Migration Patching to P25

[kc7aad]

Has anyone used the JPS ACU-1000 during migrations to a new P25 PII system? I'm having audio issues with our migration, and believe it is due to the vocoder. I have aligned the radio and gone through audio level settings multiple times (DAYS WORTH!!). Still the audio mostly sounds like crap through the ACU-1000. We're connecting 450XTL1500/2500's and Tait TM9400's. The audio from the TP9400 sent to the XTL's sounds great. Consider it the quality of audio you would expect. The other way, not so much!
We've tried using both speaker audio as well as filtered audio. Different tap points in the TM9400 as well as just the mic connector.

Any ideas or thoughts would be greatly appreciated!
Rod

 

[moetorola]

Migration Patching to P25??ACU1000 for migration??? That does not have anything to do with your issue.

Sounds like an audio adjustment, you might try asking in the TAIT forum here.

Have you contacted JPS, they are great to work with. They also have templates you can run.

We run an AC1k, and Audio patch between a XTL1500/2500's too Kenwood Nextedge radio's sounds great both ways. FWIW

I would start by going back to square one and start measuring audio levels, also check pre/de emphasis settings and such. Probably something simple is being missed.

Goodluck, hope you get it going!

 

[scoutcamper]

There are way too many possibilities here, but let me list a few.

Are you using the JPS Cable for the TB9400? How about the JPS cable for the XTL?

The ACU-1000 has a spot to hook a handset, how does handset audio sound in both directions? that should narrow you down to a single cable/radio as the issue.

For ease of testing put everything on analog channels, get it sounding right, then introduce the trunking again. Analog to analog patch, either tune by ear or tune using a service monitor and injecting known audio to make sure the patch plays nicely.

And a word of caution, I have used the ACU line a LOT for interoperability on many type 1 all-hazards incidents, if you are using anything other than VMR for your carrier/audio detect you will see weird issues. VMR is the correct way to set up this type of patch, instead of COR or VOX. Otherwise you run the risk of ping-pong issues and other weirdness.

For those who dont know, VMR is Voice Modulation Recognition, think VOX but much more intelligent, it takes more than some background to trigger it, and once it is tweaked to work well(must be done per individual radio), it is bulletproof reliable.

 

[phonebuff]

As @moetorola said. The ACU-1000 is an Analog audio bridge. It's possible to under drive or over drive audio, but there are no vocoders involved...

I would second the recommendation if you think you need help with the ACU-1000 to call support and Benny and company are the best, but also look at the pre-built configurations and templates in the directory you installed
the software on your PC. The PDF often has notes relating the code plug of a specific subscriber.

 

[RFI-EMI-GUY]

Is your problem in going from analog system to digital? In that case, any multi path noise in the analog channel will have to be dealt with by the vocoder, and the vocoder wont have a clue what to do with it. Can you apply some LP filtering at 3200 Hz? Can you get audio somewhere better like at the system voter?

 

[kc7aad]

@Moetrola .. Yep.. Patching the legacy 450 system toa new P25 system, using an ACU1k... Have checked audio levels from the 450 through the ACU to where it injects into the Tait, and the audio is great up to that point. Once it hits the Tait, the audio is pretty wonky! We've gone through level adjustments many times over the last couple of weeks, and just can't get it to sound any better! Not sue why. I stepped away and had someone else (2 other folks, actually) come in to look at it too. They have been as stumped as I am.

@Scoutcamper.. We are using the JPS cables for the XTL's, but not the Taits. it was thought that the Tait's don't have any real components in them, when you look at the drawings from JPS. So they decided to make their own, which I've looked at, and appear to follow the JPS drawing.
The handset audio sounds fine in all directions. That's what got me the most stumped! Even outbound through the Tait, which appears to be where my audio failure is being suspected from.
I've also test on Analog and it works better, though not stellar yet. Then once I move it to the Trunked system, all goes to crap.
I do agree that it's likely an audio issue, however with only steps able to be done in the increments on the ACU DSP's, I don't feel like I have enough granularity to maybe get where I need to be. And with 3 of us having worked on this, each starting over so we know we're starting with known good radios, it leads me to think there's something more that maybe we're just glaring over.

We've also tried Microphone inputs on the tait, as well as the tap in versus Ext Audio in. Different tap points, too. I just feel bruised after days of this.

BTW: We are using COR on both the XTL and the TM9400. The 450 system through the XTL does try and ping-pong, but we've adjusted the Ignore COR after PTT to effectively null out the squelch tail. It's working OK.


Thanks for your tips and thoughts, guys! It makes me think of other things to go through..


R

 

[kc7aad]

@RFI-EMI-GUY.. You're thoughts are exactly what I have been suspecting! While some signals are more clear, they sound pretty good. Others, or the low tone talkers, sound horrible as the vocoder tries to decipher what's happening on it's incoming audio!
I'll test this a bit more tomorrow on analog channels. I just found out that one that I was suspecting was analog where I was doing some testing, may have not been so after all.


Thanks everyone!
R

 

[sarguy1941]

Is there a reason you can't patch via a console. Normally folks setup a control station on a legacy channel and patch to a TLK GRP. Makes it simple and clean. I do run a ACU-M in our command post and have a UHF P25 and VHF Analog and the patch works very well. As others said verify settings in the ACU. The ACU-M lets you select the radio and pre fills in most for you.