By Jack L. Stone, Publisher
BPL Moves Closer?
By Jack L. Stone, Publisher
INTRODUCTION
Just when you thought you had that antenna tuned to perfection, another dark cloud pops up
and looms on the horizon to possibly spoil your day — Broadband over Power Lines
(BPL) — the controversy begins and the outrage (and temperature) is rising!
What is this all about and why should those involved in various segments of the communications field be concerned? antenneX first drew attention to this issue via an article in the August 2003 editorial from one of our regular contributors, Tom Cox, KT9OM—of the same applicable title "Broadband over Power Lines."
As Tom says in his article that Hams and other users of the HF bands in the USA have reason for worry. The Federal Communications Commission (FCC), the agency that regulates the civilian use of the RF spectrum in the US, is looking at allowing the power companies to connect customers to the Internet over their power lines. Power line communications (PLC), or Broadband over Power Line (BPL) — the practice goes by either name — uses an RF signal sent over medium- and low-voltage AC power lines to allow end users to connect to the Internet. The RF signal is modulated with digital information that is converted by an interface in the home or small business into Ethernet-compatible data.
Tom goes on to define "medium- and low voltage" that the power companies mean the residential power lines that deliver AC power from the nearest substation at about 7,200 VAC, and the 220 VAC that is usually available at the service entrance to a home or small business. Unfortunately, no HF user in his right mind expects the RF energy imposed on 60-Hz power to be confined to the power company's lines.
BPL MOVES CLOSER SAYS ARRL
Lest we become complacent and think this issue will go away, just recently the FCC
unanimously approved a Notice of Proposed Rule Making (NPRM) to deploy Broadband over
Power Line (BPL). This, following a Notice of Inquiry that attracted more than 5100
comments-many from the amateur community. One may assume many of the "comments"
came in the role of complaints.
The ARRL Headquarters in Newington, Connecticut USA issued the following bulletin on February 12, 2003:
ARRL Bulletin 5 ARLB005 The FCC has unanimously approved a Notice of Proposed Rule Making (NPRM) to deploy Broadband over Power Line (BPL). The NPRM is the next step in the BPL proceeding, which began last April with a Notice of Inquiry that attracted more than 5100 comments--many from the amateur community. The FCC did not propose any changes in Part 15 rules governing unlicensed devices, but said it would require BPL providers to apply ''adaptive'' interference mitigation techniques to their systems. An ARRL delegation that included President Jim Haynie, W5JBP, attended the FCC open meeting in Washington, and later expressed disappointment in the FCC action. ''The Commission clearly recognized that the existing Part 15 emission limits are inadequate to stop interference, but it's placing the burden of interference mitigation on the licensed user that's supposed to be protected,'' said ARRL CEO David Sumner, K1ZZ. Sumner said that if the FCC really believed current Part 15 emission limits were sufficient, it would not have had to require that BPL providers institute interference mitigation systems. The FCC has not yet released the actual NPRM, and a presentation by the FCC's Office of Engineering and Technology (OET) revealed only its broad outlines. Sumner said the League would not take a formal position until it reviews the full NPRM. Anh Wride of the OET staff spelled out the scope of the NPRM, which only addresses so-called ''access BPL''--the type that would apply radio frequency energy to exterior overhead and underground low and medium-voltage power lines to distribute broadband and Internet service. She said the OET staff believes that interference concerns ''can be adequately addressed.'' Wride said the FCC's BPL NPRM: * Applies existing Part 15 emission limits for unlicensed carrier-current systems to BPL systems. Part 15 rules now require that BPL systems eliminate any harmful interference that may occur ''and must cease operation if they cannot,'' she noted. * Requires BPL systems to employ ''adaptive interference-mitigation techniques, including the capabilities to shut down a specific device, to reduce power levels on a dynamic or remote-control basis and to include or exclude specific operating frequencies or bands.'' * Subjects BPL providers to notification requirements that would establish a public database to include such information as the location of BPL devices, modulation type and operating frequencies. * Proposes guidelines to provide for consistent and repeatable measurement of the RF emissions from BPL and other carrier-current systems. Mirroring his colleagues' enthusiasm, FCC Chairman Michael Powell called BPL ''tremendously exciting.'' While conceding that BPL has ''a long way to go,'' the chairman said it could be ''the great broadband hope for a good part of rural America.'' Powell also said the FCC's OET has worked very hard to try to ''get their hands around'' the issue of interference and that the FCC would continue its vigilance in that area. The FCC is expected to issue the complete Notice of Proposed Rule Making within a few days and will invite comments on it sometime after its publication. |
LEARNING FROM OTHER COUNTRIES?
BPL is not a new thing and other countries have employed the use of this technique and no
doubt should be a part of the FCC investigation into its employment here in the USA.
One of our readers, Levente Letso, formally with AT&T Bell Labs, says:
[...]I am an subscriber to the German, Austrian, Hungarian radioamateur publications. The BPL issue started there years earlier, than here. In short, it is an unmitigated disaster as far as SW broadcasters and SW amateurs concerned.
If you like, I could translate some of their findings, including their FCC-counterparts' measurements. It does not take a genius to see, that an unshielded, unbalanced transmission is radiating in a big way, suppressing even BBC and Deutsche Welle, both in the multi-Megawatt power range is not desirable by anybody [...]
Indeed, I encouraged Levente to share that information and he is graciously sending the info he mentions above via a CD which I will make available to everyone as soon as it arrives. Many thanks to Levente for the extra effort that includes an 1800-word commentary of his own that will appear as an editorial here in the next issue of antenneX. This information would have appeared in this month's issue, but we ran out of time to meet the deadline tomorrow, March 1, 2004.
FEELINGS RUN DEEP
As one might expect, there has been a great deal of discussion about the BPL issue on our
antenna discussion list. Most postings have thoughts about how to best deal with this
issue and its potential interference with the HF amateur radio activities. If you haven't
yet joined the list, you are encouraged to do so and express your thoughts, pro or con as
well. After all, it is in your interest to participate and be heard-it's now or never
(maybe).
The new Antenna Discussion List is a infinite fountain of ideas making it a great "watering hole" for exchange of ideas, questions and answers on a wide range of antenna-related subjects.
If you haven’t already joined, you are invited and encouraged to do so. Just click here and follow the instructions on how to join and have fun with the rest of us. If you don't participate—it's a big opportunity lost!
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AN INVITATION TO CONTRIBUTORS
antenneX thrives on the contributions of antenna experimenters,
ranging from the informal home shop construction project to the theoretical investigation
of basic antenna, feedline, and propagation phenomena. Over the years, we have published
articles on the use of new or newly adapted materials, known antennas adapted to new
circumstances, modifications of antenna structures, basic explorations of both common and
unusual antennas, antenna modeling exercises, design improvements, antenna matching
techniques from both a physical and mathematical perspective, evaluations of mini-antennas
and their underlying theory of operation, new and patentable designs, propagation
tutorials, and.... The list goes on, since no antenna-related topic is irrelevant to the
readers of antenneX.
At the same time, antenneX has experienced continuous growth in its
readership—for which we are appreciative. However, all readers can help us do even
better. How? By submitting an article every now and then based on your current antenna
work that may be useful at any level to other readers.
Among the engineering and researching readers, there are undoubtedly
a number of unclassified and non-proprietary findings that antenneX readers would
like to know. Among the practical antenna designers, there are ideas, tests, and numerous
other practical findings to benefit our readers. Antenna builders very likely have some
techniques to share with other readers. Besides the regular articles, we always have the
home work shop column for shorter practical ideas and we always have the invited news and
editorial column for information about new technologies, future advances, lost old but
good ideas, and personal views on the good to bad things that are happening in the world
of antennas and propagation.
If you are uncertain about whether your ideas merit an article, please feel free to send
an outline to the general editor/publishers at submissions@antennex.com . Do not feel that you must be ready to be a regular submitter to write for antenneX,
because we welcome the individual contribution as much as monthly articles. As well, do
not believe that the slots in each issue are already spoken for—we shall always make
room for a worthy article.
To see details of our writing guidelines, please look at: Writing for antenneX
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IN THIS ISSUE
This month is our 83rd online issue! We again include many fine articles by our great writing team. Now, allow me now to introduce this month's line-up of content:
THE MARCH 2004 ONLINE ISSUE NO. 83 CONTENTS:
OUR MONTHLY COLUMNS (plus this one by yours truly):
FEATURE ARTICLES IN THE LIBRARY:
Notes
on the Batwing |
| In most antenna articles, we usually encounter models used for design or analysis. In most cases, we receive the models as if they were perfect, with the possible exception of a few minor variables related to the construction side of the ledger. However, few models are perfect, not only relative to the physical implementation of the antenna, but as models themselves. The batwing antenna is a case in point. Its complexity--both physically and electrically--demands that we examine how good the models are on which we have based our discussion. |
Lab Notes: Using & Improving an SWR Bridge |
| For quite a while now Joel has been measuring the Q of small loops and other narrow band antennas with the MFJ antenna analyzer. Often the adjustment is so sensitive that one barely touches the oversized knob to do the required adjustment. This month Joel decided to find a way to add to his equipment an SWR meter that can run with the signal generator, since for these kind of adjustments, he prefers an analog meter to the flipping numbers of a digital display. You can do this too with Joel's technique! |
Antenna
Tuner Efficiency Comparison |
| This month, Fred takes the well-known and popular Johnson Matchbox antenna tuner, his custom-built balanced PI-network and transformer coupling tuner, and the LDG Electronics AT-11MP auto antenna tuner through comparisons to see what overall efficiency differences may exist when used with his inverted vee antenna system. |
THE
ZAGI |
| Inspired by the fractal antenna works by Werner, Dan and David now present a new class of antenna based on a "slow-wave" structure. The antenna discussed here is called a Zagi. The antenna elements are formed from regularly bent wires; in this simple case they are just zigzags, but many other regularly bent structures are possible. Once again, the teamwork of these two very bright fellows may be on to something important! |
Fractal
Antennas - TESTED |
| In the antenneX Issue No. 81, Werner presented his interesting design for the fractal antenna concept. This Part 2 article follows that more general presentation in Part 1 about fractal antennas and now shows the promised measured data on three of what Werner has named the “Fractent” antenna models as performed in laboratory and free field testing conditions. |
The
L-Cube |
| We have seen the series of articles on the C-Cube. This month the new L-Cube is thoroughly discussed, which basically takes up the same amount of physical space as the C-Cube, except one acts like a dipole and the other like a loop! We have the right size for most needs and just a question of learning more from the test results. Again, the Dan and Re team are to be congratulated on their tireless efforts and apparent positive results on the Cube Family designs. Moreover, an H-Cube is being developed for its own uniqueness. Perhaps with the H-Cube also in the works, another “child” is on the way! |
Well, there you have it, folks—thanks for listening and
remember, the reading lamp is always on for you in the reading rooms. If I can be of
further help, I'm just a Stone's Throw! away. March
2004 antenneX Online Issue #83
reGARDS, Jack L. Stone, Publisher jack@antennex.com
Send mail to webmaster@antennex.com
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December 31, 2010