Reverse Burst

[N7AS]

In the MOTOTRBO CPS 2.0 there is a setting "TPL Reverse Burst".

Choices are:

None
Non-Standard
Standard

What is the difference between these choices?
What effect does this have on the squelch tail?

 

[mmckenna]

Ah, yes, "standard".

Standard depends on who's standard. Motorola assumes theirs is standard. Others assume theirs is standard.

Reverse burst is where the phase of the PL tone is changed to tell the receiving radio that the carrier is about to drop and it should close the squelch. Prevents loud squelch tail crashes.

In Motorola software, "Standard" is a 120º phase shift.
"Non-Standard, pretty much what everyone else uses: 180º shift.
Just another way Motorola tried to keep you buying their radios. If you didn't, you paid the price with loud static crashes when the carrier dropped. Gee, thanks Motorola!!!!

None just means it doesn't do anything, PL tone just shuts off.

If you are just running Motorola radios, "Standard" would be the one to use.
If you are running in mixed company, others might appreciate you running "non-standard".

On some Kenwood software, you can go in and select the reverse burst phase. You have to have the engineering level access, but on some software you can go in and program the exact amount of phase shift.

 

[N7AS]

Does this have anything to do with hearing a squelch tail?
I like to hear a squelch tail after someone stops talking on the channel.

 

[GTR8000]

In Motorola software, "Standard" is a 120º phase shift.
"Non-Standard, pretty much what everyone else uses: 180º shift.
Just another way Motorola tried to keep you buying their radios. If you didn't, you paid the price with loud static crashes when the carrier dropped. Gee, thanks Motorola!!!!

Motorola is evil...blah blah blah. Perhaps you could at least acknowledge that it was Motorola who first introduced CTCSS aka "PL" and reverse burst, and the reason they eventually settled on the 120 degree phase shift over 180 degrees was because it proved optimal for the Vibrasponder PL reeds of the time. So in fact it was the other manufacturers who got away from the 120 degrees, not some marketing scheme by Motorola to get you to buy their radios. You know, if you're the first to do it, you kind of do set the standard, I'm sure even you have to agree with that premise. By the way, TIA-603-E references both phase shifts.

To the OP: Yes, it has everything to do with squelch tails. Note that the options in TRBO CPS are for transmit, not for receive. So even if you set yours for None, the radio is still going to suppress the squelch tails upon receiving a properly coded reverse burst from another radio or repeater.

 

[mmckenna]

Motorola is evil...blah blah blah. Perhaps you could at least acknowledge that it was Motorola who first introduced CTCSS aka "PL" and reverse burst, and the reason they eventually settled on the 120 degree phase shift over 180 degrees was because it proved optimal for the Vibrasponder PL reeds of the time. So in fact it was the other manufacturers who got away from the 120 degrees, not some marketing scheme by Motorola to get you to buy their radios. You know, if you're the first to do it, you kind of do set the standard, I'm sure even you have to agree with that premise. By the way, TIA-603-E references both phase shifts.

Absolutely, but I do love poking at Motorola periodically, and it was meant in jest, not any sort of attack on them.
And yes, I do own several Motorola radios, and I absolutely like them.

But, Standard does sort of depend on the specific point of view.

And thankfully we are not still using reeds.

 

[GTR8000]

And thankfully we are not still using reeds.

Tell that to the original Minitor I've got sitting in a charger on my desk. Still alerts like the day she was issued to me too long ago to mention. 💪

 

[mmckenna]

Tell that to the original Minitor I've got sitting in a charger on my desk. Still alerts like the day she was issued to me too long ago to mention. 💪

I've got some old ones left over from when we had a VHF paging system. Hung onto it for old times sake.

 

[W9WSS]

A friend of mine was so obsessed with reverse burst, he insisted that all (ham radio) units send reverse burst, otherwise he would harass and harangue them until they complied. He ran a Micor, then an MSF500, and finally a Quantar repeater on his UHF system.
Obsession went to his non-ham license plates which were vanity “R BURST” for a period of time.

 

[IFRIED91]

follow on question I’ve asked before in other threads and posts but could never get a straight answer

Harris/MaCom/Ericsson/GE/whichever brand anyones familiar with.. when MDC1200 was introduced years ago; they 2 options:
◻️MDC STE: transmits MDC signaling packet before STE

◻️MDC: transmits MDC after STE

same options apply for GE-Star..
what setting should always be used? I want to put this to bed once and for all

 

[a417]

what setting should always be used? I want to put this to bed once and for all

Always be used?
If there was no use-case for either/both options, you wouldn't have to (or be able to) make a choice. It will depend on your situation and how other radios are programmed.


...and do you mean this thread?

 

[jruta]

I've got some old ones left over from when we had a VHF paging system. Hung onto it for old times sake.

That was THE very first Moto I ever purchased. Age 17 👍 (a VERY long time ago Lol)
Wish I still had it for nostalgia sake

 

[WPXS472]

Off topic I know, but reeds worked very well and were pretty robust too. I have worked on some old pagers that could decode a signal down in the noise.

 

[Ghost117]

Interestingly, in my KPG-111D it shows +180 degree phase shift, which is what Kenwood uses by default, but for the 120 degree phase shift, it shows + or - 120, not sure which one Moto actually uses.

 

[Echo4Thirty]

If i remember correctly, its +120 degrees.

EDIT: Repeater Builder says 120 degrees forward as well.

 

[com501]

Still have one of these in my workshop at home. Still works, until they start the P25 system where I live.

 

[BMDaug]

Regardless of who created the feature, it’s not very informative to label it ‘standard’ and ‘non-standard’. That’s what always irks me! If TIA recognizes both, then aren’t they both a standard? Why not just label the options ‘none, +120, -180’ like everyone else? Then half of this thread wouldn’t have been necessary, and nobody would have the chance to have their feelings hurt and get defensive… Maybe that’s half the fun of the forum for some folks, but I’m a fan of the Mary J. Bilge philosophy: “No More Drama”.

-B

 

[mmckenna]

"The nice thing about standards is that there are so many to choose from."

Sometimes my sense of humor goes flying over people's heads. (Rule #1, never take me seriously)

None the less, there are people that are smart enough to figure this out and make it work. Sharing that information (along with a side dish of humor) is what makes this site useful.