Simple 2m Antennas, Base and Mobile for Beginners
The club has recently had an influx of new member, some of which are new to the world of amateur radio. Some have bought the cheap Baofeng handheld transceiver to listen to activity on 2m and 70cm. It has been reported that reception on the rubber duck antenna that comes with the transceiver is not that good.
Therefore, I have put together some ideas for simple antennas that can be easily put together.
This is not meant to undermine the technical prowess of some members but is more directed to newcomers and show how some simple solutions can be developed.
The 2m FM band is from 145.200 to 145.615Mhz, channelised with 12.5Khz separation i.e. 145.200, 145.2125, 145.225 etc. With the calling channel at 145.500 Mhz. Taking the centre of the band to be approximately 145.400Mhz a half wave dipole would be 1.03m in length with two quarter wave elements of 515mm.
- The first example is a dipole made from coax stuck to a window. Trim back 520mm of the coax outer, then making a hole in the braiding pull the inner through. Inner goes up braid goes down (not that it matters much) remaining coax at right angles to the dipole. Trim both ends of dipole for best SWR at 145.4Mhz. If aesthetics are not a problem the antenna could be put on two pieces of wood in T formation and stuck out a window. This will also work in the loft. All depends where your shack is and could you hide it behind the curtains of a window. Remember the higher the antenna the better, especially if you are surrounded be higher houses than your own. This antenna can be made for 70cms by adjusting the dimensions. The half wave dipole is the basis of the most popular and easiest resonant antenna to build albeit single frequency.
2 If a more permanent solution is required, then using commercially available PL259 female dipole “T” to 3/8 screw fittings. Adaptors then hold steel rods and screw into the 3/8 screw sockets. The steel rods can come in various length lengths dependant on the supplier and can be cut to the appropriate length for best SWR. This dipole then can be attached to the wall with a TV type bracket
This setup is on a broom handle and for 2m. I stick it out of the upstairs window and work Barrow.
- For mobile use a similar setup can be used if you have a roof rack mounting or gutter mounting with a 3/8 fitting, then a steel rod with the 3/8 adaptor can be used on a car or van.
- The other option for mobile working is a mini mag mount I had this for when I first got a handheld and took it in the car. It covered 2m and 70cm.
But I now use a colinear with a PL259.
I hope this gives you food for thought and it is only quick, cheap, and cheerful solutions.
Remember initially cut long you can always remove but it is difficult to add on, and trim in small amounts until you get a feel for what your doing.
That’s why the coax solution is always a good starter for 10.
Regards and 73 Brian M0SSN