SPD and Seattle Fire Dead Air

[gmclam]

Further, I did, and do understand the concept of multicast "sites". One "site" can have several transmission and even more reflective sources, especially in the city.
My point again, is to limit the number of "site" frequencies that a non-SDS radio can lock onto.
That said, there is every chance that you'll still suffer multi path distortion/interference.
Steps can be taken with attenuation, relocation and antenna mods to minimize the issue, and if you have some constructive ideas concerning those steps, I'm all ears.
The point of my posts was to give the folks that don't have $650+ receivers a fighting chance at overcoming the issue.
Sheesh...

Each specific term has its own meaning. I don't think multi-cast is generally the same as Simulcast. Simulcast means there is more than one site on the same frequency transmiting the same thing. Certainly if you can make your non-simulcast receiver only see a single tower, you should get a clear signal from THAT tower. But you will miss stuff.

Unfortunately, when it comes to scanners, there are presently only 2 solutions to this. When it comes to receivers, there are indeed a few cheap(er) solutions.

My point again, is to limit the number of "site" frequencies that a non-SDS radio can lock onto.

Which will do NOTHING to alleviate issues caused by SimulCast. Also, just like I believe in a different definition for the terms multicast and simulcast, there are also different definitions for the term Site and Tower. With Simulcast, one "site" can come from multiple towers (physical locations).

 

[code3kid]

Each specific term has its own meaning. I don't think multi-cast is generally the same as Simulcast. Simulcast means there is more than one site on the same frequency transmiting the same thing. Certainly if you can make your non-simulcast receiver only see a single tower, you should get a clear signal from THAT tower. But you will miss stuff.

Unfortunately, when it comes to scanners, there are presently only 2 solutions to this. When it comes to receivers, there are indeed a few cheap(er) solutions.


Which will do NOTHING to alleviate issues caused by SimulCast. Also, just like I believe in a different definition for the terms multicast and simulcast, there are also different definitions for the term Site and Tower. With Simulcast, one "site" can come from multiple towers (physical locations).

Only pleb’s say tower 🤦‍♂️

 

[louisik1]

Only pleb’s say tower 🤦‍♂️

Oh you guys.


Anyway.. Does anyone know who's the person(s) broadcasting the "Seattle Fire" and "Seattle Police" streams? I'm wondering if I can help them out.

 

[code3kid]

Each specific term has its own meaning. I don't think multi-cast is generally the same as Simulcast. Simulcast means there is more than one site on the same frequency transmiting the same thing. Certainly if you can make your non-simulcast receiver only see a single tower, you should get a clear signal from THAT tower. But you will miss stuff.

Unfortunately, when it comes to scanners, there are presently only 2 solutions to this. When it comes to receivers, there are indeed a few cheap(er) solutions.


Which will do NOTHING to alleviate issues caused by SimulCast. Also, just like I believe in a different definition for the terms multicast and simulcast, there are also different definitions for the term Site and Tower. With Simulcast, one "site" can come from multiple towers (physical locations).

A “site” by definition is a physical location. By this logic, a “site” would more appropriately be called a cell if we’re talking about multiple locations transmitting the same traffic at the same frequency at the same time. People have a tendency to look at the RR database and see the lack of the word “simulcast” and assume that whomever named the “sites/cells/simulcast site” knows best, and assume because their uniden bearcat is working fine that it couldn’t be a simulcast cell. Little do they know, they live 3 blocks from a site in the simulcast cell so they don’t have to worry about multi path issues too much.

SITE and TOWER are synonyms

 

[Tortue]

Each specific term has its own meaning. I don't think multi-cast is generally the same as Simulcast. Simulcast means there is more than one site on the same frequency transmiting the same thing. Certainly if you can make your non-simulcast receiver only see a single tower, you should get a clear signal from THAT tower. But you will miss stuff.

Unfortunately, when it comes to scanners, there are presently only 2 solutions to this. When it comes to receivers, there are indeed a few cheap(er) solutions.


Which will do NOTHING to alleviate issues caused by SimulCast. Also, just like I believe in a different definition for the terms multicast and simulcast, there are also different definitions for the term Site and Tower. With Simulcast, one "site" can come from multiple towers (physical locations).

You're right about the different meanings. I'm conflating multicast with actual physical tower locations, in this instance.
In my little pea brain, the "multi" means many, and the "cast" is short for broadcast, and together, refers to two or more broadcast physical locations ie; antenna towers. While simulcast, is the transmission of identical signals through two or more antennas (in this case) at the same time (allowing for inherent transmission latencies in the system hardware/software).
When you add it all up, I suppose you get a coverage area with overlapping signals, and the dreaded multi-path distortion(s) within those overlapping locations. And, if your lucky enough (like me) to live where there's very little overlap, your .996 scanner should decode without distortion.
I sure admire the system designers that have to deal with the public and private entities that insist on 100% coverage in urban environments.
I think we agree on the basics of multicast vs simulcast concepts. But I'll reserve my stance on the "poor man's guide to cheating simulcast".

I do have a question though - Let's take King county for example.

Would a local police department in say, south King county, typically affiliate with a site in north King county?
I would assume that not all departments affiliate with all sites, unless there's gobs of space in the P2/TDMA spectrum.
Discuss...

 

[piercescan]

Only pleb’s say tower 🤦‍♂️

This is a scanning forum, for help...nobody is a "pro" they can say what they want..

 

[gmclam]

Only pleb’s say tower 🤦‍♂️

I have no clue about what you are saying. I am sure that tower engineers also call them towers.

 

[gmclam]

A “site” by definition is a physical location. By this logic, a “site” would more appropriately be called a cell if we’re talking about multiple locations transmitting the same traffic at the same frequency at the same time. People have a tendency to look at the RR database and see the lack of the word “simulcast” and assume that whomever named the “sites/cells/simulcast site” knows best, and assume because their uniden bearcat is working fine that it couldn’t be a simulcast cell. Little do they know, they live 3 blocks from a site in the simulcast cell so they don’t have to worry about multi path issues too much.

SITE and TOWER are synonyms

With regard to Simulcast systems, this is NOT true.
I don't think that RR has all the info for PSERN added to the DB, so I'll use this Simulcast Site as an example.
Note that this ONE SITE has NUMEROUS TOWERS.

Site is the label the SDS scanners are using. When it's simulcast there's no distinguishing as to different towers that are all on that site's frequencies.

 

[louisik1]

I do have a question though - Let's take King county for example.

Would a local police department in say, south King county, typically affiliate with a site in north King county?
I would assume that not all departments affiliate with all sites, unless there's gobs of space in the P2/TDMA spectrum.
Discuss...

Sorry I don't have references, but my understanding specifically for King is that all the sites all broadcast the same stuff, though I heard somewhere that some talk groups might be prioritized to sites they are more pertinent to.

Regarding gobs of space, as you probably know, the KCERS spans something 851.0 to 860.9, so yeah there's a lot of space. The Seattle simulcast site alone traverses 851.08 to 856.8. That's one of the reasons I gave up on my first try with SDR. I didn't want to buy a more expensive sdr and the software wasn't as robust as it is now.

Fortunately the PSERN is a little narrower. Seattle's site is 851.8 to 854.3. Phew!

(I barely know anything though so ... big grains of salt)

 

[FFSOD7189]

Are SPD and SFD encrypted on PSERN?

NO!