D-Link Forums
The Graveyard - Products No Longer Supported => Access Points / Extenders => DAP-1522 => Topic started by: OldTechy on July 20, 2012, 12:16:53 AM
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Hi
DAP-1522 wave-guide (cantenna) external antennna project.
... later I will provide reasons for this project ( it's late now )
I plan to do the ext. ANT. mods as descibed elsewhere .. with a twist ...
(stay tuned ).
as 1st, initial test, ( i.e proof of concept )
I drilled a ( ~3/8' ?) hole 1-1/3" from bottom of Coffee can (bottom ridge; MasterChef 33oz,, walmart)
( can is apprx . 6-1/6" O.D. and 6-3/8" high )
This drilled hole was to just-fit the "ANT-jack" end of a usb WiFi adapter ( TL-WN722N TP_Link ) from outside the can ...
...and then firmly, re-attach the ANT to the adapter's ANT-jack, inside the "CAN".
My initial readings (using in "inSSIDer" ) for this simple rig pleased me.
below are some findings from my early, baseline tests.
(with and without the wave-guide, "cantenna" )
... best-case (steady-state)
rSSi ( received signal strength indicator; from inSSIDer )
(smaller negative is stronger signal)
P - PREFERRED-AP (max-avg value for "my Good-AP" )
I - Interfering AP's : avg-max. value of strongest interferring BAD-AP(s)
D - Dominance (P - I) ( larger negative is better )
Antenna rSSi-P rSSi-I ( D ) note
w / cantenna -59 -89 -30 this is really good!
w/o cantenna -66 -85 -19
signal chg total -7 +4 -11
note improved atten'd
GOOD AP BAD
improved AP's signal-ratio (P - I) ; SNR: ~55%
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Please provide pics :o
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... mod: improved this table layout for 'readability' ; pixs forthcoming..
Antenna rSSi-P rSSi-I ( D ) note
w / cantenna -59 -89 -30 <=this is BIG improvment
w/o cantenna -66 -85 -19
===== ===== =====
signal chg total -7 +4 -11
note: Improved atten'd improved
'good' AP 'BAD' AP(s) rSSi-ratio
rSNR: ~55%
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whats "atten'd" ???
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whats "atten'd" ???
attenuated ( opposite of GAIN )
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;)
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https://public.bay.livefilestore.com/y1pEfQsmy4H716Cf3O1ss1-PsmmRaUUkuMCu8e9gPEDxK7Sn4N5qiXWdsOiDVlWUCNj1ZBsgky3Ul3xXMfSSrQazA/100e2884s.jpg?psid=1
(https://public.bay.livefilestore.com/y1pEfQsmy4H716Cf3O1ss1-PsmmRaUUkuMCu8e9gPEDxK7Sn4N5qiXWdsOiDVlWUCNj1ZBsgky3Ul3xXMfSSrQazA/100e2884s.jpg?psid=1)
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Got a pic of what the connection looks like on the inside of the can?
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(https://public.bay.livefilestore.com/y1pxAA3MU_42UzFbD7ljRFxkdY29wSukxAEmNqhzEjL-N7BHBvNIrK_g5SiBD8Qzr9ebN7W-j5bKLxnW8Cf6YCgHA/100e2889-s.jpg?psid=1)
neglected to really clean coffee residue ... he he
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(https://public.bay.livefilestore.com/y1pSQIsUU3xmnaTxjF7GfNqN1nJhPkQ7v2NVn_Me-DBlAdlhHmXA2H0Wyy9aQKYrz1JBmzXqUZXQu6l0o0UpJwCzQ/100_2879s.jpg?psid=1)
this experiment was all just the proof-of concept ...
Next : I am Modding the DAP-1522 to use RP-SMA ext.. ANT connections (x2) ...
then, with 1m RP-SMA extension coax cables, connect the DAP-1522
to the two (2 ) external Cantennas ( cantenni? )
QUESTION :
aligning & tuning the cantennas, is going to be problemattic.
afik: WiFi sniffer prgs only with the adpters & not an external bridge , hmm
anybody know of any software/app trick to continuously "site-survey" monitor/update signal connextion for the DAP-1522?
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(https://public.bay.livefilestore.com/y1p5yANFy1MOZILhyy_Z1an0iU2f6XpQjPqfBQ2GXwMlkeVBgStYltLWMBduoomcEo0MTL1mEK8tpmNkWrbaVQl7w/100_2877s.jpg?psid=1)
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(https://public.bay.livefilestore.com/y1p7isu6yyDaBaUhqlTKHLGVUjzub0h3z1zVz1ZmcwZV2AgSxIyE5nrf-8en_4TO8QM96ImYkiYc9_P4ULB5ddWlA/100e2890-s.jpg?psid=1)
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(https://public.bay.livefilestore.com/y1pBGEuKS8LEtYH-nx44UwRn8qZMXQ0b0KHSAg6DzQLW8wIWdQMOGmGKFvl5o-e9ySZH9YYBEFkR2IqD1VJLI7YXw/100e2888s.gif?psid=1)
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update: I am awaiting delivery of the "fiddly-bits" from H.K. (ebay) (2-wks?)
[i.e. rp-SMA doodads :(pig-tails, antennas, 1m coax cable, M/F jacks)]
( don't laugh, but those prices were irresistible ... )
While waiting on the "doodads", I was planning to construct & test a double-length,coffee-Cantenna- waveguide. So, I asked the "better-1/2" to pick-up another coffee-can. Well, the similar size can from a different grocer is ... wait for it .... cardboard. grr. Coffee anyone?
So, in the meantime, I'd like to ask he knowledgable viewer(s) a question.
--> [Assuming the probe is properly positioned near the "focus"]
Would replacing the can's flat-bottom with a suitable, parabolic-reflector,
provide additional signal-gain for a waveguide-cantenna?
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update : my coffee-cantenna tests ...
suprisingly, my 1st attempt at a cantenna ( as reported at top of this thread)
provided my best results ( signal strengths & directivity , etc.)
other variations tested : ( unimproved on initial results )
- ANT. (probe) location [ 1.2" & 1.4" ] from bottom of coffee can
- smaller ANT ( from DIR-655)
- sgl-coffee-can with various parabolic "reflective-bottoms
[ 1-solid bowl, 2-colander(holes), 3-strainer(mesh) ]
- dbl. length coffee-cans
- smaller can (No.3 : 4-1/4" x 7")
curious ...