Usable frequency ranges, depending on the application:
broadband transformers: 1 – 30 MHz
RFI / EMI / CMC suppression: 1 – 20 MHz
An impedance> 1000Ω (for operating frequency) is sufficient for most applications. The coils should be made with very good quality RG-316 coaxial cable. Any high quality RG-316 coaxial cable can allow 500W-1kW power in 160 /80/40m bands. For higher bands> 10MHz, it is recommended to use the additional Teflon insulated coaxial cable to keep the losses low.
According to the table below, for Wurth Elektronik 742700790 (our case), between 5 – 8 turns would be enough to obtain an impedance of at least 1000-2500Ω, from 1.8 – 14MHz .
|Dimensions||3 × 1.6 × 1.6 cm|