Doubt a few volts of RF carried by wiring 100+ feet over our heads will do
much...especially since they're conducting hundreds of amps at 70kV+ at 60
Hz, at the same time. I'm not at all concerned about health and safety (to
consumers) with BPL, just RFI! Gotta believe there will be the occasional
accident at the couplers, though..."oops, when connecting up this modem,
somehow 140kV jumped out and grabbed me..." might read the epitaph of some
field techs... -WB2WIK/6
"Success is the ability to go from failure to failure with no loss of
enthusiasm." -Winston Churchill
> -----Original Message-----
> From: on4kj [SMTP:on4kj@skynet.be]
> Sent: Friday, April 30, 2004 2:00 PM
> To: towertalk@contesting.com; Bill Fuqua
> Subject: [BULK] - Re: [TowerTalk] The Trojan Horse (BPL)
>
> RF exposure
> And what about RF radiation and electromagnetic field safety when all
> those power lines carry the broadband signals ?
> Maybe a stupid question.............
>
> Jos on4kj
>
> ----- Original Message -----
> From: "Bill Fuqua" <wlfuqu00@uky.edu>
> To: <towertalk@contesting.com>
> Sent: Friday, April 30, 2004 10:22 PM
> Subject: [TowerTalk] The Trojan Horse (BPL)
>
>
> > The Trojan Horse (BPL)
> >
> > A scaled down version of BPL is available at many computer
> stores
> > right now. It comes in the from of special modems that use RF
> frequencies
> > to allow a person to route relatively high speed internet connections
> thru
> > out their home via the house wiring. HomePlug products worked out a
> deal
> > with the ARRL to program their modem DSPs not to produce any signals
> in
> the
> > ham bands. This can be seen in the data sheets of the DSP products
> produced
> > by Analog Devices just for HomePlug products
> > <http://www.analog.com/UploadedFiles/Data_Sheets/35466054AD9975_0.pdf>
> and
> > look at spectra plot "TPC 8". Or find other examples by doing a
> google
> > search for Analog Devices and HomePlug. Looking at the spectra of the
> ouput
> > of these DSP chips you will see that no carriers are produced in the
> ham
> > bands. But are produced everywhere else such as the Short Wave
> Listening
> > bands, WWV frequencies, aviation, marine and wether fax frequencies.
> > The BPL modems will most likely if not already be programmed
> to
> do
> > the same thus resolving most amateur radio concerns. Now for the
> Trojan
> Horse.
> > Lets say they do not produce ANY interference on the ham
> bands.
> > And BPL is raised to the level of being a valuable asset to Homeland
> > Security and is used in every community. The Power Line companies want
> to
> > do more than to just get into the internet business and provide
> service
> to
> > rural areas. They want to get into the Telephone (VoIP) and
> > Paid-Per-View-Movie business. And while doing so they totally control
> the
> > access thru the power lines to peoples' homes thus giving them a real
> > advantage over other ISP companies and even the Telephone companies
> > themselves. Now you begin to transmit on 20 meters with your 100 watt
> > transceiver and your spouse tells you that the neighbor's telephone
> has
> > stopped working. OOPS, it is a BPL VoIP phone and you are disabling
> the
> > entire area network in for a block. They complain to the FCC who
> tells
> you
> > that Homeland Security in a National Priority and you will have to
> just
> > stop what it is that you are doing that disables the BPL network.
> > This is a real possibility. The public backlash at the ham
> > community along with the current Homeland Security mind fix could
> cause
> > serious changes in ham radio either by FCC rulings or executive order
> from
> > the President.
> > You see, even though it is easy to prevent the BPL modems
> from
> > producing ANY QRM on the ham bands by simple programming it is not so
> easy
> > to make them immune to overload from ham radio transmissions. The
> Analog
> > to Digital Converters (ADC) could easily be overwhelmed by the RF
> received
> > by the power lines and data would stop flowing. The only way to
> prevent
> > this is to have passive filters for each and every ham band on the
> input
> of
> > each ADC. And if they were also in the path of between the DAC and the
> > power lines it would be even better. But that may add excessive cost
> to
> the
> > Modems.
> > Presently, the FCC is only looking at Part 15. This has to do
> with
> > the interference of unlicensed devices to other services. Not how
> licensed
> > services may affect the BPL modems. The FCC must also set standards
> for
> > BPL not only those having to do with the signals that they may
> > inadvertently radiate. These must have various details for the
> modulation
> > methods ,data transfer protocol, and encryption. They should also
> include
> > details of how the above filters will be implemented and what will be
> done
> > to resolve problems between licensed services and BPL.
> > However, this still does nothing for the Short Wave
> Listeners.
> HF
> > propagation is too valuable to ruin by implementation of BPL. One
> solution
> > would be to allow BPL to use frequencies above 30MHz and to 80 MHz
> > filtering out the range from 50 to 54 MHz thus only adding 2 filters
> to
> the
> > Modems. This would reduce their usable bandwidth from 78 MHz to 46
> > MHz. And by increasing the amount of power allowed on the
> transmission
> > lines by 6 db they can double their data bandwidth thus taking them
> back
> to
> > the same data bandwidth that they started at. Actually a little bit
> > better. Another approach would be to increase the transmission power
> a
> bit
> > more and limit their RF bandwidth to the low VHF TV channels (56 to 80
> > MHz). Increasing the signal to noise ratio allows you do to do the
> same
> > thing as your 56Kbaud modem. You are able to use a 4KHz (actually a
> bit
> > less) bandwidth telephone line to transmit much higher data
> bandwidths.
> But
> > only if you have sufficient signal to noise ratio.
> >
> > Sorry for the long (hopefully non-political) message. And those of you
> that
> > are sending in last minute comments may consider these technical
> suggestions.
> >
> > A few other comments.
> > Shortwave Listeners have been having problems with the HomePlug
> devices
> > producing interference. BPL is likely to be even worse for them.
> >
> > By the way. A little over 15 years ago some of the power utility
> companies
> > started running fiber optic cables across the nation with plans to
> create a
> > new telephone system ,but forgot to get the approval of the FCC before
> they
> > started. The FCC stopped them cold in their tracks.
> >
> > 73
> > Bill wa4lav
> >
> >
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers",
> "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any
> questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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