n a message dated 3/7/00 11:01:36 AM Eastern Standard Time,
Peter_Chadwick@mitel.com writes:
> Dave says:
>
> >(2) Neither does he have any concept of the DIFFERENCE in the
> application
> >of that small amount of power for 500ms, the length of which is
> controlled by
> >the pushing of a microphone button, as opposed to the UNCONTROLLED
> avalanche
> >of the dumping of ca. several joules of energy in a very short time
> which
> >usually ends in the catatrsopic destruction of a bandswitch or
> other tank
> >component.
>
> Dave, are you saying that the amount of energy involved in 160 watts for
> 500msec is not the same as 1600watts for 50msec or 16kW for 5msec? Or am I
> misunderstanding you?
>
> 73
>
> Peter G3RZP
>
------------------------------------------------------------------------------
-------------------------------------
No Peter,
I know there are times when you might think that we lads over here in the
colonies are a bit slow on the uptake, or that we don't speak/write the
King's English, so please read again what I said in my original post:
This is the point where ignorance overtakes (overshadows) common sense. (1)
Apparently Jon hasn't the slightest idea (CLUE) of the MAGNITUDES of
difference between the AMOUNT of energy stored in the power supply of a multi-
kilowatt power supply hooked to 220 VAC mains and a TOY desk top 160 watt amp.
2) Neither does he have ANY concept of the DIFFERENCE in the application of
that small amount of power for 500ms (or 2 seconds), the length of which is CO
NTROLLED by the pushing of a microphone button, as opposed to the UNCONTROLLED
avalanch of the dumping of ca. several joules of energy in a very short
(extremely short time) time which usually ends in the catatrsopic destruction
of a bandswitch or other tank component.
What I am saying here is, that if the capacitor bank in a 5KW, 4000 VDC power
supply, with 16 or 32 uF of capacitance discharges through an arc (however it
is initiated) into a bandswitch or other component, the discharge will take
place so quickly that it will be totally unexpected (unanticipated) with a
resultant bang and explosion with accompanying light that all that will be
left are crispy critters . Obviously this is the result of currents and
voltages of such magnitude and such short duration as to vaporize metal.
> What follows is pure sophistry and, Yes, he has not thought it through.
> For that matter, I've not thought this through, but how many RF cycles at
> VHF could take place in a matter of a few milliseconds? I guess you'd need
> to calculate the period, which is 1/F. At 144 MHz, this is 6.9
> nano-seconds. So if our event is on the order of nanoseconds you could get
> just a couple of RF cycles going which ain't gonna hurt anything. The
point
> is that a short event as Rich claims is what happens isn't going to stress
> components beyond a breaking point especially when it is so short it
doesn't
> even show up on the meter movements.
>
> At least that's the way I see it.
>
> 73,
>
> Jon
> KE9NA
>
------------------------------------------------------------------------------
------------------------------------
> Dave in Dayton, WT8R
Jon's phony baloney SCIENTIFIC method of taking the D cells out of his Boy
Scout flashlight to perform some silly experiment where he zaps a 50W
resistor for 2 seconds and then exclaims, see I put my money where my mouth
is and no spurious oscillation occurred nor did the resistor explode or even
get warm.
Let me tell you, he has made a believer out of me. I can't wait to see his
next post for another scientific revelation...!!!
Dave, WT8R
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|