[Lowfer] Rulemaking Ruminations - TWO: Supporting Data Needed

[JD]

* TWO:  We need more technical showings this time, with as many hard numbers 
as possible.  I hope the Part 5 licensees are prepared to crunch numbers, 
but those of us who only monitored are also able to contribute.  (Much more 
on this in future correspondence, I expect.)  In par. 169. the FCC enquires: 
"to meet our goal of providing for the coexistence of amateur services and 
PLC systems in these bands, we seek detailed comment on the technical 
characteristics of both the PLC systems and the amateur stations. This 
information will allow us to set an appropriate separation distance."  The 
very next sentence, though, I recognize as a somewhat worrisome bit of 
FCC-speak: "Although the Commission in the WRC-07 NPRM inquired into the 
technical rules and methods that would assure coexistence, commenters 
provided little in the way of concrete information."  Read that with a 
slightly scolding tone of voice, but with a facial expression that says 
they're keeping an open mind.

The utilities, IMO, provided no concrete technical information at all.  ARRL 
cited the 1985 NTIA study on which the 1 W EIRP and 1 km separation idea is 
based, but the FCC is concerned whether that's still valid.  Well, one would 
HOPE that any changes made to PLC operation the past 30 years would be 
toward making the system more robust, not more vulnerable to evildoers and 
natural disasters, but this could prove an area of contention.  That may be 
something the big guys have to fight out; I don't know how much we as 
individual licensees or observers can contribute to that.  But there ARE 
other technical matters the FCC needs and wants to know, which we may be 
able to furnish.

For instance, what sort of PLC interference levels have we actually 
experienced in the proposed bands?  How have PLCs been coped with in actual 
operation?  Also at paragraphs 171, 178, and 178, the FCC is asking for some 
really fundamental, crucial data.  What sort of power levels have the Part 5 
licensees actually radiated, and at what actual separations from 
transmission lines?  What maximum size should an amateur antenna be, 
and--the biggie, in my view--what is the true efficiency of both "typical" 
and potential amateur antenna systems?

Those operators who have the capability of measuring their true field 
strength are in an especially excellent position to help quantify current 
practice.  Those who can't do that, but are able to measure their ground 
losses accurately, can make reasonable calculations to show the maximum 
efficiency possible with antennas of various heights.  (That's likely 
preferable to doing it all in an NEC-based model, since not all such 
software is really good at predicting ground system losses, especially at 
LF.)  I'll gladly offer my own ground system's numbers to anyone who wants 
to do the math, for instance, as its 32 radials of 104 to 135 ft length in 
15 mS/m soil are probably representative of a fairly decent ground for 
antennas up to 100 feet high...and I'll be doing another set of readings 
very soon, which can include measurements at 2200 m in addition to the runs 
I usually do at 1750 m.

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