King/Seattle DB Questions.

[AlmostHandy]

Hey everyone. Maybe I'm overthinking this. I seem to be getting confused at this DB page. At the top, it lists 15 different sites, each with a number of frequencies. Underneath that is a big list of talkgroups.

I'm having trouble figuring out which talkgroups go with which control channels.

I know that some of them are really obvious. I have the Seattle Simulcast in one bank, with all of the Seattle PD, and Seattle Fire in those Talkgroups. I have the King County, and Valcom control channels in another bank, with the KC Fire and KC Sheriff in those talkgroups. I know that the Bellevue groups go with the Eastside cities probably go with the EPSCA Simulcast.

The thing is, I'm not sure where are those listed cities are, so I'm not too sure which control channels to use with them. There's a large list labeled "Other Talkgroups". Some of them seem sort of obvious, such as the KC Courts TG's probably go with the KC Courthouse Control Channel, and the ones labeled "Valcom" or "KC" probably go with the valcom control channels.

But some of them I'm just not sure.

So, is there an easy way to figure this out, without asking you guys each one individually?

Also, I've read thread that say you can program more than one control channel in a bank (pro97), but that you have to leave a blank channel in between, but I don't quite understand.

Take the "KC Valleycom Simulcast" frequency list. It has 1 control channel in red, and 3 alternates in blue. Should I add all 4? Can I add the courthouse channels too?

So should my bank look like this?

000 851.81250 KC Valcom 1
001 000.0000
002 867.86250 KC Valcom 2
003 000.0000
004 868.42500 KC Valcom 3
005 000.0000
006 868.45000 KC Valcom 4
007 000.0000
008 851.06250 KC Courthouse 1
009 000.0000
010 867.91250 KC Courthouse 2

Thanks again. You guys are awesome.

 

[kellykeeton]

all talkgroups are on all trunk systems these days (for the most part) but you got the rest figured out.

general rule of thumb, if its a Seattle agency listen to it on the Seattle trunk system
if its a valleycom fire listen on the KC-Trunk

Just about all of the EPSCA and Valley cities are 100% broadcast on each epsca and valley trunk.

if your in north seattle or bothel use north seattle

if your wanting metro tunnels or courthouse use them...

check out the sites for EPSCA ValleyCom and the upcomming NorCom for which city is under which system, but all the control channels will handle any user in the system for the most part, even goes for snoqualmie pass which will hold users that happen to key up in range, otherwise it will drop that TGID after some time of no use to keep the air clear.


hope that helps get you in the right direction

in your example...

000 851.81250 KC Valcom 1
001 000.0000
002 867.86250 KC Valcom 2
003 000.0000
004 868.42500 KC Valcom 3
005 000.0000
006 868.45000 KC Valcom 4
007 000.0000

I would cut out the courthouse as they only broadcast courthouse and jail activity.

 

[K7SCH]

http://www.northwestradio.net/interceptnw/kcpd.htm
This link provides some help.

 

[AlmostHandy]

Awesome link. That helps with a few cities I didn't really know.

I'm still confused about a couple of the sites. Grass, sobieski, and mcdonald mt.s Education hill, apple cove and snoqualmie dodge ridge all simulcast the same things?

 

[K7SCH]

Also, I've read thread that say you can program more than one control channel in a bank (pro97), but that you have to leave a blank channel in between, but I don't quite understand.
So should my bank look like this?

000 851.81250 KC Valcom 1
001 000.0000
002 867.86250 KC Valcom 2
003 000.0000
004 868.42500 KC Valcom 3
005 000.0000
006 868.45000 KC Valcom 4
007 000.0000
008 851.06250 KC Courthouse 1
009 000.0000
010 867.91250 KC Courthouse 2

Thanks again. You guys are awesome.

I have two pro97s and I have all the control channels programed into one bank without the blank channels and seem to pick up conversations fine, does the blank channels help in any way?

 

[K7SCH]

I'm still confused about a couple of the sites. Grass, sobieski, and mcdonald mt.s Education hill, apple cove and snoqualmie dodge ridge all simulcast the same things?

http://www.radioreference.com/apps/db/?action=siteMap&sid=604&type=fcc
This site shows you a map of all the sites, so this might help a little...sorry I don't have the exact answer, but I know what you are getting at and I am waiting for someone to reply, because the people here are pretty savvy with this radio stuff

 

[AlmostHandy]

Ok, so it's a repeater network that blankets the entire area?

I would imagine that they would either repeat Eastside, KC, or Seattle simulcasts.

I'm still a little confused. So then, can I pick up eastside talkgroups with a seattle simulcast control channel?

 

[AtomicTaco]

Ok, so it's a repeater network that blankets the entire area?

I would imagine that they would either repeat Eastside, KC, or Seattle simulcasts.

I'm still a little confused. So then, can I pick up eastside talkgroups with a seattle simulcast control channel?

Correct you are on the first two! Here is a better version of that map, and this is the absolute best map available for the King County Trunked system.

As to which talkgroups appear on which systems, there really no is no "general rule of thumb." It can't really be summarized, so I'll give you a long explanation and hopefully some of it will make sense

First I'll give a quick refresher on how this trunked system is set up. Each physical site has a group of repeaters acting together. I'm sure you know by now how trunking works and that there's a dedicated control channel and voice channels are assigned as needed.

This is a SmartZone system, which means there are multiple sites connected to each other. Each "site" acts independently. Each "site" can actually be made up of multiple physical sites. For an example, site 6 is made up of a bunch of physical repeater sites. There's a tower at Station 63 in Federal Way, Station 73 in Kent, the East end of Port Orchard, and some other places. I know where they all are on the map, I just can't remember which ones are hot--I'm pretty sure Squak doesn't carry any trunked traffic. But again I stray from your question...

So we've established that there are a bunch of repeater sites, and that they're all connected (via microwaves) to each other. So when does a particular talkgroup appear on a particular control channel? Only when it's needed.

Everyone else got the general idea: the Seattle system is designed to cover the City of Seattle; King County/Valleycom is basically everything south of Seattle, and EPSCA is basically everything north of Seattle.

Now say a Tukwila PD officer turns on his radio just outside the station. He's probably going to affiliate with the King County site, as it'll probably come in the strongest for him. Maybe that day he'll be doing some surveillance work, so he switches over to another talkgroup so they don't tie up their dispatch channel. During the course of the day, they follow their suspect into Auburn. Most of Auburn has really good coverage on the King County system, but they follow their suspect further East towards Enumclaw, and the coverage from the King County site is getting spotty. But luckilly there's a site on Rattlesnake ridge, so their radios reaffilate with this site without them even knowing. Now their suspect is on the move again, and they head into Georgetown. Along the way, the singal from Rattlesnake grew weak, so they switched back to the KC/VC simulcast. But as they travelled closer to Seattle, the signal from KC/VC grew weaker, so their radios hopped onto the Seattle site.

If there were only two radios that were on this talkgroup the whole time, then you'd only hear their traffic on the sites that both of their radios were affiliated with. If they both reaffiliated with Seattle, then you'll no longer hear them on the King County site.

It's been a long day for this officer, and let's say his shift is just about over and they've determined that this suspect is of no more interest. So he switches back to Dispatch to tell them that he's going out of service for the night. He's authorized to drive the car home. He lives in Bellevue, and forgets to turn his radio off. On his way home, the signal from the Seattle simulcast grows weak, but EPSCA booms in*. During his entire drive home, he's carrying all of Tukwila's dispatch traffic on the Seattle and later EPSCA systems. He's the only Tukwila unit up there and really doesn't need to hear dispatch traffic, but he's still tying up a frequency pair by leaving his radio on. The repeater doesn't know he's off duty--it just knows his radio is affiliated with that site so it does its job.

So if it seems like the system was doing a bit of extra work when it doesn't need to--you're right. And that's why radios can be configured to have a "home" system. They can also be told that they can or can't roam onto other systems, what order they roam, and which systems they can roam onto. And yes, Seattle does send a bill to King County requesting money for airtime, and vice versa. EPSCA also bills and gets billed.


So about the sites--001, 003, and 006 are the three main sites. The rest are fill-in sites. They carry traffic as needed.

One more example that'll explain fill in sites:
Inside the Metro bus tunnel, you're blocked out from almost everything. That's why they added fill in sites inside the tunnel. I'm not entirely sure where the signal radiates from, but that's not really important for this example. There's a talkgroup that they use for all of the security officers inside the tunnel. While they're inside the tunnel, they can't reach anything but the repeaters inside the tunnel. However there's a little security hut (for lack of a better term) just outside the tunnel at Royal Brougham. The signal from the tunnel is very weak out there, but the signal from atop Columbia Tower comes in great. So the radio inside the hut affiliates with Seattle, while the others inside the tunnel affiiate with the two tunnel sites.

For the Courthouse site--it has pretty limited range, and as its name suggests, it's designed to cover the King County Courthouse. If you're interested in listening to the court security talkgroups, this might be the only site that they're on. It just depends on where the radios are and what kind of signal they're getting. But if you're just interested in hearing Seattle PD units that are working in the vicinity of the courthouse you're better off using the Seattle simulcast. There's always going to be at least one in that area unit affiliated with the Seattle simulcast, so you'd be wasting your time programming in the Courthouse site for Seattle PD.


I hope that made sense. If not, ask away. And if anyone else has corrections, correct away.



*That won't be the case all the time; EPSCA was designed with lower coverage standards than the other systems.

 

[AtomicTaco]

Wow, that was long!

One other thing--the list of system frequencies here isn't 100% accurate or complete. It changes often. I can tell you for sure that site 005 has more than one voice channel.

 

[AlmostHandy]

Wow, Far out! That totally explains a lot of things. I keep an eye on that page of seattle/king frequencies, and check it often.

Ok, and one last question.

Why, oh why, do we need a blank/conventional channel between control freqs?

 

[AtomicTaco]

Wow, Far out! That totally explains a lot of things. I keep an eye on that page of seattle/king frequencies, and check it often.

Ok, and one last question.

Why, oh why, do we need a blank/conventional channel between control freqs?

If you're really curious, run trunker and you can see exactly what's going on.
As to the blank channel thing, I've only seen threads about that concerning the Pro-96. I couldn't tell you why on the 97. Browsing the Radio Shack forum here might help.

 

[lowboy654]

Correct you are on the first two! Here is a better version of that map, and this is the absolute best map available for the King County Trunked system.

As to which talkgroups appear on which systems, there really no is no "general rule of thumb." It can't really be summarized, so I'll give you a long explanation and hopefully some of it will make sense

First I'll give a quick refresher on how this trunked system is set up. Each physical site has a group of repeaters acting together. I'm sure you know by now how trunking works and that there's a dedicated control channel and voice channels are assigned as needed.

This is a SmartZone system, which means there are multiple sites connected to each other. Each "site" acts independently. Each "site" can actually be made up of multiple physical sites. For an example, site 6 is made up of a bunch of physical repeater sites. There's a tower at Station 63 in Federal Way, Station 73 in Kent, the East end of Port Orchard, and some other places. I know where they all are on the map, I just can't remember which ones are hot--I'm pretty sure Squak doesn't carry any trunked traffic. But again I stray from your question...

So we've established that there are a bunch of repeater sites, and that they're all connected (via microwaves) to each other. So when does a particular talkgroup appear on a particular control channel? Only when it's needed.

Everyone else got the general idea: the Seattle system is designed to cover the City of Seattle; King County/Valleycom is basically everything south of Seattle, and EPSCA is basically everything north of Seattle.

Now say a Tukwila PD officer turns on his radio just outside the station. He's probably going to affiliate with the King County site, as it'll probably come in the strongest for him. Maybe that day he'll be doing some surveillance work, so he switches over to another talkgroup so they don't tie up their dispatch channel. During the course of the day, they follow their suspect into Auburn. Most of Auburn has really good coverage on the King County system, but they follow their suspect further East towards Enumclaw, and the coverage from the King County site is getting spotty. But luckilly there's a site on Rattlesnake ridge, so their radios reaffilate with this site without them even knowing. Now their suspect is on the move again, and they head into Georgetown. Along the way, the singal from Rattlesnake grew weak, so they switched back to the KC/VC simulcast. But as they travelled closer to Seattle, the signal from KC/VC grew weaker, so their radios hopped onto the Seattle site.

If there were only two radios that were on this talkgroup the whole time, then you'd only hear their traffic on the sites that both of their radios were affiliated with. If they both reaffiliated with Seattle, then you'll no longer hear them on the King County site.

It's been a long day for this officer, and let's say his shift is just about over and they've determined that this suspect is of no more interest. So he switches back to Dispatch to tell them that he's going out of service for the night. He's authorized to drive the car home. He lives in Bellevue, and forgets to turn his radio off. On his way home, the signal from the Seattle simulcast grows weak, but EPSCA booms in*. During his entire drive home, he's carrying all of Tukwila's dispatch traffic on the Seattle and later EPSCA systems. He's the only Tukwila unit up there and really doesn't need to hear dispatch traffic, but he's still tying up a frequency pair by leaving his radio on. The repeater doesn't know he's off duty--it just knows his radio is affiliated with that site so it does its job.

So if it seems like the system was doing a bit of extra work when it doesn't need to--you're right. And that's why radios can be configured to have a "home" system. They can also be told that they can or can't roam onto other systems, what order they roam, and which systems they can roam onto. And yes, Seattle does send a bill to King County requesting money for airtime, and vice versa. EPSCA also bills and gets billed.


So about the sites--001, 003, and 006 are the three main sites. The rest are fill-in sites. They carry traffic as needed.

One more example that'll explain fill in sites:
Inside the Metro bus tunnel, you're blocked out from almost everything. That's why they added fill in sites inside the tunnel. I'm not entirely sure where the signal radiates from, but that's not really important for this example. There's a talkgroup that they use for all of the security officers inside the tunnel. While they're inside the tunnel, they can't reach anything but the repeaters inside the tunnel. However there's a little security hut (for lack of a better term) just outside the tunnel at Royal Brougham. The signal from the tunnel is very weak out there, but the signal from atop Columbia Tower comes in great. So the radio inside the hut affiliates with Seattle, while the others inside the tunnel affiiate with the two tunnel sites.

For the Courthouse site--it has pretty limited range, and as its name suggests, it's designed to cover the King County Courthouse. If you're interested in listening to the court security talkgroups, this might be the only site that they're on. It just depends on where the radios are and what kind of signal they're getting. But if you're just interested in hearing Seattle PD units that are working in the vicinity of the courthouse you're better off using the Seattle simulcast. There's always going to be at least one in that area unit affiliated with the Seattle simulcast, so you'd be wasting your time programming in the Courthouse site for Seattle PD.


I hope that made sense. If not, ask away. And if anyone else has corrections, correct away.



*That won't be the case all the time; EPSCA was designed with lower coverage standards than the other systems.

WOW great job.

 

[AlmostHandy]

Yeah totally. I mean, I had a decent understanding of how trunking worked, but I had no idea the network worked that way. Very informative.

I am so utterly fascinated with this hobby.

I'm going to attempt to install a discriminator tap on my pro97 soon. Money is hard to come by with a one year old in the house, but I've recently inherited a guitar. I don't play much at all anymore, so I'm actively trying to sell it. I've got a nice list of parts and tools I'm going to buy as soon as it sells, and I'm going to try my hand at making some better outdoor antennas for my scanner.

I really can't get enough of this hobby.

 

[AlmostHandy]

Ok, I have a few more questions.

So, I have, in Bank1 only two channels programmed.

868.17500 and 851.41250

I have my 5 banks of TGIDs sorted and programmed with all of the local PD, FD, and City TG's I want.

Today, out of boredom, I decided to set the bank to open, and see what else was happening on that control channel.

I wrote down the TGIDs as they popped up, so I could look them up later. There were tons of IDs from outside the Seattle Area. Algona Pacific, Bellevue, Enumclaw, Redmond.


So, does that mean that there were PD and FD radios from those areas that had affiliated themselves with a Seattle repeater?

Sorry, I'm still a little confused I guess.

Like, why would an enumclaw fire radio be anywhere near seattle?

 

[AtomicTaco]

So, does that mean that there were PD and FD radios from those areas that had affiliated themselves with a Seattle repeater?

Yep. And repeater network; I know of the one on top of Columbia Tower, there's the one up in Roosevelt too; I just don't remember all the locations. And they could be affiliated for various reasons, but if you're hearing them on that control channel that's what it means.

If this is all starting to sound like cell networks, then it shouldn't be surprising. Other than using a different type of modulation (and frequencies), trunked radios and cell phones are very similar.

 

[AlmostHandy]

Wow, far out.

Thanks dude!

 

[Joshs_Email]

Freq.

OKay..newbie here. But definitely found a new hobby.

I live in the Redmond area and am trying to listen to Redmond PD calls. I had everything working, but the signal was somewhat weak; my BC246T scanner already came programmed with the channel. I thought maybe if I put in every frequency (from this page) http://www.radioreference.com/apps/db/?sid=604 that it might help.

I can't seem to tell a quality difference ...

Did I accomplish anything/cause extra unneccsary work for my scanner?

Thanks,
JS

 

[AtomicTaco]

I live in the Redmond area and am trying to listen to Redmond PD calls. I had everything working, but the signal was somewhat weak; my BC246T scanner already came programmed with the channel. I thought maybe if I put in every frequency (from this page) http://www.radioreference.com/apps/db/?sid=604 that it might help.

I can't seem to tell a quality difference ...

Did I accomplish anything/cause extra unneccsary work for my scanner?

Try inputting all of the red frequencies in as conventional, and see which ones come in the strongest. 99.99% of the time you'll hear them on EPSCA, but they roam onto other sites, so if other sites come in better then you might use that control channel instead.
It's also possible that you live near something that can cause interference to the 800 bands, mainly Next(h)el.

 

[Joshs_Email]

Haha seriously. Thanks will do.

Also, the squelch on my radio doesn't seem to do anything....any thoughts?
I turn it fully in both directions and get no change...

 

[AtomicTaco]

Also, the squelch on my radio doesn't seem to do anything....any thoughts?
I turn it fully in both directions and get no change...

I've never played with a 246, but while trunking it won't do anything. While in conventional mode, you'll notice it if it's working. Otherwise the solder might be lose, among many other possibilities.