RadioBanter - View Single Post - Connectors for MFJ-269

[email protected] · September 18th 06, 07:33 PM posted to rec.radio.amateur.homebrew

wrote:
Hello all of you,
I am using my MFJ-269 now more frequently.
The more I use it the more I have questions.
What kind of connection do you use when you want to measure inductor
or capacitor or to check the impedance of a resistor ?
I have use the cable of my scope and a homebrew pl259 with wire and
aligator grip with various result.

Happy day
72 de Jean (VE2GHI)

Hi Jean, I use a PL259 and a couple of short pig tails (6cm) with an
minature alligator clip.

If you are measuring L or C, their Reactance is frequency dependent.
The frequency at which you measure must be such that Xl or Xc is less
than 650 ohms. (the MFJ takes the reactance and the frequency and
converts that to L or C). Sometimes the frequency will be high enough
that the stray L or C of the pig tails will affect your reading. Up
above 20-25 Mhz I measure the L and C without the component hooked up
and subtract that reading from the one I get with the component
connected. Hopefully that takes some of the error introduced by the
long leads out.

Gary N4AST