Please recommend me a WIFI amplifier - Page 1
Forum section: electronics / projects

author: sam1275
author_rank: Frequent Contributor
timestamp: June 14, 2015, 04:21:11 pm
content: Hi!Could any one recommend me aQUALITYWIFI amplifier? I know there are many Chinese cheap ones, but I want a real big branded one.I want it to be at least 1 watt-30dbm RAW power, and support 802.11N, if it have a stock LOW gain antenna (<4dbm), it will be great.Thank you!

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 14, 2015, 05:13:19 pm
content: Just get a router that has one built in?

author: lapm
author_rank: Frequent Contributor
timestamp: June 14, 2015, 06:14:41 pm
content: Check your local laws, most countries has limitations on how much power you are legally allowed to use in WiFi signals.Maybe you could use wifi repeater instead...

author: kripton2035
author_rank: Super Contributor
timestamp: June 14, 2015, 06:36:14 pm
content: and the limitations is around 20mW ... you want 50x more !better use a focalised antenna, or one or more repeaters, or a 802.11ac hotspot

author: calexanian
author_rank: Super Contributor
timestamp: June 14, 2015, 08:37:02 pm
content: A friend of mine has been developing one that is actually really good. Unfortunately the company he is developing it for is having financial troubles and i don't know if its on the market yet. I will look into it.

author: LabSpokane
author_rank: Super Contributor
timestamp: June 14, 2015, 10:11:01 pm
content: What you're asking for is likely illegal. Max EIRP in the US is 36dBm with a 30dBm (1W) max TX power. That said, L-Com sells amps.Do NOT be surprised if the FCC or another federal agency comes a knocking. Someone with a directional antenna will be able to pick you out as an interferer for miles.Also, 1W on wifi is really silly unless both sides are amplified on TX. You would be better served by simply elevating the base station antenna to get it out of the ground clutter and using an antenna with a few degrees of down tilt.

author: Howardlong
author_rank: Super Contributor
timestamp: June 14, 2015, 10:13:30 pm
content: Limit for the OP in the US is 30dBm with EIRP Max of 36dBm. An exception arises for point to point where the max EIRP is dependent on both transmit power and antenna gain. For 30dBm the maximum For a point to point link remains 36dBm EIRP, but if you're prepared to reduce Tx power but increase antenna gain, you can do 52dBm (~160W) EIRP with 22dBm and a 30dBi antenna, but at 2.4GHz that's a big antenna, 6' diameter or so.Without doubt you are better off improving your antenna first or distributing several wired APs, and then finally worrying about Tx power because antennas are reciprocal devices: you get gain on transmit and receive. The same is not true of increasing Tx power unless all nodes do it. Little point in having a 1W router unless your connecting devices are also capable of that too, or you want to piss off your neighbours.

author: LabSpokane
author_rank: Super Contributor
timestamp: June 14, 2015, 10:31:48 pm
content: Quote from: Howardlong on June 14, 2015, 10:13:30 pmIf your pissed off neighbor is the federal government, they can force you to power down immediately. In fact, they just may disconnect your transmitter for you. And nobody at the FCC or in law enforcement will cry for you or do anything about it as you're effectively running a jamming device over 36dBm EIRP.

author: calexanian
author_rank: Super Contributor
timestamp: June 15, 2015, 04:29:51 am
content: I came up bust on my friends system. What about Sonus? They are expensive, but they are pretty good.

author: sam1275
author_rank: Frequent Contributor
timestamp: June 15, 2015, 04:36:48 am
content: Thank you everyone for help

author: lincoln
author_rank: Regular Contributor
timestamp: June 17, 2015, 07:06:00 pm
content: Quote from: LabSpokane on June 14, 2015, 10:11:01 pmIt really depends on the area (as always with rf) in a heavily populated area we were able to get about 5.5 miles with a point to point link 21 dbi grid dish antenna and 1 watt amps on both sides. FCC? For get them, they don't bother cracking down on CBer running linear amps.For point to multi-point, one thing is to set the link speed to a fixed minimum acceptable. Slower speeds put more tx power in each bit. Overall links stability is often improved by setting the fixed link speeds rather than bouncing up and down trying to auto negotiate a speed.

author: LabSpokane
author_rank: Super Contributor
timestamp: June 17, 2015, 07:38:54 pm
content: Quote from: lincoln on June 17, 2015, 07:06:00 pm21dBi is a very narrow beam angle, which is why you likely didn't get singled out in an urban environment. You likely caused a lot of people connectivity issues in the side lobe areas, however.And the FCC is rarely the instigating agency. It will be someone else who is interfered with who will have the equipment to track down your transmitter(s). If they are a federal agency, they can pretty much chop your link right then and there with impunity.And there's really no reason to be running these super-hot links anyway when there are solutions like Motorola Canopy with dishes on each side that will do the job with adequate fade margin. This stuff is just causing everyone grief in the very limited unlicensed spectrum we all have to share.

author: lincoln
author_rank: Regular Contributor
timestamp: June 17, 2015, 08:03:53 pm
content: Quote from: LabSpokane on June 17, 2015, 07:38:54 pmtrue, but we also use the same setup for 180 and 90 degree multi-point sectors.Quote from: LabSpokane on June 17, 2015, 07:38:54 pmWe were doing this in markets where dsl was not available, so thats probalby why we weren't bothering anybody/ didn't get reported. We were also running fixed channels. Looking at the wiki page, Canopy probably was not around yet. There were other wireless back hauls but were very expensive. Now there is wimax etc..Also at the time I vaguely remember the FCC was busy with hoards of pissed off cell / pager networks operators. It may just have been luck that were weren't shut down before the company ran into money issues.