On 12/4/2013 4:25 AM, amdx wrote:
On 12/4/2013 3:07 AM, Helmut Wabnig wrote:
On Tue, 03 Dec 2013 21:07:35 -0600, amdx wrote:

I may be asking for something that doesn't have an answer.

I connected a voltmeter to the R meter of my MFJ259.
I checked a bunch of resistors and recorded the voltages.
Now I have all these voltage readings vs. Resistance and
don't know how to relate them except for a conversion graph.

Is there a math function that relates these voltages to Resistance?

Load Resistance Voltage reading

7.5 ohms 0.0388 volts
15 0.0444 volts
25.5 0.0478 volts
39 0.0577 volts
50 0.0614 volts
100 0.0807 volts
140 0.0891 volts
174 0.0935 volts
221 0.0980 volts
249 0.0100 volts
365 0.0106 volts
498 0.0109 volts

If you can figure this out, I'll reward you with the
SWR chart :-)

Thanks, Mikek


Ever heard about OHM'S LAW?


w.


Yes Helmut I have. Obviously you don't have any understanding
of my question or you wouldn't have ask a smart ass question.
An MFJ259 is an antenna analyzer, it has two analog meters on it,
one displays the resistance of the load and the other the SWR.
Both meters have a non linear scale on the faceplate.

One would normally think a 50 ohm resistor would display a ratio
of 2 to 1 when compared to a 100 ohm resistor. As you can see the ratio
is 1.3 to 1. Also a 500 ohm and a 50 ohm resistor have a ratio of 10.
But the voltage ratio is 3.56.
So, do you have any other ideas?
Mikek

I noticed I slipped a decimal point on the last few measuements.


7.5 ohms 0.0388 volts
15 0.0444 volts
25.5 0.0478 volts
39 0.0577 volts
50 0.0614 volts
100 0.0807 volts
140 0.0891 volts
174 0.0935 volts
221 0.0980 volts
249 0.1000 volts
365 0.1060 volts
498 0.1090 volts
The last Ratio I posted as 3.56 to 1 should be 2.8 to 1.