1. Marlon K. Schafer (509) 982-2181 Michael Anderson (630)859-1987
WISP Basics
Marlon K. Schafer (509)
Michael Anderson (630)
A full day primer on the design, construction, and operation of a Wireless ISP.
Mike Anderson & Marlon Schafer
11/21/2018

2. Introduction WISP = Wireless Internet Service Provider
In this course you are going to learn the starting points and basics of becoming an profitable WISP.
We are going to assume you know nothing. If you have a question that we are not answering, please ask it.
Mike Anderson & Marlon Schafer
11/21/2018

3. Agenda License Free Bands Types of Unlicensed Radios
Basic system design
Definitions
Base Station (WPOP) Systems
Customer Premises Equipment (CPE)
Antennas
Calculations
Business plan
System design
Site Survey
Interference Issues
System examples
Cable Building/Connector sealing
Mike Anderson & Marlon Schafer
11/21/2018

4. Conventions 1 MHz = 1,000,000 Hz 1 GHz = 1,000 MHz
1 GHz = 1,000,000,000 Hz
IE:
2400 MHz is the same as 2.4 GHz
928 MHz is the same as 928 MHz
5.8 GHz is the same as 5800 GHz
Mike Anderson & Marlon Schafer
11/21/2018

5. Conventions Continued
Hz = Radio Spectrum
Bits = Data
K= 1,000
M = 1,000,000
G = 1,000,000,000
IE:
83.3 MHz is the amount of spectrum available in the 2.4 GHz band
11 MB/s is the over the air data rate of b (wi-fi) radios
Mike Anderson & Marlon Schafer
11/21/2018

6. License Free Bands ISM UNI-I (or UNII)
ISM: Industrial, Scientific, and Medical
UNI-I (or UNII)
Unlicensed National Information Infrastructure
ISM =
902 to 928 MHz
2,400 to 2,483.5 MHz
5,725 to 5,850 HHz
UNII =
5,150 to 5,250 MHz
5,250 to 5,350 MHz
5,725 to 5,825 MHz
For some more info go to:
Mike Anderson & Marlon Schafer
11/21/2018

7. 900 MHz 902 to 928 MHz Data rates up to 3 megs Non line of sight
Mostly abandoned but making a comeback
Unaffected by weather
Only a few manufacturers of gear
Expensive compared to b gear
Mike Anderson & Marlon Schafer
11/21/2018

8. 2.4 GHz 2,400 to 2,483.5 MHz 83.5 MHz of spectrum FHSS and DSSS
Speeds up to 22 Mbps common
Cheap Equipment
Not affected by weather
Needs Line of Sight
Unlicensed in Most Countries
Mike Anderson & Marlon Schafer
11/21/2018

9. 5 GHz
5,150 to 5,350/5,725 – 5,825/5,725-5,850(ISM)
Complicated power rules
Gobs of spectrum
Speeds up to 480 Mbps
Speeds up to 54 Mbps becoming common
Less congested than 2.4 GHz in most areas
Migrating from backhaul to distribution
Expensive gear
Mostly proprietary gear
Mike Anderson & Marlon Schafer
11/21/2018

10. Basic Wireless Diagram
Mike Anderson & Marlon Schafer
11/21/2018

11. Communications Methods
Two ways are common to all radios
Half duplex
Uses the same frequency to send and rec.
Uses different time slots
Commonly called TDD (time division duplexing)
Full duplex
Uses different frequencies to send and rec.
Uses the same time slots
Commonly called FDD (frequency division duplexing)
Mike Anderson & Marlon Schafer
11/21/2018

12. Vocabulary http://www.odessaoffice.com/wireless/definitions.htm
There is not enough time to go through them all.
LOS: Line of sight
NLOS: Near/non LOS
BWA: broadband wireless access
PtMP: point-to-multipoint
PtP: Point-to-point
CPE: customer premises equipment
AP: access point
AU: access unit (same as above)
DS (or DSSS): direct sequence spread spectrum
FH (or FHSS): frequency hopping spread spectrum
RSSI: receive(r) signal strength index/indication
TDD: time division duplex
FDD: frequency division duplex
TDMA: time division multiple access
CSMA/CA: carrier sense multiple access/collision avoidance
CDMA: code division multiple access
ESSID: extended service set ID
Mike Anderson & Marlon Schafer
11/21/2018

13. Vocabulary
dB: The dB convention is an abbreviation for decibels. It is a mathematical expression showing the relationship between two values.
RF Power Level: RF power level at either transmitter output or receiver input is expressed in Watts. It can also be expressed in dBm. The relation between dBm and Watts can be expressed as follows: PdBm = 10 x Log Pmw. For example: 1 Watt = 1000 mW; PdBm = 10 x Log 1000 = 30 dBm 100 mW; PdBm = 10 x Log 100 = 20 dBm. For link budget calculations, the dBm convention is more convenient than the Watts convention.
Attenuation: Loss of power, expressed in dB. Attenuation is expressed in dB as follows:PdB = 10 x Log (Pout/Pin). For example: If, due to attenuation, half the power is lost (Pout/Pin = 2), attenuation in dB is 10 x Log (2) = 3dB.
Path Loss: Path loss is the loss of power of an RF signal travelling (propagating) through space. It is expressed in dB. Path loss depends on: 1. The distance between transmitting and receiving antennas. 2. Line of sight clearance between the receiving and transmitting antennas. 3. Antenna height.
Free Space Loss: Attenuation of the electromagnetic wave while propagating through space. This attenuation is calculated using the following formula: Free space loss = xLog F(MHz) + 20xLog R(Km) F is the RF frequency expressed in MHz. R is the distance between the transmitting and receiving antennas. At 2.4 Ghz, this formula is: xLog R(Km).
Mike Anderson & Marlon Schafer
11/21/2018

14. Calculations No amp With amp Add radio output
Subtract cable/connector losses
Add antenna gain
With amp
Add amp gain
Subtract coax loss
For AGC amps use amp output instead of radio output and don’t count cable/connector loss
Mike Anderson & Marlon Schafer
11/21/2018

15. Effective Isotropic Radiated Power
17.5 dB radio – 1 dB misc. connectors – 2.3 dB coax loss + 24 dB antenna gain = 38.2 dB EIRP
30’ LMR 400 coax
Mike Anderson & Marlon Schafer
11/21/2018

16. Effective Isotropic Radiated Power
27 dB amp + 8 dB omni = 35 dB
In this case, the amp has AGC (automatic gain control) so the radio output is not counted.
Mike Anderson & Marlon Schafer
11/21/2018

17. Free Space Loss Also known as Path Loss
Amount of signal lost between the two ends of an RF link.
Calculated with the formula:
Free space loss = xLog F(MHz) + 20xLog R(Km) F is the RF frequency expressed in MHz. R is the distance between the transmitting and receiving antennas.
At 2.4 Ghz, this formula is: xLog R(Km).
Mike Anderson & Marlon Schafer
11/21/2018

18. Coverage
Coverage is affected by a combination of EIRP and receiver sensitivity
Add 3 dB and you DOUBLE your wattage
Every 6 dB doubles or halves your coverage range
36 dB cell
4 x more area
30 dB cell
Mike Anderson & Marlon Schafer
11/21/2018

19. DSSS Signal Issues
Notice how there are actually only 3 out of 11 channels that don’t significantly interfere with each other.
Mike Anderson & Marlon Schafer
11/21/2018

20. DSSS Signal Issues
DSSS from a WiLan radio used for a video surveillance system shown on a spectrum analyzer.
Mike Anderson & Marlon Schafer
11/21/2018

21. 802.11 Versions 802.11 - 2 Mbps - 2.4 GHz 802.11b - 11 Mbps - 2.4 GHz
DSSS
FHSS
Infrared
802.11b - 11 Mbps GHz
802.11a - 54 Mbps - UNII
OFDM
802.11g - 11 and 54 Mbps GHz
There are several others but there’s no product for them at this time
Mike Anderson & Marlon Schafer
11/21/2018

22. Antennas Antennas are also called “Intentional Radiators” by the FCC
Antennas focus energy
Focusing the energy causes a rise in energy in one direction equal to the loss of it in another. This is called “Gain”
Mike Anderson & Marlon Schafer
11/21/2018

23. Antennas
Antenna gain is measured at the highest spot on the coverage pattern
Beamwidth is measured at the point that the signal drops off by 3 dB
XPol (cross polarization) indicates how well an antenna isolates signals in the wrong polarization
F/B (front to back) ratio is an indication of how well an antenna squelches out signal coming in from behind it’s self
Mike Anderson & Marlon Schafer
11/21/2018

24. Antennas
When an antenna focuses it’s energy into a pattern it develops a “Beamwidth”
This would be an approximate pattern for a highish gain dish type antenna
Notice the large side lobes
Mike Anderson & Marlon Schafer
11/21/2018

25. Antennas Here is a better picture of main beam vs. side lobes
Mike Anderson & Marlon Schafer
11/21/2018

26. Antennas This is how antenna patterns are normally drawn
Mike Anderson & Marlon Schafer
11/21/2018

27. Antennas Sample of a vertical pattern for a high gain (15 dB) omni
This is NOT the kind of coverage you will usually want
Notice how much more signal actually goes UP into lala land
Mike Anderson & Marlon Schafer
11/21/2018

28. Antennas Not all antennas are created equal
Notice the much cleaner pattern from the panel antenna (bottom) vs. the grid antenna (top)
Pay special attention to the amount of signal that goes out the BACK of the grid
Mike Anderson & Marlon Schafer
11/21/2018

29. Antennas H-Pol grid V-Pol omni Panel H-Pol yagi
Mike Anderson & Marlon Schafer
11/21/2018

30. Antennas Rat Nest All antennas on this tower are in use
It’s in South America
The 24 dB grids are all running P-Com back haul radios. As I recall there are 20+ of them!
Mike Anderson & Marlon Schafer
11/21/2018

31. Amplifiers Don't! Design your system with NO amps as much as possible.
Don’t use amps at customer installs
Amps go at the antenna
For most amps try to keep coax loss down below 6 to 10 dB between the radio and the amp
Don’t over amp, as a rule the FCC HATES amps
There are basically two different types of amps:
AGC (automatic gain control)
Adjusts it’s output as needed to give a set dB total output
Generally easier to deploy as cable loss isn’t as much of an issue
Constant output
Gives the same boost to the signal at all times
Less complicated and sometimes less expensive
All amps add noise to the system
Usually about 3 dB
Amps do NOT add coverage to a system, power does that
Bigger amps do not always mean that a system will go further
For ptmp systems you are generally allowed 36 dB (4 watts)
A 9 dB omni with a 500mW (27 dB) will go NO further than a 12 dB omni with a 250 mW (24 dB) amp
Mike Anderson & Marlon Schafer
11/21/2018

32. Fresnel Zone Pronounced Frunel
The area around a LASER beam tight radio link, a buffer zone if you will
Cigar shaped
Is all they way around an RF link but usually thought of as being on the bottom of it
Anything that’s in the RF path’s buffer zone is considered to be in the Fresnel Zone
Mike Anderson & Marlon Schafer
11/21/2018

33. Calculations Receive signal Level Free Space Loss
RSL=Tx Power-Tx cable loss+Tx andtenna gain-FSL+RX antenna gain-Rx cable loss
Free Space Loss
FSL = 20Log10(MHz)+20Log10(distance in miles)+36.6
SOM (system operating margin)
SOM=Rx signal level-Rx sensitivity
Mike Anderson & Marlon Schafer
11/21/2018

34. Calculations milliWatt to dBm dBm to Watt dBm=(10Log10(mW)) 1 mW=0dBm
Watts=10((dBm-30)/10)
mW=10(dBm/10)
Mike Anderson & Marlon Schafer
11/21/2018

35. Business Plan Realistic customer base in 12 to 18 months
Assume 20% of the population split among all broadband providers
What kind of customers do you want
How many live/work within your expected coverage
What kind of service will you give
What will they be willing to pay
What kind of equipment will your service require
How many wpops will you need to cover them
Both from an RF and from a BW stanpoint
Mike Anderson & Marlon Schafer
11/21/2018

36. Marketing Ideas Local paper Billboards Radio TV Door to door
Word of mouth
Flyers at local businesses
Mike Anderson & Marlon Schafer
11/21/2018

37. WPOP Design Choosing a site Look before you leap
First do a visual sweep of the area
Can you see your customer base well?
Is there a better spot?
Are there others already up there?
Are there any other systems up there?
This system is in Greece. The customer’s antennas are the two grids. He has to amp them to go 15 miles due to all of the noise in the area. He’d have been better off to use solid dish antennas, or better yet a different local.
Mike Anderson & Marlon Schafer
11/21/2018

38. WPOP Design Look for causes of interference.
It could be your own
It could be from someone else
One of this person’s other towers was on a cell phone tower. It looked even worse than this.
The red arrow is showing a DSSS backhaul, blue is ONE of the dead areas of the FHSS distribution system caused by another DSSS backhaul link on the same tower.
Notice how little of the system is actually working. If this were a correctly designed and installed wpop the FHSS system would have filled in pretty evenly all the way across the display.
Mike Anderson & Marlon Schafer
11/21/2018

39. The orange arrow is from the OTHER and of that link, 30 miles away.
WPOP Design
Make sure that there are no high end radio systems in the same frequency range as you
This was from a Western Multiplex Lynx FDD system. Transmits one direction on one frequency and the other direction on another frequency
Very nice system
Unless it’s not yours…..
The Blue arrow is from a 30 mile cell phone tower link. It’s 1 mile away and ¼ mile to the side of my site.
The orange arrow is from the OTHER and of that link, 30 miles away.
Mike Anderson & Marlon Schafer
11/21/2018

40. WPOP Design Try to locate your system where no one else is
Look for places that can see the most (notice that I didn’t say all) potential customers
The arrow points to the NOC where the wireless backhaul is located.
This is the view of downtown Odessa as seen from the 200’ hill where my main broadcast antenna is.
The antenna is 20’ higher, on the peak of Herman’s second story roof.
Mike Anderson & Marlon Schafer
11/21/2018

41. WPOP Design This would be a typical small WPOP broadcast setup
You can see the radio, pigail, dc injector, amp, coax, antenna and a mount for the side of a building/pole
Mike Anderson & Marlon Schafer
11/21/2018

42. WPOP Design
Mike Anderson & Marlon Schafer
11/21/2018

43. WPOP Design
Mike Anderson & Marlon Schafer
11/21/2018

44. WPOP Design
Mike Anderson & Marlon Schafer
11/21/2018

45. Customer Premisis Equipment
Mike Anderson & Marlon Schafer
11/21/2018

46. Customer Premisis Equipment
Mike Anderson & Marlon Schafer
11/21/2018

47. Tool Kits
Mike Anderson & Marlon Schafer
11/21/2018

48. Making Cables
Mike Anderson & Marlon Schafer
11/21/2018

49. Resources www.isp-lists.com www.wispcon.info www.part-15.org
Mike Anderson & Marlon Schafer
11/21/2018