BCD325P2/BCD996P2: BCD996P2 much better than SDS100 on P25-phase II?

[djmorgan]

I have both these radios and have downloaded our local bus company (San Antonio VIA Metro P25) system from RR. As far as I can see by reviewing the two radios via their menus in the radios themselves they are programmed the same. I also monitor this system on Unitracker and it shows the system to be APCO P25 with FDMA frequencies. This is a non-simulcast system but has two sites. I have locked out one to be sure I am comparing the same things.

The BCD996P2 tracks transmissions nearly perfectly. The SDS100 is barely functional. When a talkgroup moves to another frequency between transmissions the SDS100 struggles to follow it. The SDS100 rapidly switches between the control channel and the correct audio channel being used but won't lock on to the audio channel or takes so much time that you miss the transmission altogether. Sometimes it will catch it but not often. It looks like it is trying to figure out that the audio channel is an FDMA channel and which slot to lock on. I have a 7 second video of this but I guess it won't attach to this message.

Any ideas about what I can do to make this much more expensive SDS100 radio perform better than a radio costing half the price?
PS... signal strength is strong on SDS100, BCD996P2 and the Unitrunker and I don't have this problem on a very large regional Project 25 Phase II system (that does not use FDMA). Thoughts very much appreciated!

 

[Whiskey3JMC]

With the SDS100 are you only scanning one site at a time (site hold)? I'm seeing two on the system in question. It's recommended to only scan one site whenever possible to avoid missed transmissions. Have you experimented with different filter settings?

 

[djmorgan]

Yes I am on hold on both radios.

 

[djmorgan]

And the hold is on the same site on both radios.

 

[KC1UA]

As suggested, try changing the SDS100's filter settings. They will almost certainly make a difference. There is no real guideline for their use, the best settings will be unique to your location, antenna, interference from area sources, etc.

 

[djmorgan]

Great suggestion...much better performance now. I set the Filter to OFF and the SDS100 is now tracking comparably to the BCD996P2. Of course, it was the last setting of seven or eight possibilities that I tried one by one but it works much better.

Thanks so much for the help!

 

[Ubbe]

I recommend to first try IFX to a frequency as that will switch to another mechanical filter in the scanner that will totally change the interference conditions. Either hold on to the frequency or enter it manually, Channel+freq+Channel, and do Fn+7 to toggle IFX to that particular frequency instead of all frequencies of a whole site that filter changes do.

/Ubbe

 

[djmorgan]

Excellent response...thanks so much for the detailed information. Right now it is fairly stable and I don't think it is an interference problem. I can hear the channel on my unitrunker and it is clear and crisp and when the radio does receive a transmission the D-error rate is low or zero. If I continue to have problems with it I will try the IFX settings per your suggestion. Great help, thanks Ubbe! Tack!

 

[Anderegg]

I have found the best filter settings for my local 700 and 800 LSM systems, and both need Wide Invert. For a military UHF P25 system, needs Wide Normal. The filters can be such a big deal as to prevent CC lock or RX if you don't select the correct one.

I also throw IFX at any freq in a trunking system that when it comes up the ERR rate climbs sky high vs all the other freqs being 0 ERR.

Paul