ProScan RSSI levels

[natedawg1604]

So this afternoon I've been adjusting the RSSI threshold levels under "ProScan Options" in RPM so my XG and P radios can pick up fairly weak CCs, and I'm a little confused about how to interpret the settings. The RPM help guide states the following about this setting:

Priority System Minimum Level:
If the selected priority systems’ control channel signal quality level deteriorates to a level equal to or below the value this control corresponds with (ProScan), then the radio switches to the full time or Adjacent System Scan Mode (Wide Area System Scan Mode ).

Type a numeric value in the range from 60 to 122.
Default: 122 dBm

I would think that 122 dBm would be the LEAST sensitive setting. However after playing with the settings it appears to the opposite. In other words, I can't pick up a few weaker CC's unless I set Priority System Minimum Level to way under 122, I tried 65 and that brings in pretty weak signals. For testing purposes I created a special Personality with Fixed ProScan and a single control channel on several systems, so it's very obvious when the weak signal is being received vs. when the radio goes into CC scan with no other CC to find. Anyhow I thought 65 was a much better RSSI value than 122, what am I missing here?

 

[Whiskey3JMC]

Since no replies here, I clicked "report" and asked if this thread can be moved to the Scanner Programming Software Forum where a majority of Proscan questions are addressed

 

[KevinC]

This thread has nothing to do with ProScan scanner software, so no need to move it.

 

[mancow]

-122 dbm is a hell of a lot weaker signal than - 65.

 

[natedawg1604]

-122 dbm is a hell of a lot weaker signal than - 65.

That's what I thought too, maybe it's just a software bug or something. I assumed a lot of people have messed with the ProScan RSSI settings in RPM, hopefully someone else can chime in.

 

[KevinC]

I'm not wise to this feature, but maybe -122 means your current CC needs to drop to that level to switch sites.

 

[mancow]

I mean - 122 is more sensitive than - 65 since the radio is being told to try to see a signal that far down. The bigger the number the weaker the signal.

 

[wa8pyr]

-122 dbm is a hell of a lot weaker signal than - 65.

And how.

To the OP: Yes, you can tinker with the Proscan settings. However, what they mainly do is control when your radio will roam to a new site, and it takes a lot of fiddling to get it right; if you screw up you'll be even worse off, and can really put yourself in a bad situation. I might add that the settings don't necessarily do what it would seem they do based on the name.

I recommend reading the help information in RPM; it's chock full of useful information.

I mean - 122 is more sensitive than - 65 since the radio is being told to try to see a signal that far down. The bigger the number the weaker the signal.

That's not really what the sensitivity setting means; yes, it will cause the radio to look at much weaker signals, but there's a lot more to it than that.

 

[natedawg1604]

And how.

To the OP: Yes, you can tinker with the Proscan settings. However, what they mainly do is control when your radio will roam to a new site, and it takes a lot of fiddling to get it right; if you screw up you'll be even worse off, and can really put yourself in a bad situation. I might add that the settings don't necessarily do what it would seem they do based on the name.

I recommend reading the help information in RPM; it's chock full of useful information.



That's not really what the sensitivity setting means; yes, it will cause the radio to look at much weaker signals, but there's a lot more to it than that.

Well I am using the radios for NAS and I'm only programming my own radios, so nothing bad will happen regardless.

But can you elaborate on what the "more" is? Like I said in my original post, I messed with the RSSI settings because I want the ability to pick up fairly weak CCs under certain circumstances, the default settings ignore those sites.

The default settings would work fine if the radio was affiliating.

 

[mancow]

And how.

To the OP: Yes, you can tinker with the Proscan settings. However, what they mainly do is control when your radio will roam to a new site, and it takes a lot of fiddling to get it right; if you screw up you'll be even worse off, and can really put yourself in a bad situation. I might add that the settings don't necessarily do what it would seem they do based on the name.

I recommend reading the help information in RPM; it's chock full of useful information.



That's not really what the sensitivity setting means; yes, it will cause the radio to look at much weaker signals, but there's a lot more to it than that.

Well yes but relative to the user experience
It's more sensitive / tolerant of weaker control channels.

 

[wa8pyr]

Well I am using the radios for NAS and I'm only programming my own radios, so nothing bad will happen regardless.

But can you elaborate on what the "more" is? Like I said in my original post, I messed with the RSSI settings because I want the ability to pick up fairly weak CCs under certain circumstances, the default settings ignore those sites. The default settings would work fine if the radio was affiliating.

Changing ProScan settings really isn't going to help you if you're doing NAS and not roaming; these settings determine when the radio roams to another site. If you're really determined to receive more distant control channels I'd recommend starting with an alignment; this cures a multitude of ills.

However, if you're going to mess with the ProScan settings, you definitely need to read the help file included with RPM; it's listed under ProScan Options Dialog Box. All of these controls work together (so what you do in one will affect others); it's really too involved to get into in detail but in a large nutshell:

Sensitivity: Controls the radio’s sensitivity to fluctuations in signal quality levels, and thus determines when the radio will enter Transition Scan Mode (it doesn't raise or lower the actual sensitivity of the radio). Set this too low and you'll find the radio trying to hop all over the place every time there's a momentary drop in CC strength.

Switch Delta: The difference in signal quality at which the radio will switch to a new site.

System Sample Time: The amount of time between sampling adjacent control channels.

Priority System Minimum Level: Determines the point in signal quality of the selected Priority System at which the radio will begin searching for another control channel. Applies when using Fixed or Dynamic ProScan.

Priority System Transition Level: Determines when to enter the Transition Scan Mode or when to switch to the priority system.

Non-Priority System Minimum Level: Determines the point in signal quality of the selected Non-Priority System at which the radio will begin searching for another control channel. Applies when using Fixed or Dynamic ProScan.

Non-Priority System Transition Level: Determines the point when a selected non-priority system enters the Transition Scan Mode and will start monitoring the adjacent systems identified in the adjacency table. Applies when using Fixed or Dynamic ProScan.

On our system, we did change all of these settings (except the Priority and Non-Priority minimum levels) and it did improve roaming, but when I set up an NAS radio in the office for monitoring purposes, the only thing that really helped receive quality was a good antenna and a proper alignment.

 

[TDR-94]

The default ProScan settings where determined to be ideal for 98% of systems out there. L3HARRIS did not come up with those settings arbitrarily. To properly change them, requires test equipment and field signal strength measurements of the system in question.

 

[wa8pyr]

The default ProScan settings where determined to be ideal for 98% of systems out there. L3HARRIS did not come up with those settings arbitrarily. To properly change them, requires test equipment and field signal strength measurements of the system in question.

I'm sure the Harris defaults are fine on Harris systems. Maybe not so much on Motorola systems.

We didn't come up with our changed settings arbitrarily. We started with converting the corresponding Motorola roaming settings (it's a Motorola system) to dBm from RSSI, and then continued with a great deal of measuring, testing and adjusting, before rolling them out. Made a definite improvement.

Had similar issues with Kenwood/EFJ radios at my previous job and had to go through a similar process to change their default settings to something which worked much better.

 

[TDR-94]

I'm sure the Harris defaults are fine on Harris systems. Maybe not so much on Motorola systems.

We didn't come up with our changed settings arbitrarily. We started with converting the corresponding Motorola roaming settings (it's a Motorola system) to dBm from RSSI, and then continued with a great deal of measuring, testing and adjusting, before rolling them out. Made a definite improvement.

Had similar issues with Kenwood/EFJ radios at my previous job and had to go through a similar process to change their default settings to something which worked much better.

Which would be the correct way to optimize the ProScan settings to gain any tangible improvements over the default setting.

 

[TDR-94]

Well I am using the radios for NAS and I'm only programming my own radios, so nothing bad will happen regardless.

But can you elaborate on what the "more" is? Like I said in my original post, I messed with the RSSI settings because I want the ability to pick up fairly weak CCs under certain circumstances, the default settings ignore those sites.

The default settings would work fine if the radio was affiliating.

You are trying to make ProScan operate in the opposite manner in which it was designed, by roaming to the weakest sites. It's not likely to work quite the way you want it to. The whole point of the radio roaming is to always stay connected to a site that has the acceptable signal strength parameters to insure that voice traffic is still fairly intelligible and in the case of digital voice and data, not corrupted.

That of course would be ideally how ProScan, and raoming in general would work, but variables always come into tho play that these algorithms can't account for.

 

[natedawg1604]

You are trying to make ProScan operate in the opposite manner in which it was designed, by roaming to the weakest sites. It's not likely to work quite the way you want it to. The whole point of the radio roaming is to always stay connected to a site that has the acceptable signal strength parameters to insure that voice traffic is still fairly intelligible and in the case of digital voice and data, not corrupted.

That of course would be ideally how ProScan, and raoming in general would work, but variables always come into tho play that these algorithms can't account for.

So you are correct, I basically want the ability to force the radio onto the weakest site under certain limited circumstances. The reasons why should be pretty obvious, given I'm using my radios for NAS.

However in general the default roaming settings work just fine, I'm very happy overall with how my XG and P radios roam, and it's really cool that you can go into the FCC menu and see what site the radio is currently parked on. If I were using these radios for regular usage, the RSSI settings would definitely be fine. Given that I'm only programming for NAS, I'm not too concerned about playing with the RSSI settings, it's very trivial to go back to the default settings. Unless I'm missing something, playing with these settings doesn't change anything you can't re-set to default.

I may end up going back to the default settings in the end; I really don't think the radios need an alignment, although it's an interesting idea I might look into at some point. I do appreciate everyone's feedback.

 

[apco25]

RSSI is RSSI regardless of vendor. Put the default settings back in as listed in the help file and leave it alone.