From Ed Hare (W1RFI) of the ARRL on BPL replies to comments;
(repost from QRZ)

What I believe to be most important at this point is that the FCC get
a wide range of input that is not all "ARRL" material. Analyzing
ARRL's material is fine, but it really does need to appear as an
individual contribution, not just a "me-too." That is why ARRL hasn't
put out a "form letter" to be used, because especially in the NOI
stages, this is not a vote. I have seen a number of excellent posts
here outlining things I hadn't thought of.

Over this evening and into early next week, I intend to start reading
the various company and organizational filings in detail. Naturally, I
will put together a technical recommendation to the DC guys, who will
use them to develop ARRL's "political" position and to write the ARRL
filings. Because this is a rulemaking process, all the major players
tend to keep their "stuff" close until the last day, to give those
with different positions less ammunition. So, unfortunately, I am not
sharing what I have learned with even the amateur community, except in
the most general terms.

I can say that I just got back from a 1300-mile drive to several of
the test areas, and the ARRL article used a description I considered
carefully before being quoted -- the interference to HF that I
observed was devastating. The APPA folks demanded that any claims of
interference be proven. I believe we can give them exactly what they
wanted and do just that. It is not just amateur radio that is at risk
here, but any use of HF that operates near BPL installations operating
on their frequencies at the limit of the present FCC rules cannot help
but hear the BPL signals loud and clear. I had done calculations of
what to expect, and the system that operate at the present limits did
just what I knew they would.

The real issue is interference. The BPL industry is claiming that
there is no interference problem, but where are THEIR calculations?
Where are their interference studies? They have offered no information
about the frequencies their systems use, no information about what
field strength they measured in their Part 15 verification tests. The
only basis on which they make that claim is that they have "no reports
of interference" and by pretending all the overseas amateur studies
don't exist, and claiming that there has been no interference
worldwide.

Some did provide some power levels, of -50 dBm/Hz. This power level
results in a conducted signal level of 48 dB higher than the present
limits for conducted emissions for most other devices, upsetting the
present order by a factor of 70,000. How can this not have an
effect. They want to add 10 dB, so their conducted signals would be
almost a million times more powerful than the present conducted
emissions limits. Ever hear a neighbor's computer system? Want to
multiply that by a lot?