In-house PLC system kills DRM

[dk8cb]

Hi,

read these test results (http://www.uba.be/dossiers/bpl/bpl_1.htm) on the adverse effect of an in-house powerline communications system on reception of DRM and other shortwave services.

Roland

[df9rb]

Hello,

in the radio magazine "CQ DL" a link is mentioned to a technical report composed by NATO in which HF interference of Power Line Communication (PLC) is investigated.
http://ftp.rta.nato.int/public//PubFullText/RTO/TR/RTO-TR-IST-050/$$TR-IST-050-ALL.pdf
In this article the main focus is to investigate negative effects to military communication
but several times the influence to DRM is emphasised:
" .... drop-outs are more severe than higher background noise ...."

I think now the PLC pressure group has an equal opposition.....

Bernd, DF9RB

[mvs sarma]

Hello,

in the radio magazine "CQ DL" a link is mentioned to a technical report composed by NATO in which HF interference of Power Line Communication (PLC) is investigated.
http://ftp.rta.nato.int/public//PubFullText/RTO/TR/RTO-TR-IST-050/$$TR-IST-050-ALL.pdf
In this article the main focus is to investigate negative effects to military communication
but several times the influence to DRM is emphasised:
" .... drop-outs are more severe than higher background noise ...."

I think now the PLC pressure group has an equal opposition.....

Bernd, DF9RB

Hi Bernd,
thanks for a very useful info.

I fear power controll devices like TRIAC controlled (proportional control) in house wiring, that too with inadequate filtering -- will interefere severely with DRM signal. Same is case with computer monitors' and TV's smps, as it is located in a plastic container.

[df9rb]

Hi Sarma,

there is a big differnece concerning PLC and HF interfernece of i. e. PCs.
For most of electronic equipment international standards (or laws) are existing which are limiting the levels of HF-radiation. For PLC no standards are existing yet and the PLC-people argueing that 15 db higher noise would be acceptable....

I work in a R&D department and we do quite often measurments according to radiation standards. My experience is that it is often difficult to keep the limits but is is possible and a product which fullfills these limits don t produce noise to receivers when the antenna is some meters away from this product.

An alarming result of this report is that also radiated PLC signals will produce noise in remote areas by sky wave propagation. At the moment people living in cities with PLC are plagued by high noise. If the number of PLC-networks increase also receiver in some 1000 km will detect a higher noise level.....

Bernd, DF9RB

[mvs sarma]

Thanks Bernd,
I learnt something new and very needed info today.
it will be useful to me . Thanks again

[df9rb]

Hi all,

during this weekend I borrowed two powerline modems. The result is terrible!
I use outdoor antennas but on 6 MHz the noise increases up to 40 dB (7 to 7.4 Mhz is excluded by the modems I tried).
Have a look to the attachment - RTL disapears nearly complete, DW on 6075 has an high background noise when data are transfered over PLC (upper line).
For comparison the lower lines shows the spectrum when no data are transfered (SNR for RTL > 26 dB then).

Bernd, DF9RB