[MLB-WIRELESS] Antennas questions

[Tony Langdon, VK3JED]

At 03:55 PM 18/02/2002 +1100, you wrote:


>>I don't know why they do this) they just give dimensions for one or two 
>>frequencies and don't provide
>>the formulae for deriving dimensions for other frequencies.
>
>Heh, well, for antennas I read recently that they are scalable.  So if 
>there is an antenna design for 1GHz, you halve all the dimensions for it 
>to work just as well at 2GHz.  Just multiply the dimensions by the 
>frequency ratio of the design/desired.
>
>>It's mainly all for freq's much lower than ours as well :-(
>
>Yeah, most of that amateur stuff is for long distance work which is HF to 
>UHF (sub GHz).

Within reason scaling works.  UHF (430 MHZ for example) designs can be 
readily scaled to 2.4 GHz in most cases.  1.2 GHz stuff definitely will 
scale well.

Do do this, you have to multiply the dimensions by

OLD FREQ/NEW FREQ.

Example, if you're looking at a 435 MHz Yagi design to try on 2.4 GHz, 
multiply all dimensions by 435/2400.

73 de Tony, VK3JED
http://www.qsl.net/vk3jed