ARRL

ARRL Testing of Home-Phone Network Card

Field Testing Worksheet

 

--- HPN Version 1 testing at W1AW ---

Date: 5/25/1999 Test Engineer: Ed Hare, W1RFI, ARRL Lab Supervisor
Time: 1530 Z Weather: Partly cloudy
Amateur Station Callsign: W1AW Station Operator: Ed Hare, W1RFI

Station location: ARRL HQ, 225 Main St, Newington, CT 06111, located in separate building about 75 meters from ARRL administrative offices. This is a typical suburban neighborhood. The administrative offices have about 75 computers, a 100-baseT LAN, copy machines, etc.

Test equipment used:
(2) Gateway 90-MHz Pentium computers, monitor, keyboard
(2) TUT HPNA Version 1 interface cards
(1) Rohde and Schwartz ESH-2 test receiver

Amateur receiver and equipment description: Yaesu FT-1000, 50 ohm input.

7.0 MHz receive antenna description: 7.0 MHz halfwave dipole, horizontally polarized, approximately 21 meters in height, approximately 7.5 meters horizontally from the W1AW station building. It is fed with 50-ohm coaxial cable, running down the 21 meter tower, and horizontally over to the station building. A 2-element Yagi at a height of approximately 33 meters was also used.

Other antenna description: Numerous other antennas co-located on premises within approximately 30 meters maximum of receiving antenna.

Telephone wiring description: The server computer was located on the first floor at W1AW, at ground level, above a cement/mortar-walled basement. A Radio Shack 50-foot telephone extension cord in series with a 25-foot telephone extension cord were strung from this computer, at ceiling level, to client computer located on the 2nd floor. The client computer was also tied in parallel to existing telephone wiring on the 2nd floor. A telephone and a modem were on this telephone line, on the 2nd floor. Both computers were minimally configured Gateway 2000, 90 MHz Pentiums.

Distance between telephone wiring and receive antenna (horizontal, vertical, diagonal): The vertical separation between the telephone wiring and the dipole antenna was approximately 18.5 meters. The horizontal separation was approximately 9.5 meters, as determined by eye.


Ambient noise level:
Receive frequency: 7005 kHz
S meter: <S1                Receiver bandwidth: 2.4 kHz
Calibrated measurement:           Measurement bandwidth: 2.4 kHz
            Average: -2 dBuV/50 ohms,     -109 dBm
            Quasi-peak: +10 dBuV/50 ohms

Description of ambient noise: Combination of general broadband noise, some "bursty" noise that sounds like an intermittent arc on power lines and some small amount of birdies and other "computer" noises. The receive frequency was adjusted by several kHz to avoid audible, discreet noise. Some rather loud lightning static crashes were occasionally observed; all measurements were made at times when static crashes were not audible.

Noise level during test:
Receive frequency: 7005 kHz
S meter: <S1                Receiver bandwidth: 2.4 kHz
Calibrated measurement:           Measurement bandwidth: 2.4 kHz
            Average: -1 dBuV/50 ohms,     -108 dBm
            Quasi-peak: +12 dBuV/50 ohms

Notes: This test represents a "best case" for residential neighborhoods in a moderate noise environment. The location of the receive antenna, at 21 meters in height, results in minimal pickup of any noise radiated from the phone lines. The simple configuration of the connection between the two computers and the high-quality phone wiring used in W1AW results in minimal radiation. The noise level during the test increased only just perceptibly. A second test was performed with the 2-element Yagi as the receive antenna. No discernable HPN signal could be heard or measured at any azimuth heading.

Susceptibility: Transmitting with more than 10 W PEP on 7 MHz dropped the throughput to 0%. This occurred in spite of the 65- or 120-foot height of the transmitting antennas. A 200-watt transmission on 14 MHz had little effect on the throughput.

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ARRL Testing of Home-Phone Network Card - Field Testing Worksheet
--- HPN Version 1 testing at W1RFI ---

Date: 5/26/99              Test Engineer: Ed Hare, W1RFI, ARRL Lab Supervisor
Time: 1400-2000 Z     Weather: Partly cloudy
Amateur Station Callsign: W1RFI Station Operator: Ed Hare, W1RFI

Station location: 304 George Washington Tpke, Burlington, CT. Station is located in a residential neighborhood with approximately 30 meters between residences. Local power lines are relatively quiet in noise level. At the time of the tests, all television receivers and all computing devices other than the ones being tested were turned off. Other household appliances were not considered. There is a digital cable TV installed at the residence. The building has a ground-level basement, with a single story living area above, plus an attic.

Test equipment used:
(2) Gateway 90-MHz Pentium computers, monitor, keyboard
(2) TUT HPNA Version 1 interface cards
(1) Rohde and Schwartz ESH-2 test receiver

Amateur receiver and equipment description: Ten Tec Omni D

7.0 MHz receive antenna description: 7.0 MHz halfwave fan, trap dipole (W9INN), inverted V configuration. Apex is approximately 10 meters above sloping ground. The antenna apex was directly over one end of the house, at about 1 meter above the roof.

Other antenna description: No other antennas in use at this location.

Telephone wiring description: Several configurations were employed. In the first, one computer was located in the basement, near the amateur station. The other was located in a bedroom on the first floor. A 50-foot telephone wire was connected between the two computers, without being tied into the telephone wiring. In the 2nd configuration, the computers were interconnected via the residence telephone wiring. This residence was built in 1950, with numerous "handyman" installations of various telephone wiring. The wiring uses a combination of "star" and "daisy-chain" techniques. It all appears to be actual phone wiring, but is probably a combination of wiring supplied by the phone company and various "aftermarket" wiring. There are telephone jacks at 6 locations in the house. There are numerous devices connected to the phone line, including 4 telephones, one FAX/answering machine, one computer modem (off) and the telephone connection to the Scientific Atlanta cable downconverter. In the 3rd configuration, all consumer devices were disconnected from the telephone wiring. The cable-TV phone connection was left in place.

--- HPN Version 1 testing at W1RFI- page 2 of 3 ---

Distance between telephone wiring and receive antenna (horizontal, vertical, diagonal): The vertical separation between the telephone wiring and the antenna was approximately 7 meters. The horizontal separation was approximately 5 meters, as determined by eye.

Ambient noise level:
Receive frequency: 7005 kHz
S meter: N/A                Receiver bandwidth: 2.4 kHz
Calibrated measurement:           Measurement bandwidth: 2.4 kHz
            No computer devices active:
                        Average: - 18 dBuV/50 ohms,  -125 dBm
                        Quasi-peak: -8 dBuV/50 ohms
            Computers on, monitors off:
                        Average: -13 dBuV/50 ohms,   -120 dBm
                        Quasi-peak: +6 dBuV 
            Computers on, monitors on:
                        Average: - 2 dBuV/50 ohms     -109 dBm
                        Quasi-peak: +9 dBuV/50 ohms

            Note: Station is usually operated with the home computers turned off. The level of -125 dBm is the typical station condition. This is considered "quiet rural" by amateur standards.

Description of ambient noise: Combination of general broadband noise and atmospheric noises. During any testing that required that the test computers be on, the quietest frequency was selected near the test frequency of 7005 kHz. Very sporadic lightning static crashes were occasionally observed; all measurements were made at times when static crashes were not audible.

Noise level during test: Configuration #1: 50-foot telephone extension, no connection to residential wiring
Receive frequency: 7005 kHz
S meter: N/A                Receiver bandwidth: 2.4 kHz
Calibrated measurement:           Measurement bandwidth: 2.4 kHz
            Average: -2 dBuV/50 ohms,     -109 dBm
            Quasi-peak: +10 dBuV/50 ohms

            Note: This is an increase of 16 dB over ambient noise at this station. This would cause harmful interference to weaker amateur communication, which is often accomplished at signal/noise ratios of 0 dB.

Configuration #2: Connection to residential wiring, telephone devices installed
Receive frequency: 7005 kHz
S meter: N/A                Receiver bandwidth: 2.4 kHz
Calibrated measurement:           Measurement bandwidth: 2.4 kHz
            Average: +24 dBuV/50 ohms, -83 dBm
            Quasi-peak: +35 dBuV/50 ohms

            Note: This is an increase of 42 dB over ambient noise at this station. A level of - 83 dBm is an "S7" signal strength -- characterized as a "moderately strong" signal reading. At this level, most of the weaker signals on the band were inaudible. This level would be considered "harmful interference" by most observers.

Configuration #3: Connection to residential wiring, telephone devices disconnected
Receive frequency: 7005 kHz
S meter: N/A                Receiver bandwidth: 2.4 kHz
Calibrated measurement:           Measurement bandwidth: 2.4 kHz
            Average: +32 dBuV/50 ohms, -75 dBm
            Quasi-peak: +44 dBuV/50 ohms

            Note: This is an increase of 50 dB over ambient noise at this station. A level of -75 dBm is an "S9" signal strength -- characterized as a "very strong" signal reading. At this level, only the strongest signals on the band were audible. This level would be considered "harmful interference" by most observers.

Notes: This test represents pretty much a worst case, with the close proximity of the amateur antenna and the residential phone wiring. This is not, however, an atypical amateur installation because many amateur installations are limited by tower ordinances or CC&Rs, or are found in apartment buildings or other areas where it is just not desired to install a large antenna array and tower. It is by no means an absolute worst case -- that would probably be found in apartment installations with indoor antennas.

This test also provides a reasonable estimate of the type of interference signal levels that may be expected in very crowded residential area, such as an apartment building or in some southern California neighborhoods. While the ambient noise in those circumstances would be expected to as much as 20 dB higher (typical), the interference levels can be compared to -115 to -105 dBm for a reasonable estimate of the interference potential.

This test demonstrates that it is likely that this amateur would interfere with his own station. Applying the inverse-square law as an approximation, one can extrapolate that there could be moderate interference from HPNA V1 technology from a neighboring system in a similar configuration located 30-75 meters distance.

Susceptibility: Susceptibility was not tested at this location at this time.