A project log for VUHF Radio

A dual band VHF/UHF module based around two AX5043 radios. Built to work with HAM Radio communications using AFSK and G3RUH modulations.

NotBlackMagicNotBlackMagic 06/30/2020 at 21:160 Comments

Some months ago, I ordered a bunch of dual-band antennas to use in this project and they finally arrived! The antennas I bought are shown in the figure bellow, from left to right they are a Nagoya NA-771 Clone, a Nagoya NA-771 Original, a UV-106UT Clone and a UV-108UT Clone.

All four antennas where tested with a R&S VNA to get there S11 parameters and in the future, I will perform field tests with the VUHFRadio to compare their ranges and “gain”.

The figure bellow shows the comparative result of the two NA-771 antennas in the Sub-GHZ band:

And the results for the same band for the UV-106UT and UV-108UT antennas are shown in the figure below:

Overall the NA-771 antennas have better S11 characteristics for the desired bands of this project. In general a S11 of bellow -10dBm is desirable (VSWR better then 2:1) as this means that over 90% of the power is delivered to the antenna, less than 10% is reflected.

A bit more in-depth results are available on my website as well as all S11 results files for download. I will also, overtime, add more results for other antennas to that page.