robert15987
Member
What is p/zip ( probably spelled it wrong ) can’t find any information on it, I know law enforcement use for dispatcher to other dispatcher been out for a while
South Texas
- Thread starter robert15987
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PSAP? A public-safety answering point (PSAP), sometimes called a public-safety access point, is a type of call center where the public's telephone calls for first responders (such as police, fire department, or emergency medical services/ambulance) are received and handled. I think this may be what you're talking about.
gus nailed it, just to add a bit more information there are a few different kinds of PSAPs, although you'll never hear them referred to as "primary" or "secondary" on the radio, just some info to have.
When someone dials 911 it'll go to a primary PSAP, as far as I remember it's based off cell towers, I don't believe it routes based on the callers GPS, but that may have changed since I last took my TCOLE class..
Then there are secondary PSAP's. Say someone is driving down the Dallas North Tollway in Dallas, Texas and has a car accident. They call 911 and based off the nearest cell tower it'll route them to the primary PSAP, in this case being Dallas 911. The call taker will ask questions and determines the incident has occurred in NTTA jurisdiction, the Dallas 911 call taker then transfers the call to the secondary PSAP, in this case NTTA/DPS Tollway and allows them to handle the response to the call.
From there the secondary PSAP is responsible for the outcome of the response to the call, and the primary PSAP will disconnect.
You may ask, why isn't NTTA a primary PSAP? Wouldn't that make more sense for them take all the calls within their jurisdiction rather than having the 911 caller have to go through numerous call takers to reach the right person to get help from? - The reason this isn't the case is because NTTA has a lot of toll road, their tollways go through dozens of cities and quite a few counties, if 911 calls are still based on the nearest cell tower, they'd be getting a lot of calls from not only incidents occurring on the tollway but also calls from off the tollway and would have to transfer back to the city it's occurring in. Pretty big headache so it makes more sense to keep it secondary.
Same goes with smaller cities, like Van Alstyne, Texas has their own fully staffed 24/7, 911 center but they're only a secondary PSAP, you could be standing right outside the police station, call 911, and it'll go to the county sheriff's office where then they'll transfer you to Van Alstyne. Not every city is like this of course, but I believe it's because of something to do with the size or population of the city, not necessarily the staffing. But I don't know the specifics on that.
There are also backup PSAP's but pretty much every agency is a backup PSAP in some regard, like if Plano has an overload of 911 calls, after x amount of rings it'll automatically go to their backup PSAP, which is typically the nearest city but could also be the county. So it may go to Frisco, or Prosper, or Allen, or Collin County, etc. There is also a physical switch the center can press where it will reroute all the calls to the preset backup PSAP, so if Plano had to evacuate their 911 call center, the assigned backup PSAP could take care of Plano's 911 calls until they get to their backup call center or are ready to return to their main call center.
Just some extra info you may find interesting.
When someone dials 911 it'll go to a primary PSAP, as far as I remember it's based off cell towers, I don't believe it routes based on the callers GPS, but that may have changed since I last took my TCOLE class..
Then there are secondary PSAP's. Say someone is driving down the Dallas North Tollway in Dallas, Texas and has a car accident. They call 911 and based off the nearest cell tower it'll route them to the primary PSAP, in this case being Dallas 911. The call taker will ask questions and determines the incident has occurred in NTTA jurisdiction, the Dallas 911 call taker then transfers the call to the secondary PSAP, in this case NTTA/DPS Tollway and allows them to handle the response to the call.
From there the secondary PSAP is responsible for the outcome of the response to the call, and the primary PSAP will disconnect.
You may ask, why isn't NTTA a primary PSAP? Wouldn't that make more sense for them take all the calls within their jurisdiction rather than having the 911 caller have to go through numerous call takers to reach the right person to get help from? - The reason this isn't the case is because NTTA has a lot of toll road, their tollways go through dozens of cities and quite a few counties, if 911 calls are still based on the nearest cell tower, they'd be getting a lot of calls from not only incidents occurring on the tollway but also calls from off the tollway and would have to transfer back to the city it's occurring in. Pretty big headache so it makes more sense to keep it secondary.
Same goes with smaller cities, like Van Alstyne, Texas has their own fully staffed 24/7, 911 center but they're only a secondary PSAP, you could be standing right outside the police station, call 911, and it'll go to the county sheriff's office where then they'll transfer you to Van Alstyne. Not every city is like this of course, but I believe it's because of something to do with the size or population of the city, not necessarily the staffing. But I don't know the specifics on that.
There are also backup PSAP's but pretty much every agency is a backup PSAP in some regard, like if Plano has an overload of 911 calls, after x amount of rings it'll automatically go to their backup PSAP, which is typically the nearest city but could also be the county. So it may go to Frisco, or Prosper, or Allen, or Collin County, etc. There is also a physical switch the center can press where it will reroute all the calls to the preset backup PSAP, so if Plano had to evacuate their 911 call center, the assigned backup PSAP could take care of Plano's 911 calls until they get to their backup call center or are ready to return to their main call center.
Just some extra info you may find interesting.
Last edited:
robert15987
Member
Thank you, pick up a ch dispatch to dispatch are talking on psap, I’ll submit it with the other ones
Project25_MASTR
Millennial Graying OBT Guy
Now…excercise two primary PSAPs that are also secondary PSAPs to one another in the same county. So you can literally have the primary be a SO located in a city where the PD is dispatched by a secondary PSAP in another city in the county so even thought the call came into the primary it has to be transferred to the secondary.
We love that, wouldn't have it any other way lol..
nueces162
Member
Think he's asking about a group on the Coastal Bend system, it was on the old EDACS system too - the area dispatchers call it "PSAP" or "PSAP channel" it seems to be a wide area interop on the P25 net - you'll hear something Like "Duval SO to Kennedy SO on PSAP" - have heard departments as far as away Goliad and Bee on it - the unit ID always stays the same so I think it is probably a link to the current VHF InterCity freq, don't remember the group number offhand but I think it is in the Coastal Bend listings - if you monitor area VHF you should hear the same on InterCity base
nueces162
Member
Yup, group ID is 21051, listed as Coastal Bend Dispatch Interop but the area county dispatchers call it "PSAP" for whatever reason
That's cool that they use the intercity VHF down there, up in the DFW metroplex that was gone long ago, now most agencies use the "Law Call" or "Fire Call" talkgroups on their local systems, only issue is all of the systems have their own and some don't have access to each others...Even though NTIRN is the largest system and has the most coverage, not every agency participates even just with access to the IO/calling channels, so at that point might as well just make a phone call rather than guessing who is monitoring what channel..
Another thing is agencies will have large scale incidents or even just a pursuit and keep it on the IO calling channel rather than assigning it to a IO TAC....So now everyone not involved naturally turns the volume down because they don't need to hear a pursuit 5 cities over going away from them when they have plenty of calls they gotta worry about in their own jurisdiction, but I digress.
Thank you for sharing that!
Another thing is agencies will have large scale incidents or even just a pursuit and keep it on the IO calling channel rather than assigning it to a IO TAC....So now everyone not involved naturally turns the volume down because they don't need to hear a pursuit 5 cities over going away from them when they have plenty of calls they gotta worry about in their own jurisdiction, but I digress.
Thank you for sharing that!
robert15987
Member
Now they talk on 20003 Id it as PSAP
There this a vhf channel but it been Quiet , a I think it was 154.310 or something like that, Bishop fire have the same frequency but different tone
nueces162
Member
Lots of departments in South Texas are still on VHF and since they have gone to P25 conventional they are showing few signs of migrating to trunking - don't know what they use these days as the digital equivalent of the intercity pair of 154.950 mobile and 155.370 base from back in the day - I could really show my age by remembering when county sheriffs in Texas were on low band VHF and used what they called "180/260" or just "sheriff common" for inter-communications- the freqs were 37.180 and 37.260 hence the 180/260 reference - and back then DPS was at 45 MHz with trunk mount radios that used dynamotors to power the transmitter, at night when they keyed up their headlights would go dim because of the drain and you could almost warm a cup of coffee by putting it close to the antenna when they were doing a long transmission
That is super cool!! I had to do some research on dynamotors, I've never heard of that before.
What was the output power of those DPS 45MHz radios back then? To warm a cup of coffee, that sounds like a pretty powerful transmitter!
One of my ham radio elmers is a retired firefighter, he said back then each of the fire stations had huge base station radios with tubes in them, each station had their own callsign and a radio man would come and inspect them once a year. Now I wanna ask him about dynamotors and if he had any experience with them. That old stuff is so fascinating to me.
What was the output power of those DPS 45MHz radios back then? To warm a cup of coffee, that sounds like a pretty powerful transmitter!
One of my ham radio elmers is a retired firefighter, he said back then each of the fire stations had huge base station radios with tubes in them, each station had their own callsign and a radio man would come and inspect them once a year. Now I wanna ask him about dynamotors and if he had any experience with them. That old stuff is so fascinating to me.
nd5y
Member
DPS was on 42 MHz. The old channel plan is here.
Department of Public Safety (TX) - The RadioReference Wiki
I don't know what equipment DPS used back when they were on low band. Towards the end in the late 1970s any new radios would probably have been GE MASTR IIs but I never saw inside a of DPS car when I was a kid. I think their max power option was 110 W on low band and high band.
Some of the old tube type low band mobile radios put out 250 watts but I think most were around 50. The legal limit for most of Part 90 is 300 W. A lot of base stations were 300 W. I don't remember seeing any DPS licenses for more than that.
There is an exception for 42 MHz state police base stations to run up to 5 kW (or 15 kW ERP). Missouri (my home state) did that. Each troop HQ has a high power base station with several remote receivers and fill-in base stations for a few poor coverage areas. They have a statewide VHF/700 MHz trunked stystem now but they still keep low band for backup. Last time I saw one of their cars in the late 1980s it had a GE MASTR II with the scanning head. I think they use 110 W Midland radios now. I think Midland is the only mobile radio manufacturer left.
This web site has a lot of info on old police radio systems
nueces162
Member
Would have sworn they were at 45 MHz, I remember the techs at the shop I hung around at back then swapping crystals and re-tuning some state radios, 45.150 is what I remember but that was WAY back in the past - I "volunteered" part time work at a local radio shop back in the late 60's to early 70"s while I decided whether to make electronics or law enforcement my career choice - we got some DPS units in for work and from what I remember, and a DPS historian may correct me, most of them were running GE Progress Line with a dynamotor in the green painted case, some of them were swapping over to the "P-line" radios that had been converted to the new, for then, transistorized power supply - one of the techs told me that the Dodge units could run 120 watts or a bit more but the Fords had to be tuned to 90 because their alternators and wiring could not take the draw for higher power - I do remember several units still had the old Motorola radios that used to be referred to as "coffin box" radios, the transmitter with the dynamotor was in one case and the and the receiver in another separate case, they were usually mounted on opposite sides of the trunk and the shape of the case kind of looked like a coffin, although one of the older techs told me they were called that because if you did not pay attention to what you were doing the transmitter would put you in your coffin - as they moved to VHF high most units had both radios installed for a while, the high band was GE MASTR II with the C800 scan control head
lenk911
Member
I worked for a state policing agency during this period. Our main 42 MHZ stations had 10,000 watt amplifiers. I believe only Motorola manufactured these stations (Research Line). The supplemental stations were typically 300 watts output. They could be either GE, Motorola or RCA. High talk-out power was required to overcome vehicular noise. When noise blankers /extenders were developed most agencies slowly retired the 10K stations.
The 42 MHZ state police band was coordinated on a North American basis. The coordinator tried hard to match up states due east/west from one another, never north to south due to summer skip. In your Texas channel plan, I would guess due to FCC rules all bases transmitted on 42.900 and received on 42.84 MHZ. Mobiles could switch to TR 42.9 for car-car communications. The 42.88 MHZ was an interesting assignment. It was considered a supplementary channel and not protected to the degree of the main channels. Most agencies used these (42.88, 42.56 etc) for special events where some interference could be tolerated.
Mobiles started as 50-60 watts as Motorola and GE "turkey roasters" but in the end the Motracs and Mastr Pro's could easily boom over 100 watts. The FCC's narrow band rule of 1963 wiped out the Motorola "turkey roasters" and all but the last series of GE's. You had to be careful with the power. During a response or pursuit with the mechanical siren and warning lights operational, operating the 100 watts radio could fry the vehicle's electrical system. Especially with the dynamotor radios. There is a direct short on the battery for a few milliseconds when you start to transmit.
nd5y
Member
Back in the day I don't think any other states were on 42.90 except Texas.
I don't know how they coordinated with Canada but Missouri State Highway Patrol and Ontario Provinical Police both used 42.06 B/42.22 M. That made things interesting at times.
I don't know how they coordinated with Canada but Missouri State Highway Patrol and Ontario Provinical Police both used 42.06 B/42.22 M. That made things interesting at times.
lenk911
Member
Minnesota shared 42.82/42.66 with Wyoming and when there was a storm front in between we all became one system. Problem was we had the same car numbers. Fortunately we had different station names and slightly different accents. Many of the east/west highways are the same.
BTW: With the 1958 sunspot peak, a 5 watt TV station in Germany wiped out the 42 Mhz band for most of the summer. In Europe 42 MHZ is in TV channel 1. Caused many states to look at moving to VHF or adding tone squelch. Changing a whole statewide system takes time and money and it took Minnesota 10-years to start the process.
nd5y
Member
MO had Link base stations. I don't know if that inculded the amps.
Not related specifically to South Texas but were any observations recorded or informally discussed back then about how far out (local, not skip) those 10,000 watt low VHF signal would reach under normal conditions, minus the ignition interference? Did the DOT use 10K watt transmitters or just the police?
That kind of power must have covered multiple State Patrol Districts for receive with engines off. Too bad I presume there were no 10,000 watt VHF high band transmitters...that would have offered up an interesting side by side distance comparison for local VHF range, sort of like a comparison of the original 42-50 MHz FM broadcasting band vs. the 88-108 MHz FM band.
nd5y
Member
The multi-kW stations were only authorized for state police and only on the 42 MHz channels that were formerly available only for state police use.
I can tell you from experience back in the 80s when the noise level in cars and outdoors was probably way less, using a scanner with a mag mount antenna that was probably resonant around 40 MHz I could receive MO SHP Troop H in St. Joe up to about the IA state line on I-29 and a few miles NE of Topeka when you get up out of the river valley. I could receive Lees Summit (SE KC) most places in St. Joe. All the other high power stations were way too far away. Most of the MO SHP troops had a 335' towers with a 4-dipole array. Back then the cars had fender mount ball & spring 1/4 wave whips and GE MASTR II radios. One of the hams in St. Joe was a dispatcher and told me their cars could receive reliably out to about 60 miles. He said they had a 5 kW amp and normally ran it at about 2 kW. I think that was the original Fred Link equipment that was all replaced in the late 90s or early 2000s.
On time I was on US-69 on the south side of Overland Park, KS and heard Sprigfield MO. That was in the late summer in the afternoon. I don't know if there was enhanced conditions, sporadic E, meteor burst or if that was normal in that location.
I can tell you from experience back in the 80s when the noise level in cars and outdoors was probably way less, using a scanner with a mag mount antenna that was probably resonant around 40 MHz I could receive MO SHP Troop H in St. Joe up to about the IA state line on I-29 and a few miles NE of Topeka when you get up out of the river valley. I could receive Lees Summit (SE KC) most places in St. Joe. All the other high power stations were way too far away. Most of the MO SHP troops had a 335' towers with a 4-dipole array. Back then the cars had fender mount ball & spring 1/4 wave whips and GE MASTR II radios. One of the hams in St. Joe was a dispatcher and told me their cars could receive reliably out to about 60 miles. He said they had a 5 kW amp and normally ran it at about 2 kW. I think that was the original Fred Link equipment that was all replaced in the late 90s or early 2000s.
On time I was on US-69 on the south side of Overland Park, KS and heard Sprigfield MO. That was in the late summer in the afternoon. I don't know if there was enhanced conditions, sporadic E, meteor burst or if that was normal in that location.
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