200mW EliteConnect

[ed_po]

Hello every one.
I whant to buy a rig and can not make a decision : ORiNOCO GOLD or SMC 200mW EliteConnect 802.11b High Power ?!
This is not a big difference - only 20$ but is 8dbm more...
I was thinking: if a cheap 8.5$ antenna with ORiNOCO 15dm(less then 50mW of power) do not provide a good performence, so may be EliteConnect with 200mW will do? EliteConnect-70$+8.5$ antenna=78$, another choice is ORiNOCO-50$+55$ 5dBi good performance antenna=105$ !
78$ vs. 105$ and the first option is more power in any way, even if the cheap antenna provide a little loss instead of gain..
What do you think guys?

[Thorn]

Which card depends more on the intended use than anything else. Whichever card you decide on get the better antenna. The antenna can make all the difference.

Good card + good antenna = good performace
Crappy card + good antenna = moderate performace
Good card + crappy antenna = bad performace
Crappy card + crappy antenna = give up now

Here's a link to the Cheap Antenna FAQ I wrote on this very subject over at the NetStumbler Forums:
http://www.netstumbler.org/showthread.php?t=13860

[ed_po]

200mW

Thanks for reply.
I've already read your FAQ that was actually very helpful, but i wanted to know something else.
As long as IERP power is intentional radiator power+antenna gain, with the first option i described we have 23dBm(200mW ) - loss of pigtail+5.5dBi of antenna gain. Suppose the poor quality antenna do not have gain at all than we still have about 23dBm of power.
In second example we have 15dBm ORiNOCO+5dBm good quality antenna=20dBm(100mW) and this is for 105$ when you can get 200mW only for 78$, that is the point.
Now i must tell you that although i have a little knowledge and experience from my work as a technician in local residential integrator i do not have any experience in wardriving and use of detachable high gain omni or directional. I understand also that my calculation is only a theory and the reality might not be the same, but the calculation is the thing we always start from and i'd like to know how to continue.
Another thing that i always have in mind is that most manufacturers interested in advertising and selling their product more than in product quality, here comes the question- can 200mW ElitConnect be the same poor quality as the cheap 8.5$ antenna????. If so than the answer is clear: 15dBm ORiNOCO CLASSIC GOLD+5dBi good quality omni is the best choice even if it 30$ more expensive!
I know that i miss something so please feel free to correct me.

[Thorn]

Some people have reported negative gain on the cheap antenna. It could drag a high output card down to below the level of the low output card. Like I said:

Whichever card you decide on get the better antenna. The antenna can make all the difference.

I've been in the same position. I bought the ORiNOCO and more expensive antenna.

[EvilMoFo]

i cant stand orinoco cards and heart my smc elite connects (i have 2, w00)

go with the elite connect, its a kickass card..... and remember, the plug is rp-mmcx ;)

[evad123]

Output power for WLAN Client Adaptors

The performance WLAN client's adaptor is described by a few things, hopefully this explanation may be useful for your decision,

802.11b uses a 22MHz wide spread spectrum modulation technique, thus the theoretical noise floor of any receiver is described by N = kTB.
Where
N = Noise Level (Watts)
K = Boltzmann’s Constant (Joules/Kelvin) = 1.38E-23
T = Temperature (Kelvin)= lets say 23 degs C + 273 deg K (absolute zero) = 296
B = Bandwidth (Hz) = 22E+6 (Hz)

thus the theoretical noise floor is
1.38E-23 * 296 * 22E+6 = 8.9865600E-14 W

Which in if Expressed in dBm which is more usual for small powers like this :-
Power dBm = 10*log10( 8.9865600E-14 (W) *1000) = -100.46dBm

This is the absolute minimum level observable by any receiver of 22MHz wide (ie 802.11b & g WLAN) signals at around room temperature. (there is a bit bit of processing gain provided for managment frames by the 1Mb/s BPSK rate but thats a different story)

Most WLAN cards will have an implementation noise figure of around 4dB, this gets added to the noise observed by a theoretical perfect receiver and gets us to a theoretical noise figure of

-100.46 dBm Noise + 4dB implementation noise = -96.46dBm.

(This is noise internal to the receiver, and is separate from any noise that may come from external sources i.e. interference from microwave ovens or other WLAN's etc)

As stated above ability of the card to decode packets without error relates directly to the level of the signal Vs the Noise. To get a continuously successful decode (<2% probability of bit error per packet) at the 11Mb/s clock rate (the fastest in the 802.11b protocol) the signal must be at around 10dB above the observed noise floor . This ratio of Signal to Noise is unsurprisingly referred to the SNR or Signal to noise ratio

So for our receiver,

-94.46dBm (Noise floor) + 10 dB (required SNR) = -84.46 dBm (required signal level)

Next antennas

Antennas effectively act as a matching transformer between the impedance of an electrical circuit (in this case 50 ohm one), and the impedance of free space 377 ohms. If an antenna was perfectly efficient 100% of the energy incident on the electrical input of antenna would be radiated into space (and vice versa. Unfortunately nothing is perfectly efficient (i.e. matched) so much of the energy that hits the antenna is reflected back where it came (either back to the electrical circuit during transmission or back into space during reception), this inefficiency is some of the reason why WLAN client adaptors with internal antennas tend to be deaf, in making the antenna small the antenna tends to be more inefficient.

The other side of antennas is Gain, in life never get something for nothing and thus what is gain?. A theoretical perfect point source antenna would have 100% efficiency and radiate equally in all directions, (i.e. a sphere of power from a point in the centre). This perfect (and unmakeable) antenna is in fact often what antenna gains are compared againsed (dBi decibels relative to the gain of an isotropic (equal in all directions) radiator). The other theoretical antenna used is a perfect dipole expressed in dBd (infact 2.15dBi = 0dBd), Dipoles are possible to make (although not perfect ones) and have a gain pattern like a ring donut on a table rather than the isotropic sphere).

I find it easy to visualise antenna gain like a spherical rubber balloon filled with water, The volume of the balloon is given by the efficiency of the antenna, if you squash the balloon downwards it will expand sideways giving a higher gain in those directions, and consequently a lower gain in vertical directions, If the balloon is squashed into a sausage shape, it will have a very high gain at one angle but extremely low gain every ware else.

So back to the WLAN card conversation.

Lets say we had a Client Card that could transmit at 1W (30dBm) and an AP that could transmit at 100mW (20dBm), The Client card with a low gain antenna (2dBi) and the AP with a high gain antenna (10dBi). The pathloss between the two devices (caused by the distance between them plus walls people etc ) for this example is 128dB

Both the AP and the Client card need a received signal level of -84.46dBm. To see if a conversation could be successful for these devices we can work out a link budget.

AP Recevied level = 30dBm + 2dBi - 128dB + 10dBi = -86dBm thus the AP successfully receives the packet and sends an acknowledgement to the client

Client Received Level = 20dBm +10dBi - 128dB + 2dBi = -106dBm

Note the client cannot decode the acknowledgement packet as it is to week to be decoded thus the AP and client cannot communicate using the 802.11b protocol.

The upshot of this is that Output power is great but only if it is present at both ends of the conversation. Only if both the AP and the Client have the same high output power is it useful to give more range. QED

(also note that the limit EIRP i.e. foreword power + antenna gain under FCC regs is 30dBm (1W) so 20dBm with a 12dBi Gain antenna is illegal, in the EU the limit under ETSI is 100mW ERP (20dBm) thus 20dBm ERP + 2.15dB (dipole vs Isotropic) = 22.15dBm EIRP = 164mW EIRP )this could easily be exceeded with a high gain antenna so watch your backs)

[phreakmonkey]

I happen to have both of these cards and use them in Linux all the time to do Non-Standard Things(tm). There have been some great posts about antenna/power tradeoffs. There are some additional quirks to consider depending on your application:

Environment:
I dual-boot Linux (Slackware 10.x) and Windows XP SP2. I usually run Linux Kernel 2.4.(latest) with the external pcmcia-cs drivers. (I've had better luck modifying and reloading the wifi drivers with this configuration.)

Lucent/Agere/Orinoco/Wavelan Gold card:
Using patched pcmcia-cs orinoco.c driver:

Pros:
Supports monitor mode
Can change own MAC address
Excellent integrated antenna (albeit bulky)
External antenna connector (albeit flimsy)

Cons:
Cannot force MAC address of AP you want to associate with.
Cannot run in "Master" (AP) mode
Cannot send "raw frames" (ala host-ap driver)

SMC "EliteConnect" SMC2532W-B High Power card:
Using latest hostap driver with pcmcia-cs:

Pros:
Supports monitor mode
Can change own MAC address
Removable integrated antenna (takes up less space)
Selectable, dual external antenna connectors
Support "Master" (AP) mode in firmware
Can send "raw frames"
Much higher power (better range with external antenna)

Cons:
Has a bad habit of re-associating with stronger APs when "signal hunting"
Signal strength / Noise readout seems to be very flakey. (Almost unusable)
Gets very warm (to be expected)


Despite the longer list of "Cons" on the Orinoco card, I tend to use it more often because the first two cons on the SMC card drive me nuts.

Both are decent cards, and both have their place in my toolbox. I'm adding an Atheros-based card for 802.11a/g support tomorrow... we'll see how well the madwifi drivers mix with this bag of tricks.

[Edit: One additional note - the Windows XP drivers for the SMC2532W-B seem to be very flakey as well. I never use the card in XP as a result.]

Just my $.02

- PM

[ck3k]

I have both cards in question, but I must say for the price I would check out the smc, I have had little or no issues getting it to work in all sorts of varied nix. The orinoco is nice, and I had one from back in the day when they where the coolest thing since sliced bread. Also for you linux fans, you do not have to fudge with the kernel with the smc, it already supports monitor mode, so no fun with kernel patching.

[Chris]

I guess if I was going to just buy one card I would probably go with the Senao 2511 CD Plus EXT2 over either of those two options. 200mW, two antenna jacks, comes with those spiffy little black antennae, and you can get them for under 60 bucks.

[FunkyChicken]

hi, im looking for a replacement for my orinoco gold cardm i like the sound of the Senao 2511CD Plus EXT2, anyone here know hwere i can get one of these from in the UK?

cheers

[evad123]

The joy of european regulation

hi, im looking for a replacement for my orinoco gold cardm i like the sound of the Senao 2511CD Plus EXT2, anyone here know hwere i can get one of these from in the UK?

cheers

Unfortunately we come under do gooder ETSI regulations in the UK, so there is a max 100mW ERP limit (Ofcom Interface requirement IR 2005 ) unlike the FCC's 1W ERIP limt FCC Part 15.247 (although the FCC did put on the utterly crazy requirement for slightly difficult to find antenna connectors, in doing so spawning an entire market in mail order RP-SMA and RP-TNC interseries adaptors, its like child proof caps on pill bottles... only children can open the damm things), anyway.. this means that if you want a 200mW card your gonna have to get one mail order from our friends in the US.

Oh, and by the way, don't use it as that would be illegal anyware in Europe.

[FunkyChicken]

jsut say i had one of these "illegal" cards, i guess i wouldn't be allowed to use it? just say i did buy one, and i did use it, would i be the only one, or is there possibly more people in the uk using them? (if u get my drift)