5 watts to KPA500

[John's email]

Hi,

Out of curiosity ... those fortunate owners of the KPA500 could take
a look and let me know what output they produce when the input to the
amp is exactly 5W

Into a 1.3-1 SWR on 7250 I get right at 50 watts output for 5 watts input. My dummy load is on back order from MFJ or I could be more accurate!

John KE4D

K2 #7231 KPA500 #636
 
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[Bill Breeden]

Here are some measurements I made a couple of weeks ago with my FT-817 and KPA500:

Band: FT-817 Out = KPA500 Out

160 Meters: 6.0 Watts = 70 Watts.
80 Meters: 5.8 Watts = 75 Watts.
40 Meters: 5.3 Watts = 75 Watts.
30 Meters: 5.1 Watts = 75 Watts.
20 Meters: 5.1 Watts = 75 Watts.
17 Meters: 5.0 Watts = 80 Watts.
15 Meters: 5.0 Watts = 80 Watts.
12 Meters: 4.9 Watts = 90 Watts.
10 Meters: 4.9 Watts = 100 Watts.
6 Meters: 4.2 Watts = 125 Watts.

The power output from my FT-817 was measured with an Oak Hills Research WM-2 QRP Wattmeter inserted between the FT-817 and the KPA500. The power output from the KPA500 into a MFJ-264 dummy load was measured with the KPA500's internal wattmeter and read from the digital readout on the front panel of the KPA500. All measurements were made with the FT-817 key down in CW mode on a frequency in the CW segment of each band.

I use my KPA500 with my K3, not my FT-817, but an amplifier discussion on the FT-817 group led me to make this test to satisfy my own curiosity.

73,

Bill - NA5DX


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[Don Wilhelm-4]

 From related comments on the Elecraft reflector in the past few days
plus the data provided by these measurements, one would multiply the
input power by 15 and obtain an approximation for the output power.  
There will be some variation from band to band, and some variation from
KPA500 to KPA500, but this seems to be an average.  Based on those
figures, if the gain of the KPA500 were expressed in dB it would be
somewhere between 11.5 and 12 dB.

73,
Don W3FPR

On 1/15/2012 6:55 PM, Bill Breeden wrote:

> Here are some measurements I made a couple of weeks ago with my FT-817 and KPA500:
>
> Band: FT-817 Out = KPA500 Out
>
> 160 Meters: 6.0 Watts = 70 Watts.
> 80 Meters: 5.8 Watts = 75 Watts.
> 40 Meters: 5.3 Watts = 75 Watts.
> 30 Meters: 5.1 Watts = 75 Watts.
> 20 Meters: 5.1 Watts = 75 Watts.
> 17 Meters: 5.0 Watts = 80 Watts.
> 15 Meters: 5.0 Watts = 80 Watts.
> 12 Meters: 4.9 Watts = 90 Watts.
> 10 Meters: 4.9 Watts = 100 Watts.
> 6 Meters: 4.2 Watts = 125 Watts.
>
> The power output from my FT-817 was measured with an Oak Hills Research WM-2 QRP Wattmeter inserted between the FT-817 and the KPA500. The power output from the KPA500 into a MFJ-264 dummy load was measured with the KPA500's internal wattmeter and read from the digital readout on the front panel of the KPA500. All measurements were made with the FT-817 key down in CW mode on a frequency in the CW segment of each band.
>
> I use my KPA500 with my K3, not my FT-817, but an amplifier discussion on the FT-817 group led me to make this test to satisfy my own curiosity.
>
>

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