XTS5000 squelch flush in analog NON-Astro

radioactive69 · Post by **radioactive69** » Sun Jul 24, 2005 3:43 pm

I have UHF and VHF model III HT's with Host/DSP 05.00.00.

On many frequencies that RX in NON-Astro mode I have squelch that will flush (allow squelch noise to reach the speaker) after a transmission has ceased. This irks me slightly as this occurs on only a few channels but, the ones I have alot of traffic on.

I desire the squelch to close as if in PL Decode with reverst burst or like my Digital channels.

I have tried MIXED Mode and sqeulch settings no higher then 9 without clearing up the flush noise.

Any ideas?

Doug.

d119 · Post by **d119** » Mon Jul 25, 2005 9:55 am

Are you sure that the base station you're listening to is sending Reverse Burst? Is it a Motorola base station?

Certain things just don't match up sometimes. A Kenwood repeater will only properly mute a Motorola handheld via Reverse Burst every now and then. This is due to a difference in phase shift duration betwen Kewnood and Motorola reverse burst (120ms vs 180ms I believe).

Could that be it?

radioactive69 · Post by **radioactive69** » Mon Jul 25, 2005 2:39 pm

The problem exists on the frequencies that are in CSQ. No PL decode enabled.

Doug.

radioactive69 · Post by **radioactive69** » Mon Jul 25, 2005 2:42 pm

Also, most of the repeaters I access are Motorola MSF & MSR as well as some Daniels.

Doug.

mastr · Post by **mastr** » Mon Jul 25, 2005 3:08 pm

The best advice I can give is get used to it. A minor squelch "crash" in CSQ is one of the drawbacks of CSQ operation.

d119 · Post by **d119** » Mon Jul 25, 2005 5:03 pm

I didn't catch that it was carrier squelch operation.

There's no Reverse Burst for the radio to decode in CSQ operation. The function of Reverse Burst is that of PL. Reverse burst creates a 180 degree phase shift at the end of the transmission prior to the unkeying of the transmitter that mutes the receiving radio, provided the receiving radio is programmed for PL operation, and has a decoder that can sense reverse burst.

In DPL, reverse burst is not used. DPL uses a 134.4Hz "turn off code" to mute the receiving radio(s).

If you want the radio to mute, you must program the radio to decode PL, AND the base station your listening to must send reverse burst. Kenwood and other repeaters use a 120 degree phase shift which sometimes doesn't agree with Motorola portables, just as some Motorola portables will cause a squelch crash on non-Motorola repeaters. In the newer radios (and the XTS 3000 is not one of these), the phase shift of the reverse burst feature is adjustable.

Good luck!

libuff · Post by **libuff** » Tue Jul 26, 2005 4:47 pm

just to add some more information... i have had expierence with Motorola MTR repeaters with ZETRON Controllers, whereby the standards motorola phase shift was not enough to elminate the squelch trail...

d119 · Post by **d119** » Tue Jul 26, 2005 9:48 pm

libuff wrote:just to add some more information... i have had expierence with Motorola MTR repeaters with ZETRON Controllers, whereby the standards motorola phase shift was not enough to elminate the squelch trail...

I believe thats because the ZETRON Controllers, if you're speaking of the "Community Tone Panel" type and not the telephone interconnect type, handle the PL on their own, thus bypassing the reverse burst decode action of the actual decoder in the repeater. (Meaning the repeater is actually running CSQ, but the ZETRON is handling all PL decoding & encoding, audio gating & keying/control)

The ZETRON might not've been looking for the 180deg phase shift, and instead the 120 or something like that, thus causing a squelch tail.

Post by Pj » Tue Jul 26, 2005 10:29 pm

There was a thread not too long ago. I believe the Pro series is the only line out that allows the selecting of the 180 or 120 phase shift for the "non standard" reverse burst (meaning motorola, and then everyone else)

d119 · Post by **d119** » Wed Jul 27, 2005 1:23 am

I recall that thread, PJ. Though I don't know if they are in the Pro series or not, the CP200/etc MAY support the selectable reverse burst phase option.... Can anyone confirm?

libuff · Post by **libuff** » Wed Jul 27, 2005 10:36 am

the pro-series DOES have a option for non-standard reverse burst...

Post by **wavetar** » Wed Jul 27, 2005 11:41 am

The Commercial Series (CM/CP200/300, etc) definitely have the choice of 'standard' and 'non standard' reverse burst.

Todd

d119 · Post by **d119** » Wed Jul 27, 2005 12:30 pm

Excellent. One could venture to say that perhaps Motorola is adding this feature to all of it's newer analogue portables.

ASTROMODAT · Post by **ASTROMODAT** » Wed Jul 27, 2005 4:00 pm

We use IMBE 100% of the time on our radios, but in experimenting around with legacy analog FM on our XTL5000/XTS5000 radios, Yes, in CSQ you do hear a squelch crash. I was told there is no way around this, and I didn't open up a GCI, etc, as we never use analog anymore for any reason.

d119 · Post by **d119** » Wed Jul 27, 2005 4:50 pm

The squelch crash is inherent to every CSQ radio. It's a factor of the timing of the squelch circuit detecting a loss of signal, and then muting the speaker audio. Nothing is ever instantaneous. Or is it?

The MICOR series mobiles, repeaters and base stations (believe it or not), had a "dual-action" or "bi-level" squelch that was probably one of the most famous and popular things that Motorola ever developed.

The M7716 squelch chip was able to, on strong enough signals, mute the speaker audio with a mere click instead of a squelch crash when in CSQ mode. Amazing stuff.

Unfortunately Motorola chose not to carry that over past the MICOR series. A few repeater controller manufacturers, including the now-defunct Palomar Telecom, Link Communications and a few others manufactured Squelch Boards for base station/repeater equipment that used the M7716 squelch chip and enabled virtually any base station or repeater to have the "dual-action/bi-level" squelch. For those interested, the current product is the Link Communications "RLC-MOT".

I've personally installed one of these boards, and while they do work extraordinarily well, they are not for use in portable radios due to size limitations and the fact that integrating such a device into a portable would be extremely difficult from an interfacing perspective, considering todays microprocessor driven radios.

One could probably make one work in something like an MT500 or the like, but I digress.

radio-link · Post by **radio-link** » Wed Jul 27, 2005 11:43 pm

mastr wrote:The best advice I can give is get used to it. A minor squelch "crash" in CSQ is one of the drawbacks of CSQ operation.

I wonder why thjey do not simply delay the AF a bit. We have some really nice radios in germany, avoiding any squelch noisetail by simply adding some delay to the AF with a delay IC, I just do not know the exact english name, some kind of bucket device :)

mr.syntrx · Post by **mr.syntrx** » Wed Jul 27, 2005 11:53 pm

A buffer?

radio-link · Post by **radio-link** » Thu Jul 28, 2005 2:10 am

mr.syntrx wrote:A buffer?

It is also used for CB mics with echo effect, I have something like "something" bucket device or smoething like that in the back of my mind, but I really have forgotten the right name, the shortcut should be BBD, and the german word is Eimerkettenspeicher.

d119 · Post by **d119** » Thu Jul 28, 2005 5:58 pm

The "Bucket-Brigade" delay IC. Relatively old technology. While this does work just fine, it makes monitoring yourself on another radio a pain in the butt...

Probably just another cost factor that 90% of manufacturers have chosen not to integrate.

radioactive69 · Post by **radioactive69** » Fri Jul 29, 2005 10:33 am

I am glad to see this has generated some discussion.

It's seems that no one has addressed any CPS software switches or settings that would improve this squelch crash. I would have thought with newer technology this would have been addressed. Why would you build and mixed mode radio with out addressing this like they did with the Micor?

Surely a software driven solution could have been invented.

I have enabled the AGC "enhanced" switch with some reduction in the squelch crash. Enabling the "second LO side injection" did not seem to do anything to help.

Any other comments or ideas are welcome.

d119 · Post by **d119** » Fri Jul 29, 2005 12:23 pm

Thats because it was probably assumed that nobody posessing this caliber of radio would be using it in CSQ mode. They figured it'd all be digital or PL/DPL coded, so they probably didnt bother investing much in the CSQ end of things.

AGC has to do with transmitted audio, not received audio, IIRC. It is for noisy environments when ambient noise is an issue and the user can't be heard properly due to noisy conditions.

2nd LO injection has to do with RFI and internal "birdies" of the radio and keeping them from becoming an issue.

radio-link · Post by **radio-link** » Fri Jul 29, 2005 12:54 pm

d119 wrote:Thats because it was probably assumed that nobody posessing this caliber of radio would be using it in CSQ mode. They figured it'd all be digital or PL/DPL coded, so they probably didnt bother investing much in the CSQ end of things.

Yes, it seems, they only have the american view on radio usage :-) Here in Germany CSQ is not very often used for commercial radio, and never ever for police stuff.

radioactive69 · Post by **radioactive69** » Mon Aug 01, 2005 7:03 pm

I do not deal with commercial end of users I am a state government user. Our Agency only employs PL encode on the fixed repeaters and not all of the technicians can properly enable this on the Repeaters, resulting in disabled reverst burst. But revest burst was a band-aid of yester-years radios receivers.

Tactical traffic involving many outside agencies all using different tones (on their own systems) are assigned tactical frequencies to use once at scene of the incident. Using PL decode in your HT would prevent all of the cooperating agencies from being heard. There still is a need for CSQ in our case.

As we know even the cooperating agencies don't use the same brand radios as we do. Not all of the phase shiffting is standardized so squelch noise will be present even under these circumstances.

Our agency desires to implement Digital in the future but our BUDGET limits our desires.

For these reasons CSQ has a purpose and needs to have a solution to resolve this issue. Perhaps M will no longer make mixed-mode and will only be able to get digital or analog only. There will still be a place for analog for many years otherwise the XTS would not have this capability

Bring back Smart Squelch in a redesigned package or write a software enhancement that deals with CSQ mode.

Doug.

apco25 · Post by **apco25** » Mon Aug 01, 2005 7:35 pm

Micor squelch is a real pleasure to hear and made their repeater and mobiles famous for the "click".

Youl could always go back and re-engineer the system to allow multi PL input witha common ouput tone....

Only suggestion I could possible think of to cut the crash down a bit more is to increase the squelch setting itself a bit higher.

otherwise a slight bit of squelch clibk is normal and expected.