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
