that is very interesting. About the 16.7 – 33.3 Hz and multiples of that, I
never think about railways. But I have also a railway station with conversion
units at 700 m south of my location !
I am sure that the QRM is coming from south (I notice a deep rejection when
I swich my RX K9AY antenna to north), and the south is also the direction of my
neighbor. So, I think now that this 16.7 Hz QRM is not due to PLC but railway
!
I’ll need to go to south by my car, with my PC portable and a PA0RDT small
antenna to confirm that.
Thanks a lot for this info Markus.
Andy, LF,
the German ham radio club magazine "cqDL" reported
a couple of cases where complaints from amateurs to the authorities (BNetzA) had
led to local measurements and ultimately to the removal of offending plasma-TV
sets.
I assume CPL is synonym for PLC, homeplug, "D-Link"
etc? Your remark about 16.7 Hz harmonics is interesting, I wasn't aware that
these protocols may induce three-cycle periodicities. Here I do see a lot of
16.7 and 33.3 Hz modulated interference on LF and especially lower VLF, and I
had always been convinced that it is an unambiguous signature of railway-related
power conversion units - there is a freight yard with a large number of overhead
lines about 400 m south of my location.
Best 73,
Markus (DF6NM)
Sent: Friday, March 14, 2014 10:37 AM
Subject: LF: Plasma TV and CPL QRM
Hi John, and yes Eddie !
Same problem here.
My neighbor bought a Plasma TV some months ago. When he
turns it on, the QRM
is very high each 50 Hz also.
On other way, he is also using CPL to carry
on electrical lines the TV
signal coming from Internet. That adds others
lines each 16.7 Hertz.
That is very nice to see that on the screen, but a
pity for the Ham's boys
indeed ! What is the most important ? HI.
73
de F6CNI Andy.
-----Message d'origine-----
From: g3zjo
Sent:
Friday, March 14, 2014 10:15 AM
To:
[email protected]Subject:
Re: LF: LF tonite
Hi John
Has someone in the locality, recently
purchased a Plasma TV.
http://i221.photobucket.com/albums/dd243/radiotalk/zjo_grab600.jpg73
Eddie G3ZJO
On 14/03/2014 07:02, John Rabson wrote:
> Recently a
new source of QRM has started here Still trying to find it. On
> Argo it
appears as a comb of lines with 50/100Hz spacing. Not even Stefan
> is
detectable..
