TEST RESULTS ON WIDE BAND IN-HOUSE PLC SYSTEM

(8 juillet 2005, jd) Ce rapport a été présenté à la réunion d’Eurocom à Friedrichshafen en juin 2005. Il a également été envoyé à toutes les personnes qui étaient impliquées dans les tests. Nous publions ce rapport sur notre site pour que tous les radioamateurs Belges (et autres) soient conscients de l’énorme danger que représente le PLC (BPL), et également pour que tous sachent quel est le travail fait par l’UBA et Eurocom (groupe de travail IARU, Région 1) en cette matière. Nous vous tenons au courant.

SUMMARY

A wide band (100 Mbps spec) in-house PLC system using a pair of modems of a European manufacturer, was tested and evaluated in various real life environments at 3 different locations (both semi-rural as well as urban).

The level of the differential mode signal, injected in the AC receptacles in the house exceeds the CISPR 22B spec with not less than 40 dB. Spurious signals are transmitted into the mains at frequencies up to approximately 130 MHz.

The radiation exceeds the NB30 limit with 30 dB inside the house, with 10 db outside the house at approximately 3 meter from the house, and with up to 7 dB at 100 m from the house where the PLC system is installed.

The PLC system creates signals from 3.5 through 30 MHz ranging from 35 to 60 dB over the residual band noise, even in situations where antennas are used that are more than 50 m away from the house where the PLC system is operational.

The modem tested provides (switchable) notches in the amateur bands. These are somewhat effective (especially near the centre of the bands), but what appear to be intermodulation products from the PLC signals near the band edges spill into the bands (notches are typically 20 dB deep near band edges –largely insufficient- and approximately 40 dB at the band centre). We made a suggestion to widen the notches to enhance the effectiveness near the band edges.

The PLC system tested is extremely sensitive to interference from legitimate transmitter signals inside the amateur bands. Power levels as low as 5 Watt have shown to disrupt the link. Tests were done by pinging the network and by transmitting a film over the network.

Reception of broadcast signals in the short wave BC bands is greatly impaired, and DRM (Digital Radio Mondiale) signals dropped out completely during the test. The tested prototype models were not (yet) CE-approved.

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