On 13 November 2013 22:45, Larry Benko <xxw0qe@comcast.net> wrote:
> I had made some UHF connector measurements recently and this discussion
> encouraged me to publish them.
>
> If interested see
> http://www.w0qe.com/Technical_Topics/uhf_connector_compensation.html
>
> 73,
> Larry, W0QE
Larry,
I'm not a fan of UHF connectors, but your article was interesting, but
there are a few things I don't understand.
1) You don't describe how you calibrated the VNA which is not so easy
with PL259 as I'm not aware of any cal kits!
It looks to me like you have the open, short and load from an Agilent
85033E 3.5 mm cal kit in the picture, with BNC adapters on them. But
if they are present when the calibration of the VNA is performed, the
error correction will not be correct, as the offset delays of all the
standards will be increased dramatically.
>From memory the offset delays of the opens and short in that kit are
around the 30 to 32 ps, but your adapters will probably add double
that, so all the error correction wil be wrong.
2) Assuming you got a valid calibration, again there is no mention of
the effect of the BNC to SMA adapters. But if the calibration is not
valid, it changes things a lot.
Dave
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