At 04:40 15/01/2004, James Ewing wrote:
You can read the Broadcom specifications for the 2050 radio chips in the Linksys WRT54G here -
<http://www.sveasoft.com/postt48.html>http://www.sveasoft.com/postt48.html
84 mw is well within their design limits.
Read the PDF linked, not the (wrong) summary in the post which, as far as I understand it, gives power... consumption of the card!
Also, check out the (real) specifications in the PDF. The 802.11a chip has an internal PA, and the Tx power limit is 18.7 dBm (74 mW) up to 36 Mbps, and goes down to 12.8 dBm (19 mW) at 54 Mbps! Given that higher rates require a better signal at the far end (Rx sensitivity gets worse with higher rates), you don't want to go the 54 Mbps route for long links!
The 802.11g chip has no internal PA. The Tx power limit for that chip is 5 dBm (3 mW), so the "real" output power will depend on the PA used. But as others stated (and as shown in the document for the 802.11a internal PA), there are quite a bunch of factors that limit the output power you get use while staying within the specs. The "real" result will vary based on the characteristics of the PA used, but I would be surprised if you could actually get to the 19.2 dBm you want in all cases, especially at the higher rates, without significant damage either to the spectrum (i.e. your AP is blasting over the whole 2.4 GHz band rather than just the channel it's supposed to be on), to the hardware (overheating), and/or to link quality (introducing distorsion in the signal).
Without full specs for the PA used, and more importantly, testing as shown in the PDF, you might want to limit your ambitions a little bit. Instead, consider separating rx and tx antennas (with high gain rx antennas) to stay within legal limits and get the longest range. Theory says you can get to 53 km at 1 Mbps that way with that chip, while pushing up the power to 84 mW will only give you 5 km, while being already over the legal limits everywhere in the world except FCC-land.
Jacques.
-- Jacques Caron, IP Sector Technologies Join the discussion on public WLAN open global roaming: http://lists.ipsector.com/listinfo/openroaming
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