RF Detector - Transponder

[AJ_K]

Hi everyone,

I hope you guys can help me out. I have missing person situation where a good friend of mine's father-in-law disappeared without a trace about a week ago. He was in a rural area on business, made one last phone call late in the evening informing his wife he would be home in a few hours, then completely vanished without a trace. On his trip to this location, he drove on the turnpike through an electronic toll collector which registered that he had indeed passed through it. On his return trip when he disappeared, there was no such entry that he passed back through. Here is where you may be able to help me. Those transponders use RF to communicate with the Electronic Toll Collectors. Here in Oklahoma we call the transponder a PikePass. Now assuming this missing person had an accident and drove off the road would we be able to use an RF Detector to pick up the signal from that PikePass? And if so, what is the range on those transponders? I imagine not much greater than 20 feet, if that. I appreciate any input you can offer me.

Best Regards,
AJ Keltner
Oklahoma City

 

[fineshot1]

I imagine not much greater than 20 feet, if that. I appreciate any input you can offer me.

AJ - sorry to say you would be correct in that range/distance - not much use is trying to track someone.

However - if he had a cellphone with him its possible the service provider could be helpful with either a last call AMA record or possibly the last know registration message from the cellphone which may narrow down the general area. Not sure if they could provide that to you but a police agency can request those type records in cases like this.

 

[N_Jay]

Interesting thought.

I bet you could ping a transponder from several hundred (maybe 1000) feet with the right equipment.

I assume the police have been contacted.

 

[AJ_K]

Fineshot - Thanks for the reply. Yes, the cell phone has been looked into. After his last phone call, there is no further trace of it contacting a cell tower. I was in the area on Wednesday and I have the same provider as he has; the reception is horrible. Making a call is difficult and he easily could have been in a dead spot after pulling out of the driveway.

Let's say his vehicle was only hidden in the brush about 20 feet off the highway. Do you think it could not be detected from the road?

 

[AJ_K]

NJH - I appreciate the response. Yeah, a missing persons report was filed 24 hours after the disappearance. We've had helicopters, airplanes, and search teams on the ground. The area is so overgrown it would be easy for a car to disappear off the road. Explain to me more about the ping - is that something different than using an RF detector?

 

[fineshot1]

Let's say his vehicle was only hidden in the brush about 20 feet off the highway. Do you think it could not be detected from the road?

I would have to agree with NJH that with the right equipment it may be possible to ping that transponder but the distance would be very limited - perhaps 100 or 200 feet at most as these devices emit extremely low power and are only designed to be detected at very close range. I hope this helps & Good luck & keep us posted......

 

[AJ_K]

Thanks fineshot1, even 100 feet is far better than I was anticipating. I was planning on driving the area in a car. I could at least check all the roads that are close. Please let me know if you guys have any idea what kind of equipment I would need to pull off something like this. I have a transponder similar to the one that his vehicle will have so if I get the equipment to do the ping, I could test with that.

 

[N_Jay]

NJH - I appreciate the response. Yeah, a missing persons report was filed 24 hours after the disappearance. We've had helicopters, airplanes, and search teams on the ground. The area is so overgrown it would be easy for a car to disappear off the road. Explain to me more about the ping - is that something different than using an RF detector?

You would need the equivalent of the equipment used by the "open road tolling" collection systems.
You send out a ping, and the transponder replies with its ID,

 

[AJ_K]

Great, thanks NJH. If anyone has further info please let me know. I have sent an email to the Oklahoma Turnpike Authority inquiring about this topic. I'll let you know what they say.

 

[SCPD]

Great, thanks NJH. If anyone has further info please let me know. I have sent an email to the Oklahoma Turnpike Authority inquiring about this topic. I'll let you know what they say.

\\
being an emergency why not pick up the phone, instead wasting time on line???

 

[N_Jay]

\\
being an emergency why not pick up the phone, instead wasting time on line???

While at it, call the company that did the system.

It would be a PR win for them to save a life instead of just taking cash.

 

[chrismol1]

what if a heli was 100-200 feet off the ground with one of those detectors that it could ping and get a response?

 

[N_Jay]

what if a heli was 100-200 feet off the ground with one of those detectors that it could ping and get a response?

That's is what I would do.

Build a small package connected to relatively high gain directional antennas.

Fly passes over scanning for the transponder.

Considering how much $$ these companies are getting from each state they could build the search unit to loan to any state with a bonified search. It would be great PR.

 

[N_Jay]

http://www.transcore.com/index.html

 

[kb2vxa]

I hate to be the one to give you a reality check BUT if the technology were in place would it not be used? Here you're talking about research and development from the ground up, etc. etc. which usually takes years. Toss that idea out the window but let's say there were such a thing beyond the idea stage, do you realize the huge number of square miles to be searched? The way I read it the guy could be anywhere from here to Kalamazoo so unless you have a very specific search area pinned down you'll just have to wait for something to turn up. Now ask yourself why you're looking for a vehicle when it's the man that's lost, you're barking up the wrong tree when it's the investigators who know what to do.

Relax and let them do their job, no point freaking out when it's out of your hands so do the only thing you can do, pray.

 

[N_Jay]

I hate to be the one to give you a reality check BUT if the technology were in place would it not be used? Here you're talking about research and development from the ground up, etc. etc. which usually takes years. Toss that idea out the window but let's say there were such a thing beyond the idea stage, do you realize the huge number of square miles to be searched? The way I read it the guy could be anywhere from here to Kalamazoo so unless you have a very specific search area pinned down you'll just have to wait for something to turn up. Now ask yourself why you're looking for a vehicle when it's the man that's lost, you're barking up the wrong tree when it's the investigators who know what to do.

Relax and let them do their job, no point freaking out when it's out of your hands so do the only thing you can do, pray.

Yep, would take a little configuration and packaging work.
Why do you think it is "ground up" research and development?

No real technology beyond antenna gains and link budgets.

It would take only the decision to do it.

Yes, that decision is a 1000 to one shot.

Yep, the likely search would be with FLIR at night.

 

[AJ_K]

Hi guys,

I did get a hold of the Oklahoma Turnpike Authority (OTA) and they were pretty helpful. They did not have any kind of mobile device that could do something like this. They only have the normal equipment that they use on the turnpike. They were concerned that the transponder is very low-voltage and wouldn't give me much of a range. Apparently, if you place a transponder in a car's glove box, that can be enough interference to not make a connection. They called Transcore for me, who makes the product, and their first response was that they did not have any device like this. The gal helping me at OTA called them back a second time and got a hold of a couple guys who were willing to talk to me. They were both software engineers so they couldn't answer my hardware questions but I got the name and number of their Operations Manager who I'm trying to get a hold of currently.

It has been eight days now since this gentleman has gone missing. He's 65 and diabetic. I won't extrapolate on the odds of him being alive but at this point I don't like them. That doesn't mean we won't keep trying. Thank you all for your help and I'll update you again later.

 

[AJ_K]

Hi Kb2vxa,

If the technology were available I'd hate to be the guy who didn't ask for it. And yes, I realize the vast number of square miles to be searched. I've driven them. And I'm looking for the vehicle because it will point me to the whereabouts of the man - who very well may still be inside the vehicle. The odds aren't in my favor of finding him but I'm really not too concerned with that.

 

[SAR923]

The best hope you have, or possibly had, was to call his cellphone once an hour. Even if didn't answer but had voice mail, the provider would still be able to give you the nearest tower that was able to transmit to the phone. This has a much higher probability of success than trying to ping a transponder device that may not even have a line of sight of more than 30 feet. I'm surprised this hasn't been tried since this was common technique we used when we had missing persons in the same circumstances. If this hasn't already been done, I suggest calling whoever is the incident commander of the search and asking them to start trying this immediately since the cellphone battery may be very close to dead. If the cell phone battery is dead, the next thing to do is plot all his probable routes of travel and then send ground teams to look for signs of a car leaving the road at places like sharp turns or bridges. If the vehicle was easily visible, it would have been seen by now. You only hope is to find evidence of where he went off the road and hope that leads you to his car. Good luck and I hope you at last find him, even if the worst has already happened.

 

[AJ_K]

Hi Sar2401,

Thank you for the suggestions. The idea you suggest with the cell phone was tried very soon after he disappeared and there is no further evidence that his cell phone contacted the tower after his last phone call. We did plot all of his probable routes and those areas have been searched pretty thoroughly. My idea with the transponder is a stretch. Unfortunately, stretches are all we have to go on at this point.