[Elecraft] Contact your Representatives (BPL)

[Guy Olinger, K2AV]

Well, if that was all there was to it, I would agree with you.

Digital is no panacea, it has it's own particular weak spots not
shared by analog. In most respects it REQUIRES shielding to survive.
One of the reasons why BPL is such a lurch. It's not that it can't
DISCERN the digital signal out of a mixed environment. That's just
firmware. It's all the shortcuts that get taken to reduce chip count
and squeeze a little more profit in the hardware. (Didn't think they
would use the high-priced stuff, did you? After all it's a naked money
grab, the whole thing),

Start the picture by adding 12 dbi for a beam antenna, that gets you a
bit farther away for the same interference potential.

Then remember that digital circuits are at root non-linear, e.g.,
rectifying devices, more so in the el-cheepo stuff that the power
companies are going to want to use. All that has to happen is to
introduce enough steady state carrier to produce a false steady one or
zero in ANY of the circuits, and it's off-line. Or maybe just noise up
a packet enough that it has to be sent over and over, and maybe the
only symptom is that it's just abysmally slow.

If you want to demonstrate this, take one of connections on the your
home LAN router box, construct a NON cat 5 jumper of miscellaneous
wires between two cat 5 connectors. Add an antenna wire (5 or 6 feet)
to ONE of the wire of an active pair, thus unbalancing it and
eliminating the natural shielding of the regular cat 5 twisted pairs.

Then key up 1.5KW on 28 MHz aimed at the house, and see if your LAN is
still working through that connection. I've done that to my self
unintentionally by letting a piece of cat 5 get cut into by a metal
edge on top of it.

All these people that design this stuff have for years been ducking
any measures to make electronics RFI proof.

If it comes on your block, QRO will be getting into it, and if the
neighborhood figures it out, the hams will be the object of
complaints.

73, Guy.

----- Original Message ----- 
From: "John A. Magliacane" <kd2bd@yahoo.com>


> --- "Guy Olinger, K2AV" <olinger@bellsouth.net> wrote:
> > 5 watts in band on the antenna of a spread spectrum receiver will
> > certainly swamp it. Spread spectrum overcomes that kind of
> > interference when it's at the SAME power level as it's desired
receive
> > signal.
>
> Hmmm...  I'm not fully convinced that's true.  Remember, these are
> digital signals, presumably sent with enough redundancy to tolerate
> certain errors.  If the transmission system is adaptive, then
perhaps
> it could even compensate for interference of this sort.
>
> I do agree that 5-watts into the front-ends of MOST receivers would
> overload them to the point of being pretty useless.  But coupling
> 5-watts of RF into a power line ain't easy!
>
   ....snip....