http://elecraft.85.s1.nabble.com/KPA-500-Output-for-Input-schedule-tp6352735p6353889.html
> Joe,
>
> 325W @ 15W drive
> 410W @ 20W drive
> 490W @ 25W drive
> 510W @ 26W drive
> 530W @ 27W drive
> 560W @ 28W drive
> 580W @ 29W drive
> 600W @ 30W drive
> 630W @ 31W drive
> 650W @ 32W drive
> 675W @ 35W drive
> 690W @ 37W drive
> 700W @ 40W drive
>
> Is this still about right for your calculations.....
>
> Gary
>
>
> On 12 May 2011 08:18, Joe Subich, W4TV <
[hidden email]> wrote:
>
>>
>> Adding gain calculation ...
>>
>>
>> > 2W = 30W 11.8 dB
>> > 2.5W = 40W 12.0 dB
>> > 3w = 50w 12.2 dB
>> > 3.5w = 60w 12.3 dB
>> > 4w = 70w 12.4 dB
>> > 4.5w = 75w 12.2 dB
>> > 5w = 80w 12.0 dB
>> > 5.5w = 90w 12.1 dB
>> > 6w = 100w 12.2 dB
>> > 6.5w = 110w 12.3 dB
>> > 7w = 120w 12.3 dB
>> > 7.5w = 130w 12.4 dB
>> > 8w = 150w 12.7 dB
>> > 8.5w = 160w 12.7 dB
>> > 9w = 170w 12.8 dB
>> > 9.5w = 180w 12.8 dB
>> > 10w = 190w 12.8 dB
>> > 11w = 200w 12.6 dB
>> > 12w = 225w 12.7 dB
>>
>> The numbers look about right including the decreased gain at low level
>> (as expected). Using 12.6/12.7 dB would indicate 33W drive for 600W
>> out. 40W drive for 600W output would indicate ~1 dB of compression.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>> On 5/11/2011 5:28 PM, Gary Gregory wrote:
>> > Stan,
>> >
>> > Allow some variation to antenna variations also.
>> >
>> > This on 15M, swr is 1.0:1
>> >
>> > 2W = 30W out
>> > 2.5W = 40W
>> > 3w = 50w
>> > 3.5w = 60w
>> > 4w = 70w
>> > 4.5w = 75w out
>> > 5w = 80w
>> > 5.5w = 90w
>> > 6w = 100w
>> > 6.5w = 110w
>> > 7w = 120w
>> > 7.5w = 130w
>> > 8w = 150w
>> > 8.5w = 160w
>> > 9w = 170w
>> > 9.5w = 180w
>> > 10w = 190w
>> > 11w = 200w
>> > 12w = 225w
>> >
>> > NOTE to ALL: This was not done with lab equipment or even a dummy load.
>> This
>> > was measured using a K3 and a tri-band yagi and a cw tone.
>> >
>> > Gary
>> >
>> > On 12 May 2011 07:13, Al Lorona<
[hidden email]> wrote:
>> >
>> >> It's very easy to measure the 1-tone gain compression characteristics
>> of an
>> >> amplifier. The desired result is a graph of Pout vs. Pin, with Pin on
>> the
>> >> horizontal axis and Pout on the vertical.
>> >>
>> >> So what one needs to do is set Pin to the amp, and measure Pout into a
>> >> dummy
>> >> load. If you do this for several values of Pin, you'll be able to plot
>> all
>> >> of
>> >> those measured points on the graph. It will look like a pretty straight
>> >> line
>> >> toward the lower Pin values, then it will flatten out (become more
>> >> horizontal)
>> >> as Pin (and Pout) get higher.
>> >>
>> >> The slope of the line is the gain of the amplifier.
>> >>
>> >> Very often the Pin values are 1 dB apart. One dB is about a 25%
>> increase in
>> >> power. Meaning that if you are measuring Pin in Watts, then you can set
>> Pin
>> >> to
>> >> roughly the following values:
>> >>
>> >> 1, 1.5, 2, 3, 4, 5, 7, 10, 13 Watts, etc.,
>> >>
>> >> and measure the Pout at each value. The values should be converted to
>> dBm
>> >> before
>> >> plotting. That's all there is to it.
>> >>
>> >> This is all done in CW mode. If you want to go further, you can go into
>> SSB
>> >> mode
>> >> and apply two tones to the amp (which a K3 has the ability to do) and
>> then
>> >> look
>> >> at the output of both the K3 and the KPA500 with a spectrum analyzer...
>> but
>> >> I'll
>> >> leave that explanation for another day... or it can be found on the
>> web.
>> >>
>> >> Al W6LX
>> >> ______________________________________________________________
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>> >
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