[R-390] Manassas BPL

[Bob Camp]

Hi

An awful long time ago I had some exposure to "carrier current 
broadcasting". This is a wonderful idea where you transmit AM directly 
into a building's power system in order to provide a listening 
experience for all the occupants.

The first thing you find out is that power lines were not designed as 
RF transmission lines, even at AM radio frequencies. The impedance 
between the conductors is well below an ohm at RF. You need to feed a 
lot more into the lines than you might think to get anything useful to 
happen.

The next amazing thing was that after you got all that power in there 
it would pop up all over the place. We would get hot spots as much as a 
couple of blocks away. This happened at power levels that just barely 
covered the building that was our target. Multiple feeds to the 
building made things even more exciting. Nulls and peaks all over the 
place.

If it's that tough to control at 500 KC then it's going to be a whole 
lot harder to control at 30 MHz. The primary and secondary power 
distribution systems were never intended  to be part of an RF system in 
the first place. Anybody who has ever had a RFI complaint into them can 
tell you just how good they generally are at RF.

The cable company runs a system that is designed from the ground up to 
be RF tight. Finding their carriers floating around in free air is 
awfully easy. It doesn't even take a R390, you can do it on a rice box. 
Even with that kind of system they have an awful time tracking down 
problems as well. The power company won't be any better.

The one hope is that the combination of complaints and competition will 
make this a system that nobody ever makes any money off of. If so it 
will die out. Remember the woodpecker back in the 1980's - it died 
eventually. If this thing interferes with what you want to do on HF 
COMPLAIN ABOUT IT TO THE FCC. The guy that comes around every couple of 
years looking to get re-elected to the House of Representatives might 
also be a good one to talk to. This is especially true if elections in 
your area tend to be closely contested.

Boy .. this has me going even harder than the ballast tubes ...

	Take Care!

		Bob Camp
		KB8TQ



On Jul 10, 2004, at 9:57 PM, JamesMiller wrote:

> As I understand BPL (which isnt much) it comes right to the wall 
> outlet.
> That's the sell feature, your internet comes in on the same plug as 
> power.
> So it may be in your house.  I wonder if a heavy duty RF filter across 
> the
> power main coming into the house wouild help?
>
> Yje ARRL is trying to fight it and needs support. www.arrl.org
>
> ----- Original Message -----
> From: "Rbethman" <rbethman at comcast.net>
> To: <R-390 at mailman.qth.net>
> Sent: Saturday, July 10, 2004 8:54 PM
> Subject: [R-390] Manassas BPL
>
>
>> Well, I've used the R-390A and <groan> a TS-930SAT to narrow it down.
>>
>> The bursts show s-5 on the Kenwood at 1.616Kc.  At 29.6Mc it doesn't
>> move the needle so much as it IS a constant audio pop.
>>
>> The results are the same on the R-390A.  I just used the Kenwood to
>> provide S Units for description.
>>
>> As I have said before - I live in the part of the city that the power 
>> is
>> UNDERGROUND.
>>
>> I've put up to 5 rf toroidal chokes on both radios power cords with NO
>> effect at all.  It is definitely radiated!
>>
>> Now where is riley Hollingsworth's email address.  I know I've seen
> it......
>>
>> Bob - N0DGN
>>
>> -- 
>> <                      Bob Bethman - N0DGN
>> +-------------------------------+----------------------------------+
>> | N0DGN AMRadio Manassas, VA    |    REAL Tube Radio and AM        |
>> +-------------------------------+----------------------------------+
>> |       Manassas Radio - Home of Homemade Kielbasa & Pirogi        |
>> +-------------------------------+----------------------------------+
>> | Bob Bethman                \\\|///     " The absence of a danger |
>> | rbethman(at)comcast.net   \\ ~ ~ //      signal does *NOT* mean  |
>> |                           (/ @ @ /)      that everything is OK " |
>> +-------------------------oOOo-(_)-oOOo----------------------------+
>> |               <http://home.comcast.net/~rbethman>                |
>> | 1 BC-610I w/BC-614I,1 T-213/GRC-26 w/BC614I 1 '51 Collins R-390A |
>> | 1 '67 EAC R-390A, Heathkit DX-60, Apache, Mohawk, SX-101, HT-32A |
>> +------------------------------------------------------------------+
>> |           Amateur Astronomer - Celestron Nexstar 8               |
>> |             12" f5 Dob coming soon!  Being built                 |
>> |                  Meade ETX-60 (Got it back!)                     |
>> |               38 Deg 46.8' N - 77 Deg 28.5' W                    |
>> +------------------------------------------------------------------+
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