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robertwo • Jul 28, 2008

Find my Cat

Hoping someone here might be able to help....

Not sure if any of you have seen this product (Loc8tor but I have one that I brought to keep track of my cats....

Lets just say it would be great if the cats only went 30m from the house.....

What I need!

I have a cat, which I have had for the last 8 years, that has a Loc8tor tag hanging around her kneck but she is nowhere to be found for the last 8 days and I have searched everywhere I can for her with this Loca8or product but the range is just to short for the area I live in.

The area that is most probable I will need to search in is up to a 3Km radius.

What I need is someway of significantely increasing the signal strength of the transmitter/reciever so that I can broadcast the signal over... lets say 1000 meters (or more if it's possible), so that the tag around the cats kneck can be activated.

Secondly I need a way of picking up what I guess is going to be a incredibly weak signal coming back from the tag on the cat....

The terrain I will be broadcasting/tracking in is basically hilly fields with hedges and some trees/woods splitting the fields up. I have access to most of the highest points in the area so can try from from these areas to give be the best possible chance of avoiding obstructions. This map will give you an idea of the terrain (chapelle-aux-lys - Google Maps)

I have read that establishing a Bluetooth connection over distances of up to 1Km is possible and am hoping that the same is possible here since this device seem to work in nearly the same frequecy range as Bluetooth. (Wi-Fi Toys)

If any one can help I'd be VERY greatful to here back from you as I would really like to find my cat as she really is one of the family and the kids are missing her a lot.

It been a long time since I studied electonic engineering and my knowledge is very limited on this subject, but I'm sure it will all come flooding back with some help.


gohm • Jul 28, 2008
Wow Rob, best of luck! For the short term to locate your beloved pet, you'll of course need to inhance the receiving strength. You will need to know the exact frequency the transmitter uses and we can go from there. I'm not an eletronic wiz but there are many other on here. After you're reunited, there is a chip you can have your vet insert under the skin of your pet for tracking, though no little about it as I currently do not have pets. I guess it would depend on your budget ability.
robertwo • Jul 28, 2008
Direcly from the manufacturers website:

Q - Does Loc8tor work abroad?
A - Yes, Loc8tor works on the 2.45GHz ISM frequency band which is available worldwide.

As for enhancing the recieving strength, I think I will also need to enhance the transmitting strength as when you track a specific 'tag' you select it from the menu and the tag activates, but the tag needs to recieve the signal from the handheld device before it will activate and the tracker will only track once it has established the tag is active.

I was thinking that a 24db Parabolic Antenna might do the trick.

Here is a picure of the PCB inside the handheld tracker:

Oh no.. a cat owner's worse nightmare 😔

The main problem you'll face is the terrain. Signal strength would greatly attenuate after reaching past obstacles of various materials. The greatest one would be trees and grass: their moisture unfortunately affects the 2.4GHz waves transmitted by your tracker (and accordingly, the signal transmitted from the cat tag).

24dB is certainly very powerful, but parabolic antennas are sometimes hard to work with. Logic states that the waves would spread over a certain angle.. but when working with 2.4Ghz waves, you might need to aim almost precisely at the cat to get it working. I'm not too sure why, most hobbyists who build DIY antennas for their WiFi gear face this problem when aiming at the Access Point.

One more thing, I believe the maximum power you can transmit in any direction (in Europe) is 20dB 😛 You might need to check with your local authority.

I can suggest you try fabricating Omni direction antennas if you find the time to:
Easy Homemade 2.4 Ghz Omni Antenna - Gumph

With this, you don't have to worry about aiming it too much. They are not 100% omni directional.. but have greater spread. I'll try finding out the range.

Here's another trick. I remember watching MacGyver once in an episode that was a tribute (or rip off?) to the Italian Job. He attached a radio jammer to some helium balloons, and let them float in the air. Now, sometimes his gadgets defy engineering practicality, but this time it makes full sense: Your "Line of Sight" factor greatly increases from the air. If you can attach a portable transmitter to a large balloon and tether it somewhere (a tower or slow moving car), the signal can theoretically reach your cat's tag with lesser interference along the way.

I hope your cat comes back. They usually have a good sense of direction (and adventure!), and may come back after. But 8 days is indeed quite long 😔
Anthony88 • Jul 29, 2008
Try criss-crossing the area with the unit in locate pointing the handheld in all directions every 10metres, then move on. A parabolic antenna would be tricky to focus and then to cover all angles, remembering that the transmission sequence is 2.5s on, 2.5s listening, so I'm not convinced of its usefulness
banu • Jul 29, 2008
you can use device similar to transponders in satellites so that the signal is amplified and then sent back to you

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