Did you do an OSL calibration of the NanoVNA over the frequency range of
interest? How is the antenna supported? How is it fed? I cannot imagine an
antenna being that far off. Your length calculations for 172 MHz are
correct. The third harmonic of 172 MHz IS 513 MHz. So the antenna will work
at that frequency. Dipole antennas typically work well at odd harmonics of
the lowest resonant frequency.
What is the SWR at 172 MHz?
Zack W9SZ
On Mon, Mar 31, 2025 at 2:51?AM hobride via groups.io <hobride=
[email protected]> wrote:
Hello everyone,
I have bought a NANO VNA H4 to build simple dipole antennas.
Now I have made a simple dipole antenna for testing. This should be tuned
for 172 MHz. The total length is ~83 cm (2,72 feet), one leg is ~41.5 cm
(1,36 feet).
When I now connect this antenna and try to measure it, the result is a
lowest SWR (1.15) at 513 MHz.
Can this be possible? I am not a radio specialist. I am an IT guy.
I have flashed the NANO VNA H4 to the latest firmware (tried DiSlord and
Hugen) and also calibrated it.
Perhaps I need to make further settings after flashing?
