Thanks Jim.
I learned about the DG8SAQ device after I'd already bought the AIM4170C. The
AIM is a fine analyser but it tops out at 180MHz so I won't see quite such fine
detail. May be time to upgrade!
73, David G3WGN M6O
On Tue,4/12/2016 12:17 PM, David Aslin G3WGN wrote:
> I do have a short length (maybe 60ft or so) of properly stored near-new
> LDF4-50 so I can use that as the baseline.
> Anyone actually attempted impedance or another measurement to check for
> performance change?
Hi Dave,
The best way I know of to measure coax parameters is to do an open and short Z
measurement with a vector analyzer and import both into ZPlots, which is an
Excel spreadsheet. You also need to enter the length if you want Vf and
attenuation/ft (or /m). ZPlots will yield a graph of Zo, Vf, and attenuation
vs. frequency.
My weapon of choice for measurement is DG8SAQ-designed VNWA, built and sold in
the UK by SDR Kits. About $700 shipped to the US with calibration kit. It also
does excellent TDR by sweeping over whatever frequency range you choose and
taking the inverse FFT. For best detail (and to see "little" issues, I usually
sweep 100-500 MHz. For even better detail, sweep 600-1,300 MHz.
73, Jim K9YC
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