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Thorny41587

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I'm just wondering why didn't they use DPL instead of a PL tone on the 800 MHz I call channel? Cause DPL is newer than PL.
 

2112

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There are alot of different reasons that PL might be used instead of DPL. For example, the radios in the system may not be capable of DPL. Or maybe they weren't happy with the limitations of DPL.

More info here: http://www.directcon.net/pacres/dcs.htm

Just because DPL is newer than PL doesn't mean that it is better or even suitable. :)
 

2112

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mypoppa said:
Conrail is now called NORFOLK SOUTHERN!
Thanks for the update. Actually, CR was split almost evenly between NS and CSX.
 

Joseph11

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Why should it be CSQ? PL keeps out unwanted interference from nearby electronics. If there's a standard PL for interoperability, everything works the way it should.
 

NeFire242

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Joseph11 said:
Why should it be CSQ?
I have seen where two radios programmed the same won't decode each other's PLs because different radio models, manufactures, etc. Sometimes the tolerances are not that great, so I'd rather be safe than sorry on something such as mutual aid.
 

K5MAR

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NeFire242 said:
I have seen where two radios programmed the same won't decode each other's PLs because different radio models, manufactures, etc. Sometimes the tolerances are not that great, so I'd rather be safe than sorry on something such as mutual aid.
In my 30+ years of using commercial radios I've never seen quality equipment (such as Motorola, GE, Icom, Yaesu, etc.) display that problem. Somebody needs to be buying better equipment.

Mark
 

traumacop

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Too much variable in DPL formats for different vendors. I will try to find an article that explains it.

It is the same as Motos "non-standard" reverse burst for closing the PL gate.
 

scanfan03

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NeFire242 said:
I have seen where two radios programmed the same won't decode each other's PLs because different radio models, manufactures, etc. Sometimes the tolerances are not that great, so I'd rather be safe than sorry on something such as mutual aid.
I think the only reason that happens is because some radios can only be programmed with the reverse pl (I can't remember what it's called, someone on here knows i'm shure). There is a chart online which shows the reverse pl and it's equivcalince to the "regular" pl.
 

kb2vxa

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Hi all,

You guys have it well in hand so here I go totally off topic. (;->)

"Actually, CR was split almost evenly between NS and CSX."

CR (NS/CSX Shared Assets) is alive and well in NJ and the Detroit area, the radio licenses are held by Penn Central Communications. Yup, it's the "wrath of Conrail" alright with a dash of PC thrown in for flavor. Personally I like the smell of a GG-1 cooking on the ex PRR 11KV electric stove.

Well, it had SOMETHING to do with radio! (;->)
 

grem467

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You are thinking of DPL, there is no such "opposite" PL, as its simply a subaudable tone at a specific audio freqency, not a stream of 1's and 0's. Reverse burst/soft mute is achieved by changing the phase at the end of the transmission, some use 120 degrees out of phase, some use 180... BUT even with this, that does not make it incompatable with other vendors. Generally speaking, as long as your radios are properly aligned to spec a PL is a PL is a PL regardless of the "bells and whistles".

as for running them in CSQ, even the most ancient 800Mhz part 90 compliant radio that can do conventional operation can still do PL, and PL can help keep intermod and other crap out of the repeater. There is no reason NOT to use PL on ANY repeater, including hammy repeaters.
 

traumacop

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It's different

grem467 said:
You are thinking of DPL, there is no such "opposite" PL, as its simply a subaudable tone at a specific audio freqency, not a stream of 1's and 0's. Reverse burst/soft mute is achieved by changing the phase at the end of the transmission, some use 120 degrees out of phase, some use 180... BUT even with this, that does not make it incompatable with other vendors. Generally speaking, as long as your radios are properly aligned to spec a PL is a PL is a PL regardless of the "bells and whistles".

as for running them in CSQ, even the most ancient 800Mhz part 90 compliant radio that can do conventional operation can still do PL, and PL can help keep intermod and other crap out of the repeater. There is no reason NOT to use PL on ANY repeater, including hammy repeaters.
grem, there is a reverse DPL and pls and dpls are not perfectly compatible. Incompatible PLs cause long squelch tails and incompatible DPLs sometimes won't open the repeaters input or causes the carrier to drop out. Motos algorithm compared to Kenwood, Vertex and Icoms are different.

Just went over all of this spec.ing a repeater. Spent 15K and ended up using standard PL because of the variety of radios in our area.

I just can't find the article in my email
 

grem467

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umm thats EXACTLY what i was saying, that there WAS a reverse DPL but not a reverse PL (CTCSS)

you also proved my point that while different companies do reverse burst different, they DO work, ie bring up the repeater and allow the user to be repeated.

I NEVER said PL and DPL are the same or compatable, i DID say that PL (CTCSS) is the same regardless of the "bells and whistles" meaning how they implement softmute/reverse burst etc
 
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