MPSCS: Do I only need to program the control freq for each site?

[chipjumper]

I have a 996XT - will it figure out the rest? I'm having trouble getting a definitive answer on this.

One more question: for Washtenaw county I can only receive fire and EMS. Is the sheriff encrypted? I have their ID's programmed but I don't hear anything. The live feed gets them.

 

[kd8ati]

I have a 996XT - will it figure out the rest? I'm having trouble getting a definitive answer on this.

One more question: for Washtenaw county I can only receive fire and EMS. Is the sheriff encrypted? I have their ID's programmed but I don't hear anything. The live feed gets them.

All you need is the control channel... however it is also a good idea to put in the alternate freqs (blue ones on the RR database).

As far as I know, the sheriff is dispatched with almost everyone else on the Metro West/East talkgroups on 2191 (west), 12302 (east), and 12303 (west - patched to 2191). They are not encrypted.

 

[chipjumper]

Excellent! I did what you said and everything works. I do have a couple more questions though. This is something that I've wondered about the digital scanners since they came out -- how come their receiver is subpar to the "real thing"? I use the MPSCS system (as secondary) with my employment and I've noticed that my 996XT doesn't always "hear" whats going on but the APX7000 doesn't miss a beat. Here are some examples of the strange scanner phenomena:

-I can hear the dispatcher clearly but the opposite end is broken (digitized) and unreadable yet the dispatcher acknowledges them as if they were crystal clear.
-On hold mode on a certain ID on the Washtenaw County Simulcast I show full signal strength. I miss communications that the Motorola receives.
-Nearly full signal strength showing yet broken communications on both ends.

I was trained by the MPSCS that "scanning is evil" and that there can be issues when users are hooked onto adjacent radio sites and that if my prep locked onto an adjacent tower site (Northville) that I might not hear whats going on etc. Is there anyway that this is fixed? It is my understanding that distant tower sites will only rebroadcast traffic on a talkgroup if and only if a user of such talkgroup is within the range of that site and has affiliated. So, for example, if I'm a regular user on the Washtenaw County Simulcast and I travel to Missaukee County and I affiliate with a tower site there, scanner listeners of that Missaukee County tower site should start receive communications on the Washtenaw County based talkgroup that my APX7000 is on - correct?

 

[jaspence]

Washtenaw

One of the problems with monitoring the Washtenaw system is that it uses simulcast, which does sometimes cause the signal to be distorted.

 

[mikey60]

This is something that I've wondered about the digital scanners since they came out -- how come their receiver is subpar to the "real thing"? I use the MPSCS system (as secondary) with my employment and I've noticed that my 996XT doesn't always "hear" whats going on but the APX7000 doesn't miss a beat.

That's the difference between a $500 scanner and a $5000 Motorola Radio. I would guess that if the scanner manufacturers made a scanner that worked as well as the "real thing", that the cost would probably be at least double what it is now. Some people would pay that, but most people can't afford that amount.

Also keep in mind that the professional radios are designed for one relatively small frequency range (~760MHz to ~870MHz) so they can add good filtering. Scanners have to deal with a large range of frequencies, usually between 25MHz and 1.3GHz depending on the model. Much more difficult to add filters with that range, and still keep the radio somewhat affordable.

Here are some examples of the strange scanner phenomena:
-I can hear the dispatcher clearly but the opposite end is broken (digitized) and unreadable yet the dispatcher acknowledges them as if they were crystal clear.
-On hold mode on a certain ID on the Washtenaw County Simulcast I show full signal strength. I miss communications that the Motorola receives.
-Nearly full signal strength showing yet broken communications on both ends.

Most of this is probably simulcast distortion at work. The scanners have a difficult time dealing with signals coming from multiple sources at the same time. With a simulcast system like Washtenaw, multiple tower sites are transmitting the same data at the same time on the same frequency. Those signals reach the scanner at slightly different times, which start to cancel each other out. Moving the scanner an inch or two can make a world of difference in receiving the signal.

I was trained by the MPSCS that "scanning is evil" and that there can be issues when users are hooked onto adjacent radio sites and that if my prep locked onto an adjacent tower site (Northville) that I might not hear whats going on etc. Is there anyway that this is fixed? It is my understanding that distant tower sites will only rebroadcast traffic on a talkgroup if and only if a user of such talkgroup is within the range of that site and has affiliated. So, for example, if I'm a regular user on the Washtenaw County Simulcast and I travel to Missaukee County and I affiliate with a tower site there, scanner listeners of that Missaukee County tower site should start receive communications on the Washtenaw County based talkgroup that my APX7000 is on - correct?

Correct. The only way a scanner will hear the traffic on a talkgroup is if there is at least one radio affiliated with the site being monitored on that talkgroup. Scanners cannot affiliate to a site, so they can't bring a talkgroup to a site like a system radio can.

Mike

 

[chipjumper]

Thank you very much for the info guys. Well I guess I'm glad I got it super cheap in the black friday blowout sale. Thats all I can say lol. Glad the P110 still receives VHF Paging crystal clear.

 

[ks4ui]

When you say scanning is evil I think you mean scanning on your prep (portable radio). Yes your prep can lock on to a signal from another tower other than the one that is providing you with the best signal. Does your prep have scan vote capability? If so then when your prep is scanning it should lock onto the strongest signal. Many of the radios out there have scan but without the scan vote feature...in that respect the scan feature is evil.

 

[kd8ati]

When you say scanning is evil I think you mean scanning on your prep (portable radio). Yes your prep can lock on to a signal from another tower other than the one that is providing you with the best signal. Does your prep have scan vote capability? If so then when your prep is scanning it should lock onto the strongest signal. Many of the radios out there have scan but without the scan vote feature...in that respect the scan feature is evil.

Vote scan would not apply to this situation. Vote scan only applies to conventional dispatch channels. Don't preps by default lock on to the strongest programed tower signal when affiliating to a trunk system?

 

[drdispatch]

Scanning, Site Affiliation & Other Stuff

..... Don't preps by default lock on to the strongest programed tower signal when affiliating to a trunk system?

Sort of.
Radios will affiliate with the site that has the strongest signal and the highest level of service. So if the best signal is from a site that is in site trunking, (& therefore isolated from the rest of the system) the radio will find the next best signal from an adjacent site.

The thing to remember in comparing system radios to scanners is that the system "sees" its radios, but doesn't "see" a scanner. So if your system radio is on talkgroup 1234, & in scan mode & affiliated with site A, it won't pick up traffic on TG 5678 if there are no radios affiliated with site A on TG 5678; they might all be affiliated with site B & chattering away. Yet your scanner, since it can monitor several sites at a time, can hear sites A and B, and will pick up the traffic on TG 5678.

So; if the dispatcher's radio is on site A, and the unit they are talking to is also on site A, they might hear each other fine; but if you are on site B, the signal might get distorted or "go digital". We experience this all the time since we're a countywide dispatch center; mobile units who are all affiliated with one site will hear each other fine, & since we affiliate with a different site, sometimes traffic is garbled.