73 Lf

摘要

Things at lf are starting to move quite fast. In early July, when this was being written, the RA began issuing Notices of Variation. On 7 July Peter Robinson, G4IZH successfully sent ICW to Dave Ackrill, GODJA in Wakefield, although only over 350 metres. We may never know who had the first QSO; by the time you read this, better should have been achieved. The initial results seem to support the theory - it will be hard to get any real distance, and transmitting aerials will be the main hurdle. Even if you erect a 20 metre end-fed aerial, which not everyone could, this is only 0.5%λ. Its radiation resistance would be about 0.01Ω. Even if the total resistance of your transmitter PA, connectors and aerial feeder were only 1Ω, 99% of your power would be wasted in these resistances. John Rabson, G3PAI, estimates such a 1% radiation efficiency to be hard but attainable. Effective radiation will require ingenuity.