NX-5200 Scan Optimization

[ConistonSafetyServices]

I'm working on some NX-5000 series radios, and looking for some suggested scan settings to minimize the "picket fence" effect on the audio while scan is on.

Compared to the Motorolas which I am way more familiar with, it seems like even 1 or 2 channels in the NX list produces significant skipping, compared to it sounding okay until a heavily overloaded list is used on the Motorolas.

Seems like the default KPG settings just need some tweaks.

 

[otobmark]

Are you using priority channels? When landed on a non priority channel, the radio “looks back” at priority channel(s) to check for traffic. You can adjust how often the radio checks priority channels. Every time radio looks back there is an interruption in audio on landed channel. Very noticeable at once or twice a second rate needed to ensure not missing much or any of priority traffic. Use a longer interval or don’t use priority channels in scan list if it annoys you.

 

[ConistonSafetyServices]

Are you using priority channels? When landed on a non priority channel, the radio “looks back” at priority channel(s) to check for traffic. You can adjust how often the radio checks priority channels. Every time radio looks back there is an interruption in audio on landed channel. Very noticeable at once or twice a second rate needed to ensure not missing much or any of priority traffic. Use a longer interval or don’t use priority channels in scan list if it annoys you.

Yes, Priority 1 is currently selected, P2 is also programmed, and theres a third non-priority channel in the list. Do you have a suggestion on lookback times that balance both goals?

 

[otobmark]

I'm working from memory right now so no chiseling in stone just yet--maybe pencil in for now. There is a lookback "A" and "B". A is the shorter interval used for initial look backs when first landed on non-priority channel. After a few samples of priority channel (while non P channel is chattering on) it will switch to looking back less often (B). When all conversations end it starts back at A. Now as to the intervals to use it depends on what your priority is: If P channel is "YOUR" operating or assigned channel where you absolutely need to hear all traffic on that channel you need short lookbacks (for me- A = .50 seconds and B = 2.0 seconds). If in a critical situation NO ONE should use scan except on a secondary radio (eventually it will catch up with you). If I'm doing casual monitoring or especially Ham channels where traffic drags on and on, I will use longer intervals (A = 2-5 seconds and B = 10sec or maybe more). I'm public safety focused on my Kenwood, Moto and EFJ radios so I default to A= .5 and B= 2.0). Most of the time I use the knob selected channel as priority 1. I don't use a priority 2 since I find it iffy in NX5K radios and I don't trust it. I have FPP and have never been able to front panel use P2 or alter it reliably. On my Viking radios I haven't noticed any problems but I haven't actually tortured the scan feature. Moto works as advertised. So, decide how much of the P1 channel initial conversation you can afford to miss. If you are listening for your callsign then even 1 second can cause you to miss it. Given the way NX5k radio scan works, use zone scan if you can and only use list scan when you absolutely have to. If you have a channel in one or more lists and decide to alter or delete the channel, you have to manually search every list and delete the channel there before you can delete the channel from a zone. If you use a lot of lists like I did early on, it became an easter egg hunt to eliminate a channel from every scan list. Under zone/channel information page, check the "Scan List No." column to make sure it is correct. I can reset itself if you change from zone scan to list scan so definitely check it before saving plug. Usually the setting is "Zone Common" or "None". I can be an actual scan list number.

 

[ConistonSafetyServices]

Yeah I'm with you that you shouldn't be scanning if on a tac channel, but I also like to make things end-user proof for people who don't follow best practices.

I do currently have it at 0.5/2.0 but if that's just a KW quirk that it doesn't work as well on P2 I can always just make it non priority and see how that behaves.

 

[ramal121]

Radios that employ priority scan will have an audio hole as the receiver switches frequency to check for activity on the priority channel. How fast the radio does this (receiver switches, VCO locks, check is made and then returns) varies from radio to radio. Kenwood across the board is only mediocre for this function. You cannot change the size of the hole which during the reception of a non-priority scan member can gobble up a whole syllable or more.

You can, however, change the timing for how often it checks the priority channel. You can increase the "Lookback" time that will make the non-priority scan member more intelligible while sacrificing the ability to catch the beginning part of a priority transmission. This is a personal preference thing and you just have to play with it. When programming a radio I like Lookback Time A at 0.8 or 0.9 seconds and Lookback Time B as default of 2.0 seconds. But you do you Joe!

Lookback Time A is when the radio goes off to check the priority channel and does not see a carrier on the channel. With this condition it will continue to use timing for Lookback A. If the receiver switches to the priority channel and sees a carrier but does not have the signaling qualifier to open up the speaker it will flag the channel and switch to Lookback Timer B. It will continue to use timer B until during priority check it sees no carrier in which it will revert back to timer A.

If you use priority 2 this will slow down your ability to receive either priority channel as it alternates between the two. I do not use a second priority channel unless I absolutely need to.

This scheme works, sort of. If you run a loose squelch and you have interference or co-channel users that show up during priority scan (as indicated by the busy LED flashing) you will continue to switch to Lookback Timer B which will slow down down your scan speed. A tighter squelch will help.

 

[dryfb]

Radios that employ priority scan will have an audio hole as the receiver switches frequency to check for activity on the priority channel. How fast the radio does this (receiver switches, VCO locks, check is made and then returns) varies from radio to radio. Kenwood across the board is only mediocre for this function. You cannot change the size of the hole which during the reception of a non-priority scan member can gobble up a whole syllable or more.

You can, however, change the timing for how often it checks the priority channel. You can increase the "Lookback" time that will make the non-priority scan member more intelligible while sacrificing the ability to catch the beginning part of a priority transmission. This is a personal preference thing and you just have to play with it. When programming a radio I like Lookback Time A at 0.8 or 0.9 seconds and Lookback Time B as default of 2.0 seconds. But you do you Joe!

Lookback Time A is when the radio goes off to check the priority channel and does not see a carrier on the channel. With this condition it will continue to use timing for Lookback A. If the receiver switches to the priority channel and sees a carrier but does not have the signaling qualifier to open up the speaker it will flag the channel and switch to Lookback Timer B. It will continue to use timer B until during priority check it sees no carrier in which it will revert back to timer A.

If you use priority 2 this will slow down your ability to receive either priority channel as it alternates between the two. I do not use a second priority channel unless I absolutely need to.

This scheme works, sort of. If you run a loose squelch and you have interference or co-channel users that show up during priority scan (as indicated by the busy LED flashing) you will continue to switch to Lookback Timer B which will slow down down your scan speed. A tighter squelch will help.

A quirk I've found regarding Lookback Time B: on a DMR priority channel, if any signal greater than -120 dBm (basically everywhere with other electronics) is present, it will use Lookback Time B.

Minimal effect on analog, NXDN, and P25 channels if it checks a DMR priority channel, but if on a DMR channel, and the priority is DMR as well I've found it to be almost unusable. It just takes so long to lock back onto the channel that by the time it does it's already checking again if using default settings. I suppose it could be a radio-specific issue, but I haven't been able to confirm this yet.