Hi,

I friend of mine, ham, is handicapped and cannot move without his wheelchair
He experiments QRM on low bands 160/80/75m induced by the fence installed by
his neighbor
I don't know what kind of fence it is, and if it is really close to his
house or miles away...

He would like to know if a rotaty loop antenna could remove this QRM ?

I used a Wellbrooks ALA1530 and I am not sure that he could remove such QRM
as it.

Usually a fence has HV pulses generated by a large ignition coil or similar
transformer or this is maybe a thermostatic device

I see three solutions:
- I 'd like to know if there is a way to install on the fence itself a
"de-parasiter", something like a low-pass filter that 'd cut all trancient
emissions in HF bands ?
- or could the MFJ noise canceller (MFJ 1025/1026) be a solution (tightening
a second antenna like a long wire 20m long outdoor)
- at last is there another model of receive antenna that could really reject
this kind of QRM ?

Any other idea or an URL ?

Thanks in advance

Thierry, ON4SKY
http://www.astrosurf.com/lombry

Thierry:

Two answers:

The interference is pulse in nature, and a "noise blanker" of the type which was effective against the "Woodpecker" HF
Radar is effective.

In the States, there are fence chargers which emit no RFI. Their charging pulses are shaped to prevent it.
Unfortunately, it has been 10 years since I have dealt with that problem, and I no longer recall any brand names or
model numbers.

And, Jacques is correct, that interference is against radio regulations, and there are legal recourses which can be
pursued if all else fails.

--
Crazy George
Remove N O and S P A M imbedded in return address

"Thierry" - wrote in message ...
Hi,

I friend of mine, ham, is handicapped and cannot move without his
wheelchair
He experiments QRM on low bands 160/80/75m induced by the fence installed
by
his neighbor
I don't know what kind of fence it is, and if it is really close to his
house or miles away...

He would like to know if a rotaty loop antenna could remove this QRM ?

I used a Wellbrooks ALA1530 and I am not sure that he could remove such
QRM
as it.

Usually a fence has HV pulses generated by a large ignition coil or
similar
transformer or this is maybe a thermostatic device

I see three solutions:
- I 'd like to know if there is a way to install on the fence itself a
"de-parasiter", something like a low-pass filter that 'd cut all trancient
emissions in HF bands ?
- or could the MFJ noise canceller (MFJ 1025/1026) be a solution
(tightening
a second antenna like a long wire 20m long outdoor)
- at last is there another model of receive antenna that could really
reject
this kind of QRM ?

Any other idea or an URL ?

Thanks in advance

Thierry, ON4SKY
http://www.astrosurf.com/lombry


Best fix would be to repair the fence. As a first step, they should contact
the manufacturer of the fence charger, and whatever regulatory agency is in
charge.

Tam/WB2TT

OK, thanks to all your advices.
Good to know that the regulation protect our rights in such circumstances
too ;-)

73
Thierry, ON4SKY


"Tam/WB2TT" wrote in message
...

"Thierry" - wrote in message ...
Hi,

I friend of mine, ham, is handicapped and cannot move without his
wheelchair
He experiments QRM on low bands 160/80/75m induced by the fence
installed
by
his neighbor
I don't know what kind of fence it is, and if it is really close to his
house or miles away...

He would like to know if a rotaty loop antenna could remove this QRM ?

I used a Wellbrooks ALA1530 and I am not sure that he could remove such
QRM
as it.

Usually a fence has HV pulses generated by a large ignition coil or
similar
transformer or this is maybe a thermostatic device

I see three solutions:
- I 'd like to know if there is a way to install on the fence itself a
"de-parasiter", something like a low-pass filter that 'd cut all
trancient
emissions in HF bands ?
- or could the MFJ noise canceller (MFJ 1025/1026) be a solution
(tightening
a second antenna like a long wire 20m long outdoor)
- at last is there another model of receive antenna that could really
reject
this kind of QRM ?

Any other idea or an URL ?

Thanks in advance

Thierry, ON4SKY
http://www.astrosurf.com/lombry


Best fix would be to repair the fence. As a first step, they should
contact
the manufacturer of the fence charger, and whatever regulatory agency is
in
charge.

Tam/WB2TT

On Sun, 24 Oct 2004 13:30:05 +0200, "Thierry" - wrote:

QRM on low bands 160/80/75m induced by the fence installed by
his neighbor
I don't know what kind of fence it is, and if it is really close to his
house or miles away...

Hi Thierry,

First, find the offender. This is easy because, as you have
experienced, the noise is everywhere. With that in mind, hop in the
car and tune it in. Drive around and make it louder. You will then
have answered the question as to where it is located.

Second, the reason why it is loud, much less louder. Electric fences
fail for one of several reasons. Poor ground (how about that?) can
offer problems, but it ranks pretty low. Poor connections can
frustrate, but they are simple to fix if you simply walk the fence and
inspect. Arcing can occur, but this is often confined to the lowest
wire that is being brushed by grass, which then burns off with a
sizzle (across the spectrum). Trimming vegetation takes care of that
(and has you walking the fence line once again).

A useful tool to take along is a circuit tester with a neon bulb. It
should light up at the right places (or the wrong places) or dim in
the wrong places (or the right places). Again, this has you walking
the fence line.

Expect to visually inspect along the fence line.

73's
Richard Clark, KB7QHC

He could change the type of fence charger. I have one which uses a
continuous HV charge (with current limiting of course) and it works
quite well and causes zero QRN.

Hi Bill, I have a homebrew one with a capacitor discharge into an auto
ignition coil. What kind of diode and filter cap. specification do they have
on the DC version you use? I would guess it is hard to let go of the DC
version:-)
73 Gary N4AST

"Thierry" - wrote in message ...
Hi,

I friend of mine, ham, is handicapped and cannot move without his
wheelchair
He experiments QRM on low bands 160/80/75m induced by the fence installed
by
his neighbor
I don't know what kind of fence it is, and if it is really close to his
house or miles away...

He would like to know if a rotaty loop antenna could remove this QRM ?

I used a Wellbrooks ALA1530 and I am not sure that he could remove such
QRM
as it.

Usually a fence has HV pulses generated by a large ignition coil or
similar
transformer or this is maybe a thermostatic device

I see three solutions:
- I 'd like to know if there is a way to install on the fence itself a
"de-parasiter", something like a low-pass filter that 'd cut all trancient
emissions in HF bands ?
- or could the MFJ noise canceller (MFJ 1025/1026) be a solution
(tightening
a second antenna like a long wire 20m long outdoor)
- at last is there another model of receive antenna that could really
reject
this kind of QRM ?

Any other idea or an URL ?

Thanks in advance

Thierry, ON4SKY
http://www.astrosurf.com/lombry



I forget where I saw it (maybe in the MFJ catalog) - but I've seen a device
used for cancelling unwanted signals.
I think the principle is that the second (smaller) antenna should pick up
the unwanted signal -and have an attenuator on it - it adds to the original
signal, but in opposite phase so as to cancel.
Used mainly to block locally strong signals so you can hear remote weaker
signals.
The second antenna - being smaller - only picks up the strong local signal.
---
HTH
Hal


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"Thierry" - wrote in message ...
Hi,

I friend of mine, ham, is handicapped and cannot move without his wheelchair
He experiments QRM on low bands 160/80/75m induced by the fence installed by
his neighbor
I don't know what kind of fence it is, and if it is really close to his
house or miles away...

He would like to know if a rotaty loop antenna could remove this QRM ?

Yes, if it's from a single source, and it will also tell him which
direction it's in. Well, it's bidirectional, but common sense will
tell which way it probably is, if you already know about the
fence...But yes, most likely a small loop would take most of it out.
Maybe even all of it. The nulls on a good balanced loop are sharp and
deep. I know my loops can take a single noise source right out of the
picture. Or an undesired station for that matter if it's ground
wave... MK