Anyone know any details on the highway advisory radio systems, specifically for the state of California? I'm specifically looking for the transmitter power strengths, or, more specifically, the lack-of-power strengths. Also, any idea why they still use AM and not simulcast on FM?
The FCC has a page about Highway Advisory Radio - HAR (a.k.a. Travelers' Information Stations - TIS) here:
https://www.fcc.gov/media/radio/travelers-information-stations-search
You can also use this page to find stations in a specific state or within a range of frequencies. Each separate station has a detailed info page listing its total radiated power, frequency, transmitter location, transmitter height, call sign (like WQQG691), licensing agency, etc.
For AM broadcast, HAR stations are limited to a radiated power of 10 watts, a tower height of 15 meters, and a coverage radius of 3 km.
States and municipalities may also broadcast on FM through the FCCs Low Power FM (LPFM) program, and you will find some FM travel and weather stations in places. If I had to guess as to why AM is by far the more popular band, it may be due to the fact that FM requires a clear line of sight between the transmitter and the motorist receiving the broadcast, requiring that the tower be much higher (the FCC allows 30 m instead of 10 m for AM transmitters), particularly in hilly terrain where FM may not work well at all.
I was getting one of these TIS stations while at the Ballpark At Harbor Yards in Bridgeport, CT, on the evening of August 31, 2016. Seeing as it was after sunset, the transmitter had to be awfully close by. A piece of I-95 goes by near the left field foul pole. :banghead:
It was in the area under the lit-up whitish rectangle:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F7Ed3OAF.jpg&hash=d34fe5aac2d89eaefa954568dc55136770569ccc)
Good to know!
One fun fact about NY's advisory radio: Everyone cheered when I-190 became a free road through Buffalo and the toll plazas were removed.
However, suddenly NYSDOT and NYSTA noticed that the advisory radio's reception became terrible. Turns out the engineers forgot that the toll plazas were being used as ground plates for the transmissions. Whoops.
(heard the story a few years ago in Region 5)
The audio on every one I've heard on the NY Thruway is so overdriven it's barely intelligible.
Quote from: KEVIN_224 on September 04, 2016, 11:42:51 PM
I was getting one of these TIS stations while at the Ballpark At Harbor Yards in Bridgeport, CT, on the evening of August 31, 2016. Seeing as it was after sunset, the transmitter had to be awfully close by. A piece of I-95 goes by near the left field foul pole.
IIRC, the HAR for I-95 in that area comes out of the state police barracks which is on surface streets in between the I-95/CT 8-25 interchange, which isn't too far away at all from the ballpark.
Quote from: KEVIN_224 on September 04, 2016, 11:42:51 PM
I was getting one of these TIS stations while at the Ballpark At Harbor Yards in Bridgeport, CT, on the evening of August 31, 2016. Seeing as it was after sunset, the transmitter had to be awfully close by. A piece of I-95 goes by near the left field foul pole. :banghead:
It was in the area under the lit-up whitish rectangle:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F7Ed3OAF.jpg&hash=d34fe5aac2d89eaefa954568dc55136770569ccc)
Another HAR transmitter is at the Exit 9 NB exit in Stamford it sits kinda at the middle of the field I think one is near Fairfield but I never could find the data on where it's located.
When they installed a HAR on I-295 in NJ, the transmitter was located at the 295/38 Interchange (Exit 40). However, the signs were located near Exit 31 NB, and near Exit 47 going SB...which is well beyond that 2 or so mile limit you mentioned. Anytime I tried listening to it, it had nothing on but static. I don't think I ever saw the lights attached to the signs light up. One sign got destroyed in a vehicle accident; another was supposed to be moved to another location during construction. Neither sign was replaced. I seriously doubt the system ever got used. The antenna and pole used are still located within the 38W to 295S cloverleaf ramp: https://goo.gl/maps/974XsifFuZ72
One guy who I believe is a member here (Rob) used to work for the NJ Turnpike Authority, and I think I recalled him saying at one point he wanted to learn how to use their HAR system (which they actually used), which operated more/less every two or three interchanges or so. However, I don't think he ever was trained on the system, and as part of the system-wide VMS upgrades, they got rid of the system all together.