NanoVNA and EFHW

The NanoVNA arrived the other week, these units are very good value and work remarkably well.  With small size and weight (63 grams)including battery, it can easily be taken out in the field, providing it is protected from the elements.  The NanoVNA is a PCB sandwich essentially, with open sides.

The first test was to sweep the filters in the compact 20 metre transceiver.  The filters came out pretty well spot on.

Next test was the 3 band SOTA portable end fed half wave antenna to see if it was still in resonance after many activations over the last few years.  It had been repaired a couple of times after tree snags, and maybe lost a cm or two.

The antenna was tested as a sloper in the back yard with one end supported by a 6 metre squid pole, and the feed end supported by a walking pole.  It was also tested in the same configuration but using an 8 metre squid pole.  The results only changed slightly, lowering the resonant frequency.
A short counterpoise was connected but this made very little difference to resonance.
The shots below have some light reflections, it would have been better to connect a PC, but convenience won.

40 metres using 6 metre pole



20m using 6 metre pole

10 metres on 6 metre pole


40 metres using 8 metre pole

20 metres using 8 metre pole

10 metres using 8 metre pole









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5 Responses to NanoVNA and EFHW

  1. Paul Taylor says:

    Watching, watching, finger hovering over BUY button. Is it easy to use? At $75 great value, just don’t want to discover a clunky user experience with this unit.

    • vk3yy says:

      Hi Paul, it is very easy to use although the touch screen is too tiny to use accurately with your finger. I use a stylus with mine and its fine. The touch screen is a resistive one, so you don’t need a conductive stylus. The screen is a little small to read, but I am willing to live with it for the cost, portabilty and functionality.

  2. vk3yy says:

    It is light enough to take on an activation, but would need weatherproofing. The selector switch is rather fragile. It is not necessary to use the selector switch anyway, I have only used the touch screen. It was fairly readable outside on the weekend, but I can’t remember how bright the sky was. There are some 3d printed case designs on thingverse that look ok, one from a VK5.

  3. Andrew VK1DA says:

    These devices represent a revolution in simple instrumentation for what was a very complex subject when we just had SWR meters, dip meters or noise bridges to assess antennas. they were good when they cost much more than this one does, but at this price everyone should have one if they are experimenting with antennas.

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