Simple dual-band antennas for the 144 and 433 MHz amateur radio bands

June

2024

Simple dual-band antennas for the 144 and 433 MHz amateur radio bands

антенны, УКВ

18 June 2024 10:55

Dipoles for two bands 144 and 433 MHz for operation through VHF repeaters (gain 0 dBd / 3 dBd).

Previously (10 years ago) I was working on calculating Open Sleeve antennas, but the hard drive with the antenna models failed. I recently restored the HDD in the service and am starting to post models of antennas from it, accompanied by drawings.

Antenna No. 1 - dual-band dipole 144/433 for 75 Ohm cable

Power supply to the central dipole section with a 75 Ohm cable.

Dimensions for a tube with a diameter of 8 mm (acceptable diameter from 4 to 10 mm):

Element	A	S1	S2
Position, mm	0	43	-43
Length, mm	980	328	328

Matching with 75 Ohm cable in the range of 144 MHz SWR < 1.2, in the range of 433 MHz < 1.2.

Antenna No. 2 - dual-band dipole 144/433 for 50 Ohm cable

Antenna split dipole 2-band 144/433 for 50 Ohm cable.
Power supply in the section of the central dipole.

Dimensions for a tube with a diameter of 8 mm (acceptable diameter from 4 to 10 mm):

Element	A	S1	S2
Position, mm	0	31	-31
Length, mm	968	316	316

SWR in the 144 and 433 MHz bands (50 Ohm cable):

Matching with 50 Ohm cable in the range of 144 MHz SWR < 1.5, in the range of 433 MHz < 1.3.

The gain in the 435 MHz band is 5.4 dbi (or 3 dbd):

Antenna No. 3 - simplified dual-band dipole 144 / 433 MHz (50 Ohm)

A further simplification of the "open sleeve" antenna is the elimination of the second driven element. Optimization leads to the same SWR parameters, but the radiation pattern in the 433 MHz range is not circular, but is elongated towards the short element.

Simple dual-band antenna 144/433 MHz