1. Wi-Fi Booster Antennas Reid Palmeira EE 469 Final Project Review

2. Overview Goals Design overview Construction Testing Overview Results Problems Conclusions Commentary and Future Considerations Questions and Demo (time permitting)

3. Goals Design, build, test an external antenna to boost performance and range of an 802.11 (Wi-Fi) wireless network. Keep it cheap but make it work Don’t break the law  FCC restrictions on antennas

4. Design Two antenna designs Parabolic dish reflector  One 16”  Two 8” Pringles Yagi  Using matched N-connector

5. Design Considerations Performance Network Range Data Transfer Rate Size and portability Security Cost and ease of construction Setup and Configuration time

6. Design – Parabolic Dish Placed so that the antenna of the AP sits at or near the focal point of the parabola Single 16” wide dish more applicable for case where antennas are close together Pair of 8” wide dishes more applicable for cases where the antennas are spaced farther apart Each dish is 4” in height

7. Design – Parabolic Dish, small Field of view limited by direction of antenna – This is the design for a 6” dish, which was scaled up to 8” A pair of smaller antennas with overlapping fields is used to boost the signal strength and range of the network The limited field of view also has the effect of increasing security by limiting area of exposure.

8. Design – Parabolic Dish, large This is the pattern for a 9” array, scaled to 16” A single large 16” dish is used with both antennas of the access point operating near but not at the focal point. Most of the energy is reflect to the forward region with some bleeding to the outer edges distorting the field.

9. Design – Pringles Yagi Collector rod divided into quarter wavelengths  Channel 1 = 2.412 GHz Collector length => L = 4.88 inches  Channel 11 => L = 4.80 inches  Split into ¼ λ = Max = 1.22” Min = 1.20” Pringles can acts as a reflector for the collector rod to improve received signal strength

10. Construction - Parabolic Initial intent was an aluminum sheet or wire mesh formed around Styrofoam mold which attaches to the AP Used a spare Pringles can instead of an aluminum sheet and cardboard instead of Styrofoam because it was easer to shape Alterative reflectors  Aluminum cansFoilTin

11. Construction - Yagi Collector rod wrapped in aluminum tubing split at 1.2” ( ¼ λ ) by a washer. Plastic spacers (Pringles lids) at center and one end Lock nuts to hold assembly together Trim excess all-thread Reflector made by attaching a bulkhead N- type connector to the Pringles can  Location by trial and error mostly – 3.5” from end

12. Testing Two test sites  University  Home Test Hardware  Dell Inspiron 4150SE  Orinoco PCMCIA “Silver” 802.11b compatible Wi-Fi card  At UHM: SMC model SMC2655W Access Point. WEP Encryption turned on  At home: SMC model SMC7004VWBR AP/Router. WEP Encryption turned on

13. Testing - Measurements Reported results are the averages of three testing sessions Because antennas are directional and require aiming and adjustment in some cases, recorded scores are maximum sustain levels Yagi antenna tested under 3 situations  Attached to AP, attached to mobile, attached to both AP and mobile

14. Results – Tabular Results - UHM Distance in ft. (approx)Yagi Distance in ft. (approx) Para bolic 4.80" AP 4.80" mobile 4.80" both2x8"1x16" 20182432202831 50182428502427 75122224752224 1001112221001624 1501012221501218 20061219200312 250381825003 500031250000 Yes, I did appear to violate the FCC regulations

15. Results – Tabular Results - Home Yes, I did appear to violate the FCC regulations DistanceYagiDistanceParabolic 4.80" AP 4.80" mobile 4.80" both2x8"1x16" 2022 40202818 50182034502422 75121632751812 10012 2810012 150101226150103 20010112420060 2506101625030 500361250000

16. Problems Finding the matched cables for the Yagi antenna was difficult and costly Locating interference sources Maintaining a direct line of sight between the mobile and access point, especially over long ranges

17. Conclusions – Theoretical Loss The decrease in gain should closely follow a logarithmic curve resulting in a loss of 6 dB for each doubling of distance using a model of Free Space Loss (FSL)

18. Conclusions – Parabola at UHM

19. Conclusions Real loss over distance does not hold well to model possible reasons include  Interference  Reflected power Parabolic reflector dish has a limited forward range Yagi antenna requires adjustment when moving Both offer significant performance improvement over normal operation)

20. Conclusions - What’s important? Data RatesPringles SecurityParabola Signal Strength Overall TIE RangePringles Ease of Construction Parabola CostParabola MobilityParabola Secondary UsesPringles The best antenna design depends heavily on personal preference and the needs of the network Each of the designs had benefits and tradeoffs which determine their best usage conditions

21. Comments There are a number of other antenna types  Discone antenna seems interesting Test for range of view would have been interesting Thanks to the makers of Pringles for such tasty antenna materials Security is discussed more in the final report

22. Questions and Demo Time permitting