[MLB-WIRELESS] Microtik 200mW Wireless cards for $125USD

[evilbunny]

Hello Andrew,

>> This may not be quite true, if the card's RX is poor then the
>> additional TX isn't of much use, as it will send much further
>> (reducing reuse) while being able to "hear" much shorter distances... 

AD> Sure, but if you use 2 of these cards @ 200mW they can "PUSH" the
AD> signal further hence they don't need as much receive sens ? which
AD> would make them even better than say 2 cisco cards :)

What about receiving? Cisco has about the best RX of any gear I know
of, and they don't tend to cut corners (you usually pay through the
nose however)

AD> Fair enough i understand how a antenna with gain works both ways,
AD> helps pick up a weaker signal etc... but hadn't heard about the
AD> higher output could  limit the useable signal....

Reason being is exactly as Tony put it... I'll add an example of 23dBm
just for this...

Example 4 - +23dBm Tx, +13dBi antenna at both ends (and assume no
cable losses etc)

for this system to be able to do 11Mbits and allow of thermal margins
etc etc etc, the biggest distance would be under 10km...

FSL at 10km is 120dBm, assuming those cards have an RX of about -79dBm
for 11Mbits

23 + 13 + 13 + 69 = 118dBm

8km has a FSL of 118.06dBm @ 2400Mhz

Then of course there is the legality thing someone else brought up
earlier...

>> Even a 15dBm card with an 8dBi omni is capable of usable signal at
>> 20km or further, by using a high gain antenna at the client end, such
>> as a 24dBi galaxy... even just using a cantenna the range is capable
>> of being 10km or further... and 2 24dBi dishes have the ability to do
>> 100km on a 15dBm cards...

AD> wow, hadn't heard anyone peel figures like this before, enterasys
AD> card, 8dBi omni with a cantenna reaching 10k's, nice, good to know, taa     

Actually those numbers are based on -70dBm and the DLink 520's which
have -80dBm for 11Mbits, the extra 10 is for environmental
fluctuations...

-- 
Best regards,
 evilbunny                            mailto:evilbunny at sydneywireless.com

http://www.SydneyWireless.com - Exercise your communications
freedom to make it do what you never thought possible... 
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