[Amps] SWR and amplifiers

[Carl]

But the Bird manual is very clear and even the 2 way shop users understand 
that.

Carl


----- Original Message ----- 
From: <donroden at hiwaay.net>
To: <amps at contesting.com>
Sent: Thursday, May 25, 2017 10:05 AM
Subject: Re: [Amps] SWR and amplifiers


> Just like the clock that is only correct twice a day, even the highly 
> regarded Bird 43 "wattmeter" isn't always measuring what you think it  is 
> measuring.
>
> Don W4DNR
>
>
>
> Quoting Bill Turner <dezrat at outlook.com>:
>
>> According to Ron, K4INM, (original post below) my hypothetical
>> transmitter is putting out 1000 watts but only 900 is actually
>> radiated into space. The 100 watt difference is lost in the
>> transmission line. Correct?
>>
>> OK, lets suppose I have a superconductive transmission line,
>> cryogenically cooled conductors with a vacuum dielectric, zero loss.
>> The SWR is still the same, reflected power is the same, but now where
>> does the lost power go? Would my SWR meter still show 1000 forward and
>> 100 reflected?
>>
>> 73, Bill W6WRT
>>
>> **********************************************************************************
>>
>> Here is Ron's original post:
>>
>>  Do not worry about the confusion, it is all too common among HAMs
>> even
>> highly seasoned ones, to get this wrong.
>> You will soon here the opposite of the following here, but they are
>> wrong.
>>
>>    The amplifier outputs 1,000 Watts.
>>
>>    900 Watts minus "transmission line loss" X 1.0 is radiated.
>>
>>    100 Watts are reflected by a line to "load mismatch" back to the
>> "generator" the amplifier (the only cause of any SWR) or reflected
>> power.  This power when it reaches the (generator" the amplifier)
>> finds
>> a source impedance of under one Ohm, so it is reflected back up the
>> transmission line experiencing a "transmission line loss" X 2.0 where
>> 90% of that power is radiated.
>>
>>    10 Watts are reflected by a line to "load mismatch" back to the
>> amplifier finding a source impedance of under one Ohm, so it is
>> reflected back up the transmission line experiencing a "transmission
>> line loss" X 2.0 where 90% of that power is radiated.
>>
>>    1.0 Watts are reflected by a line to "load mismatch" back to the
>> amplifier finding a source impedance of under one Ohm, so it is
>> reflected back up the transmission line experiencing a "transmission
>> line loss" X 2.0 where 90% of that power is radiated.
>>
>>    0.1 Watts are reflected by a line to "load mismatch" back to the
>> amplifier finding a source impedance of under one Ohm, so it is
>> reflected back up the transmission line experiencing a "transmission
>> line loss" X 2.0 where 90% of that power is radiated.
>>
>>    100% of the generated power is either radiated or turned into heat
>> from the transmission line (and balun + antenna wire) losses.  (mostly
>> resistive)
>>
>>    None of the forward power stays in the amplifier, although the
>> reflected power does change the "loading" of the amplifier, changing
>> it's operating conditions, from what it was with a pure reactive-less
>> resistive load.
>>
>> --
>>    Ron  KA4INM - Youvan's corollary:
>>                  Every action results in unwanted side effects.
>>
>>
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>
>
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