how do i find out how much db my antenna is - Page 2

TheSovereign · 07-27-2002

hmm i was never told
just that it needed 28 and 25 turns
i got them at about 1mm apart

lincomatic · 07-27-2002

Quote:

Originally posted by mentat
I believe lincomatic was asking what the spacing was between individual turns was, not between the sets of coils.

thanks mentat, that's what i meant.

the sovereign,
when you did the antenna comparison, did you experiment with the orientation for each antenna? to do a fair comparison you must play with the orientation until you get the maximum gain for each antenna. otherwise, you might just be comparing which antenna currently has its polarization matched better to the AP.
also, if you took the readings indoors, they are not accurate enough.

TheSovereign · 07-27-2002

i was outside with the linksys access point i was about 30 feet away my signal from the stock orinoco ant. was good
then i just plugged in my ext ant. and counted the gain
it was 12. am i doing something wrong?

lincomatic · 07-27-2002

Quote:

Originally posted by TheSovereign
i was outside with the linksys access point i was about 30 feet away my signal from the stock orinoco ant. was good
then i just plugged in my ext ant. and counted the gain
it was 12. am i doing something wrong?

yes. you still need to play w/ orientation of both antennas, find the max # for each, and take the difference. otherwise, you're just comparing which one has its polarization lined up the best.
try rotating the antennas around along all axes while outside and you'll see how the signal level fluctuates wildly by several dB.

TheSovereign · 07-27-2002

ok will do
ill let u know my results
why dont one u build one of these things so we can double check
couldnt hurt and it cost me pretty much nothing
i used a female bnc instead of a female N
the male N connecter fits perfectly into the female bnc

TheSovereign · 07-27-2002

ok did what u said
i get anywhere from +8 to +15 but more around 12 and 11
i tested on my linsys and my freinds agere ap
we repositioned the antenna's and everything and i even tried the antenna on his card

lincomatic · 07-27-2002

wow that is pretty amazing. i'll try it out when i have some time and see if i get the same results. but if true, your simple little antenna outperforms stuff much larger and more complex. it would be nice to get some more technical info on the design if possible.

TheSovereign · 07-27-2002

i will ask him for all the technical info

TheSovereign · 07-28-2002

Quote:

ok. well, here goes.
speed of light = 300,000,000 Mps
take these for example
1 megahert = 300 meters wavelength
2.4gig = .125 meters or 12.5 centimeters wavelength
the best area of the wavlength to interrupt the signal is 4.445 cm or 1.75 inches(I dont know why this is, they just showed it to me in training) the reason for coiling the copper is to ensure that the signal does get interrupted. If it doesnt it will pass right thru your antenna and you will recieve nothing. the reason why one has more coiling than the other is because of the range of microwaves if it misses one coil the other will get it. the grounding of coil is not imparitive but it will, in a sense "attract" the signal to it. remembeer the antenna I showed you with the formica? that works alot better but it requires surgeons hands to contruct

thats what he sent me i hope that helps

Dr3D1zzl3 · 07-28-2002

post pics please!

fordem · 07-28-2002

Quote:

Originally posted by TheSovereign
remembeer the antenna I showed you with the formica? that works alot better but it requires surgeons hands to contruct

Got any more info on this antenna?

TheSovereign · 07-28-2002

its just a directional flat panel antenna
u need some kitchen top formica and maluable copper sheeting
about twice as thick as aluminum foil

well u cut them into 2 inch sqaures all of them and start making big mac's with them

------------------------ coppersheet
_______________ formica

------------------------ coppersheet
_______________ formica

------------------------ coppersheet

then u gotta soldier copper braided wire thru the middle of all 3 of them u make a bunch of these and put them about 3 or 4 inches apart from each other and solder the braided wire to copper strips then finally to your high efficiency low loss cable

seems like alot of work for a stupid antenna to me

next im just gonna try to built a multi coiled version of the antenna i got now

lincomatic · 07-29-2002

ok, i tried building your coiled antenna. it was a b*tch winding all those coils...my hands are sore! anyway, i didn't have any #8 wire, so i used #14 instead. I tightly wound the coils around a 7.5mm drill bit, then "cut" them with a steak knife, turning the knife thru all the coils to get the separation between them.

thesovereign, does it look like i built it correctly?

went outside and compared w/ the ORiNOCO built-in. here are the best readings i got:

antenna: SNR/Signal/Noise
ORiNOCO: 30/-60/-90
coils: 36/-65/-101

the best signal from the orinoco was by holding it vertical, with the bottom facing my AP. the coils antenna worked best w/ the coils parallel to the ground.

interesting results. note that while the SNR went up by 6dB w/ the coil antenna, the signal actually lost 5dB, but it also reduced the noise by 11dB; thus the improved SNR.

Thunderforge · 07-29-2002

Running this antenna parallel to the ground would be pretty inconspicuous. We're they positioned side-by-side or top-and-bottom while you had them parallel to the group or did it matter? Also were you able to get an idea of how directional it's pattern is?

101

lincomatic · 07-29-2002

Quote:

Originally posted by Thunderforge
Running this antenna parallel to the ground would be pretty inconspicuous. We're they positioned side-by-side or top-and-bottom while you had them parallel to the group or did it matter? Also were you able to get an idea of how directional it's pattern is?

101

sorry, my description of the orientation was difficult to understand. look at my photo above w/ the antenna laying flat on the floor and imagine the AP being at the bottom of your computer screen. it isn't terribly directional but is not omni. i estimate about 3-6dB diff if you rotate it while keeping parallel to the ground. i'm going to throw this thing on my dash when i go driving later and see how it fares.

07-27-2002	#16 (permalink)
TheSovereign Master of the universe Join Date: Jun 2002 Location: chicago Posts: 658	hmm i was never told just that it needed 28 and 25 turns i got them at about 1mm apart __________________ SO SAYS TheSovereign

07-27-2002	#18 (permalink)
TheSovereign Master of the universe Join Date: Jun 2002 Location: chicago Posts: 658	i was outside with the linksys access point i was about 30 feet away my signal from the stock orinoco ant. was good then i just plugged in my ext ant. and counted the gain it was 12. am i doing something wrong? __________________ SO SAYS TheSovereign

07-27-2002	#20 (permalink)
TheSovereign Master of the universe Join Date: Jun 2002 Location: chicago Posts: 658	ok will do ill let u know my results why dont one u build one of these things so we can double check couldnt hurt and it cost me pretty much nothing i used a female bnc instead of a female N the male N connecter fits perfectly into the female bnc __________________ SO SAYS TheSovereign

07-27-2002	#21 (permalink)
TheSovereign Master of the universe Join Date: Jun 2002 Location: chicago Posts: 658	ok did what u said i get anywhere from +8 to +15 but more around 12 and 11 i tested on my linsys and my freinds agere ap we repositioned the antenna's and everything and i even tried the antenna on his card __________________ SO SAYS TheSovereign

07-27-2002	#22 (permalink)
lincomatic Squaaawk! WiFi! WiFi! Join Date: Apr 2002 Location: Tinsel Town Posts: 1,682	wow that is pretty amazing. i'll try it out when i have some time and see if i get the same results. but if true, your simple little antenna outperforms stuff much larger and more complex. it would be nice to get some more technical info on the design if possible. __________________ ~lincomatic

07-27-2002	#23 (permalink)
TheSovereign Master of the universe Join Date: Jun 2002 Location: chicago Posts: 658	i will ask him for all the technical info __________________ SO SAYS TheSovereign

07-28-2002	#25 (permalink)
Dr3D1zzl3 Mental Penis Fencer Join Date: Apr 2002 Posts: 371	post pics please!

07-28-2002	#27 (permalink)
TheSovereign Master of the universe Join Date: Jun 2002 Location: chicago Posts: 658	its just a directional flat panel antenna u need some kitchen top formica and maluable copper sheeting about twice as thick as aluminum foil well u cut them into 2 inch sqaures all of them and start making big mac's with them ------------------------ coppersheet _______________ formica ------------------------ coppersheet _______________ formica ------------------------ coppersheet then u gotta soldier copper braided wire thru the middle of all 3 of them u make a bunch of these and put them about 3 or 4 inches apart from each other and solder the braided wire to copper strips then finally to your high efficiency low loss cable seems like alot of work for a stupid antenna to me next im just gonna try to built a multi coiled version of the antenna i got now __________________ SO SAYS TheSovereign Last edited by TheSovereign : 07-28-2002 at 01:47 PM.

07-29-2002	#29 (permalink)
Thunderforge Registered Member Join Date: Jun 2002 Location: Florida Posts: 342	Running this antenna parallel to the ground would be pretty inconspicuous. We're they positioned side-by-side or top-and-bottom while you had them parallel to the group or did it matter? Also were you able to get an idea of how directional it's pattern is? 101 __________________ Back to the forge, TF

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