[Lowfer] Rulemaking Ruminations - TWO: Supporting Data Needed

[N6IO]

I found an industry publication recently that gave some numbers of value. (
http://docslide.us/documents/plcc-overview.html)  It said that PLC systems
had a sensitivity of -24dbm.  So if we transmit at +30dbm we need to
provide for 54db of decoupling between the antenna and the receiver.

I'm not a math major - but there should be some information out there to
determine how much signal would get picked up by the power line.  We could
add in losses between the coupling point and the receiver at the nearest
substation, but for worst case numbers we could assume that is zero.

>From another document (
http://electrical-engineering-portal.com/power-line-carrier-communication-plcc)
it mentioned the loss as being .029db/km.  In that example a typical system
had a received signal level of +10dbm and a noise level of -15dbm, so our 1
watt transmitter would have to be isolated by 45db.

Another part of that document mentioned that expected noise levels at the
receiver could be -7dbm.  If we use that as the threshold for interference
then the transmitter and the PLC receiver only need 37db of decoupling, but
we should try for the -54 number to be safe.

Common sense tells me that at a separation of 1km you will have a lot more
than 40-50db of isolation between the antenna and the transmission line,
but we need real facts.  If anyone knows how to calculate this - let me
know.

Thanks!

Craig



On Sun, May 31, 2015 at 5:40 PM, JD <listread at lwca.org> wrote:

> * TWO:  We need more technical showings this time, with as many hard
> numbers
> as possible.