Posted by
Francis Belliveau on
Jul 23, 2006; 10:22pm
URL: http://elecraft.85.s1.nabble.com/Funny-power-measurements-tp392406.html
I created what I thought was a reliable method of measuring the power out of
my K2 and am puzzled by the results. What I did was:
1. Built the RF probe from the K2 manual onto a 50 ohm dummy load.
2. Attach that to one of the antenna connections on my KAT2.
3. Tune the load on all bands at the band-center frequency to be
measured.
4. Attach my DMM to the probe connection points.
The table below shows my voltage measurements and computed power. I am very
puzzled about 80- meters and have done that one twice without significant
difference.
The top end of 10 meters resulted in HiCur=3.00 so that one may need some
help but only that one. I am using a 5 amp supply so that should not be an
issue.
Anybody with any ideas as to where I should start untangling things?
Fran
P.S. If the table below does not look ve4ry good, just paste it into notepad
and it should be more easily read.
--------------------------------------------------------
| Freq (Mhz) | V (RMS) || Watts for R = 50 |
| PwrSet-> | 1 | 4 | 10 || 1 | 4 | 10 |
|------------+------+------+------++------+------+-------|
| 3.500 | 3.6 | 14.4 | 14.4 || 0.26 | 4.15 | 4.15 |
| 3.750 | 6.2 | 21.8 | 21.7 || 0.76 | 9.50 | 9.42 |
| 4.000 | 6.2 | 20.8 | 20.8 || 0.76 | 8.65 | 8.65 |
|------------+------+------+------++------+------+-------|
| 7.000 | 7.9 | 14.2 | 20.3 || 1.25 | 4.03 | 8.24 |
| 7.150 | 8.7 | 15.5 | 21.6 || 1.50 | 4.81 | 9.33 |
| 7.300 | 8.2 | 14.6 | 20.5 || 1.33 | 4.26 | 8.41 |
|------------+------+------+------++------+------+-------|
| 10.100 | 8.2 | 10.7 | 18.3 || 1.35 | 2.29 | 6.70 |
| 10.125 | 8.2 | 10.7 | 18.2 || 1.33 | 2.29 | 6.62 |
| 10.150 | 8.2 | 10.7 | 18.1 || 1.33 | 2.29 | 6.55 |
|------------+------+------+------++------+------+-------|
| 14.000 | 9.8 | 10.7 | 22.3 || 1.90 | 2.29 | 9.95 |
| 14.175 | 10.2 | 11.2 | 22.7 || 2.06 | 2.51 | 10.31 |
| 14.350 | 8.0 | 8.7 | 20.1 || 1.26 | 1.51 | 8.08 |
|------------+------+------+------++------+------+-------|
| 18.068 | 7.2 | 13.0 | 16.7 || 1.02 | 3.38 | 5.58 |
| 18.118 | 7.3 | 13.3 | 16.9 || 1.05 | 3.54 | 5.71 |
| 18.168 | 7.3 | 13.4 | 16.9 || 1.06 | 3.59 | 5.71 |
|------------+------+------+------++------+------+-------|
| 21.000 | 9.0 | 12.8 | 20.0 || 1.63 | 3.28 | 8.00 |
| 21.225 | 8.8 | 12.6 | 19.7 || 1.53 | 3.18 | 7.76 |
| 21.450 | 7.8 | 11.2 | 18.8 || 1.20 | 2.51 | 7.07 |
|------------+------+------+------++------+------+-------|
| 24.890 | 8.6 | 12.8 | 19.8 || 1.48 | 3.28 | 7.84 |
| 24.940 | 8.2 | 12.4 | 19.5 || 1.34 | 3.08 | 7.61 |
| 24.990 | 7.8 | 11.9 | 19.1 || 1.23 | 2.83 | 7.30 |
|------------+------+------+------++------+------+-------|
| 28.000 | | 14.6 | 19.5 || | 4.26 | 7.61 |
| 28.400 | | 13.9 | 18.9 || | 3.86 | 7.14 |
| 28.800 | | 9.7 | 15.5 || | 1.88 | 4.81 |
--------------------------------------------------------
Expect | 7.07 | 14.14| 22.36
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