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On Wed, 10 Dec 2003 21:28:22 GMT, Dave Shrader
wrote: Question[s]: In the UK, is 433 MHz allocated to Amateur Radio? Simon, in other words, is a license required for operation on 433 MHz in the UK? Observation[s]: A yagi receives from ALL directions but has a preferred direction where it has gain. Yagis may not meet your requirements for narrow beam. A high gain Yagi may have a beamwidth of +/-10 degrees or more. A moderate gain Yagi will have a beamwidth of 30-40 degrees. I would add that unless the antennas are relatively close anything much narrower can be a real bi...er... bear to align. It can be done, but one degree (if you could get it) would be a nightmare. With that kind of beam width you'd most likely have to worry about elevation as well as azmuth. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair?) www.rogerhalstead.com Return address modified due to dumb virus checkers DD, W1MCE Simon wrote: Hi, I'm playing around with some 433MHz transmitter and receiver pairs. Ideally I would like the transmitter to transmit in a narrow directional beam, but I'm new to the art of radio waves and antenna design, so I was wondering if you guys would be able to help me with my project. I've read about a Yagi design for the antenna, I know it receives from one direction only, but does it transmit in just one direction too? I thought I'd be able to basically stick the transmitter antenna in a tube, sealed at one end, line either the inside or outside of the tube with tin foil (or both) and it would transmit in whatever direction the open end was facing. So far my tests haven't been too conclusive but could that be poor setup on my part or is the idea fundamentally flawed? Many thanks for your time, Simon. |
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