Customer Reviews


1,400 Reviews
5 star:
 (907)
4 star:
 (210)
3 star:
 (83)
2 star:
 (70)
1 star:
 (130)
 
 
 
 
 
Average Customer Review
Share your thoughts with other customers
Create your own review
 
 

The most helpful favorable review
The most helpful critical review


371 of 377 people found the following review helpful
5.0 out of 5 stars Best WiFi antenna on the market. Best performance with the 7dBi panel antenna
Nearly all Amazon.com reviewers agree, the Alfa AWUS036H is the long range WiFi antenna on the market. But with 3 antenna options to chose from, which is the best setup?

I own the all 3 wi-fi antennas from Alpha: 5dBi omni-directional, 7dBi panel, 9dBi omni-directional. The Alfa AWUS036H with the 7dBi antenna is the best performing set up: Alfa AWUS036H...
Published on August 25, 2011 by Lincoln

versus
23 of 27 people found the following review helpful
3.0 out of 5 stars limited merchant support, 9dBi antenna no improvement
The Alfa adapter is great. Significantly pulled in more signals. The additional 9dBi antenna does not provide any improvement from the original 3" antenna. It is misleading that the vendor sells a companion produce that offers no improvement. The vendor has a very strict all sales are final policy, and requires customers to send email to a gmail account for support...
Published on November 9, 2009 by B. Sullivan


‹ Previous | 1 2140 | Next ›
Most Helpful First | Newest First

371 of 377 people found the following review helpful
5.0 out of 5 stars Best WiFi antenna on the market. Best performance with the 7dBi panel antenna, August 25, 2011
By 
This review is from: Alfa AWUS036H High power 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with 5dBi Rubber Antenna and a 7dBi Panel Antenna and Suction cup / Clip Window Mount - for Wardriving & Range Extension (Personal Computers)
Nearly all Amazon.com reviewers agree, the Alfa AWUS036H is the long range WiFi antenna on the market. But with 3 antenna options to chose from, which is the best setup?

I own the all 3 wi-fi antennas from Alpha: 5dBi omni-directional, 7dBi panel, 9dBi omni-directional. The Alfa AWUS036H with the 7dBi antenna is the best performing set up: Alfa AWUS036H Upgraded to 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with 5dBi Rubber Antenna and a 7dBi Panel Antenna - for Wardriving & Range Extension *Strongest on the Market*

With the 5dBi omni antenna, I can get 2-3 bars from a public wi-fi signal a little over 1 mile away (direct line of sight).

With the 9dBi omni antenna, I get only 0-1 bar with dropped signals.

With the 7dBi panel antenna, I get 3-4 bars with the fastest data transfer rates.

I have even tested the 5dBi and 7 dBi side by side and the 7dBi loads web pages in less than 1/2 the speed as the 5dBi antenna.

I have done a fair amount of research before purchasing the Alfa AWUS036H unit. The general consensus is that this unit has much better performance for B and G networks than the newer Alfa AWUS036NH model. But for accessing N networks, the newer model is necessary.

Although I still own the 5dBi and 9dBi antennas, I only ever use the 7dBi panel antenan. It's actually shorter in size and easier to transport than the 5dBi model. Go with the 7dBi - you'll get the best performance.

***** UPDATED COMPARISON *****

Aug 25, 2011: Using Xirrus Wi-Fi Monitor software, I compared the signal strength of this Alfa AWUS036H with the 7dBi panel antenna Alfa 2.4HGz 7dBi Booster SMA Panel High-Gain Screw-On Swivel Antenna or to the new High Power USB-Yagi Plug and Play directional WiFi Antenna 802.11n 2200mW / NextG USB-Yagi Plug & Play 11N Long Range WiFi antenna 2200mW. In nearly every test location, the Alfa rated 1 bar better and -10 RSSI (Receiving Signal Strength Indication) better (with RSSI signals negative numbers are better).

Although the 2200mW Yagi antenna is much larger and twice the power, it pulls in a weaker signal and slower data transfer than the 1000mW Alfa 7dBi panel antenna.

Still this Alfa AWUS036H is the best performing wi-fi antenna on the market. Thank you Alfa!

*** IMPORTANT ***

Please rate this review as 'helpful' to push this review to the product's home page so that everyone can get the best performing WiFi antenna setup: Alfa AWUS036H Upgraded to 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with 5dBi Rubber Antenna and a 7dBi Panel Antenna - for Wardriving & Range Extension *Strongest on the Market*
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


77 of 78 people found the following review helpful
5.0 out of 5 stars Great antenna, June 7, 2010
Verified Purchase(What's this?)
I rent a house on a lake in the Ozarks of Missouri. The house has no internet connection. The owners of the house live 3 doors down the street, a good 300 feet away. In their house they have a wireless router. From the rental house I could not get a signal on my laptop from their router. To do my work I would walk down the street to the patio at the back of their house and sit there to do my work. That didn't work so well when it rained.

I searched NewEgg, Circuit City, Radio Shack, Best Buy and Amazon. It seemed the greatest volume of reviews and the best reviews was for this unit. So I purchased the unit with the 5dbi antenna and the suction cup mount. It worked great! I thought I might need to sit in the back yard of the house I rent to get a signal even with the new antenna, but no I was able to sit in the kitchen at the table and get a good signal. I mounted the antenna to the window of the kitchen door and added a 15 foot USB extension cable to the antenna and I was able to move from the kitchen to the living room and check my email and web sites.

I highly recommended this Alfe unit.
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


105 of 111 people found the following review helpful
5.0 out of 5 stars WOW! works beyond expectations!, May 16, 2009
Verified Purchase(What's this?)
We kinda bought this figuring it was "snake oil". Well, we were wrong...dead wrong! We plugged this into the Vista laptop, Vista found it and we were using it in less than 1 minute, and to our surprise it picked up our neighbor's router 1000 ft down the road and on the other side of his house! We used to get his signal intermittently on the laptop, but with this plugged in with the hi-gain antenna, we get 4 out of 5 bars! This is through tall, thick trees and a motor home!
When the first reviewer (I read)says it got her father in law's signal 1000 feet or yards down the road, she isn't lying!!!

I just put it on my Windows 7 desktop and it works just the same. I just plugged it in, and windows found it, installed drivers and it's fine.

I ALWAYS suggest going online for the latest drivers for any computer hardware, but this one seems to work fine off of Windows Vista and 7's proprietary drivers.
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


77 of 82 people found the following review helpful
5.0 out of 5 stars Best WiFi antenna on the market but better with the 7dBi panel antenna, August 25, 2011
By 
Verified Purchase(What's this?)
Nearly all Amazon.com reviewers agree, the Alfa AWUS036H is the long range WiFi antenna on the market. But with 3 antenna options to chose from, which is the best setup?

I own the all 3 wi-fi antennas from Alpha: 5dBi omni-directional, 7dBi panel, 9dBi omni-directional. The Alfa AWUS036H with the 7dBi antenna is the best performing set up: Alfa AWUS036H Upgraded to 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with 5dBi Rubber Antenna and a 7dBi Panel Antenna - for Wardriving & Range Extension *Strongest on the Market*

With the 5dBi omni antenna, I can get 2-3 bars from a public wi-fi signal a little over 1 mile away (direct line of sight).

With the 9dBi omni antenna, I get only 0-1 bar with dropped signals.

With the 7dBi panel antenna, I get 3-4 bars with the fastest data transfer rates.

I have even tested the 5dBi and 7 dBi side by side and the 7dBi loads web pages in less than 1/2 the speed as the 5dBi antenna.

I have done a fair amount of research before purchasing the Alfa AWUS036H unit. The general consensus is that this unit has much better performance for B and G networks than the newer Alfa AWUS036NH model. But for accessing N networks, the newer model is necessary.

Although I still own the 5dBi and 9dBi antennas, I only ever use the 7dBi panel antenan. It's actually shorter in size and easier to transport than the 5dBi model. Go with the 7dBi - you'll get the best performance.

***** UPDATED COMPARISON *****

Aug 25, 2011: Using Xirrus Wi-Fi Monitor software, I compared the signal strength of this Alfa AWUS036H with the 7dBi panel antenna Alfa 2.4HGz 7dBi Booster SMA Panel High-Gain Screw-On Swivel Antenna or to the new High Power USB-Yagi Plug and Play directional WiFi Antenna 802.11n 2200mW / NextG USB-Yagi Plug & Play 11N Long Range WiFi antenna 2200mW. In nearly every test location, the Alfa rated 1 bar better and -10 RSSI (Receiving Signal Strength Indication) better (with RSSI signals negative numbers are better).

Although the 2200mW Yagi antenna is much larger and twice the power, it pulls in a weaker signal and slower data transfer than the 1000mW Alfa 7dBi panel antenna.

Still this Alfa AWUS036H is the best performing wi-fi antenna on the market. Thank you Alfa!

*** IMPORTANT ***

Please rate this review as 'helpful' to push this review to the product's home page so that everyone can get the best performing WiFi antenna setup: Alfa AWUS036H Upgraded to 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with 5dBi Rubber Antenna and a 7dBi Panel Antenna - for Wardriving & Range Extension *Strongest on the Market*
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


65 of 69 people found the following review helpful
5.0 out of 5 stars AAlpha1 watt remote USB aadapter, December 13, 2009
By 
Gary (Tennessee) - See all my reviews
Verified Purchase(What's this?)
This is a good little USB network adaptor and works as advertised.

Background: I have a Dell laptop with an internal network card. I travel a lot and use it in hotels and hot spots quite a bit. The signal I was getting on the internal card with its two internal antenna's was weaker then I would like and usually doesn't get a strong enough signal to maintain 54 Mbps speed. I was usually down around 11 Mbps in a hotel room. Sometimes I have had to move to a different room, move to a balcony, or a certain point in the room to get a signal at all. In one hotel room I checked signal right after checking in and I could only get a usable signal near the door holding the computer up near the ceiling. I had to walk around the hotel to find a group of rooms that I thought would work and then coordinate with he front desk on availability and change rooms.

I researched many options, reading reviews, etc. Most other options were more expensive or problematic, including modifying my computer to install an external antenna. I looked at USB cards with the mail plug that plug into the computer without using an extension, pcmcia cards with external antenna's, directional antenna's, etc. Most of the reviews I read were from kids "War Driving" but still shed some light on how well this card works.

What I got: I went with the Alpha because of good reviews I read, and the fact that I can remote locate it using an extension giving more options then one mounted to the computer. The unit looks pretty cheap being plastic. Nothing special. It came with the two antennas. I ordered the two extension cables. One is passive and one is active (active is required for longer extensions).

Functionality/Results: It works well. So far I have not been in a Hotel where I didn't get an 88% or better connection (signal strength) with 85 or 90% link quality or better, and more importantly a link with 54 Mbps speed. I get many more signals too, but that is not what I was looking for in most cases. I have tried it in a dozen or so hotels and played with outside signals a bit. There are a lot of them out there.

The ability to move the antenna 10 to 25 feet away could be useful to get it on a balcony, outside a window, get around a concrete wall, etc. but I haven't had to do that yet with the Alpha. Once in the Bahamas, using the computers internal card, I had to get out on a balcony with a 40 mph wind coming off the ocean that would knock over the laptop if I didn't hold on to it, to get a clear shot to the hotel main building where the router was located. I had to weather the salt spray and either had to hold the computer screen to keep it from swaying so I could see it or hold my wine glass to keep it from tipping over. I needed three hands and it was a tough decision as to which two things to hold. That is when I decided to order this card. I read about folks on sail boats running the Alpha up the mast and getting a signal 4 or 10 miles off shore and putting the unit in a zip-loc bag to keep it out of the elements.

If I had modified my computer for an external antenna, or gotten a pcmcia card with external antenna, I could have run coaxial cable to a remote antenna to get the same position benefits, but the signal losses are large that way and signal cuts in half with every few feet of coax. With this adapter the antenna is run right into the transmitter/receiver and there is no loss, however you still have the ability to remote locate it up high in a room, outside a window, on a balcony, etc. without the loss. You don't get the signal loss from a USB cable, although you do run out of power if run too far. 25 feet with the two supplied cables is plenty for me.

Power: The high power is meaningless and probably a lie. I think they are claiming equivalent radiated power with a good antenna to some poor antenna standard like the antenna's printed on a pcmcia adapter card circuit board or something. Anyway it is not really a 1000mW adapter, but it does work well. The allowable power output is somewhat complicated but is based on radiated power (the combined effect of the transmitter and antenna). Anyway a balance of output power, receiver sensitivity, and selectivity is what is important and this one does a good job. It gets quite warm too only having passive cooling (vents).

Antenna's: Like many folks have reported, the big antenna doesn't seem to work any better for me then the little one. Sometimes it will get a slightly stronger signal and more signals with it, but the link quality (signal to noise ratio) is worse. The little antenna has worked fine in all cases so far and just as well as the big one on comparison.

Software: The software installed easily for me with Windows XP and I have had no problems. The software is between OK to fairly nice. I can still enable my internal card and use it when the signal is strong and I don't want to carry the Alpha. I disable it when using the Alpha.

Works great. Hope it last a long time.

If you are looking for solutions for your home (or work) because of problems with range on your Wifi you might also try one of the homemade paper directional parabolic antenna's that you print off from the internet. They really work and also increase security if positioned properly by directing coverage to within your house and decreasing coverage outside. They work will with this unit too. Requires a router with external antenna(s). You can also put one on the antenna of the Alpha and beam signals between the router and the Alpha. Quite effective. You print out a template from the internet, cutout a couple pieces of paper, cover one with foil or aluminum tape, stick the parabolic template together to the flat sheet to form the shape, and position the unit on the antenna of your router. Just do a search on "DIY windsurfer parabolic WIFI antenna" as Amazon doesn't' allow links. Also watch one of the Vid's on it.
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


42 of 43 people found the following review helpful
5.0 out of 5 stars Best of it's kind, March 14, 2012
Verified Purchase(What's this?)
This is definitely what I would call the cookie-cutter of all WiFi adapters. Pure, brute-force power! Nothing fancy, it's just one hell of a device. Plus if you're interested in pentesting WiFi this is also one, if not THE best card to work with. Very good Linux support. Cracking WEP is so fast it turns into a complete joke.

My only side-notes are:

- No N support. The product isn't being advertised as one either, so not the biggest issue. Plus I can easily max out my 35 mbit internet connection using this so I have no need for N for the time being!
- After a few months of usage, I hear a slight buzzing inside. Especially when I scan with airodump-ng while channel hopping, the noise goes a bit crazy.
- Keep this away from body parts, just to be on the safe side. Because of it's power and how Alfa the manufacturer is a bit obscure (at least to me), I wouldn't trust this close to my body for longer intervals. Get a USB extension cable!
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


41 of 43 people found the following review helpful
5.0 out of 5 stars Excellent USB Wireless Adaptor, January 6, 2010
A Kid's Review
The Alfa USB wireless adapter works very well in both Windows and Linux. Using the internal wireless adapter in my Asus 1000HA netbook, I could only detect a few networks in my neighborhood. After attaching this adapter, I was able to detect 15+ networks.

The Alfa adapter works great with Backtrack, as I'm sure you've read from various forums. The card allows for monitor mode, packet injection, etc. If you're looking for a card for wireless pen-testing, then this is the one for you. You will not be disappointed.
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


26 of 26 people found the following review helpful
4.0 out of 5 stars RV user says it works like a hot damn but a fussy set up for a rookie, December 15, 2011
Verified Purchase(What's this?)
This review is from: Alfa AWUS036H High power 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with 5dBi Rubber Antenna and a 7dBi Panel Antenna and Suction cup / Clip Window Mount - for Wardriving & Range Extension (Personal Computers)
Hi,

Just want to start out by saying when it comes to computer hardware and software I would give myself a 5 out of 10 in knowledge for instillation and set up of most things. So if you are a 1 out of 10 this might be a bit of a challenge to get up and running but it does work well once you tweak it.

I'm in RV parks/resorts most of the winter in SoCal and most offer a park WiFi set up that is very slow. The way it works is the more people in the park the slower it gets which is common in these kinds of set ups. Trying to get some decent use out of the park supplied WiFi I turned to Amazon and found this..

Alfa AWUS036H High power 1000mW 1W 802.11b/g High Gain USB Wireless Long-Rang WiFi network Adapter with 5dBi Rubber Antenna and a 7dBi Panel Antenna and Suction cup / Clip Window Mount - for Wardriving & Range Extension

There are no paper instructions but they do provide a disc with instructions on a pdf and a short (no sound) video that boggles the rookie mind. The company website leaves a lot to to be desired when it comes to start up help but I did manage to get it working with out their online or phone help. I'm in Palm Springs right now and my lap top could only pull in a few towers that were usable. Once I set up the antenna I got 25+ at pretty much full strength. They provide a window antenna with suction cup and WOW what a great difference that made in a RV with metal frame and fiberglass walls plus all the other gadgets in a RV.

I would have given it 5 stars except for the set up experience as for the antenna itself it gets 5 stars. I would recommend this to anyone who needs a stronger signal.
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


290 of 346 people found the following review helpful
4.0 out of 5 stars The Alfa 1000mw/1 Watt Wi-Fi Wirless Transceiver is A+ but it won't always produce 1 watt of output, See why as well as advice.., February 1, 2010
Verified Purchase(What's this?)
Alfa 1000mW 1W 802.11b/g USB Wireless WiFi Network Adapter

This review is more for the technically oriented group who want to look more deeply into the technology but written in easy to understand terms.

From what I've seen there is nothing better you can buy anywhere right now. However, let me point out that the 1000mw/1 watt output rating might not always be true but before I start on that let me outline what I like about the unit:

1. The Wi-Fi transceiver produces far more power than what any laptop computer or external Wi-Fi transceiver I know of will output.
2. Has a "RP" or what is called reverse polarity coaxial antenna connector which allows me to use a higher gain antenna. See my notes on this type of connector further in this review.
3. Is external and powered by a USB cord allowing me to place the unit with its whip antenna at a better spot than where my computer is at, up to about 15 feet away if using a USB extension cable.

OK, to get to my question of whether the Alfa produces the amount of RF power they say it can:

I was curious if this unit could really produce 1 watt of output power, it seemed far too light weight to do that so I took my AWUS036H unit and fed its RF output into a lab quality spectrum analyzer on maximum hold to record its highest RF carrier level power output as it pulsed to interrogate a remote Wi-Fi system, which of course it couldn't while hooked up to the spectrum analyzer instead of an antenna. I was right about the lower output power, I measured the output to be about 250 mw or +24 dBm, that's 6 dB lower than its advertised power capability of +30 dBm which is four times lower output than the specified 1000mw/1 watt (The difference between +24 and +30 dBm is a factor of -6 dB which as a logarithmic power factor is four times less power). Just to be clear to the folk who don't work with decibels or dB; +30 dBm (referenced to 1 mw/milliwatt) is 1000 mw or 1 watt or +30 dBm = 1 watt.

IMPORTANT: If you have the one watt output version of this Alfa and have the dual USB cable they are now providing with the units which plugs into two USB receptacles at the same time do so! The second USB connector is needed due to the high current demand of the higher power unit, one is for data the other for more current supply to the Alfa. I did not know this and only used the one USB connector which passed both data and power and now that USB port on my computer does not work. Apparently, too much current had been drawn and damaged it. I expect there is an automatic current limitation built into most computers but in my case it did not prevent the USB port from becoming damaged. Mine ran fine for a week with just one of the USB connectors plugged in to my computer but it eventually caused that port to fail. I would have used both ports but I needed the other USB port for something else, unknowing the resulting damage that action would produce leaving me with just one good USB port on that laptop now.

Finding that my Alfa only produced one forth the advertised RF power output I figured either Alfa was misrepresenting its true output or I had a defective unit. I then went to the Alfa web site and found some specs for the unit, their specs show this unit has different output levels for different modes of modulation! For OFDM modulation the RF output is rated at +24 dBm which is 250mw or a quarter of a watt/.25 watt. When using CCK modulation the output is rated at the full +30 dBm output which is 1000mw/1 watt. So, you don't really get a full watt of output in some modes of operation! From what I've been able to find on the net regarding these two kinds of modulation is that the Alfa is rated at less power for OFDM because the efficiency of its built in power amplifier is fairly low due to requiring the amplifier to operate in a highly linear manner which is less efficient producing less output power where CCK modulation does not require the amplifier to be linear and thus more efficient producing more output power. I am still trying to determine if CCK is a short burst of data and OFDM a longer or continuous transmission which would also explain why one mode allows more output power over the other, if the shorter bursts allow the amplifier to transmit a higher peak of power without overheating. I have not found what I'm looking for on this yet, when I do I will update this review. (More on CCK and OFDM at the bottom).

According to law, in the USA when the unit is transmitting with CCK modulation (fast pulsed short duty cycle) producing 1000 milliwatts or 1 watt of output at 2.4 GHz the highest gain antenna you can legally use is 6 dBi which produces an effective radiated power (reference to isotropic radiation pattern) of 4 watts, that's the maximum power you can legally radiate which is higher than many other countries if not all. When the modulation uses OFDM producing 250 milliwatts of output the highest gain antenna you can legally connect and transmit with is 12 dBi which will produce an EIRP of 4 watts. The highest gain antenna you can legally use in the CCK mode of modulation producing 1000mw/1 watt of RF output at 2.4 GHz is 6 dBi which also produces a EIRP of 4 watts of EIRP. What does EIRP mean? It is the abbreviation for "Effective Isotropic Radiated Power" which means the combination of RF power input and gain of the antenna you are using (when measuring the area of its maximum radiated power) will equal the same amount of signal level that a antenna which radiates equally in all directions would produce when being fed with the same amount of RF power at its feed point (not counting feed line or coax and connector losses along the way to it).

If the above doesn't make sense there are plenty of web sites you can Google which better explains EIRP but in short, it just means how much signal level your antenna can produce... some antennas have such high "gain" that they can make a very low power signal seem like a very large amount of power due to squeezing most of the transmit power into a very tight and narrow bream width. In the case of a collinear Wi-Fi whip antenna which has several dB of gain the design of the internal elements of the antenna cause the area of reception as well as transmit power to be squashed down into the shape of a doughnut so that little power is wasted strait above or below the antenna and radiated outward in a pattern which is more useful for line of sight point to point communications but omni-directional as a whip.

Want more receive and transmit gain than a collinear whip can produce? Try a flat panel, Yagi or parabolic dish antenna. The flat panel antennas are really a phased array of dipoles in the form of "slot" antenna which give gain, the more which are phased together inside the panel the higher the gain and consequently the larger the panel. High gain Yagi antennas are very long and bulky, not so good for high winds but can produce good gain too. A parabolic dish or paraflector type of antenna has very high gain and is mechanically stable but the more gain you want the larger they get. As a general rule, every time you double the diameter of a dish you get six dB more gain or equal to four times more effective power output or higher receive gain, at a given frequency. Double the frequency instead of the size of the dish and you get the same, 6 dB more gain. That said, every time you double the diameter of a dish there is four times more surface area... thus, 6 dB more gain which is 4 times more power! Why? When receiving the larger sized dish is collecting more signal and focusing it into the feed point, when transmitting the surface of the dish is concentrating the transmit power into a much smaller beam width of RF power so less of it is wasted going out into directions you don't want the power to go, as a point to point antenna.

Regarding the Alfa's coaxial RF connector:

I am not yet sure why the unlicensed (not requiring a license to transmit) Wi-Fi industry did so, but the RF connectors used on their equipment are non-standard and because of this won't fit together with normal coaxial connectors. The antenna connector on the Alfa, at a distance without viewing carefully enough looks just like a normal SMA RF connector but it isn't! That connector would normally be called a female connector which you would screw a male SMA connector on to but they made a change to the center pin, instead of a female center receptacle which a male pin slides into the manufacturers reverse it by making it a stub instead of a hole, or in other words there is a pin coming out of the center. Yes, it's reversed inside but the outside looks like a normal connector. I've wondered why they did this and I could research this more but my bet is that it was a regulatory action placed on them or something the industry decided to do to make it harder for people to find ways to illegally use the equipment by hooking up high gain antennas which have the same connector, but made for F.C.C. licensed point to point communication systems. If you are breaking the law by using a antenna which has a gain which is a little too high I wouldn't worry about the F.C.C. knocking on your door too much as the agency is severely under-funded, have been for their entire history except in the hay day of CB, and don't have very many employees and very few offices which are scattered around the USA many hundreds of miles apart. There is just too much Wi-Fi for them to chase after those complaints and users are left to solve problems themselves. Of course, if you were interfering with a licensed station they could drag the F.C.C. into it but the Wi-Fi spectrum these units use is unlicensed so how likely is that to happen? It can happen but I'd expect to be hit by lightning first.

Back to the technical issues of the "RP" or reverse polarity RF connectors. It seems the whole unlicensed Wi-Fi industry is using RP/Reverse Polarity RF connectors on their equipment. I've looked at the RF connectors on a LinkSys wireless router, the type used in most homes to produce an in home Wi-Fi system and the model I took apart uses a RP TNC connector which is much larger than the SMA connector used on the Alpha, so again more of these special coax connectors which have their center pins backwards. Why they call it reverse "polarity" I don't know, this has nothing to do with electrical polarity, it is merely that the center pins are physically opposite of what normal RF connectors of the same type use, except in the unlicensed Wi-Fi industry. If you want to find an adapter just search the net for "RP SMA" or "reverse polarity coax connectors" etc and you will find vendors who sell them, including several here on Amazon.com.

Want to run a length of regular coax which already has a normal RF connector (not RP) on it to remote your antenna further away or hook up to a bigger one?

You can certainly do so all you need is a "RP" coaxial adapter which will allow you to use it with this units RP SMA connector but you must choose coax which was made for the high frequency these units receive and transmit. 2.4 GHz or 2400 MHz is microwave frequency, the same part of the radio frequency spectrum your microwave oven uses so don't place your antenna near one because whenever someone heats something in that oven you will likely lose your wireless internet connection until it is done cooking.

Choosing the right coax may take some study if you aren't a techie type familiar with such but with what I've written here shouldn't be too difficult to discern. If you ask a vendor to choose coax for you make sure you specify it is for the 2.4 GHz spectrum (which these Alfa's use for both transmit and receive). Also, no matter what length you choose I'd make sure the total attenuation or loss is no more than about 3 db at 2.4 GHz or you will lose half of your transmit power before it even reaches the antenna, as well as your receive strength too. However, there are some exceptions to this advice, if you were to use a very long run of high quality CATV cable which had loss of 10 dB that loss would become moot if you were able to use a high enough gain antenna on the end of it to allow you to have wireless connectivity to the internet. Who cares how much loss the coax has if inside the building you can't reach the internet but when running 100 feet or more of coax with a high enough gain antenna you can? Doesn't matter, you have internet. However, it is best to use as short a length of coax you can or the lowest loss coaxial feedline possible but what is best is having both, the lowest loss coax as short as possible. With low loss coax such as 1/2 inch diameter foam dielectric Heliax made by Andrew/CommScope, product identifier LDF 4-50A you can have a 100 foot long run with only a little more than 3.5 dB of loss at 2.4 GHz. If you use a high gain antenna on the end of that hundred foot length with a gain of 12 dBi you have an equivalent of using a 8.5 dBi gain antenna directly connected to the Alfa without any feed line at all but having the antenna where it isn't obstructed by the walls in your building, etc.

If the run of coax must be long you should as a rule use the lowest loss coax you can afford to buy. What are examples of fairly low loss coax? Most CATV coax which uses a foam dielectric inside to insulate the center conductor from the outer shield wrapping is fairly low loss but the lowest loss coax you can buy is air dielectric or in other words, no insulator between the center wire of the coax and its outer shield, using only small non conductive spacers every few inches to keep the two from contacting. Who manufactures that coax? Andrew Inc. (Now CommScope Inc.) makes extremely high quality coax with either a low loss foam dielectric insulation or what is considered air dielectric, even though this coax really isn't 100% air because it has a plastic spiral running throughout its length it is about as low loss as you can get (for a specific diameter) as a feedline except for hollow waveguide which would be far too costly and fairly large at 2.4 GHz. Their coax has the trademarked name of Heliax(R) and in my opinion is the best you can buy but expensive, even for the smaller half inch diameter coax it is more expensive than most people would want to buy new but you can sometimes find this coax for sale at much better prices used. Heliax can last for decades without degradation so if you can find it that way don't be afraid of it unless it has significant dents in it or has been malformed by bending or crushed which will change it from the characteristic 50 ohms impedance to who knows what at that point in the line where the damage is. Many ham radio operators use this kind of coax and if you know one they can help you locate a place to find some fairly cheap but even then not nearly as inexpensive (per foot) as normal CATV cable used for cable television, even if new. So, that's what I'd recommend, high quality cable television coax but be sure to check the specifications for loss at 2.4 GHz, not all manufacturers CATV coax are equal.

What kind of coax should you stay away from at 2.4 GHz? Any of the types which start with RG such as RG-213 with a hard or solid center insulator or dielectric, it is very lossy at these frequencies, even a short 10 foot long length of high quality RG-213 can have close to the same amount of loss a 100 foot run of quality CATV/cable television cable has. The RG-types of cable have been around my entire life and they are good for lower frequencies, but not so good for these frequencies but I've seen people use it! For example, 10 feet of RG-213 has a loss of close to 2 dB at 2.4 GHz and that's for the best you can buy, some of the low quality RG-213 far more, twice as much or more. You can't always believe what is stamped on the coax, some of the manufacturers specs don't hold up to what they are claiming. That said, one manufacturer I know you can believe is Belden Cable, if they say their coax has a loss of such and such at a certain length for a specific frequency you can believe it.

Decibels/dB, how to understand their relationship to power loss:

1 dB loss: 80% of power remains.
2 dB loss: 63% of power remains.
3 dB loss: 50% of power remains.
6 dB loss: 25% of power remains.
9 dB loss: 12.5% of power remains.
10 dB loss: 10% of power remains.
12 dB loss: 6.25% of power remains.
20 dB loss: 1 percent of power remains.
30 dB loss: .1 percent of power remains.
60 dB loss: One millionth percent of power remains.

Decibels in relation to power gain:

60 dB is an increase of 1,000,000X in power
30 dB is an increase of 1000X in power
20 dB is an increase of 100X in power
10 dB is an increase of 10X in power
6 dB is an increase of 4X in power
3 dB is an increase of 2X in power
2 dB is an increase of 1.6X in power
1 dB is an increase of 1.25X in power
0 dB is no increase or decrease in power

Alfa Specifications from the manufacturers web site:

IEEE 802.11g/b, WPA/WPA2 Compliant, Attachable Antenna

Connects at a full 54Mbps via USB 2.0, up to 8 times faster than a USB 1.1 adapter
High gain upgradeable
Compact size for greater flexibility
Also compatible with USB 1.1 desktop and notebook computers
Plug-and-Play Compatible with windows 98SE, 2000, Millennium, XP and Linux
High security 64/128/256bit WEP Encryption, TKIP, WPA, 802.11

Specification :

Model AWUS036H
Standards Wireless: IEEE 802.11b/g
USB 2.0 standard
Data Rate 802.11b: UP to 11Mbps
802.11g: 54Mbps
OS Supported Windows 98SE, Windows ME, Windows 2000, Windows XP, Linux 2.6, Mac 10.4
Interface USB 2.0 mini USB
Antenna Type 1 x 2.4Ghz SMA connector
Chipset Realtek 8187L
One LED

Power/Status, Wireless Act.
Frequency Range 2412~2462 MHz (N.A)
2412~2472 MHz (EU)
2412~2484 MHz (Japan)
Channel
1~11 channels (North America)
1~13 channels (General Europe)
1~14 channels (Japan)
Emission Type DSSS/OFDM
Output Power 24dBm (OFDM), 30dBm (CCK)
Sensitivity for 802.11b

1, 2 Mbps (BPSK, QPSK): - 96dBm
11 Mbps (CCK): -91dBm
(Typically @PER < 8% packet size 1024 and
@25ºC + 5ºC)
Sensitivity for 802.11g 54Mpbs (64QAM): -76dbm
48Mbps (64QAM): -71dbm
36Mpbs (16QAM): -78dbm
24Mbps (16QAM): -80dbm
18Mbps (QPSK): -81dbm
12Mpbs (QPSK): -82dbm
9Mbps (BPSK): -85dbm
6Mbps (BPSK): -91dbm
(typically @PER < 10% packet size 1024 and @25ºC + 5ºC)
Frequency Stability within +25 ppm
Data Modulation Type BPSK,QPSK, CCK and OFDM
Power Voltage: 5V+5%
Security WEP 64/128
802.1X support
Wi-Fi Protected Access (WPA)
WPA-PSK
WPA II
Operating Temp 0°C ~ +50°C
Storage -10°C ~ +65°C
Humidity 5%~98% non-condensing
Dimention 8.5*2.2*6.3cm
Weight 38.5g

- - - - - - - -

"Complementary Code Keying (CCK)

Is a modulation scheme used with wireless networks (WLANs) that employ the IEEE 802.11b specification. In 1999, CCK was adopted to replace the Barker code in wireless digital networks.

Complementary codes, first introduced by Golay in 1961 are sets of finite sequences of equal length, such that the number of pairs of identical elements with any given separation in one sequence is equal to the number of pairs of unlike elements having the same separation in the other sequences.

The complementary codes first discussed by Golay were pairs of binary complementary codes and he noted that when the elements of a code of length N were either [-1 or 1] it followed immediately from their definition that the sum of their respective autocorrelation sequences was zero at all points except for the zero shift where it is equal to K*N. (K being the number of code words in the set).

CCK is a variation and improvement on, M-ary Orthogonal Keying and utilizes `polyphase complementary codes'. They were developed by Lucent Technologies and Harris Semiconductor and were adopted by the 802.11 working group in 1998. CCK is the form of modulation utilised when 802.11b operates at either 5.5 or 11 Mbit/s. CCK was selected over competing modulation techniques as it utilized approximately the same bandwidth and could utilize the same preamble and header as pre-existing 1 and 2 Mbit/s wireless networks and thus facilitated interoperability.

Polyphase complementary codes, first proposed by Sivaswamy, 1978, are codes where each element is a complex number of unit magnitude and arbitrary phase, or more specifically for 802.11b is one of [1,-1, j,-j].

Wireless networks using the 802.11b specification employ CCK to operate at either 5.5 or 11 Mbit/s in the radio-frequency (RF) band at 2.400 GHz to 2.4835 GHz. Networks using the 802.11g specification employ CCK when operating at 802.11b speeds. At higher speeds (up to a theoretical maximum of 54 Mbit/s), 802.11g WLANs use a more sophisticated modulation scheme called orthogonal frequency division multiplexing (OFDM). This is the modulation method used by 802.11a WLANs in the RF band at 5.725 GHz to 5.850 GHz."

- - - - -

Orthogonal frequency-division multiplexing (OFDM)

Essentially identical to coded OFDM (COFDM) and discrete multi-tone modulation (DMT), is a frequency-division multiplexing (FDM) scheme utilized as a digital multi-carrier modulation method. A large number of closely-spaced orthogonal sub-carriers are used to carry data. The data is divided into several parallel data streams or channels, one for each sub-carrier. Each sub-carrier is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase-shift keying) at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth.

OFDM has developed into a popular scheme for wideband digital communication, whether wireless or over copper wires, used in applications such as digital television and audio broadcasting, wireless networking and broadband internet access.

The primary advantage of OFDM over single-carrier schemes is its ability to cope with severe channel conditions (for example, attenuation of high frequencies in a long copper wire, narrowband interference and frequency-selective fading due to multipath) without complex equalization filters. Channel equalization is simplified because OFDM may be viewed as using many slowly-modulated narrowband signals rather than one rapidly-modulated wideband signal. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to handle time-spreading and eliminate intersymbol interference (ISI). This mechanism also facilitates the design of single frequency networks (SFNs), where several adjacent transmitters send the same signal simultaneously at the same frequency, as the signals from multiple distant transmitters may be combined constructively, rather than interfering as would typically occur in a traditional single-carrier system.
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


42 of 48 people found the following review helpful
5.0 out of 5 stars manliest wifi adapter ever!!!, November 21, 2010
okay, let's cut through the baloney and get real...

if you're reading this review and you're not some geeky i.t. tech, chances are there's only one question on your mind: "can i use this bad boy to steal free wifi from my neighbor?"

let me put your mind at ease. the answer is "HELL YES!"

i'm running the alfa on a dell latitude d4000 laptop with windows xp pro. installation was a snap with the included mini cd. seriously, a monkey could install this wifi adapter. i really have to wonder about the reviews by people who said they had trouble installing this thing.

i have the alfa running concurrently with my laptop's internal wifi card and when i open both of the utility managers, the difference couldn't be more obvious. my internal wifi adapter is detecting four access points right now... the alfa is detecting six.

i used to have to drive to the local net cafe everytime i wanted to steal a movie because i'm too cheap to pay for home internet service. i'm happy to say those days are over.

there are only two problems with this adapter...

the first problem is that this thing is a beast when it comes to power consumption. the first few times i used it i kept getting this error message:

"The Realtek RTL8187 Wireless 802.11b/g 54Mbps USB 2.0 Network Adapter has malfunctioned and exceeded the power limits of its hub port. You should disconnect the device."

i worked around this problem by purchasing a powered usb hub from best buy.

the second problem is that wildpackets doesn't offer a driver that's compatible with this thing, so you won't be able to crack w.e.p. encryption with it.

fortunately, with the kind of range this sucker gets, you won't need to crack any secured signals. there's bound to be at least one or two open connections within range no matter where you are.

so, in conclusion, buy the alfa awuS036h usb wifi adapter and NEVER PAY FOR INTERNET SERVICE AGAIN!

lol
Help other customers find the most helpful reviews 
Was this review helpful to you? Yes No


‹ Previous | 1 2140 | Next ›
Most Helpful First | Newest First

Details

Search these reviews only
Rate and Discover Movies
Send us feedback How can we make Amazon Customer Reviews better for you? Let us know here.