Technical Topics, September 2003
NASWA Files Reply Comments to FCC BPL Inquiry
On August 20 NASWA filed reply comments to the FCC in response to comments that were made by BPL proponents during the initial phase of the inquiry. Here is the substance of that submission. If you have not yet read the July and August editions of this column, I suggest you do so before continuing with this one. It will make much more sense if you have the background information explained in those other columns.
NASWA represents the interests of people who choose to get their news and information about other cultures via shortwave radio broadcasts on frequencies internationally allocated by the ITU and the FCC for this purpose.
There are several common threads that have been expressed by multiple BPL proponents that deserve further comment. Many of the proponents of using HF frequencies for BPL transmissions have made the point that their systems work at currently authorized Part 15 signal levels and should, therefore, be immediately authorized for commercial deployment. They assert that interference, if it occurs, can be mitigated by providing notches in the spectral mask for frequencies that are used for amateur radio. Many proudly proclaim that no complaints of interference from their technology have resulted from their test demonstrations. NASWA addresses each of these assertions in this response.
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Technical Topics, August 2003
NASWA Alerts FCC To BPL Danger
For the first time in its long history, NASWA has publicly defended the interests of shortwave broadcast listeners in the USA. On June 30, 2003 NASWA submitted an 18-page filing to the FCC in response to Notice of Inquiry 03-104 concerning Broadband Power Line (BPL) communications. The Journal does not have the room to print the entire submission, but this month I will attempt to summarize many of the points made in that submission. Comments by AMRAD and the NAB also mentioned the impact to shortwave listeners and I have included part of their comments too.
As you probably already know from the Musings in the June NASWA Journal, there are well-funded interests who want to use the commercial power lines as a way to conduct high-speed data communications. Many of the proponents of this technology have chosen to design systems using frequencies that are between 2 and 30 MHz.
The number of shortwave listeners in the USA is hard to estimate accurately since Arbitron does not survey such listeners. The CIA Factbook says there are 575 million radios here. If only one percent of these radios have shortwave capability, that would be almost 6 million shortwave receivers. A reasonable estimate would be that hundreds of thousands of listeners tune in to shortwave broadcasts weekly.
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Technical Topics, June 2003
The Next Threat To SW Listeners
(And What You Can Do To Help)
It seems like every few years I feel obligated to warn NASWA members of a new threat to our ability to listen to shortwave radio. I remember my first Tech Topics column over a decade ago concerned the interference potential of RF excited light bulbs that GE was getting ready to market. As President Ronald Reagan said, "Well, there you go again."
The latest communications fad is a way of transmitting high data rate internet traffic over your house electrical wiring and the wires that connect your house to a nearby pole. There is a standard, developed by an industry consortium called the HomePlug Alliance, that plans to use the HF spectrum between 2 and 30 MHz for this connection. You plug your modem into a convenient power outlet. A similar modem near your service transformer picks the signals off the power line and converts them to a series of light pulses which travel via fiber optic cable to the internet interface. Because the power wiring in residential settings is unshielded, these signals will radiate and may cause interference to SW reception.
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Technical Topics, April 2000
The NASWA Short-wave Simulator
Short-wave listeners have recently discovered the many radio stations, available free for the listening, via the Internet. With RealAudio’s Real Player 7.0, and Windows Media Player software, streaming audio has never sounded better. Stations from all over the world are just a mouse click away. Some stations are even in stereo. CBC Radio Two from Toronto streams a beautiful stereo signal as do WQXR in New York and KING-FM in Seattle. All four BBC domestic radio services are now available 24 hours a day.
As more and more of us get cable TV modems or DSL service via our telephone lines, we can all listen 24 hours a day to any station of our choice. And we can listen at higher data rates than previously possible on ordinary dial-up modems. What a wonderful time to be alive.
But every sunny day has a dark cloud lurking just below the horizon. Something is wrong. While I was at the SWL Winterfest last year I became aware of an ominous trend among NASWA’s program listeners. Can the sound actually be too good?
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Technical Topics, February 2000
Collaborative Receiver Design: The RX320 Saga
Hello Dolly
Sevierville Tennessee is famous for three things. One is TenTec. Two are country music legend Dolly Parton. TenTec is the only full-line manufacturer of ham radio equipment and short-wave receivers remaining in the United States. Like Dolly Parton, TenTec often pleasantly surprises us with capabilities that are not immediately obvious at first glance.
Rave Reviews
Back in December 1988, Alan Johnson reviewed the new TenTec RX-320 receiver in the NASWA Journal. Alan’s review introduced NASWA members to a first class radio. While it had no knobs or display, it sold at a price below that of some portable radios. If you have never read that review, I encourage you to go back and read it now. If you are new to NASWA, and you have Internet access, you can read the review on the NASWA web site. This page also has a link to an independent review for Radio Netherlands by NASWA member Tom Sundstrom. If that doesn’t do it for you, check out the year 2000 issue of Passport To World Band Radio for a review by NASWA member Chuck Rippel and Dave Zantow.
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Technical Topics, June 1999
Digital Shortwave Update
The quest for a digital shortwave broadcast standard grinds steadily forward. The Digital Radio Mundial (DRM) steering group met recently. The VOA was there and Dr. Kim Andrew Elliott presented a synopsis on Communications World on April 24, 1999. Here is what was said. (The following is an approximate transcript from the RealAudio archive file.)
Elliott: Don Messer is Chief of the VOA Office of Engineering, Spectrum Management Division. He was one of VOA’s delegates at a DRM steering group meeting, held in Las Vegas just before the annual convention of the National Association of Broadcasters. Don told me that some progress was made at that meeting towards the development of a digital shortwave standard.
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Technical Topics, May 1999
The Radio Boys Search For The Mystery Phantom Signal
NASWA member, Journal compositor, and NASWA web site guru, Ralph Brandi, ran into an interesting problem recently which I would like to share with you this month.
One of the problems we encounter when moving into a new location is not knowing what to expect in the way of radio interference. The prudent person will take a portable radio and listen for the usual power line leakage, light dimmer buzzes, etc. But some of the more subtle problems are sometimes missed. That was Ralph’s problem. Ralph wrote to me to see if I had any suggestions. Here is what he said.
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Technical Topics, March 1999
The Sun And Short-Wave Reception
(Part 10)
This month we conclude our examination of how the sun influences shortwave propagation. We will look at some of the information available on the Internet at a click of the mouse to help you make your own propagation predictions. I will be presenting some pretty complicated URL’s (Internet web site addresses) so you may want to wait for this article to be posted on the NASWA web site so you can then just copy and paste the URL’s.
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Technical Topics, June 1998
The Sun And Short-Wave Reception
(Part 1)
The ionosphere refracts short-wave signals back to earth. The sun strongly affects the ionosphere. But you probably knew that.
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Technical Topics, April 1998
Better DXing Through Chemistry
The number of short-wave listeners has declined over the past 5 years. The decline is due mainly to two causes: The rise of the Internet; and the absence of any really bloody wars to follow on short-wave radio. This fall-off in SWLs has really put the squeeze on NASWA’s finances. To save money NASWA management contemplated shutting down the world famous research facility, The NASWA Research Lab (NRL).
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