NX800 6.25KHz issues?

[70cutlass442]

We recently moved about 80 radios to 6.25KHz from 12.5KHz. I hear the field units really well most of the time with very infrequent issues. I noticed however, that dispatchers are sometimes not hearing the field units. This is pretty frequent. Then once the field unit repeats itself, dispatch may hear them fine. Has anyone had issues with 6.25 on the NX800? Does the NX3820 offer any improvements over the NX800 when using 6.25? Could this be a firmware issue and should I upgrade that as step one?

 

[mmckenna]

What are the dispatchers using on the RF side? Is it a radio linked into the system or is the console directly interfaced to the system?

 

[70cutlass442]

What are the dispatchers using on the RF side? Is it a radio linked into the system or is the console directly interfaced to the system?

They are using a control base which are all NX800s. Most of the fleet are NX800 with a few new 3820s being added.

 

[mmckenna]

Are they scanning? I had issues with my original NX-900's on a 2.8x firmware that would sometimes miss traffic when scanning. Updated firmware and fixed it, but those were running in 12.5KHz.

With 6.25KHz, it's really important that the radios are right on frequency. Since these NX-800's have been out there a while, it would be worth having them benched to check frequency error.

 

[70cutlass442]

Are they scanning? I had issues with my original NX-900's on a 2.8x firmware that would sometimes miss traffic when scanning. Updated firmware and fixed it, but those were running in 12.5KHz.

With 6.25KHz, it's really important that the radios are right on frequency. Since these NX-800's have been out there a while, it would be worth having them benched to check frequency error.

These are not scanning, but I agree, these probably should be checked out. I also could not tell you what F/W they are, I am just assuming it is old. These guys may just replace the radios with the 3820 before they pay to have them aligned.

 

[kd4efm]

you need to make sure the radios are within +/- 200 Hz of center frequency for true and proper operation. 12.5 has about +/- 600 Hz give or take, but 6.25 you need to be pretty much dead on for seamless ops.
This is 12 years with running a Gen1 system, and working with simplex / single repeater systems.

So, when was the last PM done fleet wide?

 

[kd4efm]

Just buying new radios wont solve the core issue. Having a well tuned system for the user / customer is the key goal. Keep them happy, and the price of PM pays for itself.

 

[70cutlass442]

you need to make sure the radios are within +/- 200 Hz of center frequency for true and proper operation. 12.5 has about +/- 600 Hz give or take, but 6.25 you need to be pretty much dead on for seamless ops.
This is 12 years with running a Gen1 system, and working with simplex / single repeater systems.

So, when was the last PM done fleet wide?

We are new to this account, my guess is the trucks have never been PMed, nor have the dispatch control stations. My first step is to upgrade F/W, but that is assuming these are really old and that the older F/W did not work well with 6.25. Not sure if that is the case though.

 

[70cutlass442]

Just buying new radios wont solve the core issue. Having a well tuned system for the user / customer is the key goal. Keep them happy, and the price of PM pays for itself.

I am watching the system as well, the fact that I can hear the field units more so than dispatch can makes me want to start in dispatch. They are more likely to buy a new radio than to send a 12 year old unit out for alignment.

 

[kd4efm]

We are new to this account, my guess is the trucks have never been PMed, nor have the dispatch control stations. My first step is to upgrade F/W, but that is assuming these are really old and that the older F/W did not work well with 6.25. Not sure if that is the case though.

FW update wont fix off frequency.

Yes, updates are worthy, but if you're going to update, might as well tune it too!

 

[kd4efm]

I am watching the system as well, the fact that I can hear the field units more so than dispatch can makes me want to start in dispatch. They are more likely to buy a new radio than to send a 12 year old unit out for alignment.

NX-800 is a brick house, like Monty-Python says, I'm NOT DEAD YET! Tune it.

 

[70cutlass442]

NX-800 is a brick house, like Monty-Python says, I'm NOT DEAD YET! Tune it.

this is good to know.

 

[kd4efm]

Here is the next point, if you change out the dispatch radio (being DB25) to a NX3820, your going to spend more then it would be to just tune it and make them happy. Beside, the 5800 would be the ideal for swap out, like pin outs. No changes. plug and play.

 

[kd4efm]

by the way, I have a 14 year old NX-800 I use for ham and commercial on my bench, I tune it every 3 years, and only had to warp the VCO once as it drifted below - 180 cycles, and that was 2 years ago.

 

[70cutlass442]

One of the guys here just bought an aeroflex, once we figure out how to use it, I would like to do exactly that with a few of these. The customer has a very aggressive replacement plan for IT items. This falls in that category so we may just end up buying new stuff.

 

[kd4efm]

One of the guys here just bought an aeroflex, once we figure out how to use it, I would like to do exactly that with a few of these. The customer has a very aggressive replacement plan for IT items. This falls in that category so we may just end up buying new stuff.

Smart plan, transitioning is a good thing, I will have the Viavi CX200 soon, looking forward to this jewel!
You can align the radio with any monitor, in analog mode. Email me via the email I sent you in the PM.
We can discuss more.

 

[mmckenna]

The customer has a very aggressive replacement plan for IT items. This falls in that category so we may just end up buying new stuff.

Most IT guys (and all the young IT guys) can't understand the life cycles of two way radio systems or large PBX platforms. It's absolutely foreign to them that equipment can last that long, can be repaired, and it actually designed to not be "throw away".

If your dispatch uses radio consoles, wiring the NX-3820's will be a big difference. There's a bunch of tiny chip resistors that often need moving to make it work. My eyesight isn't good enough to do that, so we wired audio input through the front RJ-45. Not a big deal, but not a plug and play replacement for the NX-800's. Kind of annoying. Realigning the NX-800's would be much easier, and cheaper than the NX-5800 as Evans said. My NX-900's connected to our dispatch consoles have been running since 2011 with zero issues. I'm sure they'd run another 10 years, easy.

 

[kd4efm]

Matt, the 5900 (hahaha) kinda pricey but yup, why throw out something that works like a iron house or brick house, screaming I'm not dead YET!

 

[AM909]

The NX-3820 mobiles are only spec'd at 1.0 ppm "Frequency Stability" (i.e., 450 Hz at UHF) and the NX-3300K are 2.5 ppm (1.0 ppm for the "E" versions). I don't know if that's supposed to be per year or from cold to hot or what. We just deployed some NXDN very narrow and wondering if I really have to worry about frequency stability. I don't recall aligning freq on an NX-3k other than the ones that were way off because of the defective TCXO problem.

Of course, the manual says I need 0.001 ppm accuracy sig gen (less than 1 Hz at UHF).