[AMRadio] QRM fron Neighbor's Security System

Jay Bromley jayw5jay at cox.net
Fri Jan 22 01:38:17 EST 2010

Hi Jim,
I just went through nearly a year of this!  You would not believe how wide
or how far those signals from a little battery charger can go.  Over and
down the next street from my house that was about 1/8 a mike away!  Also
what made this even worse it was HF only!  With the help of my local hams,
we used a IC706 MKII G mobile to narrow it down to one house only. Once I
found the which house was causing the problem I had the local utility
company investigate.  The main reason I wanted them there was to have a
uniform person explain to the owner why we were looking for interference
coming from their house.  Nothing worse than to have someone come up with a
silly looking radio and having a bazaar story!  However the power company
RFI specialists came and went without letting me know he was up there.  He
called my house as he was leaving town and said the house was clean.  Sadly
they only used test gear that covers VHF only.  Ugh!  I said no it is not
clean and held up the phone to my HF receiver letting him hear what sounded
like a mad ticking clock.  I had even explained to him before hand why I
wanted him there, but I guess it didn't make sense to him and it was Sorry
Charlie for the most part after that.

 I was sort of lucky in that the home owners had the house for sale and were
already moved, but left there stuff behind for the time being.  The realtor
seemed to want to cooperate, but it took a few months to finally get him to
let me in the house.   In the mean time I was looking at similar recordings,
everything from electric blankets to swimming pool pumps.  I was loaned a
Sony shortwave handheld receiver for testing.  When I finally caught up to
the realtor, it wasn't as easy to find as I had hoped for.   Armed with the
Sony handheld as we entered the house every wall was hot from this bogus
signal, so finally had to resort to turning off breakers that were unmarked.
Of coarse it was the last breaker that finally killed the signal.  Then we
turned on all the lights in every room trying to figure out which room this
breaker was on.  What made matters worse we couldn't find the room or the
outlet affected and the realtor was in a hurry to leave.  He wanted just to
leave the breaker off, but I didn't want to do this as you never know what
problems this could have caused and I would be blamed for.  Liability is not
something to be taken lightly.

Finally we were back in the packed garage where the breaker panel was and I
saw a cord going to an outlet I hadn't seen before.  It was behind a huge
stack of boxes.  I had nothing to lose so I pulled the plug and bingo signal
was gone!  I couldn't see what was on the other end of the cord, but pulled
on it till I came up to a back plastic box with the name JingCheng.  It was
a battery changer alright with the plug missing on the end.  Nearby was the
kid's battery powered scooter with the same name.  I plugged it back in one
last time to show the realtor this what was causing the interferencing
ticking sound over the Sony handheld.  The charger had two LED's, one green
and one red, every time the red LED fired off the you could here the ticking
or pulse on the Sony handheld.  BTW, the ticking sound was about two ticks
per second.

I really wanted to do something to that charger, but it wasn't my property.
So far the owners have made it home for the holidays and the signal hasn't
returned.  I told the realtor they were lucky this cheap piece of junk
didn't start a house fire.  Most of the stuff inside the house was
unplugged, but everything electrical in the garage was left plugged in.  I
did my best to impress the realtor to tell the owners they needed to destroy
this fire hazard.  If they move back I am sure at some point I will either
have to buy them a new charger or filter it if I want to live in peace.  I
would be glad to do it even though it is not required for me to do so.

I can not tell you what a relief all this is to finally have a quieter
receiver.  I still have some interference from other sources, but they are
low in comparison and I can move around them.  The other day I was talking
to a ham on the air that works for a utility company that tells me this is
just the beginning!  This is not good and I believe him.

On the web here is sort of what the scooter looked like:

Here is the link to JingCheng:

Sadly this company makes a ton of products and I am sure most of them are
cutting corners like in the kid's scooter's battery charger.  The make
everything from Scooters to garage doors, you can bet if it has a switching
power supply with their name on it will be dirty as all get out.

73 de w5jay/jay..

> Sometime in the recent past there was a ham in Houston, TX (I believe)
> who had interference that he traced to a neighbor who had two of those
> electric scooters, one for him and one for his wife.  The noise was on
> every night and the battery charge circuits put trash on the AC lines
> that tore up the amateur bands.
> He contacted the neighbor and told him of the problem so the neighbor
> allowed him to install filters in the lines used to charge the
> batteries.  That fixed the problem, so the ham thought.  Evidently the
> scooter owners did not like the filters and removed them.  The ham tried
> for months to get the owners to reinstall the filters but they would
> not.
> The rest of the story is short.  The FCC enforcement group finally
> interceded and sent letters (more than one) telling the owners to put
> the filters back in place.  They ignored the letters and it cost them
> some fine, the amount I don't recall.  Sad deal for two people who
> refused to follow the rules.  But if you have an unintentional radiator
> then you can, after a process, get something done about it.
> If you are an ARRL member, contact Ed Hare, W1RFI and get some help.
> That will shorten the wait.
> 73
> Jim/W5JO
> ----- Original Message ----- 
>>I am not familiar with this particular system, but most X-10 equipment
>> the home's power lines for transmission. If you are both on the same
>> transformer, you may be getting interference from your home's power
>> line. You
>> may need some power line filtering. Depending on your gear, you may be
>> subject  to Part 15 rules which basically say that your equipment must
>> accept
>> various  forms of interference. Regardless, it is a sticky wicket.
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