Basic ARMER Simulcast Questions

[mattnelson26]

The x96 line of scanners does have difficult decoding simulcast systems. You'll see all bars on signal strength indicator. The problem is you are getting too much signal (receiving multiple towers) and your scanner is having trouble with decoding the multiple sets of data coming in.

There are things you can try that might lead to varying degrees of improvement:

Set Site Attenuator to On. (Reduces the sensitivity of the scanner for that site).

Also, from Mark's Easier to Read Manuals:

P25 Adjust Mode this is a hidden setting accessible only by turning off the radio and pressing Hold when you turn the scanner back on. This mode sets the algorithm for P25 decode.
Scroll to 'P25 Adjust Mode' and press E/yes.
Enter 3-15 and press E/yes to save and exit.

P25 Adjust Level this is a hidden setting accessible only by turning off the radio and pressing Hold when you turn the scanner back on. Sets the RSSI value below which the scanner will not attempt to make P25 fine tune adjustments. If the signal is too low, RX reliability is not high enough to make P25 adjustments correctly. The default value is 50. People have had better decoding with this value turned up.
Scroll to 'P25 Adjust Level' and press E/yes.
Enter 1-200 and press E/yes to save and exit.

The tricky part is that you have to spend a lot of time tinkering around to come up with the best possible combination of values. It is variable based on scanner and location of the scanner. No one size fits all. Both my son and I have 996XT scanners and listen to the same system. The values that work best for me are 13 (Mode) and 175 (Value), but his are 11 (Mode) and 150 (Value).

I think you'll probably gain some improvement by changing these.

Is his available to do on the pro197?

thanks
matt

 

[ofd8001]

Here's the link to Mark's Easier to Read Manuals for that model: Easier to Read Pro-651/652/106/197 - WS1040/1065 - PSR 500/600 Digital Scanner Manual

Some links are shown on P25 distortion.

 

[smitty54017]

The x96 line of scanners does have difficult decoding simulcast systems. You'll see all bars on signal strength indicator. The problem is you are getting too much signal (receiving multiple towers) and your scanner is having trouble with decoding the multiple sets of data coming in.

There are things you can try that might lead to varying degrees of improvement:

Set Site Attenuator to On. (Reduces the sensitivity of the scanner for that site).

Also, from Mark's Easier to Read Manuals:

P25 Adjust Mode this is a hidden setting accessible only by turning off the radio and pressing Hold when you turn the scanner back on. This mode sets the algorithm for P25 decode.
Scroll to 'P25 Adjust Mode' and press E/yes.
Enter 3-15 and press E/yes to save and exit.

P25 Adjust Level this is a hidden setting accessible only by turning off the radio and pressing Hold when you turn the scanner back on. Sets the RSSI value below which the scanner will not attempt to make P25 fine tune adjustments. If the signal is too low, RX reliability is not high enough to make P25 adjustments correctly. The default value is 50. People have had better decoding with this value turned up.
Scroll to 'P25 Adjust Level' and press E/yes.
Enter 1-200 and press E/yes to save and exit.

The tricky part is that you have to spend a lot of time tinkering around to come up with the best possible combination of values. It is variable based on scanner and location of the scanner. No one size fits all. Both my son and I have 996XT scanners and listen to the same system. The values that work best for me are 13 (Mode) and 175 (Value), but his are 11 (Mode) and 150 (Value).

I think you'll probably gain some improvement by changing these.

Thanks!

My problem is that the scanner doesn't even stop on any of the AMER channels, even though the signal meter shows 3-4 bars. Those channels worked great for a few days, then they stopped picking up anything (signal meter still shows 3-4 bars), then they come back, now they've been silent for the last several days (still showing 3-4 bars, but scanner doesn't stop on anything). When they are working, there was no distortion, etc. They were crystal clear. It's like they're switching to a control frequency that isn't listed on this site.

 

[ofd8001]

If you see signal strength meter indication, then you are receiving a control channel.

There are two symptoms of simulcast distortion. One is garble the other is no audio at all. In the second case, the signal is so confusing, the scanner doesn't even try to decorde it (more or less).

If it isn't too much trouble, on those days where you do not receive audio, take your scanner and go close to a transmitter tower and see if it clears up. If it does, that's confirmation of simulcast distortion.

 

[smitty54017]

If you see signal strength meter indication, then you are receiving a control channel.

There are two symptoms of simulcast distortion. One is garble the other is no audio at all. In the second case, the signal is so confusing, the scanner doesn't even try to decorde it (more or less).

If it isn't too much trouble, on those days where you do not receive audio, take your scanner and go close to a transmitter tower and see if it clears up. If it does, that's confirmation of simulcast distortion.

When I WAS receiving a signal, they weren't garbled. Loud and clear. The problem now is that the scanner isn't even stopping on any of the AMER channels, which to me indicates that it isn't receiving and transmissions.

 

[ofd8001]

If you are seeing 3-4 bars, the scanner has to be receiving control channel data from a site. Whether it stops on a talkgroup, that's a different matter. In other words, stopping on a site is apples and stopping on a talkgroup is pears.

Trunked scanning is a whole 'nother creature than convention scanning. The scanner monitors the control channel for channel grants. If there is a channel grant for a talkgroup in your scan list, the scanner will do some things internally so you can hear the voice traffic for the talkgroup.

The problem with simulcast systems is your scanner may be bombared with signals from multiple towers that come in a little out of sync with each other. When that happens, all bets are off. If the scanner has trouble decoding, as mentioned before it will come in garbled or no audio at all.

A little bit of puzzlement is that when you received voice traffic it was always clear. I would have expected some garble, but this is technology where strange things happen.

You haven't changed any programming, or locked anything out by chance?

Again, if it was me, I'd still get the scanner to about 1/4 mile of a transmitter just to see what happens.

Lastly, what model scanner do you have? If its a Uniden, can you read the program file, zip it and attach it to a message? I'll be happy to give it a look-see to see if anything jumps out at me.

 

[smitty54017]

If you are seeing 3-4 bars, the scanner has to be receiving control channel data from a site. Whether it stops on a talkgroup, that's a different matter. In other words, stopping on a site is apples and stopping on a talkgroup is pears.

Trunked scanning is a whole 'nother creature than convention scanning. The scanner monitors the control channel for channel grants. If there is a channel grant for a talkgroup in your scan list, the scanner will do some things internally so you can hear the voice traffic for the talkgroup.

The problem with simulcast systems is your scanner may be bombared with signals from multiple towers that come in a little out of sync with each other. When that happens, all bets are off. If the scanner has trouble decoding, as mentioned before it will come in garbled or no audio at all.

A little bit of puzzlement is that when you received voice traffic it was always clear. I would have expected some garble, but this is technology where strange things happen.

You haven't changed any programming, or locked anything out by chance?

Again, if it was me, I'd still get the scanner to about 1/4 mile of a transmitter just to see what happens.

Lastly, what model scanner do you have? If its a Uniden, can you read the program file, zip it and attach it to a message? I'll be happy to give it a look-see to see if anything jumps out at me.

I have the BCD996XT. I didn't lock out anything, or change any settings. That's what is so strange about the whole issue.

I've attached the program file. Thanks for your help!

 

[ofd8001]

I got the file okay. Will study it later today when I have a little more time.

Have you tried doing a weather search/scan just to be sure the scanner is working (assuming you are not receiving WISCOM or St. Croix county).