On Thursday, July 18, 2002, at 11:34 , Brown, Daniel G (Daniel) wrote:
>
> 1. Why, even after putting a 15.4dbi antenna on the wNIC in my
> laptop, my range was not altered/increased to a WAP with a 15.4
> dbi antenna on it.
Bad antenna connection, defective antenna, lots of noise, or
pointing wrong way. I can't think of any other possibilities.
Remember: An antenna doesn't discriminate against noise. Have
you tried another channel?
> 2. Can the Linksys WAP11 v.2.2's power output be increased to
> the 100mW that I believe it to be capable of, and how would one
> go about this?
I thought it already was. 100mW = 20dBm, what's the manual say it is?
> (The WAP11 v.2.2 has no USB port, and I can't seem to get the
> SNMP agent to respond, I've tried all sorts of community
> strings to no avail).
I didn't think it had SNMP.
> 3. Even if the WAP11's power output is set at 100mW, will this
> be sufficient to provide seriously increased range?
It's only double the power. Not that much.
> And if it's already set at, say, 50mW, why didn't the range
> increase from adding a more powerful antenna?
See above.
> 4. Would adding a 2.4 ghz amplifier boost the signal sufficiently?
Maybe, but your EIRP is already 3.5W, if I did the math right.
So the answer is "probably not legally".
> 5. (This is my truly novice question) Is there a good way to
> relate mW output to dBm gain?
Yes. But first, gain is dBi, not dBm.
dB is a relative, logarithmic scale. 10dB is 10 times the
whatever; 20dB is 100 times the whatever, etc.
In the case of dBm, whatever is 1mW. So 100mW = 20dBm.
dBm = log(mW)
In dBi, the whatever is every physicists favorite thing[-1], the
object that is not possible. In this case, a perfectly
isotropic[0] antenna --- that is, one that radiates equally in
all directions. A 48dBi antenna[1][2] hooked up to a 100mW
source would put off 20dBm + 48dBi = 68dBm[3] in a very small
beam[3], killing any annoying birds that happen to get in the
way.
Anyway, to put all this to a practical use[5] take the power
output from the WAP, add in any amplifiers, subtract cabling and
connector losses, add in the antenna(s), subtract free space
losses, and if you have a signal level above the receiver
sensitivity it should work.
FOOTNOTES: (do not read, or you'll be sorry!)
[-1] Besides coming up with weird theories to describe events that ---
theoretically --- can't happen except on a bad episode of Star
Trek
[0] Yes, dumb spell checker, that is correct.
[1] Also known as a WAP to thermo-deathray converter
[2] What, you have a problem with 12 meter dishes? ;-)
[3] Not sure how wide --- don't feel like doing the math!
Couldn't be more than
1�, I'd guess.
[4] 68dBm = 10^(6.8) = ~63KW EIRP. Mmmm, tasty burnt bird!
[5] Well, I guess world domination is a practical use. But a
48dBi dish would
be pretty expensive, and hitting anything with it would be
hard. But it'd
sure make popcorn!
>
> I pulled a lot of information from
> http://www.byte.com/documents/s=1422/byt20010926s0002/1001_marshall.html,
> but my questions remain.
>
> Any assistance that can be rendered would be a great help. (And
> yes, I am aware I work at a company that produces wireless
> equipment; however, it would be rather unprofessional for me to
> go around asking company people about a personal project, as I
> don't have any contacts in the wireless side of things (I'm an
> ATM / FR / MPLS / IP network engineer). In addition, our
> Orinoco product line was spun off with Agere Systems, so the
> people who would REALLY be the ones to ask aren't in Lucent
> anymore.)
>
> Thanks,
>
> -Daniel G. Brown
> Senior Core Network Engineer
> Advanced Core Networking Team
> Lucent Worldwide Services
>
> "If anyone can show me, and prove to me, that I am wrong in
> thought or deed,
> I will gladly change. I seek the truth, which never yet hurt anybody.
> It is only persistence in self-delusion and ignorance which does harm."
> -Roman Emperor Marcus Aurelius
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>
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