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[OldTechy]

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%

[FurryNutz]

Please provide pics 

[OldTechy]

... 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%

[FurryNutz]

whats "atten'd" 

[OldTechy]

whats "atten'd"  

attenuated ( opposite of GAIN )

[FurryNutz]

 

[OldTechy]

https://public.bay.livefilestore.com/y1pEfQsmy4H716Cf3O1ss1-PsmmRaUUkuMCu8e9gPEDxK7Sn4N5qiXWdsOiDVlWUCNj1ZBsgky3Ul3xXMfSSrQazA/100e2884s.jpg?psid=1

[FurryNutz]

Got a pic of what the connection looks like on the inside of the can?

[OldTechy]

neglected to really clean coffee residue ... he he

[OldTechy]

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?

[OldTechy]

[OldTechy]

[OldTechy]

[OldTechy]

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?

[OldTechy]

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 ...