http://elecraft.85.s1.nabble.com/K3-Internal-Tuner-Question-tp7143025p7146899.html
> Well here's one for you:
>
> My setup is K3 to wattmeter to dummy load.
>
> The K3 says 100w
> If the external wattmeter is:
> MFJ 949E tuner/SWR meter (tuner out of circuit) it says 100w
> cheapo Radio Shack SWR meter 100w
> LP 100A digital wattmeter says 70 watts
> Elecraft W2 says 70 watts
>
> Yes, I have run the transmitter calibration routine in the K3 Utility
> program. SWR in all three cases is nominal 1:1
>
> The result is the same to a real antenna although the SWR is not 1:1
>
> What could be causing the external-sensor type wattmeters to read low?
>
> Buck
> k4ia
> K3 # 101
>
> On 1/2/2012 10:14 PM, Ron D'Eau Claire wrote:
>> Quite right.
>>
>> There a couple of impedance transformations that occur between the
>> collectors (or plates) of the power amplifiers and the antenna. The first is
>> done by the output filters. In modern rigs, they are fixed tuned and
>> designed in common Ham rigs to convert the impedance at the collectors to 50
>> ohms, resistive.
>>
>> If your antenna presents that impedance, no further conversion is necessary.
>> But many antennas don't.
>>
>> In the "old" days the output network was adjustable and we simply did the
>> necessary adjustments and all was good.
>>
>> Nowadays, with fixed tuned amplifier output networks, we need another
>> matching network to handle the conversion when the antenna doesn't present a
>> 50 ohms resistive load.
>>
>> Enter the "antenna tuner" that converts what the antenna shows to the 50
>> ohms needed by the output filter. The built in SWR meter displays the SWR on
>> the link between the tuner and the output filter.
>>
>> Ron AC7AC
>>
>> -----Original Message-----
>> From:
[hidden email]
>> [mailto:
[hidden email]] On Behalf Of Tom Azlin N4ZPT
>> Sent: Monday, January 02, 2012 6:19 PM
>> To:
[hidden email]
>> Subject: Re: [Elecraft] K3 Internal Tuner Question
>>
>> Thanks Matthew. I should not have spoken like that. Should just
>> have said the meter in the line would not change just because a radio
>> tuner transformed impedance to make the radio happy. 73, tom n4zpt
>>
>> On 1/2/2012 9:11 PM, Matthew Pitts wrote:
>>> Tom,
>>>
>>> All an antenna tuner does is show the radio the load it expects; the
>>> SWR will still be high at the output of the tuner, and an SWR meter
>>> in the coax at that output will show it as it actually is at that
>>> point, not as it is on the input of the tuner/output of the radio.
>>>
>>> Matthew Pitts N8OHU
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