[MLB-WIRELESS] Omni Drectional Antenna Design

[Tony Langdon, VK3JED]

At 05:52 PM 15/01/2002 +1100, you wrote:

>Could someone post the math required to establish what is the max legal
>gain for a given card output and how the card output mW relate to signal
>dBm (does dBm = decibels at one meter?)

I posted something a while back.  Should put it up on the web site, but 
basically

dBm = dB relative to 1mW (0dBm = 1mW, 10dBm = 10mW, 30dBm = 1W, 36dBm = 4W

Basically, add the power (in dBm ) and the combined antenna gain, if the 
figure is less than 36dBm, you're legal. :)


>In the following text one presumes he means a 30mW card with 24db
>amplification will exceed 4000mW power output - better be sure before I
>plug 100mW into 24dB  :¬)

20dBm + 24 dB = 44 dBm... hmm, a bit over the limit. :-)

However, if you have a looong run of coax and lost 8dB, you'd be right! :)

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