on 3/7/00 4:09 PM, sm5ki at sm5ki@algonet.se wrote:
> No it is very tiring to try to follow this endless dicussion in US English.
> What on earth are some of you trying to prove? I have been sitting here for
> more than 1 hour trying to read to-days endless Kindergarten discussion. For
> my piece in mind I have soon to leave this amps net.
I don't know how to write more clearly. Sorry.
I believe that parasitic resistors that are found to be bad are damaged by
heating over long periods of time and not by parasitic oscillations as Rich
suggests.
Rich's theory says that a parasitic event of a large enough magnitude can
occur so quickly that it burns up the resistors from the inside yet, you
don't see any indication on the front panel meters of the amp. He says it
is that quick.
To not move the meters, the oscillation must have occurred in a time less
than a few milliseconds. Perhaps much, much less.
In my experiment, I generated 320 Joules of energy across a 6 Watt 50 Ohm
resistor at 144 MHz.
A Joule is defined as 1 Watt-Second. So to find the number of Joules you
multiply Watts times Seconds. 160 Watts (my output power) * 2 seconds (key
down time).
Let's say that our parasitic oscillation event took place in 0.5
milliseconds of time. Let us also say that I am using the same resistor
network in my suppressor that I used in my bench testing. We know that it
is capable of handling 360 Joules of energy without being destroyed. At 0.5
milliseconds, 320 Joules means that my output power is 640 KILOWATTS!!!!!!
What tube in amateur service is capable of generating 640 Kilowatts of power
at VHF frequencies???
So, then how could a short, extremely intermittent parasitic oscillation
have destroyed the resistors in the suppressor?
I would like to know.
I hope this puts the context of all this in easier to understand English or
American! :-)
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
Member: ARRL, AMSAT, DXCC, NRA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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