extravagant
dismissal or myopic attention. And speaking of hands, how long would
you consider it trivial if you had to hold onto the sucker for 20
seconds?

73's
Richard Clark, KB7QHC



Hi Jim,

How close is anything to your flesh when you are holding it? Are you
still holding it, if it were 2 times further away?

73's
Richard Clark, KB7QHC

Well, Richard, tho in jest, serves purpose, that even with 30 watts lost on
surface of a balun , (or any other surface, for thatr matter), that by
doubleing the size of the SURFACE, that it would take something like 4 TIMES
as much heat to destroy it. For the same reason that a transistor, in the
size of a micron will vaporize with a slight static discharge , doesn't
necessarily mean that a POWER transistor will even feel a hickup, if it
takes you 30 minutes with a 100 watt soldering iron trying to get solder on
the leads! For the same reason , have 50 ohm coaxial resistor that fits in
a reducer for rg-174, to a SO-239, that would probably crack, with the heat,
and meantime also have a resistor, 1/3 the size, but made to mount on a heat
sink, that will dissipate 100 watts all day! (also made as a 50 ohm load--
same devices, but different uses-- Jim



Hi Jim,

How close is anything to your flesh when you are holding it? Are you
still holding it, if it were 2 times further away?

73's
Richard Clark, KB7QHC

On Wed, 6 Aug 2003 15:48:01 -0700, wrote:

Well, Richard, tho in jest, serves purpose, that even with 30 watts lost on
surface of a balun , (or any other surface, for thatr matter), that by
doubleing the size of the SURFACE, that it would take something like 4 TIMES
as much heat to destroy it.

Hi Jim,

No, this is incorrect. When discussing power dissipation, it follows
a linear relationship to surface area - not square law (you are mixing
radius and surface area arguments). Even letting this pass, power
dissipation does not even conform to doubling with doubling of surface
area. This departure from expectation arises in the increased
distance the heat has to travel to find the surface. This is usually
found in having too many fins in an effort to maximize that same
surface area (and leads to an increase in Thermal Resistance).
Further, more fins also diminish heat transfer through convection
(again increasing Thermal Resistance). 4 or 5 fins is usually
optimal.

73's
Richard Clark, KB7QHC