Not Real Active

[ccie4526]

Food for thought....

If you're running kismet or similar passive sniffer software which doesn't do active probing (a la netsumbler), you can use an MMDS receive preamplifier between your antenna and network card.

I've got a couple of Pacific Wireless MMDS receive preamplifiers, anywhere between +15dB to +25dB gain. I generally run with the +25dB preamp on my sniffing setup, and can pick up signals off some of my access points nearly 5 miles away. Without the preamp, I'm doing good to get them outside of a mile. And yes, my APs are running at the legal +36dBm EIRP limit, I'm a wireless ISP.

The MMDS preamps are broadband enough that 2.4GHz falls well within their range.

Just a way to hug a few more APs.

...da Ronster

[mentat]

How about a URL?

[Droogz]

More information please on the amplifier. I am currently useing a oronco with a 5db gain antena and would like to boost that if i can. Its a small antena at about 5 to 6 inches in height.

[bobzilla]

I've got a couple amps, the one I'm using now is a 'Teletronics 2.4 GHz 1 Watt Indoor SmartAmp' from http://www.fab-corp.com It states a 17db gain on receive. I also use an orinoco card. You'll need a pigtail to go from the orinoco mcx connector to an N-Type, which goes into the amp. Then you need an N-Type to N-Type for the amp to antenna connection (assuming the antenna you use is N-Type, I've got an 8db omni and 16db yagi I use).

[mentat]

I also use this amp. It's nice. I'm currently using it with the fab-corp 5 dBi "Stumbler Special" antenna because the 8 dBi I have is somewhat unwieldy. It magmount 7 dBi that Pacific Wireless has looks sort of interesting though.

[hratch]

yup yup
teletronics 2.4 GHz 1 watt indoor amp with a Pacific Wireless 9dBi omni attached to it for _receiving_ in kismet.

ORiNOCO gold with a 12" pigtail-->amp-->4 feet of LMR400 ultraflex-->antenna
although 8 more dB gain on the receive side would be nice...

[ccie4526]

Correction on the Preamp specification, it's not Pacific Wireless (that's the antenna source).

The RF Preamplifiers are from California Amplifier. The two preamps I predominantly use are:
http://www.calamp.com/pages/pb_part.php?prt_id=51
which is a +25dB gain preamp, and
http://www.calamp.com/pages/pb_part.php?prt_id=53
which is a +15dB gain preamp.

Can't emphasize this enough. Do NOT let your card transmit RF into the back end of one of these things. They are NOT bidirectional. Do it one time, and you'll hear nothing, and just have an expensive piece of metal.

...Ronster

[Guest]

What does one of those preamps run price-wise? Why don't they put in some kind of protection so it just grounds outgoing signal or something? (Said with little electronic experience)

[mentat]

Last message from Mentat.

[hratch]

would be good for cards with diversity antennas like cisco...

[ccie4526]

What does one of those preamps run price-wise? Why don't they put in some kind of protection so it just grounds outgoing signal or something? (Said with little electronic experience)

I bought my preamps at a hamfest in Sunnyvale a couple years ago, was going to use them on 2.3GHz for amateur stuff. In the $25/each range there, who knows what they go for new.

With regard to protection, the units were designed for receiving MMDS TV signals. Obviously, there's no need for the end-user to transmit any signal, therefore why put any of the appropriate circuitry in place. As a radio amateur, I've learned to adapt what I can, and just don't do those things I shouldn't do. A long time ago, I learned the hard way what RF into the back end of a preamp (at 144MHz) would do, and thus know not to do such a thing in the future. Learn from someone else's mistakes!(tm)

.....da Ronster

[izzy4505]

I generally run a 12 dB dish out the back window of my car, hooked up to my 32mW orinoco gold. However, I've got a friend of mine that decided to go out and get the best he could buy. Definitely an illegal setup, and it literally gave me a headache. [Not sure if this was because of radiation poisoning, or just a placebo effect.] Orinoco gold hooked up to a 2 watt amp, running into a 15.4 omni on the back of a truck. Lol, it was quite scary. He's since sold the amp.

Btw, just to clarify on the fcc restrictions. . .

1 watt for point to multipoint
4 watts for point to point

[Chuckster]

Ok,

I thought I would update my own thread...


Current Stumbling Gear:

MINI ITX car pc
xenarc touch screen
netgear wg311v3 PCI b/g card ( works great )
Proxim GOLD PCI card a/b/g ( jurry still out )
Hyperlink Tech Receive Amplifiers
Main antenna b/g is a hyperlink tech 9db 13" to N
Mag Mount from Diamond Antennas.

Various other antennas for A, as well as a plethera for
b/g that randomly get switched out.

Chuckster