On Wed, Jul 21, 2021 at 06:27 AM, Jim Lux wrote:
On 7/20/21 7:11 PM, Roger Need via groups.io wrote:
How did you calibrate? If you keep clips at a fixed distance during
calibration and measurement you will get better results.
calibrated using a 50 ohm BNC load, a BNC short, and left it open.
Yes, if I were to tape the leads down, it would probably work better,
but this was a first try at a "rough and ready" measurement
You will get much better results if you calibrate using the clips as the "reference plane". You just clamp them in a fixed position a short distance apart and then use a shorting wire, an open and a 50 ohm resistor (two 100 in parallel with short leads) to calibrate. Results are OK for HF but not much above that.
For serious measurements you need a much better test jig. I use this one made from an SMA female connector and some pin sockets/
Roger
Roger Need
