On Sat, 3 Feb 2007 15:38:04 -0500, Tom DeReggi wrote > I wanted to get some feedback from the List. > > Typically, what Dbi gain antennas are you desiring for OFDM short > Near-LOS or Mid-range CPE links? Is 18 dbi enough? > > I'm well aware that 18dbi will not be good for many applications > (long range or noisy), but what percentage of CPE installtions would > it be good for? Could 75% of the CPE installs be acheived with 18dbi? > > I personally, would pick a 21-23db antenna as a preferred choice, > but PacWireless Rootennas are 19dbi, and often used with 13-15 dbm > CM9 cards. The beamwidth of 18dbi (< 20-30 degrees) is pretty good > for interference resilience and OFDM maximized, and if more gain was > needed it could be accommodated with higher power radios such > Teletronic's >18dbm Atheros cards or Ubiquiti's SR5 18-26db cards.
Ok, where do I start... I can't tell that antenna design matters a bit whether you're using OFDM or QAM or... ??? Seems the radio waves propagate the same. I'm using 18 db grids out to well past 20 miles, with no amps and no high powered radios (using CM-9's). I have ONE client with a 24 db grid at 17 miles or so, and he's got like a -60's RSSI. Doesn't even need it, but it was mounted to his house when I hooked him up. So I saved myself 40 bucks and used his. I have one client btween 29 and 30 miles using a 16 db Vagi, from Pacwireless. Again, no high powered cards, and he's got around 12 to 15 db SNR ( -80 to -83). I was going to use a 19 db grid, but my antenna was defective, and that was the only other thing in the van. Star-OS access point, Compex WP54AG client board, running Ikarus. I think our maximum throughput in 11b mode (won't work in G, sorry) was 350KB or so. The customer is a 2M client, and we can get 2M in a speed test any hour of the day or night. My expeirience with G mode (not ofdm specifically) is that much higher RSSI is required to work at all. I've seen OFDM clients work fine for 900 mhz at -85, so long as you weren't hoping to get past 1M throughput in a 5mhz wide channel. My first 40 clients were ALL 18 db grids, be they 1 mile or 23 miles. > > Tom DeReggi > RapidDSL & Wireless, Inc > IntAirNet- Fixed Wireless Broadband > > -- > WISPA Wireless List: wireless@wispa.org > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ -------------------------------------------- Mark Koskenmaki <> Neofast, Inc Broadband for the Walla Walla Valley and Blue Mountains 541-969-8200 -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
