Figure 3-10: Pole Mount with temporary pivot bracket detail. It is often convenient to temporarily mount a spare pair of brackets below where the Access Point will be placed. This serves as a pivot point, as well as stopping slippage during installation, as in Figure 3-10. While downtilt is normally not needed, the nuts on either side of the Access Point’s “ears” also serve to establish downtilt.
Figure 3-11: Measuring bottom spacing. Figure 3-12: Measuring top spacing.
.8.1 Bracket Mount There is a wide range of hardware vendors and approaches to mounting a pipe on a utility pole. For example, Valmont or RFS Celwave (Figures 3-13 & 3-14) will mount on the common wooden utility pole and any pipe of the proper OD can be clamped to it. Arcwave makes a bracket with the pipe welded to the bracket, which is simpler and lighter than the general purpose mounting kits. This was shown in the previous photographs. The industry has many variations on utility pole materials, e.g.
Figure 3-14: RFS Celwave Pole Brackets. 3.9 Strand Mount The majority of Access Points are expected to be mounted on the wire strand that supports the coaxial cable system. The strand-mount kit is designed to support a Horizontal-Mount Access Point. There is an arm at each end of the Horizontal Access Point. The top of the arm is clamped to the strand, as in Figure 3-15. The top of the arm is designed to slip in between the strand and the coaxial cable, which is usually spiral wrapped to the strand.
Figure 3-15: Strand-mounted Access Point. In high-wind installations, the Access Point can be stabilized by clamping the bottom of the arm to a second strand.
Figure 3-16: Strand Mount bracket detail. Figure 3-16 shows the detail of the strand mount bracket.
Figure 3-17: Strand-mounted Access Point with dual clamping. 3.10 Verify Service Area When the Access Point is installed, its coverage should be verified by a sampling of building locations.
4 Command Line Interface The ARCXtend has a Command Line Interface (CLI) function. The commands will be used by a technician in preparing an Access Point for service and field installation. Some technicians like to “burn-in” a unit prior to field deployment, and this burn-in period is a practical time to also pre-configure a unit via CLI for the parameters used in the network. 4.1 Physical Interface The physical interface is a four-wire EIA/TIA-485, which is a buss interface.
8. Title 9. Initialize The system response and output is slightly different for each module, as will be explained. RX & TX Antennas From/to tap (RF + Vac) V Power Pickoff RF DX AR250 AC Power Supply TX RX RX AR105 Receive Module TX AR150 Transmit Module DX Control RS485 > Figure 4-1: Block Diagram AX1255 Access Point. 4.3 TX Command Line Interface The commands unique to the TX Module are: 1. Downstream Air Frequency 2. Downstream Enable These will be explained here. 4.3.
Note that the Login command begins with an asterisk (*), and the Module’s address is repeated twice. Prior to Login, no Module is active, and no character echo back will be received on the PC.
A Title line ends with a carriage return. Example, to set the following title: *log0202 [this typing is not echoed, not shown on the PC screen] AR150 Tx [02] Enter up to 3 lines of text, beginning with T0, T1, or T2 T0 Pole #123 @ Main St. and 4th Ave T1Strand mounted T2 Pointing 300 degrees (west) 4.3.4 TX Banner Information A quick way to establish the basic information about an Access Point is to request the Banner Information.
4.3.6 TX Initialize The Initialize command forces the software to initialize, also called a Software Reboot or a Warm Start. The Access Point Module will return to its last saved settings. *log0202 AR150TX [02] Initializing… (no parameters are displayed) 4.3.7 TX Help The Help command will cause the active Module to generate a list of allowed system setup commands.
The command is: DE, where the alphabetic is Y (yes) or N (no) DEy DEn Example: AR150TX[02]>dey DE Downstream RF Enable YES 4.3.9 TX Transmit Defaults As shipped from the factory, the Transmit Module has the following default values: DE=no (i.e., disabled) DA=0000 MHz T0=….. T1=….. T2=….. 4.3.10 TX Status This is an engineering and manufacturing/repair command. It should not be used. 4.3.11 TX Read This is an engineering and manufacturing/repair command. It should not be used. 4.3.
? Valid Downstream Air Frequencies (MHz) are 5729 5735 5741 5747 5759 5765 5771 5777 5783 5789 5795 5807 5813 5819 5825 5831 5837 5843 LO STD: 5248 MMDS A: 5504 B: 5408 AR150TX[02]>da5735 Initializing... DA Downstream Air Output 5735 MHz AR150TX[02]>de ? Enable use deY(yes) or deN(no) AR150TX[02]>dey DE Downstream RF Enable YES AR150TX[02]>b AR150 Transmitter Copyright (c) 2003 Arcwave, Inc. Software Build Aug 13 2003 20:46:38 DA Downstream Air Output 5735 MHz DE Downstream RF Enable YES ........ ........
DAxxxx Downstream Air MHz DE[Y/N] Downstream Enable AR150TX[02]>i Initializing... AR150TX[02]>q Logging off 4.4 RX Command Line Interface Commands unique to the RX Module are: a) Upstream Air Frequency b) Upstream Enable c) Upstream Attenuate 4.4.1 RX Login This command is the same for the Receiver, but uses the Receive Module address (03 hex). 4.4.2 RX Title This command is the same for the Receiver. The information in the Title can be different for all three modules. 4.4.
Example, to set the Upstream RX to 6.4 MHz, with high 5.3 GHz band channel: *log0303 [this typing is not echoed, not shown on the PC screen] AR105RX[03]>uf6.4L Initializing... UF Upstream Frequency 6.4L MHz The Table in the Section on Frequency Planning shows the cable modem frequency and the corresponding 5.3GHz-band air frequencies. Note: MSO may have a different Upstream frequency. If so, select nearest one in the above table. The AX1255 will track the actual frequency. 4.4.
4.4.7 RX Banner Information The banner command for the RX Module is the same, but the information displayed is different. B 1) Title (3 lines) 2) Upstream EIA frequency 3) Upstream Attenuator setting 4) Upstream Enable (Y/N status) Example: AR105RX[03]>b AR105 Receiver Software Build Copyright (c) 2003 Arcwave, Inc. Aug 13 2003 20:10:11 UF Upstream Frequency 19.2L MHz UE Upstream RF Enable YES UDB Upstream Attenuation 12 dB ........ ........ ........ 4.4.
Example: AR105RX[03]>h List of commands... *LOGxxxx Log into card Q Quit I Initialize W[addr][data] Write EE Memory R Read EE Memory PI1xxxxxx PLL I,F,R,N Regs T[0-2] text Write a Title line S Status B Banner UFxx.x[H/L] Upstream Freq HI/LO UE[Y/N] Upstream Enable Y/N UDBxx Upstream Attenuation 4.4.9 RX Module Status This is an engineering and manufacturing/repair command. It should not be used. 4.4.10 RX Read This is an engineering and manufacturing/repair command.
Q Quit I Initialize W[addr][data] Write EE Memory R Read EE Memory PI1xxxxxx PLL I,F,R,N Regs T[0-2] text Write a Title line S Status B Banner UFxx.x[H/L] Upstream Freq HI/LO UE[Y/N] Upstream Enable Y/N UDBxx Upstream Attenuation AR105RX[03]>b AR105 Receiver Software Build Copyright (c) 2003 Arcwave, Inc. Aug 13 2003 20:10:11 UF Upstream Frequency 19.2L MHz UE Upstream RF Enable YES UDB Upstream Attenuation 12 dB ........ ........ ........
AR105RX[03]>uey UE Upstream RF Enable YES AR105RX[03]>udb ? Attenuator: 0 to 30 dB (2dB steps) AR105RX[03]>udb12 UDB Upstream Attenuation 12 dB AR105RX[03]>b AR105 Receiver Software Build Copyright (c) 2003 Arcwave, Inc. Aug 13 2003 20:10:11 UF Upstream Frequency 6.4L MHz UE Upstream RF Enable YES UDB Upstream Attenuation 12 dB ........ ........ ........ AR105RX[03]>uen UE Upstream RF Enable NO AR105RX[03]> 4.
Write Read Phase Lock Loop Title Status Banner Downstream Cable EIA Downstream Air AGC control DAC output MT control Many of these above commands are for Engineering and Manufacturing/Repair use only. Example: AR250DX[01]>h List of commands...
4.5.3 DX Downstream Cable Channel The Downstream Cable EIA (DCE) Channel is the channel on which the DOCSIS cable modem downstream signal is being sent from the CMTS at the head end. It is set in the ARCXtend Access Point with the standard EIA channel numbers. *DCE, where nnn is an EIA channel number from 23 to 94 and 100 to 138. Note: In the EIA standard, channels 94 and 100 are adjacent, so there is no gap in frequency.
The response to the DA command is “initializing” followed by a list of registers that the CPU is writing. Successful completion is displayed by the actual frequency achieved as “air output”. Example: AR250DX[01]>da5789 Initializing...
MT2050 Write Reg 0x0A Data 0x05 MT2050 Write Reg 0x0F Data 0x0F MT2050 Write Reg 0x10 Data 0x24 AR250DX[01]> 4.5.6 DX Status This is an engineering and manufacturing/repair command. It should not be used. 4.5.7 DX AGC Control This is an engineering and manufacturing/repair command. It should not be used. 4.5.8 DX MT Control This is an engineering and manufacturing/repair command. It should not be used. 4.5.9 DX DAC Output Read Command This is an engineering and manufacturing/repair command.
DAxxxx Downstream Air MHz Ax AGC control Vcddd DAC Output M[reg][data] MT control AR250DX[01]>b Digital Cable Extender Copyright (c) 2003 Arcwave, Inc. Software Build Aug 13 2003 20:50:47 DCE CATV Input US Channel 0 ( 0 MHz) DA Air Output 0 MHz (250->150 IF 0 MHz LO: 44 MHz) ........ ........ ........ AR250DX[01]>dce ? Value 1 ? Valid CATV Input Channels are 23-94 and 100-138 AR250DX[01]>dce23 Initializing...
? Valid Downstream Air Frequencies (MHz) are 5729 5735 5741 5747 5759 5765 5771 5777 5783 5789 5795 5807 5813 5819 5825 5831 5837 5843 AR250DX[01]>da5789 Initializing...
5 Multiples Access Points As discussed elsewhere, the system supports a frequency reuse pattern. 5.1 Frequency Planning Frequency planning may involve multiple Access Points. Taking a “worst-case” where there are four pole-mounted Access Points in close proximity, as in Figure 51. The subscriber, shown as a triangle in the Figure, can be served from three of the Access Points, so the installer should point the antenna toward the Access Point with the best line of sight.
e) Frequency plan for that neighborhood f) Cable system tap to use, based on existing and future traffic.
6 Fault Localization Any fault in the system has to go through some logical filtering to try to localize the problem. This section assumes the installation used to work OK, and that someone has already gone through this filtering and now suspects the wireless portion of the system. Thus, for example if it is a user complaint, the user has already restarted their modem, checked IP addresses, verified authorization database, etc. 6.
6.2 Multiple Users Impacted If multiple users are impacted and they are clustered together, and other users served by this one Access Point are OK, then consider the following sources of the problem: 1. Misalignment 2. Antenna damage 3. Interference If the cluster of users is located at one edge of the Access Point’s beamwidth, then check the Access Point alignment. A recent storm may have changed the alignment or degraded its performance.
Lightning surges can cause any electronic system to fail. It is assumed that in lightning regions the AP has been mounted adjacent to a tap which contains surge protection. Causes of AP misalignment include: a) a cherry-picker bucket bumping it or its mounting bracket b) a utility worker using it as a foothold c) vandalism. Strand-mounted APs are not likely to be used as a foothold, but are still subject to bucket-bumps and vandalism.
7 Replacing Failed Access Point The replacement must be configured exactly like the failed unit. This is normally done in the shop prior to field installation by downloading a saved file. Install a spare pair of brackets below and tight up against the existing mount and align them exactly like the Access Point brackets, as shown in Figure 7-1.
Figure 7-2: Measuring tilt at top of pipe mount. Figure 7-3: Measuring tilt at bottom of pipe mount. To replace the failed unit, follow this procedure: 1) Remove power, if locally sourced.
3) If pole mounted, then add a spare pair of brackets under the AP, aligned exactly the same. This is a temporary guide for the new unit (see Figure 7-1). 4) Measure & record the top and bottom to determine downtilt, if any. (Figures 7-2 & 7-3) 5) If strand mounted, mark the holes on the bracket that have the AP bolts, then unbolt the AP from the strand brackets. Be sure to leave the strand brackets undisturbed.
ARCXtend manual, August 2003 7-1
8 Replacing a Failed Subscriber Unit If it has been determined that the subscriber’s outdoor unit failed, then the follow this procedure: 1) Bolt a spare bracket under but touching the existing bracket, and orient it exactly the same. 2) Measure the down tilt. A simple way is to use a ruler and write down the difference in distance between the upper and lower edges of the antenna brackets (see Figure 8-1). 3) Remove the coaxial cable, which also powers the unit.
ARCXtend manual, August 2003 8-2
9 Specifications 9.1 AX1255 ARCXtend Access Point Transceiver Channel Capacity Transmit: 18, 6.0 MHz Channels Receive: 12, 3.2 MHz Channels Downstream Transmit Input Signal Level Range 0 to +25 dBmV RF Frequency Range TX: 5.725 to 5.850 GHz RX: 5.250 to 5.350 GHz IF Frequency Range 200 to 860 MHz (DS); 5 to 42 MHz (US) Downstream Airlink Data Rate 31.0 Mbps (64 QAM) Upstream Airlink Data Rate 5.12 Mbps (QPSK) - DOCSIS 1.0/1.1 10.24 Mbps (16 QAM) - DOCSIS 1.0/1.
Protocols DOCSISTM 1.1 Compatible Range Up to 2 miles Line of Sight (LOS) using 64QAM Regulatory FCC, IC (Canada) Mounting Pole, Mast/Pipe, and Strand Dimensions 41” x 7” x 5” Weight 13 lbs. 9.2 AX3155 Customer Premise Antenna/Transceiver Specifications Transceiver Channel Capacity Transmit: 12, 3.2 MHz Channels Receive: 20, 6 MHz Channels RF Frequency Range 5.725 to 5.850 GHz (RX); 5.250 to 5.
(Wall Mounted AC Adaptor) Operating Power 12VDC (DC Inserter provides power over IF Cable) Operating Temperature Range –30°C to +60°C (-22°F to +140°F) Operating Humidity 5% to 95% non-condensing Management Remote Status and Performance Monitoring via Cable Modem Protocols DOCSIS 1.1 Compatible Range Up to 2 miles Line of Sight (LOS) using 64QAM Regulatory FCC, IC (Canada) Mounting 1-1/4” to 2-3/8” OD Pipe Mount Dimensions 14-5/8” x 14-5/8” x 2-3/8” Weight 5.1 lbs.
10 Appendix A: Radio Frequency Basics The Section covers introductory information on radio frequencies (RF) for those who have not had to deal with RF in an outdoor environment before. 10.1 The Electromagnetic Spectrum The electromagnetic waves all have similar physical behavior and their uses range from AM radio broadcast stations at the low frequencies to TV broadcasting frequencies, through microwave frequencies and then on to visible light and X-Rays. These are illustrated in Figure 10-1.
sold that uses the unlicensed bands must contain a notification to the buyer that the product must accept interference from other users. Think about how different this is from a licensed band, like a TV station, where no one is permitted to interfere with the TV station’s broadcast. Figure 10-2: The US Frequency Allocation Chart. Figure 10-3: Frequency allocation in the 5 GHz band.
The frequencies set aside for Industrial, Scientific and Medical (ISM) use have become known as the unlicensed bands, or license-free bands. In many countries the ISM band is still a licensed band, but used for the same purposes. For example, the service provider may be licensed to offer service in the ISM band, even though a user buys a PC card at a store, is not licensed, but is a subscriber to the service. 10.
Transmitter Power 1000 mW 50 mW Indoor only 5.15 250 mW FCC proposal May03 250 mW 5.25 5.35 5.47 Frequency (GHz) 5.725 5.825 Figure 10-4: Rules for 5 GHz Frequency Band. The FCC’s proposed rule making of May 2003 opens the 5.47-5.725 GHz band to ISM usage. This FCC proposal closely aligns the US band with the European band usage. This common set of Rules is expected to achieve world-wide acceptance. Notice that the lower part of the band, 5.15-5.25 GHz, is limited to indoor use.
Trees and other foliage contain a lot of water and therefore also attenuate the RF signal. So the easiest approach to making good quality radio links is to have an unobstructed line of sight between the transmitter and receiver, as illustrated in Figure 10-5. LOS NLOS X X NLOS Figure 10-5: Line of Sight (LOS) and Non-LOS. This does not mean that RF cannot penetrate buildings, or that it cannot bounce off buildings and work its way to the receiver.
LOS Fresnel Zone clearances Figure 10-6: Line of Sight (LOS) plus some clearance. 10.4 Link Budgeting This section is intended to give an overview of what an RF engineer has to consider in determining the expected performance of an RF link. The Link Budgeting starts with the output of a transmitter power amplifier. That signal goes through a cable to the antenna. The antenna radiates it in a certain pattern. It then travels through the air, where there may be additional attenuation from rain.
Cable loss = 1 dB Fixed pad at modem = 20 dB Input to Cable Modem= --45 dBm=+4 dBmV Note: 0 dBm @75Ω=+49 dBmV In the above example, the received signal is –+4 dBmV. The typical6 Cable Modem Receive Sensitivity is –15 dBmV to +15 dBmV at 64 QAM, so the Fade Margin is 4+15=19 dB. Links are generally considered to be good with 10 or 20 dB Fade Margin, so this is excellent. The Free Space Path Loss comes from the formula in Figure 10-7. Loss (dB) 130.0 120.0 110.0 7.25 6.25 5.25 4.25 3.25 2.25 1.
Table 8-1: Availability and Outage Availability Outage % Outage Time 99.9% 0.1% 9 hours/year 99.99% 0.01% 1 hour/yr 99.999% 0.001% 5 minutes/yr The Availability is often referred to by the number of nines, e.g., 99.9% is Three Nines Availability. Typical cable industry targets7 are: Downstream error rate of 1.e-9 or 1.e-10 for 64 QAM. Upstream error rate of 1.e-5 to 1.e-7 for QPSK. User Availability at least 99.7% 10.
Figure 10-8: Antenna pattern. The pattern shown in Figure 10-8 has 20 dB more gain in the forward direction (270 degrees) than in any other direction. The side lobes occur at various angles, but only two exceed the 0 dB circle on the graph (at 235 and 315 degrees). This antenna is said to have a “gain” of 20 dBi, that is, 20 dB relative to an isotropic radiator. This pattern also shows the Beamwidth of the antenna. This is usually stated as the distance between the half-power points, or 3 dB points.
The world has been mapped into Rain Regions and historical data gathered on the probability of rain at a given density (millimeters of rain per hour). The ITU has created maps8 to help visualize this rain patterns, as in Figure 10-9. In the United States, the 150 mm/hr rain rate happens only 0.001% of the time, and that is in Florida (Region N). A percentage of 0.001% is approximately equal to 5 minutes a year. Figure 10-9: Rain Regions for the Americas (ITU-R P.837-1). 8 ITU-R P837-1.
Figure 10-10: Rain Attenuation9 for 5 GHz band (ITU-R P.721-3). Figure 10-10shows that the Rain Attenuation for the 5 GHz band is really about 1 dB at the very worst rain storm (150 mm/hr), which is a cloudburst, or worse. So Rain Attenuation for this band is really small compared to cable losses, losses due to connectors, etc. 10.8 Lightning Strikes Obviously some regions have more frequent lightning strikes than others. One map of the US is shown in Figure 10-11, also see IEEE 1410 Guide10.
source: Larus Corp, “T1 Repeatered Line Transmission Engineering”, Issue 2, 1996. Figure 10-11: Lightning strikes in the USA. Although the frequency of lightning strikes varies across the USA, the same lightning protection is used everywhere. The difference is that some carriers in the regions with the most lightning schedule preventive maintenance to replace protectors annually at the most exposed locations.
11 Reader Feedback Readers of this Manual are encouraged to forward their corrections and comments to: Customer Service Arcwave, Inc. 910 Campisi Way, #1C Campbell, CA 95008 USA 408-558-2763 (direct) techsupport@arcwaveinc.
