2m Folded Dipole - a loft-mounted vertical folded dipole for the 144-146MHz band. Theory: Vertical antenna most appropriate for 2m. A fat dipole (therefore wide band) will have a lower feed impedance at resonance than a thin dipole so 50Ω feeder cable e.g. RG58C/U may be used. It's an economy, lossy cable (best to keep the length less than 10 metres) for low power use and has a stranded centre conductor so less likely to break if the cable is bent. The conductors are tinned so easy to solder.
Making it: The dipole is made from 2∙5mm2 × 90cm long power cable: strip off the outer insulation then use the two insulated cables to make the two elements of the dipole. Use a twisted pair of 1mm2 lighting cable cores 63cm long to make the balun. There is no direct connection from the coax screen to the dipole. The return current gets back across the capacitance of the balun. This is all assembled using a chocolate block connector. Coil up the balun to save space. The match to 50Ω cable is good.
Source: Dave Kimber G8HQP http://myweb.tiscali.co.uk/g8hqp/
I did write about this aerial in RadCom but people are asking about it so here it is above with Dave Kimber's pictures.
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