JPS Voting? Help

Gregg · Post by **Gregg** » Mon Sep 25, 2006 7:56 am

We have a JPS system that jut does noit seem to be voting the best channel. It sounds like*&^%. I there anyone out there that has ran in to the same problems. You can be at a site and never hear broken or weak radio traffic but if you listen to the radio traffic that the JPS votes its seems as if its voting the worst possible signal. We have had someone at the the comparator and watched this happen over and over. We have tried many different settings on the JPS, and are not ready to give up on it but its getting old running around to the sites and not gaining much headway.

Dan562 · Post by **Dan562** » Mon Sep 25, 2006 9:29 am

This problem sounds very familiar but I've only dealt with it on a /\/\ Analog Spectra-Tac comparator. The problem you've described is called Down Voting, where the comparator selects a different noisier receiver site rather than the closest Full Quieting site.

I've got a few questions for you on the JPS Comparator.

How many Receiver Site Input Modules are in the JPS Comparator?

Is your JPS Comparator colocated with the Base Station / Repeater?

Can you force Vote the receiver site that you think should be selected?

What does your customer have as far as Subscribers units, handheld Portables & RF Power Output or Mobiles & RF Power Output or combination of Portables and Mobiles?

Dan

Batwings21 · Post by **Batwings21** » Mon Sep 25, 2006 10:14 am

Is this your first JPS? If so did you replace a spectra-tac comparitor directly? We have about ten JPS comparitors and they work excellent, but they are setup different than a Motorola.

Okay in a Motorola system Status tone is -13db from voice average, on a JPS it is 0db. Did you adjust all of your tac sites that way?

RF_Burns · Post by **RF_Burns** » Mon Sep 25, 2006 5:47 pm

Is this an SNV-12 voter? If so there was an issue I found on some i bought in summer 2004.
Basically if a another site opened with a noisy signal it would jump there then vote back to the best site. If you had sites opening and squelching on noisy signals it would spend alot of time voting these noisy signals. Of course JPS had never heard of it before but it was easy to replicate and they sent a new set of proms to fix it within a couple of days and they have worked great ever since.

Couple months ago they sent an office release of this new firmware, but my motto is if its working don't mess with it so they are sitting in my desk drawer.

GEMOTO · Post by **GEMOTO** » Tue Sep 26, 2006 8:56 am

You may want to make sure all of your phone/T-1 circuits are equalized.

Gregg · Post by **Gregg** » Mon Oct 02, 2006 8:10 am

Batwings21
Our sites are levels
Pilot tone is at a -15
Voice audio is at -15 to -27

MSS-Dave · Post by **MSS-Dave** » Mon Oct 02, 2006 10:52 am

Need some more info.... Are you using the same receiver types at the sites? Are you transporting the audio all the same way? (T-1, satcom, microwave?)

It almost looks like the audio is a little too low at the channel inputs to the voter (not the pilot tone..) I'm doing beta testing on one here, all of the audio inputs are running at -10 dBm with 1 k tone at 60% of system deviation. I'm doing 900 mhz here so that's 1.5 K deviation. I'm doing E&M so not using the pilot tone. Recovered audio level should be +5 dBm on a SVM 2 module and 0 dBm on a SVM 1. at the TP 3 jack on the front of the card. Mine are all right at +5 at this point and it votes wonderful. Another thing, I'm trying to "graft" a different type of receiver into the system. The frequency response is different that the other 3. I'm having a time getting the audio equalized at the receiver site so it will show up at the JPS about the same as the others. If you do have different receivers, you could have some difficulty...

Dave