On Thu, 1 Jul 2021 at 13:13, Mikek <amdx@...> wrote:
Testing a couple of TV antennas for Signal strength and just curious about
what they might look at on the NanoVna.
I'll be looking at them through about 70 ft of RG-6 and a SMA to F adapter.
Measuring from 180MHz to 610MHz.
Pretty much a novice here.
Mikek
If you are only interested in measuring the impedance of the antenna, then
just use the 50 ohm cal kit on the end of the 50 ohm coax. The cal kit will
remove the effects of the cable. Just be aware that the minimum SWR, if
measured in a 75 ohm system, will not be the same as if measured in a 50
ohm system. I don't know if there are any settings on the nanovna which
will allow you to easily change the reference impedance, but I would not
mess around with transformers or anything like that.
You can look on a Smith chart view, find the 75 ohm point, then just note
the frequency where the antenna is closest to that point.
You can convert a Touchstone file from 50 to 75 ohm, so look at it later.
The software for the VNWA will do that, and no doubt will other software.
Dave
Dr. David Kirkby, Kirkby Microwave Ltd