On 12/6/2013 4:34 PM, John S wrote:
On 12/6/2013 11:31 AM, amdx wrote:
On 12/6/2013 6:30 AM, John S wrote:
On 12/6/2013 1:52 AM, Jeff wrote:
Maybe I am missing something,and I don't have a MFJ259, but I assume
that the resistance reading is not a true resistance reading but Mod Z.
So any reactive part of the load will contribute to the reading. So
when
used with a real antenna I am not sure why you would need such an
accurate readout, because Mod Z can have a resistive part that is well
away from the 'Resistance' reading on the meter.

73
Jeff

You are correct, Jeff. However, the exercise is to help him with
constructing an equation which relates his data points. It is his
decision to use the info or not.

I'm not trying to be nasty. I have just put blinder on myself to answer
only his direct question without offering better solutions (as if I had
any).

At a freq of 100 MHz I measured a 100 ohm resistor R = 100 SWR = 1.9
Then a 100 in series with 30pf (Xc=53 ohms) R = 85 SWR = 2.4
Then 100 ohms in parallel with 30pf R = 25 SWR = 6

This is not what I expected, so I've learned something.
I have equipment to measure up to 10 MHz, and I can measure
Q up to 50MHz.
I was hoping to use the MFJ259 to do something at higher frequencies.
I don't think this is the direction I should be looking.

Thanks for all your help, Mikek


I'm not sure how the 259 is supposed to work, but I can supply the
theoretical values I think you should get.

100 R = 100 SWR = 2
100 + 30pF R = 100 SWR = 2.7
100||30pF R = 22 SWR = 4

Hope this helps.

At this point I've pretty much given up on the idea that this device
will do what I want, even with some mods.
Thanks, Mikek