I bought two packages of DX Engineering's "non-inductive"470 ohm 2 watt
resistors with the intent of using them to terminate Beverages, calibrate/test
bridges, and build some dummy loads. Yesterday I wired one of them to a PL-259
with VERY short leads and measured it with both an AEA CIA-HF and my MFJ-
259B (carefully calibrated per Tom's excellent applications note).
I measured at 1 MHz intervals between 1 MHz and 10 MHz (down to 2 MHz on the
MFJ). The AEA and MFJ agree within reasonable experimental error that the
resistor shows considerable reactance at even the lowest frequencies.
Interestingly, the magnitude of the impedance stays fairly close to 470 ohms
this range of frequency on both analyzers, and the typical phase angle is on
order of 17 degrees. And while the phase angle does increase a bit with
frequency, the increase is not anything close to proportional.
Has anyone measured one of these resistors with a more precise device (like a
real bridge)? Is 470 ohms simply too far from 50 ohms for the CIA and MFJ to
give acceptable measurements for X and the phase angle?
The 200 ohm load I assembled from four 1/8w composition resistors to run
Tom's calibration reads 200 ohms resistive at 16 MHz, and begins to show some
inductance above 25 MHz on the CIA. The MFJ begins to see inductance well
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