[600MRG] Radiated power

[eric]

I need to add that the broadcast rules SPECIFICALLY require the use of 
an RF ammeter precisely BECAUSE it is independent of reflected power.  
The only requirement is that the feed point RESISTANCE is properly known.

eric


On 12/1/2017 11:19 AM, Michael Mussler wrote:
> It might be worth considering placement of the RF ammeter. If placed along a transmission line, the radiated power is also a function of standing waves on the transmission line. With load (antenna) mismatch and resulting standing waves the magnitude of the RF current (or RF voltage) would be the sum of incident and reflected current. The radiated power from the I squared R equation would only be valid if the standing wave ratio is 1:1, i.e. no reflected power.
>
> Mike, AI8Z
> ex WD2XSH/12
>
>> On Dec 1, 2017, at 12:54 PM, Rudy Severns <n6lf at epud.net> wrote:
>>
>> Yep, the RF ammeter is the original "must have" instrument and for many hams
>> that was pretty much it until after WWll.
>>
>>
>>
>> The radiated power (Pr) is the product of the square of the base current
>> (Io) times the radiation resistance (Rr, referred to the base).  Once you've
>> finished building the antenna, Rr is what it is.  All you can do to increase
>> Pr is to increase Io.  This is done by tuning for maximum Io with a given
>> transmitter output power.  To increase Pr further still you'll need either
>> more power or improvements to your antenna.
>>
>>
>>
>> GL and 73, Rudy N6LF
>>
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