[time-nuts] GPS backup for the stationary time and frequencyuser
jimlux at earthlink.net
Fri Oct 8 21:39:29 EDT 2010
Magnus Danielson wrote:
> On 10/08/2010 08:22 PM, jimlux wrote:
>> You might do just as well with a flat cookie sheet.
> Well, a 1 m dish gives you 48 dB gain at L1 if I calculate correctly.
I don't think so..48dBi would be huge...A numerical gain of 48 I can
let's say we have an antenna that is 2x3 wavelengths (40x60cm, 1.5 GHz
= 20 cm) or 6 square wavelengths. the gain is 4 pi * A, or about 75.
But in reality, the efficiency is typically no better than 50% (because
of sidelobes, illumination, etc.)... Call 66% to be sporty, and you've
got a numerical gain of 50, or 17dBi.
> The normal antenna is at 6 db of antenna gain?
> Even if less than perfect, not too big size is needed to get meaningful
> antenna gain.
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