In July, 2004, Rochester Public Utilities (RPU), Rochester, MN, activated a BPL test/evaluation network of approximately 10 subscribers. Main.net equipment (Generation One Technology using DSSS) was used. Our earlier BPL report at http://www.io.com/~nielw/BPL/index.htm summarizes our observations and mentions that on 17 mtrs our transmissions took TCP/Internet throughput to zero. Under part 15 regulations BPL must accept any interference from licensed users including radio amateurs. This appeared to be a potentially significant problem for the service provider interested in marketing something more than best effort email or static web page delivery. On Friday, 10/15/04, we returned to the test area to gather more information.
We found Generation One Main.net equipment to be extremely susceptible to RF. Low power transmissions on many of the HF ham bands significantly degraded BPL throughput. We even moved our mobile station two blocks away from the BPL test area and found that a 40 mtr 25 watt signal still drove BPL throughput to zero.
Our test was conducted using an ICOM 706 transceiver feeding either a Hustler mobile antenna system or a multiband dipole. Transceiver output power was measured/set to various levels using a Bird watt meter. To minimize variables we monitored IP packet throughput (measured using the Windows XP Performance Monitor in Control panel -> Administrative Tools) during 30 second continous carrier transmissions. Depending on how fast the network can recover, our observed degradation may be ratioed by the duty cycle of the actual transmission mode.
Using a Hustler mobile antenna system 81' from the power line:
Using a Hustler mobile antenna system two blocks from the BPL test area:
Using a multiband dipole 65' away and parallel to the power line: