[BC] TIS Transmitters...

[WLOYPROD WLOYPROD]

I used to try to explain to clients that they would get better audio if they did not have someone with a lisp, standing beside the highway, in a windstorm, on a bad cell connection, doing their audio recording.  Few listened.  It's like the ones that feed NOAA weather info on the systems.  No one understands it or wants to listen.

The system at LAX has always been one of the best run for audio.  There are others (Glastonbury, CT was very active), but the problem generally stems from state agencies using federal highway money to buy stuff they don't understand and then handing it off to subcontractors that understand it less and care still less...

The real FCC Part 90.242 limits are the 3kHz roll-off filter, field strength of 1mV/m @ 1.5km and the actual content being voice-only non-commercial information.  As Burt points out, you can still make it sound very good if you actually try!  GIGO applies.  The limitations have nothing to do with pirates and were implemented to make the systems distinct from commercial operations on the dial.

John

>>> On Sat, Mar 21, 2009 at  3:44 PM, in message
<200903211940.n2LJen4d014133 at mailscanner.virtbiz.com>, "Burt I. Weiner"
<biwa at att.net> wrote: 
> The LPB transmitters will easily run 125% positive peaks and that's 
> legal for the TIS/HAR service.  There is a requirement that the audio 
> bandpass be limited to 3 kHz.  On two that I maintain I'm using Orban 
> 9100B processors and Inovonics Modulation Monitors.  I've removed the 
> OpAmp Labs limiter module from the transmitters but leave the 3 kHz 
> Low Pass filter in place.  There's no reason why they can't sound as 
> good as one of Clear-Channel's AM's.
> 
> Many TIS/HAR installation will use telephone calls to feed audio to 
> the message recorder.  I remember once hearing one where it sounded 
> like they simply meant to hang up the phone, dropped it on the floor, 
> picked it back up and then hung it up.  Quite often Cal-Trans and 
> other entities will place them too close together on the same 
> frequency with horrible overlap causing severe beating and audio 
> overlapping between them.
> 
> Burt
> 
>>From: Douglas Pritchett <radiofool at gmail.com>
>>
>>Alan, most transmitters made for that service are purposely limited in
>>modulation (50%?) and freq response (3kc?). Why? So that pirates won't
>>use them to do their dastardly deeds. There is supposedly some FCC
>>rule which, of course, I can't recall.
>>
>>Regards....
>>Douglas B. Pritchett
>>radiofool at gmail.com
> 
> 
> 
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