This might be slightly off-topic, because the interference generation
problem I need to solve involves long wave radio - please suggest a
better group to post to if you know one.

Problem: Located in the UK, I have a robot mower which is guided by a
perimeter wire laid around the edge of the lawn. Works fine, but
generates RF interference which hits my neighbour's long wave radio
reception (e.g. station Europe 1 at 183 kHz).

First attempt to solve: I have put a filter provided by the mower
manufacturer in-line with the drive to the perimeter wire loop. This
makes a difference - instead of all stations being wiped-out, you can
now hear them, but listening to some stations is unpleasant because of
interference whistles which are still present at various frequencies.

Next attempt to solve: The mower manufacturer is about to send me a
second similar filter, which I can try instead of or in-line with the
current filter.

In case that does not work well enough, can anyone suggest a DIY
filter that should fix the problem?

Thanks,
John

Find out what frequency the mower needs, and filter out everything
but that. That's what the manufacturer should have done, but has
saved costs (and saved you money too, presumably) by leaving it
out. There's filters and filters, but you have to know what they
have to leave untouched before you get anywhere.

My own suggestion is take up a hobby of cutting the lawn with a scythe,
which is a pleasant way to go out and exercise for a half hour a day,
cutting a couple additional 10' wide swaths across the lawn, and
just turn the radio thing off.

http://www.scythesupply.com

--
Ron Hardin


On the internet, nobody knows you're a jerk.

wrote:
This might be slightly off-topic, because the interference generation
problem I need to solve involves long wave radio - please suggest a
better group to post to if you know one.

Problem: Located in the UK, I have a robot mower which is guided by a
perimeter wire laid around the edge of the lawn. Works fine, but
generates RF interference which hits my neighbour's long wave radio
reception (e.g. station Europe 1 at 183 kHz).

For you to get a reasonable answer, a bit more information is needed...

Is there any type of radiation from the guide wire? If so, describe the
signal (frequency, power, analog or digital). If the guide wire is
activated but the mower engine is NOT running, do you get the interference?

Or is the interference coming solely from the mower engine? What type of
motive force is the mower using? Gasoline (petrol) or electric? If
electric, AC or DC? If a DC motor, series wound, shunt wound or
universal? Type of motor speed control (if any); e.g. pulse width
modulation?

On 14 Jun, 13:30, Tommy Tootles wrote:
wrote:
This might be slightly off-topic, because the interference generation
problem I need to solve involves long wave radio - please suggest a
better group to post to if you know one.

Problem: Located in the UK, I have a robot mower which is guided by a
perimeter wire laid around the edge of the lawn. Works fine, but
generates RF interference which hits my neighbour's long wave radio
reception (e.g. station Europe 1 at 183 kHz).

For you to get a reasonable answer, a bit more information is needed...

Is there any type of radiation from the guide wire? If so, describe the
signal (frequency, power, analog or digital). If the guide wire is
activated but the mower engine is NOT running, do you get the interference?

Or is the interference coming solely from the mower engine? What type of
motive force is the mower using? Gasoline (petrol) or electric? If
electric, AC or DC? If a DC motor, series wound, shunt wound or
universal? Type of motor speed control (if any); e.g. pulse width
modulation?

The interference comes solely from the guide wire and/or the
electronics driving it. The filter supplied by the manufacturer plugs
into the output of the driver and the lead to the guide wire plugs
into the filter. I have no information on the frequencies the driver
is using (the only information about the signal is that it is
sinusoidal).

On Jun 14, 4:03 am, Ron Hardin wrote:
Find out what frequency the mower needs, and filter out everything
but that. That's what the manufacturer should have done, but has
saved costs (and saved you money too, presumably) by leaving it
out. There's filters and filters, but you have to know what they
have to leave untouched before you get anywhere.

My own suggestion is take up a hobby of cutting the lawn with a scythe,
which is a pleasant way to go out and exercise for a half hour a day,
cutting a couple additional 10' wide swaths across the lawn, and
just turn the radio thing off.

http://www.scythesupply.com

--
Ron Hardin


On the internet, nobody knows you're a jerk.

RH - and Now All You Need is the Hammer ) ~ RHF

Why not just turn it off when not in use, I'm pretty sure that for the 1/2
to 1 hour a week you'd be 'mowing' the lawn, the guy listening to the
radio can live with that, especially if you do it at a time when he's
asleep, at work, or washing the dishes. .


wrote in message
ups.com...
This might be slightly off-topic, because the interference generation
problem I need to solve involves long wave radio - please suggest a
better group to post to if you know one.

Problem: Located in the UK, I have a robot mower which is guided by a
perimeter wire laid around the edge of the lawn. Works fine, but
generates RF interference which hits my neighbour's long wave radio
reception (e.g. station Europe 1 at 183 kHz).

First attempt to solve: I have put a filter provided by the mower
manufacturer in-line with the drive to the perimeter wire loop. This
makes a difference - instead of all stations being wiped-out, you can
now hear them, but listening to some stations is unpleasant because of
interference whistles which are still present at various frequencies.

Next attempt to solve: The mower manufacturer is about to send me a
second similar filter, which I can try instead of or in-line with the
current filter.

In case that does not work well enough, can anyone suggest a DIY
filter that should fix the problem?

Thanks,
John

The interference problem now solved by fitting a second filter in-line
with the first.

John