A number of tunnels are “wired” for broadband radio reception. A bit of years ago when they were building the I-90 stretch between Bellevue and Seattle there are two major “tunnels” on each side of the I-90 floating bridge (across Lake Washington). The tunnel on Mercer Island is actually not a tunnel but a covered section of the freeway but the tunnel on the west end is through the hill (known as the Mount Baker tunnel but not because it is under Mount Baker but because it is under the Mount Baker neighborhood of Seattle).
So, a news article at the time described how the technology was employed to provide radio reception for AM, FM, and also cellular communication. I don’t remember reading about Sirius/XM radio though. I do know that my HF mobile operations come to a halt through those tunnels. As signals drop off after a 100 feet or so from the opening and don’t come back until the other side. Unfortunately, I can’t remember anything of the details of how this was done but I suspect wide-band amplifiers and wires and top-side wide-band antennas. 73, phil, K7PEH > On Apr 14, 2017, at 8:47 PM, Fred Jensen <k6...@foothill.net> wrote: > > Semi-related curiosity regarding shielding. My wife's car has Sirius/XM > radio. It usually loses contact with the satellite driving under Interstate > bridges and the like. Likewise in the garage. OTOH, at our previous home > there was a tunnel through a small hill, perhaps 1/4 mi long. The XM worked > fine through it. There are a pair of tunnels at Cave Rock next to Lake Tahoe > through a granite mountain. XM works fine through them too. Anyone know why? > > 73, > > Fred ("Skip") K6DGW > Sparks NV USA > Washoe County DM09dn > > On 4/14/2017 2:50 PM, Phil Kane wrote: >> On 4/14/2017 1:13 PM, KENT TRIMBLE wrote: >> >>> The assumption has always been that the driver and passengers are riding >>> inside a Faraday Cage and therefore are safe from RF radiated by an HF >>> antenna, regardless of where located and regardless of power level. >> When I take my 2011 Ford Focus through the car wash, I put the mag-mount >> VHF antenna inside the car but it is still connected to the radio. I >> have no problem picking up the usual 2- and 3/4- meter repeaters that >> way. So much for the "Faraday Cage". :) >> >> 73 de K2ASP - Phil Kane >> Elecraft K2/100 s/n 5402 >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to phys...@mac.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com