Hi all,

I have a wireless fence, which operates at 17 kilohertz. It is used to
create a wireless fence to keep our dog confined to area close to the
transmitter and works in conjunction with a shock collar (the receiver
is carried by the dog).

We haven't used it yet, but the literature suggests the range is
around 90 feet.

I found the transmitter schematic on the FCC website. The transmitter
is nothing more than generic audio amplifier chips fed with 17
kilohertz signals from what appears to be a PIC or ASIC device. The
antennas are large (8-9 inch) air wound coils that have MANY turns on
them.

I'd like to increase the range without spending much money-so I want
something quick and dirty::

If I disconnect one of the built in antennas, can I hook up the
transmitter to an external antenna consisting of many turns of wire
mounted in the basement (say a 5 or 10 foot diameter loop)?? Would
this give the transmitter more range, or would the range be the same
as the smaller loops that are built in?

Thanks,

A

On Mon, 28 Mar 2005 13:27:45 -0500, Albert wrote:

I'd like to increase the range without spending much money-so I want
something quick and dirty::

Hi Albert,

Hmm, more range? You should be able to fry that puppy within a
country mile if you do that.

Perhaps you should describe your goal instead of your intended method.

73's
Richard Clark, KB7QHC

Hi Richard,

We live in the country, and have all kinds of room for the dog to run.
Despite the fact that we are 700 feet from the road, the dog insists
on going to the road and chasing cars. We are worried for the dogs
safety, hence we purchased the 'wireless fence'.

The design has quite a few safeguards in it and it is very well
thought out.

BUT, it has a 90 foot maximum range. I'd like to extend the range out
to 300 or 400 feet without spending alot of time and money. The
solution offered by the manufacturer is to purchase an additional
transmitter and run them both at the same time. This is a very
expensive remedy and it only gives a modest increase in the range.

My 'goal' is to have an increased range so the beagle can have a
little more area to run in while keeping her away from the road.

Can you offer any suggestions that don't cost alot or require alot of
time to implement?

A



On Mon, 28 Mar 2005 10:48:22 -0800, Richard Clark
wrote:

On Mon, 28 Mar 2005 13:27:45 -0500, Albert wrote:

I'd like to increase the range without spending much money-so I want
something quick and dirty::

Hi Albert,

Hmm, more range? You should be able to fry that puppy within a
country mile if you do that.

Perhaps you should describe your goal instead of your intended method.

73's
Richard Clark, KB7QHC

On Mon, 28 Mar 2005 14:04:03 -0500, Albert wrote:

Can you offer any suggestions that don't cost alot or require alot of
time to implement?

Hi Albert,

I presume by this "range" that the beagle moves unhindered WITHIN the
range of the antenna, and outside of this range she gets a shock (or
some form of behavior modification).

If that is accurate, then boosting range would accomplish your goal.
The problem I had was presuming that the antenna was at the perimeter,
and if your dog penetrated towards it, entering its field, that this
would "modify" her behavior. I am more familiar with antenna
perimeter fences were a collared pooch approaching such a fence would
be -um- stimulated.

Anyway, as you have already noted the design of the transmitter and
the antenna both, then you have options with both. Using the same
antenna, you could feed your transmitter into an unused stereo (or
monaural) amplifier and use that to drive the antenna with more power
(say 1 to 5 Watts). Then you could adjust the range with the volume
control. If this worked, you could then go out an buy a dedicated
audio amp kit ($10-$20) that fits this power range.

Another method is to replace the antenna with conductive stakes driven
into the ground. At this frequency, ground conduction has a fair
range. It was one method of communication that was used with trench
warfare during WWI. The further apart the stakes are, the better. I
would add that this comes with some shock hazard and is certainly not
within the warrantee of the product (but nothing suggested here will
be). As this a strictly an experimental long shot, try the simpler
suggestions above.

73's
Richard Clark, KB7QHC

On 2005-03-28, Albert wrote:
Hi Richard,

We live in the country, and have all kinds of room for the dog to run.
Despite the fact that we are 700 feet from the road, the dog insists
on going to the road and chasing cars. We are worried for the dogs
safety, hence we purchased the 'wireless fence'.

The design has quite a few safeguards in it and it is very well
thought out.

BUT, it has a 90 foot maximum range. I'd like to extend the range out
to 300 or 400 feet without spending alot of time and money. The
solution offered by the manufacturer is to purchase an additional
transmitter and run them both at the same time. This is a very
expensive remedy and it only gives a modest increase in the range.

My 'goal' is to have an increased range so the beagle can have a
little more area to run in while keeping her away from the road.


I might be missing something here, but wouldnt increasing the range of the
transmitter/antenna combination reduce the amount of room that the dog has
to run in? Increasing the range, would trigger the collar when the pup was
farther away from the perimeter - confining the pooch to a smaller area.

What is the design of the reciever on the dogs collar? You don't have to
increase the range of the transmitter, you could just increase the
sensitivity of the receiver. If the xmitter is really running at about
17khz, then a 1/4 wave whip (about 2.75 miles) attached to the dogs collar
might work. If that does not work, you could at least reel the dog in when
she gets a bit too close to the road.



--
Alex / AB2RC
Linux is user friendly, however it is not idiot friendly

On Mon, 28 Mar 2005 11:44:33 -0800, Richard Clark
wrote:
l.

Hi Richard and Alex,

Both of you thought the wireless fence involved a buried loop, which
is NOT the case.

The transmitter is NOT connected to a buried loop, the antenna is in
fact contained within the plastic case of the housing. The antennas
are 8 or 9 inch air would coils with MANY MANY turns of small gauge
wire.

My question is.....

If I disconnect the internal coils, can I replace them with much
larger coils of similar inductance that would probably be in the
basement (out of the way)??

Thanks,

A


The problem I had was presuming that the antenna was at the perimeter,
and if your dog penetrated towards it, entering its field, that this
would "modify" her behavior. I

Putting a ferrite core in the windings of the antenna would extend its
range, wouldn't it ?
- or are you working on a way to shock the neighbor's puppy ?
:-)

I auume these thing work in reverse of conventional thinking. I assume
that as long as the receiver is receiving a signal, the dog does not get
shocked. If it strays too far and the receiver loses the signal...ZAP!
However, modifying the transmitter would violate its Part 15
certification and the owner might be the one to get the ZAP (from the
FCC)...

Scott


AB2RC wrote:

On 2005-03-28, Albert wrote:

Hi Richard,

We live in the country, and have all kinds of room for the dog to run.
Despite the fact that we are 700 feet from the road, the dog insists
on going to the road and chasing cars. We are worried for the dogs
safety, hence we purchased the 'wireless fence'.

The design has quite a few safeguards in it and it is very well
thought out.

BUT, it has a 90 foot maximum range. I'd like to extend the range out
to 300 or 400 feet without spending alot of time and money. The
solution offered by the manufacturer is to purchase an additional
transmitter and run them both at the same time. This is a very
expensive remedy and it only gives a modest increase in the range.

My 'goal' is to have an increased range so the beagle can have a
little more area to run in while keeping her away from the road.



I might be missing something here, but wouldnt increasing the range of the
transmitter/antenna combination reduce the amount of room that the dog has
to run in? Increasing the range, would trigger the collar when the pup was
farther away from the perimeter - confining the pooch to a smaller area.

What is the design of the reciever on the dogs collar? You don't have to
increase the range of the transmitter, you could just increase the
sensitivity of the receiver. If the xmitter is really running at about
17khz, then a 1/4 wave whip (about 2.75 miles) attached to the dogs collar
might work. If that does not work, you could at least reel the dog in when
she gets a bit too close to the road.

On 2005-03-28, Albert wrote:
On Mon, 28 Mar 2005 11:44:33 -0800, Richard Clark
wrote:
l.

Hi Richard and Alex,

Both of you thought the wireless fence involved a buried loop, which
is NOT the case.

The transmitter is NOT connected to a buried loop, the antenna is in
fact contained within the plastic case of the housing. The antennas
are 8 or 9 inch air would coils with MANY MANY turns of small gauge
wire.

OK, then this is very different from other "invisible" fences that I have
seen. It would appear that this device is designed to keep the dog close to
the transmitter, and then shock her when she strayed too far - when the
receiver on the collar lost the input signal.

I think that device would not give you all that much control as to what kind
of coverage area you can have. Also what would happen if the collar lost
the xmitter signal due to other reasons (dog goes behind a trash can/metal
shed/other large metal object)? Personally, I would return it, and get the
type that used a buried wire -- or just train the dog not to stray too close
to the road by other means.

That being said, it might still be easier to increase the sensitivity of the
receiver. What type of antenna is on the dogs collar? Also - what is the
brand and model of this unit? It might make tracking down the soultion a bit
easier.

--
Alex / AB2RC
Linux is user friendly, however it is not idiot friendly

Scott,

Your question brings much complication to a matter that should be easy
to answer. I'll do my best to avoid getting bogged down in the
explanation.

The transmitter has a very long range, much longer than 90 feet. I
believe the dogs collar hears the signal for a very long distance.
But, that the collar does not issue a correction if the dog wanders
past the range of the transmitter. If the collar acted in this manner,
it would preclude the dog from RE-ENTERING the protected area from the
outside of the 90 foot range.

In order for the collar to initialize, it must hear the transmitter
(initially). If the transmitter is turned off, and the collar is
turned on, no corrections are issued.

Also, if the collar is properly initialized and operating, abruptly
turning off the transmitter DOES NOT result in a correction being
issued. Corrections are only issued IF the dog is in the intermediate
zone, which appears to be a 3 foot wide area.

This type of operation is necessary to safeguard the dog, even though
it complicates the hardware some.

At 16 kilohertz with horrendously inefficient transmitting antennas, I
doubt there would be an FCC problem, especially with a modest boost in
ERP. The Earth and the solar system generates much noise on those
frequencies as well, we could probably increase the transmit power
quite a bit without creating problems.

Hope this helps.

A



On Tue, 29 Mar 2005 12:09:27 +0000, Scott
wrote:

I auume these thing work in reverse of conventional thinking. I assume
that as long as the receiver is receiving a signal, the dog does not get
shocked. If it strays too far and the receiver loses the signal...ZAP!
However, modifying the transmitter would violate its Part 15
certification and the owner might be the one to get the ZAP (from the
FCC)...

Scott