nanoVNA test board

[Jacek Radzikowski]

For frequencies within the HF range the impact of impedance mismatch caused
by using the breadboard should not be big. You may start seeing some effect
when working closer to 30MHz. However at uhf and vhf frequencies
breadboarding can be problematic.
At higher frequencies you should also start paying attention at the
location of the calibration plane, i.e. the location where the vna sees the
end of the transmission line. This is the point, to which all measurements
will be referenced, and any connections between the vna and this point are
becoming "invisible" (as long as they stay the same as during the
calibration).
At GHz frequencies using a coupler longer by a couple of mm than what was
used for "through" calibration can introduce a noticeable phase shift.

Jacek
kw4ep


On Wed, Mar 24, 2021 at 1:03 PM Alex Fraser <beatnic at comcast.net> wrote:

> I soldered the 6 SMA jacks on the little nanoVNA test board kit.   It was
> good soldering practice and a way to assess my current soldering
> abilities.  I went fairly well.  As the fumes from the flux whirled around
> my head I had some thoughts...
>
> If a made an adapter for the SMA jack so I could plug it into one of those
> plastic push pin breadboards, then could I expect any good reading with the
> nanoVNA?  Would I calibrate connected to the breadboard for open, jumpered
> for short and a 50 ohm resister pushed for resistance? What would be the
> frequency limits for using those breadboards?  Are there any tricks as to
> which way you use the rows of pin holes to plug in components?
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