Doing some precise level measurement on 50 Ohm system, I came across this termination, Model 24931 28P296-1.
It’s resistance, not quite 50 Ohms, but 51.1 Ohm… not that the DC resistance is the most important characteristics of a 50 Ohm termination, but nevertheless, a reason to check it.
This termination is constructed using a BNC connector, so I expected some kind of thin film resistor inside, maybe damaged by overload or age, leading to the incorrect resistance.
Opening it up, this it what I found:
The resistive element, a Vishay Dale R55D metal film resistor:
And, in fact, it is a 51.1 Ohm, +-100 ppm/K tempco resistor. 0.1 Watts so it is running close to its limit already at 20 dBm! Don’t have the right tools here to measure ‘low frequency’ (< 2 GHz) SWR... but will check back home at the main workshop one time in the future, just for curiosity.