Frequencies available for homemade devices

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W4KRR

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This is an inquiry for a friend.

He wants to develop a sort of tracking device that could be used, for example, to find a lost pet or child. The required range would be about a mile. He was inquiring about existing frequencies that could be used for such a device or service.

I know that amateur, FRS, and MURS are out as possibilities. He wants to know how he would obtain legal frequencies to do this, and what the frequencies or band would be.

I have no other details about what he is developing.

TIA for all responses.
 

Don_Burke

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Why is MURS out? There are dog tracking collars that use it.

You can also go Part 15 in a bunch of places.

The 900 MHz ISM band has possibilities as well.
 

Austin4Wyo

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Yeah, there's already plenty of completely legal and useful commercial production RFI devices. Unless he has some specific reason to build the network himself, it seems more practical to use something already on the market.

Tell him to make his kids wear RFI dog collars. ;)
 

SkipSanders

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The required range makes it impractical. Given that a child (or dog) is even LOWER antenna height than a normal handheld would be, you'll be lucky to get 1/2 mile, and more likely a quarter mile.

A 'long range' tracking system would mean putting detectors up on lamp posts or whatever every few blocks, in a network.

Any legal part 15 device will be unreliable past a quarter mile, but if you retransmit a lot, you can hope for one packet to get through every so often.
 

W4KRR

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Don_Burke said:
Why is MURS out? There are dog tracking collars that use it.

You can also go Part 15 in a bunch of places.

The 900 MHz ISM band has possibilities as well.
I didn't know you could use MURS for something like this. I don't know all the details of what he is wanting to do, but so far it looks like:
Part 15
MURS
900MHz ISM

These might be suitable options. I will pass this on to him.
 
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W4KRR said:
This is an inquiry for a friend.

He wants to develop a sort of tracking device that could be used, for example, to find a lost pet or child. The required range would be about a mile. He was inquiring about existing frequencies that could be used for such a device or service.

I know that amateur, FRS, and MURS are out as possibilities. He wants to know how he would obtain legal frequencies to do this, and what the frequencies or band would be.

I have no other details about what he is developing.

TIA for all responses.
Unless he has a truly unique idea, he would be reinventing the wheel. Any transmitting device would have to be type approved by the FCC, even unlicensed part 15 devices, lots of bucks for R&D and lab time for the certification.
 

57Bill

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Now, let's say the friend isn't concerned with legality, and wants a frequency where he won't be noticed, or won't draw suspicion.
 

Don_Burke

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57Bill said:
Now, let's say the friend isn't concerned with legality, and wants a frequency where he won't be noticed, or won't draw suspicion.
I would use one of the channels used for dog tracking at around 218-220 MHz.

A few extra bloops and bleeps would not be noticed there unless you get into TV channel 13.
 

SkipSanders

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Your now-prospective criminal still won't be able to make anything that works better than the alread available dog trackers. Hint: Sure, make that transmitter 100 watts. Never mind the brain damage it might be doing, think 'battery life', as in, it'll be dead before it can GET out of range. Power doesn't help VHF range significantly. It's line of sight.

Actually, since you're talking signals that will ALWAYS be low height, you want lower frequencies, where absorption is less. Good old 100 mw Part 15 CB comes to mind, though I haven't checked to see if data bursts are allowed. Should be, though, since it's used for Radio Control. Now, however, you're talking antenna efficiency problems.

Whatever, you're going to be lucky to get 1/2 to 1 mile range, no matter what you do. Anything else involves a massive system of multiple receiver sites scattered all over your coverage area.
 

kb2vxa

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Lock the dog and/or kid in the yard and when you take him out put him on a leash. That's all the tracking you need IF that is your intention.

"This is an inquiry for a friend."

Now pull the other one.

OK, setting sarcasm aside, why are you asking such a silly question here when Googling "tracking device" will give you all you need? Try it.
 
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