I have a set of SS SMA PCB mount male connectors that I soldered 4 200 ohms
0603 resistors around the clock, 12,3,6,9 and it measures very close to my
HP SMA termination.
Mel, K6KBE
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On Sat, Nov 2, 2019 at 10:38 AM hwalker <herbwalker2476@...> wrote:
On Sat, Nov 2, 2019 at 09:56 AM, QRP RX wrote:
It looks like cheap Chinese SMA-terminators. If so, they have bad
performance.
Try to measure it with multimeter, does it have 50.0 ohm?
Most of all it has high error, something like ¡À5 ohm.
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As QRP replied, there is a difference between a 50 ohm termination and a
good quality 50 ohm calibration load. That is why commercial calibration
kits cost so much money. Using an un-characterized termination, your OSL
calibration will look correct but you will be referencing all your
measurements to however good the termination is. For example if you use a
poor termination for performing your OSL calibration and then measure a
good quality load. The load will look poor.
Checking the termination with a multimeter only tells you what its DC
characteristics are. You need to measure the termination against a known
good quality load to verify its characteristics. It might prove worthwhile
to construct your own 50 ohm load using the methods presented by other
members of this group.
Herb
