SCSO Emergency Traffic Channel Marker

[RFI-EMI-GUY]

Wow in the past week the SCSO has been using the Emergency Traffic Channel Marker a lot. It sure is annoying and is at 100% modulation. I don't see how field units can put up with this. I have to turn volume waaay down.

 

[Bote]

Audio level setting is a dead art.

 

[RFI-EMI-GUY]

Audio level setting is a dead art.

It sure is. It seems the industry has no clue on how to balance digital audio on a P25 system. The IT guys must figure more is better. At least in the analog days, some tech would finally correct it.

 

[Bote]

I've been meaning to ask a contact at Big-M about that. I recall the sweet, sweet audio BITD when I first started monitoring Type II trunked systems on a conventional scanner and you could understand what they were saying from a whisper to a scream. Maybe it was the famed MICOR blue chip processing transmit audio?

Nowadays I can measure a 20 (or more) dB swing between the soft mumblers and the screamers on peaks and the relative sound power level is drastically different between them. Maybe real radios have something resembling AGC on the output, but the screamers still overdrive the A-D converter so the radio transmits splatter*. It's a real shame.

* Except on the APX, those things will accept pretty much any input level and handle it beautifully.

 

[RFI-EMI-GUY]

I've been meaning to ask a contact at Big-M about that. I recall the sweet, sweet audio BITD when I first started monitoring Type II trunked systems on a conventional scanner and you could understand what they were saying from a whisper to a scream. Maybe it was the famed MICOR blue chip processing transmit audio?

Nowadays I can measure a 20 (or more) dB swing between the soft mumblers and the screamers on peaks and the relative sound power level is drastically different between them. Maybe real radios have something resembling AGC on the output, but the screamers still overdrive the A-D converter so the radio transmits splatter*. It's a real shame.

* Except on the APX, those things will accept pretty much any input level and handle it beautifully.

Yeah, same experience here. The dispatch audio is all over the place and we have one dispatcher, female who talks a mile a minute and the vocoder seems to have trouble keeping up. Then the mumblers. Not real impressed with P25 audio.

I worked at Motorola 1976 to 1994, the sweet spot for technology in my opinion.

 

[N4DES]

PBSO (Palm Beach County) had the channel marker way on its legacy VHF system before it was even envisioned as part of a trunking infrastructure. It made its nationwide debut on COPS in the 90's and was set at 40% of peak modulation. The deputies loved what the Field Engineering team rolled out which was nothing more than a CWID board wired to the back of each voter. The dispatcher activated both it and a light over the console simultaneously to advise the Floor Supervisor that the channel was in emergency traffic. It unfortunately went away when they moved to the SmartZone 813A system and then returned with the P25 598 system.

 

[RFI-EMI-GUY]

PBSO (Palm Beach County) had the channel marker way on its legacy VHF system before it was even envisioned as part of a trunking infrastructure. It made its nationwide debut on COPS in the 90's and was set at 40% of peak modulation. The deputies loved what the Field Engineering team rolled out which was nothing more than a CWID board wired to the back of each voter. The dispatcher activated both it and a light over the console simultaneously to advise the Floor Supervisor that the channel was in emergency traffic. It unfortunately went away when they moved to the SmartZone 813A system and then returned with the P25 598 system.

Did they set the tone at 40% on the P25 system?

 

[N4DES]

Did they set the tone at 40% on the P25 system?

Motorola advised that the level isn't adjustable, but when it is used doesn't seem to be the same as the users.
Audio across the ISSI from West Palm P25 is/was more of an issue. Before I retired the City was working on reducing the mic gain.

 

[RFI-EMI-GUY]

Motorola advised that the level isn't adjustable, but when it is used doesn't seem to be the same as the users.
Audio across the ISSI from West Palm P25 is/was more of an issue. Before I retired the City was working on reducing the mic gain.

Yeah, in Seminole county it blasts my BCD536HP and wakes the entire house. I have to turn it way down and then subscribers and dispatch are hard to hear. Not a great feature. If someone has an earpiece they would be deafened. The subscriber and dispatch levels are all over the place. Sometimes crystal clear, often muffled, weak then shouting. I am constantly "riding the gain".

 

[Bote]

If only Motorola had the engineering brainpower to figure out a way to adjust audio levels, but it remains a mystery!

 

[902]

I worked at Motorola 1976 to 1994, the sweet spot for technology in my opinion.

The end timeframe was about the time the MESMRs were turned off and the licenses (frequencies) sold to Nextel. It was the beginning of the end for LMR outside of public safety use. The 70s and 80s were a time of innovation and development.

 

[radioman2008]

The end timeframe was about the time the MESMRs were turned off and the licenses (frequencies) sold to Nextel. It was the beginning of the end for LMR outside of public safety use. The 70s and 80s were a time of innovation and development.

I jumped on the local system in 1994, Motorola owned it until 1997. when nextel took it over, the billing was all screwed up. i had my radios programmed for max options, like many systems, full 3 TG on fleet, phone service, private call, but just had most turned off. once nextel took over, all the systems and features became enabled, and billed as such, then it was hell trying to get them to turn off all the extras. the local system was finally shut down in 1999. i noticed the system was increasing in activity until a peak around 1996, they had somany users they assigned my TG 3 to another business. it was cool to trunk with them using my existing radio.

interesting thing about call alert, i could call alert any radio on the system, so being the punk young guy i was, when i was bored, i would type in 6 digit ids and see which ones responded back with a page confirmation. lol so heres a useless tidbit. i had numerous radios programmed by motorola but turned off service, they still recieved but would not access the system. so......they did not require service to page. id hand out one to a friend and say page this number, once they did, my active radio would beep, i would key the system and they would jump on my carrier for free. had plenty of ragchew conversations like that. lol

 

[902]

I jumped on the local system in 1994, Motorola owned it until 1997. when nextel took it over, the billing was all screwed up.

I leased a talkgroup on the old Empire State Building's Smartnet system and had three STX and Maxtracs on it, just for various business ventures I had at the time. Originally, I had a tone on the Alpine 800 community repeater. Empire worked well until the system was turned off and most other uses moved to 900 MHz. That lasted until 9/11, when many of the 900 SMRs in the region came down with the World Trade Center. Most of the systems were sold with multi-site scan, between the WTC, Alpine, and the Claridge House in Verona, NJ. That was necessary, as none of the systems alone had the coverage the systems they replaced had.