I am in the process of testing the trial areas right now. They are coming in
right on the money -- systems that operate "at the legal limit" have
inteference that exactly matches what theory says should be there. I am
working with the BPL manufacturers, with the understanding that I will return
to test areas and make independent measurements.
73,
Ed Hare, W1RFI
ARRL Lab
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Internet: w1rfi@arrl.org
Web: http://www.arrl.org/tis
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> -----Original Message-----
> From: Michael Tope [mailto:W4EF@dellroy.com]
> Sent: Friday, June 06, 2003 10:38 PM
> To: WA2BPE; David Jordan
> Cc: RFI; KA5MGL
> Subject: Re: [RFI] re: BPL
>
>
> I think the FCC wants this BPL thing to fly as it falls into their
> political paradigm of increased competition and deregulation.
> What the amateur community needs to do is make them painfully
> aware of the potential for interference to existing spectrum users
> so that the proper testing for EMI is done in the various field trials
> that are underway. The questions that the FCC is posing in their
> NOI suggests that the engineers at FCC are aware of the potential
> problems and that they want input on how to address these
> problems. If the all of the stakeholders in this issue are represented
> fairly during the field trials, I think BPL will defeat
> itself as I think
> that
> the operating levels needed for good system performance and the
> levels needed for good EMI compatability with licensed services are
> mutually exclusive. On the other hand if only the BPL
> industry conducts
> the field trials without independent oversite, they will spin
> the results
> so that EMI issues are understated.
>
> One of the possible achilles heals of this technology is its immunity
> to overload from our transmitters. In order to meet part 15
> regulations,
> BPL systems need to run at very low power spectral densities. They
> have trouble with impulse noise, but they get around it because it is
> of short duration and they use lots of coding (FEC,
> interleaving, etc).
> On the other hand, what happens when I key up with 1500 watts into
> a TH7DX for a 2 minute RTTY transmission when my antenna is 100
> feet from an overhead powerline. Will their analog front-ends have
> sufficient dynamic range to lock to a signal with a power
> spectral density
> or -100dBm/Hz in the presence of 15KW EIRP signal 100 feet away?
> Probably not, BPL modems will have wide open front-ends as they
> are designed to look at large portions of HF spectrum at
> once. They rely on
> DSP for filtering. I don't think their ADC's will have enough
> bits to deal
> with
> close proximity to high power transmitters. Filtering this
> will be tough
> as they will need sharp ham band analog notch filters ahead of their
> front-ends to deal with this sort of problem. This could get expensive
> for BPL operators depending on the radius of suceptibility
> (area around
> offending HF transmitter where BPL hardware is overloaded). Just
> one of many potential problems with this technology.
>
> 73 de Mike,
> W4EF..........................................................
>
>
>
>
> > As has been said before, these days, the FCC seems to be
> following the
> money. If something won't pass the regulations for, e.g.,
> radiation, just
> rewrite the rules. And as far as it being rejected in Japan
> - so what.
> Classic government mentality (is there an oxymoron here?)
> says not to look
> at what
> > someone else has done when we have $$ to spend to reinvent
> the wheel. And
> if they tackled specifically that, it would likely come out
> square! Don't
> forget what happened with the 220-222MHz debacle - approved
> by the FCC yet
> unproven technology that fell flat on its face despite the
> warnings. Did we
> get
> > that 2MHz back? Ha! Remember, these folks are experts at
> finding wiggle
> room and rationalization. The real issue here is money; the
> Physics be
> damned!
> >
> > Many of the services noted below are (generally) limited to
> metro/suburban
> infrastructure. I live 4 miles from the city line; dialup is
> it - period.
> Perhaps the recent agreement on fiber to the home standards
> (it's about
> time) will have some impact here. Me - I favor fiber - I
> worked with it for
> 30+
> > years!
> >
> > 73,
> >
> > Tom - WA2BPE
> >
> > David Jordan wrote:
> >
> > > If they can't make it work in japan it's not going to work
> > > here...however, the companies have a right to try it and
> the gov. can't
> > > do much more than watch them fail at it...no one here in
> DC thinks this
> > > mode is going to fly...the competition (cable, Satellite,
> DSL, ISDN, T1,
> > > POTS dial-up, wireless 3G, etc.)has a pretty good lock on
> the market!
> > >
> > > enjoy,
> > > dave
> > > wa3gin
> > >
> > > KA5MGL wrote:
> > > > Pardon my naivte here, gang. Am I correct in thinking
> the power
> companies (or whoever) would need to clean up their systems
> before it will
> reliably *pass* data at BPL speeds? I'm thinking the bad
> connections,
> loose hardware, weak grounding, etc might be so bad it would
> hamper their
> own intentions.
> > > >
> > > > Am I far afield on this point? Just curious.
> > > >
> > > > 73,
> > > > Kelly, KA5MGL
> > > > _______________________________________________
> > > > RFI mailing list
> > > > RFI@contesting.com
> > > > http://lists.contesting.com/mailman/listinfo/rfi
> > > >
> > >
> > > _______________________________________________
> > > RFI mailing list
> > > RFI@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/rfi
> >
> > _______________________________________________
> > RFI mailing list
> > RFI@contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
>
>
>
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