Tunnel Radio: How Signals Reach Drivers Underground? RW rip...

[Kage]

Seems it may be more complicated than a simple transmitter rebroadcasting outside programming to a leaky coax...

Found this patent. Since there would be emergency equipment needed to alert drivers that disrupt usual programming
I can see how it has a high cost of instillation. The need to have repeaters along the length of a tunnel and the end of
tunnel transmitting equipment.

https://patents.google.com/patent/US20070182585

As for transmitting various programming across the AM/FM broadcast band I'd imagine that tunnel radio box is some
sort of distribution transformer for the leaky coax.
Would be interesting to find out exactly how it's setup but I can't find much more information online about it.

[tybee]

From where did you get the patent number? .. I dont see it in the description nor pictures. Maybe you contacted him and asked??,
 I had contacted him yesterday and asked what  made him call it a "Wireless transmitter", but havent heard back yet.

I notice some of his auctions appear to have additional parts and accessories to this system.

I wonder what tunnel it had come from?
pl

[Kage]

From where did you get the patent number? .. I dont see it in the description nor pictures. Maybe you contacted him and asked??,
 I had contacted him yesterday and asked what  made him call it a "Wireless transmitter", but havent heard back yet.

I notice some of his auctions appear to have additional parts and accessories to this system.

I wonder what tunnel it had come from?
pl

It's a random one I found using a search engine to find any patents similar to the topic. No idea if it's the same thing but
reads similar in the description of it.

[NJQA]

Check this out, what a coincidence, wasn't even looking and just happened to see it..

TUNNEL RADIO MODEL TR-PS-28A WIRLESS RADIO, VAC AND BATTERY OPERATED, NO MIC
https://www.ebay.com/itm/224330410702
$135.96
What strikes me is that he calls it "wireless", not sure where he got that from

There plenty more pictures but neither
them nor the description tells me nothing other than the battery works and I found no other info on it elsewhere. Any idea exactly what this is?:

This looks to be just a power supply and a battery.  I imagine the transmitter was in a separate box….which is where the left hand cable  went.

[ThaDood]

Well, as long as we're kickin' this subject around, Boomer came across this.   https://www.radioworld.com/columns-and-views/readers-forum/letter-below-ground-antenna-powered-lax-tis

[tybee]

Well, as long as we're kickin' this subject around, Boomer came across this.   https://www.radioworld.com/columns-and-views/readers-forum/letter-below-ground-antenna-powered-lax-tis

Lol.. Yes he did, it's his post that started this thread.