I still believe if simulcast is a problem (when using other scanners not designed to combat simulcast problems), programming simulcast systems should be done using only one site at a time, learning which site is strongest to your location, and attenuating that frequency to where it’s the only site the radio will hear, using squelch to eliminate other sites transmitting the on the same frequency at the same time. But I’ve received pushback on this method (they say it won’t work) and acknowledge there are others with a better understanding. To these “others” I offer my acceptance of their “take” on the matter, not wishing to get into a debate as to where my thinking has gone wrong because admittedly, I am no where near an expert and can not defend my point of view technically. So, please, do not accept this post as a challenge. I do not care to get into a give-and-take over it. Besides, it would probably be considered “hijacking” this thread which I believe is a violation on this board.
With one, occasional, situation, you cannot "program" simulcast issues away. The exception being those instances where using attenuation can reduce signal strength enough so that the scanner can ignore' the weaker, out of sync, transmissions from more distant transmitters and enable the radio to decode the stronger signal.
By definition, a '
Simulcast site' is one where there are multiple transmit towers that are part of the Simulcast site, all broadcasting the exact same radio traffic on one or more talkgroups are carried in the same frequency from each of the transmitters in the overall simulcast site. If you don't program the frequencies for the simulcast, then you will not receive that site. If you do, then the scanner has to deal with multiple signals, from various locations, using the same frequency & talkgroup radio traffic. As these signals originate from transmit towers at varying distances from your location, they arrive at different times, While the time differential may be minute, it is still enough to hamper the scanner's ability to receive & decode the traffic correctly.
I think one thing that can add to the problem for programming is that we tend to use the same name for two different items. This is a system in my area:
Garland, Mesquite, Rowlett, Sachse (GMRS) Trunking System Profile
www.radioreference.com
You see the first Site listed is the GMRS Simulcast Site.
But if you click on the site, to see its details, you'll see the term "Site" is used to mean something different:
Garland, Mesquite, Rowlett, Sachse (GMRS) Site: GMRS Simulcast Details
www.radioreference.com
In the case of the site details, we also see the term Site used to describe the fact that there are actually four locations where the same radio traffic is broadcast.
(Actually, according to the license there are more than four sites, as you can see below.)
Each of those listed locations transmits the exact same signals, on the same frequencies, as each of the others You can either program the site, and seal with the simulcast as best you can, or skip it & lose the radio traffic carried on them.
There are some locations (but not this system) where you have one large Simulcast site, but also others in the same county. But if you look at the details, these additional sites have many fewer assigned frequencies as does the main (simulcast) site. These are often 'fill-in' sites to ensure reception in areas not covered sufficiently by the main site. That is obvious because for the larger simulcast site, you may have 10, 12, or more frequencies in use, but these smaller sites have a handful, like 4 or five frequencies. There is no way that five frequencies can carry the same amount of traffic as the much larger 10 or more transmitters of the Simulcast. However, if that smaller (fewer frequencies) site carries all the radio traffic for your specific city, then you can use it, with the knowledge that you will not hear all of transmissions carried on the larger site.
