How do I know if it's simulcast

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kb5udf

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Hi all,

Long time scanist and ham op, but somewhat new to consumer p25 scanners. Other than obviously poor performance with decoding, is there a way to know if a system and/or site is simulcast? I seem to find varying/inconsistent descriptions of how the term simulcast is used in my googling.

For example, my trx-2 works great at my home QTH in Lafayette, LA on LWIN, but very poorly in my secondary QTH in Orange Beach, Alabama (Alabama system, Phase 2).

Thanks

JB
 

troymail

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Hi all,

Long time scanist and ham op, but somewhat new to consumer p25 scanners. Other than obviously poor performance with decoding, is there a way to know if a system and/or site is simulcast? I seem to find varying/inconsistent descriptions of how the term simulcast is used in my googling.

For example, my trx-2 works great at my home QTH in Lafayette, LA on LWIN, but very poorly in my secondary QTH in Orange Beach, Alabama (Alabama system, Phase 2).

Thanks

JB
Sometimes the easiest way - assuming the FCC license data is accurate (it's not 100% of the time) - is to search the ULS for the known/active control channel (or other known frequency for the system/site). If the license shows multiple tower/transmitter locations, it's probably simulcast.
 

nd5y

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You can tell by listening to the signal in analog mode.
You have to be skilled enough to recognize the sound and you can't be close enough to one site that the capture effect covers the signal from other sites.
 

troymail

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You can tell by listening to the signal in analog mode.
You have to be skilled enough to recognize the sound and you can't be close enough to one site that the capture effect covers the signal from other sites.
Funny -- many years ago, I used to tell people I could hear the difference between FSK and DFSK signals just by listening and they always told me I was crazy... I wasn't. But it does take alot of listening and experience to hear the differences in signals this way.
 

ScannerSK

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Try tuning into a control channel. If it is simulcast, the signal strength will often be rapidly fluctuating in strength and not steady (as it will be for non-simulcast control channels).

Shawn
 

phask

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troymail

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Look at the locantionfoe the individula sites - at least in Ohio they are id'd in the data as system location - various and location - xx site simulcast.

This is a known example
https://www.radioreference.com/apps/db/?siteId=23054

Not sure if your system admins enter similar.
Like nearly everything else, that's not reliable either. Example:

https://www.radioreference.com/apps/db/?siteId=19455

This is a large, multi-tower simulcast site....

RRDB data is generally limited to whatever someone submitted - which can be good, not so good, incomplete, or just wrong.

Don't get me wrong - every source of information and recommendations on places to look are helpful - but like they say - don't believe everything you read - trust but verify.
 
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ofd8001

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I agree with the first response - a system having multiple transmitter locations but use the very same frequencies is indicative of a simulcast system.

While there are always "exceptions to the rule" simulcast systems are typically associated with metropolitan areas that have large concrete/steel buildings. The FCC in dealing with limited frequency spectrum, no longer allows "blow-torch" transmitters of 200-300 watts or more needed to penetrate the buildings. So with technological advances, an area is blanketed with many transmitters at lower point to get the penetration into buildlings.
 
D

DaveNF2G

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"Simulcast" is used to cover many new technologies by some people. True simulcasting involves sending the same information over more than one channel simultaneously. The coverage of the channels involved does not necessarily have to overlap.

In simulcast P25 trunked systems, coverage generally does overlap, as others have explained above, but the difference is that the "channels" involved are on the same frequencies but transmitted from different locations.
 

troymail

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"Simulcast" is used to cover many new technologies by some people. True simulcasting involves sending the same information over more than one channel simultaneously. The coverage of the channels involved does not necessarily have to overlap.

In simulcast P25 trunked systems, coverage generally does overlap, as others have explained above, but the difference is that the "channels" involved are on the same frequencies but transmitted from different locations.
Yes - there are several terms used in various technology like these systems that has to be considered "in context" of the conversation.

For example, another confusing term is "site" - sometimes it is used to describe a "simulcast site" where there are multiple transmitters/towers that make up that single "simulcast site". In other conversations, people say "site" to refer to a single transmitter/tower "site" which may be stand-alone or one of the towers in a "simulcast site".

However, I'm pretty confident the user's original question is about system/site "simulcasting" vs. channel or talkgroup being simulcast.
 

N8IAA

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Hi all,

Long time scanist and ham op, but somewhat new to consumer p25 scanners. Other than obviously poor performance with decoding, is there a way to know if a system and/or site is simulcast? I seem to find varying/inconsistent descriptions of how the term simulcast is used in my googling.

For example, my trx-2 works great at my home QTH in Lafayette, LA on LWIN, but very poorly in my secondary QTH in Orange Beach, Alabama (Alabama system, Phase 2).

Thanks

JB
Maybe you should just put in the tower site for Orange Beach, instead of all sites for Baldwin county. It might make a difference. When loading up trunk systems in the Whistler scanners, as well as any SD card scanner, the software just picks all sites.
Larry
 

phask

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I agree - BUT it looks, at least to me, that there is just one liscense and that liscensejust states Baltimore.

Of, course there are probably more liscenses as well.

- I'm lucky - good admin. and info. in Ohio -


Like nearly everything else, that's not reliable either. Example:

https://www.radioreference.com/apps/db/?siteId=19455

This is a large, multi-tower simulcast site....

RRDB data is generally limited to whatever someone submitted - which can be good, not so good, incomplete, or just wrong.

Don't get me wrong - every source of information and recommendations on places to look are helpful - but like they say - don't believe everything you read - trust but verify.
 

jonwienke

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When loading up trunk systems in the Whistler scanners, as well as any SD card scanner, the software just picks all sites.
Not true of Uniden scanners. When Location Control is enabled (always on when using the main database) only sites within reception range are scanned by default, and you can lock out/avoid individual sites if desired.
 

Ubbe

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True simulcasting involves sending the same information over more than one channel simultaneously. The coverage of the channels involved does not necessarily have to overlap.
That's how a standard multisite trunked system works. If you want to transmit on all sites I guess that would be called a broadcast call but all sites would have their own set of frequencies. By your definition most talk group calls would be using simulcast technology.

/Ubbe
 

troymail

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I agree - BUT it looks, at least to me, that there is just one liscense and that liscensejust states Baltimore.

Of, course there are probably more liscenses as well.

- I'm lucky - good admin. and info. in Ohio -
Yup - the Maryland State system operates under a state license and in this case, they don't identify in the license every tower site. Just another "gap" in information. Not much out there is 100% (actually none of it is 100%).
 

troymail

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Not true of Uniden scanners. When Location Control is enabled (always on when using the main database) only sites within reception range are scanned by default, and you can lock out/avoid individual sites if desired.
There's just a bit more to it than that -- you also need a GPS connected and live to make that claim --or-- constantly manually change your location in the radio. Enabling location control with nothing else will probably result in hearing nothing (lat=0, lon=0).
 

jonwienke

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You only need a GPS connected if you are in a vehicle. If you are at a fixed location, you only need to enter your location once.
 
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