Mass Highway Radio Question

Aaron Read
Mon Mar 30 13:35:43 EDT 2009

Joe, usually...but not always...the TIS/HAR (Traveler's Info 
System/Highway Advisory Radio) transmitters are physically mounted on 
the highway sign announcing the presence of a TIS/HAR transmitter.  Look 
for a small metal box, usually about 1.5ft square, with a 6-10ft whip 
antenna coming out of the top.  That's usually the transmitter.

Sometimes there's two boxes (a transmitter and an ATU/Antenna Tuning 
Unit) but usually it's just one.

Often the quality of the audio does indeed stink; these units are IIRC 
limited to 10 watts ERP and the antennas are, as you might imagine, 
pretty low-efficiency.  There's often a decent ground connection via the 
steel frame of the roadsign but that's only going to help so much.  Toss 
in that the audio itself is usually fed via telephone, and not a good 
telephone (sometimes it's a cellphone) and there you go - crappy audio.

For a long time there was an amusing setup on Rt.128 southbound, between 
the Rt.3 and MassPike exits (I don't remember exactly) where there was a 
new TIS roadsign and right behind it was a totally wrecked TIS roadsign 
that clearly still had a battered and beaten TIS transmitter attached to 
it.  The new sign did not appear to have a new transmitter, so I had to 
assume that the old one was still marginally functional.

I don't think Massachusetts has any, but upstate NY and parts of VT have 
LPFM licenses for TIS/HAR purposes.  Those are different kettles of fish 
entirely as the antenna and transmitter are no different than any other 
LPFM, and may or may not (probably not) be mounted on the TIS/HAR 
announcement roadsign.

Aaron Read		    |  Finger Lakes Public Radio   |  General Manager (WEOS & WHWS-LP)
Geneva, NY 14456	    | /

I am wondering where the transmitters are for the highway radio
channels? They are advertising it in Woburn along 128, but the signal
is really scratchy.


Joe Brown

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