>
>In a message dated 3/7/00 12:36:39 AM Eastern Standard Time,
>jono@enteract.com writes:
>
>> Some of you questioned my technical sanity when I suggested dumping some
>VHF power into a 5 Watt resistor and seeing if it can handle the power.
>>
>> My original quote:
>> > If anyone doubts me, take your two meter radio and a let's say a 5 Watt
>> > resistor and hook them up. Key up your radio (at full power) and let it
>> go immediately. You won't damage the resistor nor even make it warm. And
>> > you'll likely have keyed into it for at least 250 to 500 mS which is much
>> > longer than Rich's 10s of mS.
>
>So what is your point Jon?
>>
>> Well, I decided to put my money where my mouth is. I took 2 of Rich's 100
>> Ohm 3 Watt resistors (6 Watt total dissipation), put them in parallel and
>> soldered them to a PL-259. I then hooked them up to the output of my 2
>> meter setup which consists of an FT-847 and a Mirage amp which puts out
>> about 160 Watts.
>
>And........
>>
>> The resistors measured 52.1 Ohms before I applied power. After a short CW
>> dah at full power output (160 W), I measured the resistors again - 51.2
>Ohms
>> - within the error of my power meter. Did a little longer dah again. The
>> resistors still measured 51.2 Ohms. Lastly, I did a 2 second keydown. The
>> resistors started turning a little brown, were quite warm, but were STILL
at
>> 51.2 Ohms.
>>
>> I feel my point was proven.
>
>Wow....this is rocket science or is this from the General class question
>pool?
When a point is truly proven, silence is good form. . .
>>
>> So the question is:
>>
>> Rich claims that suppressor resistor are damaged by a nearly instantaneous
>> output of VHF energy due to an "oscillation." This "oscillation" occurs so
>> fast that the panel meters on the PA don't have time to respond. This, as
>> W8JI said, is probably on the order of nano-seconds or even a few
>> milliseconds at MOST.
>>
>> If these same resistors can handle 160 Watts of VHF energy for 2 seconds,
>> how much could they really handle in less than a thousandth of the time? I
>> doubt enough to be damaged as Rich claims.
>
>This is the point where ignorance overtakes (overshadows) common sense. (1)
>Apparently Jon hasn't the slightest idea 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.
Excellent point. One of the great entertainments on the AMPS group is
specious poop.
cheers
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