BCD996XT Reverse Burst?

[Brian7M3]

Can anyone tell me if the BCD996XT responds to PL reverse burst when decoding? I have the GRE PSR 500 and I know this scanner does but was wondering if the 996XT does.

Thanks,
Brian

[russianspd]

What is a reversed burst?

[nd5y]

Motorola® Reverse Burst & And Squelch

I don't know if the 996XT is the same as the 396T. It seems to accidently mute on reverse burst some of the time on certain systems.

[Boatanchor]

Probably not.
The XT series scanners have slow CTCSS decoders that are slow to react even on quiet tail systems.
I have a nearby FM LMR system that cuts the CTCSS tone a couple of hundred mS before the carrier drops. Usually, on a 'real' radio and even GRE scanners, this eliminates the squelch burst as the repeater tail drops, but not on the Uniden scanners.

[Avery93]

I can confirm that the 996XT (as well as the 346XT and BCT15) does support reverse burst, but not very well. It works about 50% of the time with the 180° phase shift (used by every manufacturer except Motorola), and around 75% percent of the time with the Motorola standard 240° phase shift.

When it does work, Unidens keep the audio muted for too long (almost half a second I think), which means you may miss the first part of transmissions immediately after a reverse burst is detected. This is fairly common when someone replies on a repeater with a short hang time (around one second or so).

[Boatanchor]

Lets hope Uniden fixes their CTCSS decoder problems in the next models (if they are ever released).

[Brian7M3]

Thanks for the feedback guys. I currently have the PSR500 but I am looking for a base scanner. The GRE responds to some systems with reverse bursts but others it actually produces a larger squelch crash with the PL decode on than with it off. I guess it is not hearing the reverse phase and keeping the squelch open waiting for it for a few extra milliseconds.

I am considering the BCD996XT because the VHF and UHF receive seems pretty bad on the GRE. I guess a good recieve is better than proper tone decode.

I have noticed that the GRE has lots of settings to fine tune the PL/DPL decode that I have listed at the end of this message. I don't have the BCD996XT yet, but I haven't found any settings like these mentioned for it. I checked the FreeSCAN software and don't see any way to adjust the decode settings on the 996 through that either.

CTCSS/DCS/NAC ACSQ SrcInt Wait for HD5 sig in auto CSQ
srch
500 10-2000, x1 ms Search Interval Search Delay Length of time to wait for a CTCSS/DCS/NAC signal in auto carrier squelch
search
CTCSS/DCS/NAC ACSQ PolInt Interval to poll for CSQ value 100 10-1000, x1 ms Query Interval Query Interval The interval of time to check for a CTCSS/DCS/NAC signal
CTCSS/DCS/NAC HD5 Fade CSQ fade delay 2000 10-10000, x1 ms Fade Timeout Fade Delay Length of time to wait after losing a CTCSS/DCS/NAC signal. Max value changed
from 2500 to 10000 in firmware 1.4
CTCSS/DCS/NAC HD2 Qualify CSQ end detect threshold 75 1-1000, x1 ms End detect qualify Qualify Time
(Analog)
Length of time to check to detect an end of signal turn off code command

CTCSS/DCS/NAC HD2 Holdoff CSQ post-end wait time 500 10-1000, x1 ms Delay after end Mute Time Length of time to mute a signal after an end of signal turn off code command