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[Kerry Townson]

We have been doing a drive-thru Living Nativity for a number of years. Ours is laid out in a large half-loop that runs through our parking lot.

Most recently we have used audio CDs handed out at the welcome station for the narration. They are timed so that the cars can move from scene to scene, stop and hear the narration, then move to the next station.

Problems with this include drivers not following the directions and the actors not being able to hear the narration to time their actions to the story. We once tried individual CD players at each scene, but in cold or rainy weather the car occupants don't want to roll down the windows. We have to leave extra time between scenes to insure the car has made it to the next scene, which leads to a backup at our busiest times.

I have been looking into mp3 player/low power FM transmitters that would be installed at each of the six scenes and be triggered by an actor as a car pulls up. We believe this would improve our traffic flow and we could have a receiver hidden in the scene so the actors could hear the narration as the car does.

We haven't tried this out yet--I foresee crosstalk problems with multiple transmitters on the same frequency, but most of these units advertise a 15' range, and our scenes are about 25' apart. Has anyone tried anything like this or have another solution? 

I'm looking at something like this:

http://www.amazon.com/Soundfly-Player-Transmitter-Stick-Players/dp/B0018P7WZ2/ref=sr_1_2?s=electronics&ie=UTF8&qid=1357161481&sr=1-2&keywords=mp3+fm+transmitter

Naturally we don't have much of a budget for this, but these are cheap enough to buy several extras for redundancy. We'd also have to build some kind of enclosure to keep the elements at bay, and maybe incorporate some shielding to hold down the crosstalk.

Comments would be appreciated.

[Ron Balsom]

Greetings Kerry, are you addressing just one vehicle at a time while their parked at a specified position?? Or would you expect more than one vehicle parked in a 'group' ?? Would having each location with it's own frequency as .1  .2  .3  .4  .5  .6  to eliminate crosstalk.  I'm assuming your using a fm "boom-box" type thingy for a monitor. Naturally you'll need 6 ea. transmitters.  Blessings,  Ron Balsom,  Casper, Wyoming.

We have been doing a drive-thru Living Nativity for a number of years. Ours is laid out in a large half-loop that runs through our parking lot.

Most recently we have used audio CDs handed out at the welcome station for the narration. They are timed so that the cars can move from scene to scene, stop and hear the narration, then move to the next station.

Problems with this include drivers not following the directions and the actors not being able to hear the narration to time their actions to the story. We once tried individual CD players at each scene, but in cold or rainy weather the car occupants don't want to roll down the windows. We have to leave extra time between scenes to insure the car has made it to the next scene, which leads to a backup at our busiest times.

I have been looking into mp3 player/low power FM transmitters that would be installed at each of the six scenes and be triggered by an actor as a car pulls up. We believe this would improve our traffic flow and we could have a receiver hidden in the scene so the actors could hear the narration as the car does.

We haven't tried this out yet--I foresee crosstalk problems with multiple transmitters on the same frequency, but most of these units advertise a 15' range, and our scenes are about 25' apart. Has anyone tried anything like this or have another solution? 

I'm looking at something like this:

http://www.amazon.com/Soundfly-Player-Transmitter-Stick-Players/dp/B0018P7WZ2/ref=sr_1_2?s=electronics&ie=UTF8&qid=1357161481&sr=1-2&keywords=mp3+fm+transmitter

Naturally we don't have much of a budget for this, but these are cheap enough to buy several extras for redundancy. We'd also have to build some kind of enclosure to keep the elements at bay, and maybe incorporate some shielding to hold down the crosstalk.

Comments would be appreciated.

[dick rees]

Kerry.....

It will cost a bit.  Take a look at this Wiki:

http://en.wikipedia.org/wiki/FM_transmitter_%28personal_device%29

You could use 6 fractional wattage devices for your 6 stations.  It would require retuning the car radio at each station which could be addressed ahead of time by having the drivers program their FM presets on one of their FM programs (most cars have 2 FM programs available).

A quick Google search gives a price of less than $100/transmitter.

If it works to have them pre-program their FM select buttons, this could work.

 

[Kerry Townson]

Thanks for the replies. 

The cars pass by the scenes single file. The director of the pageant now informs me there are actually nine scenes, though two of them may not require any narration.

I really don't want to use different frequencies, even though I understand that would eliminate most of the crosstalk problems. Asking people to retune their radios is asking for trouble from the technically challenged, plus it distracts from the message.

I used to have a little Radio Shack transmitter that would work nicely within 10 feet of a radio and just disappear when farther away. That's what I'm hoping for, that we can "aim" the beam with parabolic reflectors and that the FM car radios will latch onto the strongest signal presented. I think we will experiment with a few of these to see what real world results are. It could be a big, fuzzy mess...that's why I was looking for anyone with some experience in this area. Or a better idea!

[dick rees]

Thanks for the replies. 

The cars pass by the scenes single file. The director of the pageant now informs me there are actually nine scenes, though two of them may not require any narration.

I really don't want to use different frequencies, even though I understand that would eliminate most of the crosstalk problems. Asking people to retune their radios is asking for trouble from the technically challenged, plus it distracts from the message.

I used to have a little Radio Shack transmitter that would work nicely within 10 feet of a radio and just disappear when farther away. That's what I'm hoping for, that we can "aim" the beam with parabolic reflectors and that the FM car radios will latch onto the strongest signal presented. I think we will experiment with a few of these to see what real world results are. It could be a big, fuzzy mess...that's why I was looking for anyone with some experience in this area. Or a better idea!

We have used low-power FM to get signal to campsite areas at rural festivals, but that's just one program.  Your multiple programs bring some problems.  My  best guess is that with the extremely close areas requiring separation, you'll be able to have some success.....but also some failures.  There will always be someone who, for whatever reason, will not be able to pick up the signal.  Additionally, there will be instances of overlap.  Whatever you do, folks will still have to tune in to a designated frequency.

If you want it to work for everyone with minimal or no effort on their part, it will require a budget to accomplish the task.  There will be a way, but you'll have to pay.

[Brad Weber]

I used to have a little Radio Shack transmitter that would work nicely within 10 feet of a radio and just disappear when farther away. That's what I'm hoping for, that we can "aim" the beam with parabolic reflectors and that the FM car radios will latch onto the strongest signal presented. I think we will experiment with a few of these to see what real world results are. It could be a big, fuzzy mess...that's why I was looking for anyone with some experience in this area. Or a better idea!

You generally have to use the transmitters as they come, including the supplied antennas, as that is how the units are approved and any modifications can open up a Pandora's Box in terms of type approval, licensing, fines, etc.
 
The one transmitter may have worked out to 10' and then dropped off but that may not be what happens for each transmitter if you have six or seven of them operating in fairly close proximity.  And even if the transmitters were directional, the receivers are not and since all the carriers would be the same frequency you would seem to perhaps be creating a situation similar to very strong multipath.  I'm sure there are others that can offer a much more authoritative opinion on that.

[Jonathan Johnson]

It's been a long time since I've been there, but Mammoth Cave in Kentucky (or was it Carlsbad in New Mexico? I don't remember exactly) uses an induction loop system. Each cave visitor is issued a personal receiver, and as they pass through different areas along the cave tour path, they leave and enter different induction loops and a different narration of what they're seeing is heard.

The system is essentially identical to the "hard of hearing" loop systems that couple with the telecoil pickup in hearing aids. Instead of a hearing aid, you can have a handheld unit that couples with the induction loop.

I wonder if something like that would work for your situation -- you would set up a loop for each station. You'd hand a receiver to each car, then as they go from station to station they'd get the narration for that station, without having to tune the radio.

Unfortunately, this might be out of your budget, since you'd probably be paying between $1000 and $2000 for each station.

[dick rees]

It's been a long time since I've been there, but Mammoth Cave in Kentucky (or was it Carlsbad in New Mexico? I don't remember exactly) uses an induction loop system. Each cave visitor is issued a personal receiver, and as they pass through different areas along the cave tour path, they leave and enter different induction loops and a different narration of what they're seeing is heard.

The system is essentially identical to the "hard of hearing" loop systems that couple with the telecoil pickup in hearing aids. Instead of a hearing aid, you can have a handheld unit that couples with the induction loop.

I wonder if something like that would work for your situation -- you would set up a loop for each station. You'd hand a receiver to each car, then as they go from station to station they'd get the narration for that station, without having to tune the radio.

Unfortunately, this might be out of your budget, since you'd probably be paying between $1000 and $2000 for each station.

Not to mention that a single receiver designed to power a set of headphones is not going to provide sound for the entire car...........

[Brad Weber]

It's been a long time since I've been there, but Mammoth Cave in Kentucky (or was it Carlsbad in New Mexico? I don't remember exactly) uses an induction loop system. Each cave visitor is issued a personal receiver, and as they pass through different areas along the cave tour path, they leave and enter different induction loops and a different narration of what they're seeing is heard.

That obviously works but I'm guessing it requires some physical separation between transmitters and their coverage areas.  Classroom buildings with ALS in each room are an example of where the multiple systems in close adjacency can be problematic with single channel RF or IL systems and thus either multi-channel RF or IR systems seem much more common.

[brian maddox]

This looks like one of those situations where yiu just need to try it and see.  The units are cheap enough that yiu could buy two or three and set them up in the parking lot and do a test run....