[amsat-bb] Re: 150 cubesats to provide global WIFI multicasting

Gregg Wonderly w5ggw at cox.net
Mon Feb 10 10:30:25 PST 2014

As the birds dropped out of the sky above the ground station, there might be 
some objections. What has to happen for long range, gigabit bandwidth, is a wide 
frequency range with little time on any particular frequency so that there is no 
concentrated effects on a single frequency where heating would start to occur. 
Frequency hopping over large spectrum is not a new thing, but it's something 
that could alleviate a number of issues with safety.

Gregg Wonderly

On 2/10/2014 11:46 AM, Howie DeFelice wrote:
> Just in case anyone was curious about the practicality of actually transmitting WiFi from a cubesat, I did a quick link budget. Based on typical 802.11 specs, the MDS of a receiver is about -90 dBm. The path loss at 2.4GHz between a ground station and a satellite overhead in a 600Km orbit is a little over 155 dB. Assuming a zero gain antenna on the typical WiFi client radio, the required EIRP from the cubesat is in the neighborhood of 4KW.  I don't think we are quite there yet with current solar cell technology.... not to mention the difficulty keeping the PA cool :)
> - Howie AB2S   		 	   		
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