GottIstGutig
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I've heard PL tones go further than DPL tones. So does CSQ go further than both?
CSQ, PL and DPL
- Thread starter GottIstGutig
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Pl distance
My experience using commerial radios (VHF motos, maxtrac and Mt2000)
suggests that reception of marginal signals is degraded using DCS/DPL. However, using
good quality gear, PL reception distance seemed identical/insignificantly different.
I've had radios which would reliably decode the PL tone, and open up the audio, when voice was not very readable (due to weak signal).
However, I wouldn't be surprised if differences were noticed with PL's when using
gear of lower quality.
My experience using commerial radios (VHF motos, maxtrac and Mt2000)
suggests that reception of marginal signals is degraded using DCS/DPL. However, using
good quality gear, PL reception distance seemed identical/insignificantly different.
I've had radios which would reliably decode the PL tone, and open up the audio, when voice was not very readable (due to weak signal).
However, I wouldn't be surprised if differences were noticed with PL's when using
gear of lower quality.
N
N_Jay
Guest
GottIstGutig said:
The signal goes just as far.
How much signal you need to decode PL or DPL would depend on how clean the original signal is, the level of the PL or DPL modulation and the alignment and quality of the receiving equipment.
As for CSQ, it is simply the absence of PL or DPL, and you are back to the unanswerable question of how far the signal goes.
Agreed
I was referring to what I thought to be the intent of the question, ability to receive. Certainly all the signals will go as "far." But my practical experience is that PL and CSQ seem to work at lower signals levels, and hence, might seem to go 'farther' than DPL.
I was referring to what I thought to be the intent of the question, ability to receive. Certainly all the signals will go as "far." But my practical experience is that PL and CSQ seem to work at lower signals levels, and hence, might seem to go 'farther' than DPL.
GottIstGutig
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- May 19, 2005
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DPL is more advanced than PL right? It's newer I mean. Cuz only one department around five counties use it.
Correct
Yes DPL is a newer technology (but it's been around for quite a while). One advantage of DPL is that it is much less susceptible to opening up the squelch in the presence of strong
interference/noise than is PL. Also, you have more DPL codes than PL codes to choose from.
Yes DPL is a newer technology (but it's been around for quite a while). One advantage of DPL is that it is much less susceptible to opening up the squelch in the presence of strong
interference/noise than is PL. Also, you have more DPL codes than PL codes to choose from.
N
N_Jay
Guest
Well since CSQ is NO-Coded squelch, then by definition it goes the furthest as it is only limited by the receiver and your tolerance to listen to a noisy signal.
PL, in theory can be decoded at S/N levels way below those needed for speech so whether it decreases range will depend on how good the decoder is (and how many false decodes you can tolerate).
DPL should also be able to be decoded at very low S/N ratios, but have not played with it enough to know how bad the audio gets before all hope is lost in decoding it.
Yes, DPL is newer and was proprietary for a long time.
PL, in theory can be decoded at S/N levels way below those needed for speech so whether it decreases range will depend on how good the decoder is (and how many false decodes you can tolerate).
DPL should also be able to be decoded at very low S/N ratios, but have not played with it enough to know how bad the audio gets before all hope is lost in decoding it.
Yes, DPL is newer and was proprietary for a long time.
GottIstGutig said:
NJ's post immediately above sums it up best. I've actually seen CDCSS decode lower than you could make out the audio on a signal, so I think in a PROPERLY set up system there is practically no difference in the distance any of them go, but CTCSS/CDCSS could actually go a little farther than CSQ if you want to split hairs. Any should work as long as you can make out the audio on a signal, and if you can't make out the audio, there is little use for the signal anyway.
There are some receivers that are also intentionally set so that this is the case. The squelch is set tight so local users can use a system CSQ, but to get more distance you have to encode the correct tone/code. This is usually in the ham band this happens.
Joe M.
N
N_Jay
Guest
Voyager said:
Can you explain what you mean?
For some of us who live this radio thing as an occupation, it's an easy thing. For those out there not living daily in the geeky technical aspects of receiver squelching, he probably means that in a great number of radios, there are several methods of determining how the audio unmuting/muting is governed in the CTCSS/CDCSS modes, and those can make the radio act differently at lower signal levels.
How the audio is unmuted and muted is partly determined by the squelch setting and partly by how the squelch circuit is allowed to influence the audio unmuting/muting. Remember, the receiver can still be receiving a readable signal when a higher squelch setting or the decoder says shutup. What method(s) are available in a scanner are purely conjecture on my part since I don't actually own or work on any of them.
In Carrier SQuelch mode, the carrier squelch setting is allowed to determine signal levels required to unmute/mute audio. A proper squelch circuit will have what's known as hysteresis, or an ability to unmute audio at a predetermined level and mute at a lower level. The difference between those two is the hysteresis factor, and is necessary to prevent audio from chopping in and out as one or both the transmitting and receiving radios change locations in relation to each other or atmospherics make for fun and games. A usual figure is something like 6db lower signal level to mute the receiver.
In CTCSS/CDCSS decode modes there are more options. Let's talk about unmuting first. Standard unmuting allows the correct CTCSS/CDCSS detection alone to determine when the receiver unmutes.
AND unmuting involves both the carrier squelch circuit AND correct CTCSS/CDCSS decoding to unmute the receiver. The carrier squelch setting determines the signal level required to allow unmuting and the CTCSS/CDCSS circuit determines IF it will unmute.
OR unmuting is reserved for receivers that unmute for alerting tones IF the correct alerting tones are decoded, OR if the correct CTCSS/CDCSS is decoded. Either will unmute the receiver.
Standard muting occurs when the CTCSS/CDCSS disappears from the signal and muting delay is usually a timed function to avoid signal chop.
OR muting occurs when either CTCSS/CDCSS OR sufficient signal level is lost. Either will cause the receiver to mute.
Since the better radios can decode CTCSS/CDCSS at a signal level that's lower than any carrier squelch setting, and way too low to pull any intelligence out of, yes, it's entirely possible that the audio will unmute at a lower level in a receiver that's set up for standard decode unmuting than one set up to unmute through the squelch setting. Doesn't have a thng to do with whether you can read the signal or not, but it in effect gets a reaction from the receiver that carrier squelch won't allow. STD/STD unmuting/muting combo is the one that produces the greatest sensitivity levels, and in that case, the signal "goes farther."
Just as an aside, I have demonstrated this effect on the test bench many times to reinforce my contention that certain base station applications, especially repeaters, need to employ the AND/OR or the AND/STD unmuting/muting combo. Mobiles I leave to operator preference.
How the audio is unmuted and muted is partly determined by the squelch setting and partly by how the squelch circuit is allowed to influence the audio unmuting/muting. Remember, the receiver can still be receiving a readable signal when a higher squelch setting or the decoder says shutup. What method(s) are available in a scanner are purely conjecture on my part since I don't actually own or work on any of them.
In Carrier SQuelch mode, the carrier squelch setting is allowed to determine signal levels required to unmute/mute audio. A proper squelch circuit will have what's known as hysteresis, or an ability to unmute audio at a predetermined level and mute at a lower level. The difference between those two is the hysteresis factor, and is necessary to prevent audio from chopping in and out as one or both the transmitting and receiving radios change locations in relation to each other or atmospherics make for fun and games. A usual figure is something like 6db lower signal level to mute the receiver.
In CTCSS/CDCSS decode modes there are more options. Let's talk about unmuting first. Standard unmuting allows the correct CTCSS/CDCSS detection alone to determine when the receiver unmutes.
AND unmuting involves both the carrier squelch circuit AND correct CTCSS/CDCSS decoding to unmute the receiver. The carrier squelch setting determines the signal level required to allow unmuting and the CTCSS/CDCSS circuit determines IF it will unmute.
OR unmuting is reserved for receivers that unmute for alerting tones IF the correct alerting tones are decoded, OR if the correct CTCSS/CDCSS is decoded. Either will unmute the receiver.
Standard muting occurs when the CTCSS/CDCSS disappears from the signal and muting delay is usually a timed function to avoid signal chop.
OR muting occurs when either CTCSS/CDCSS OR sufficient signal level is lost. Either will cause the receiver to mute.
Since the better radios can decode CTCSS/CDCSS at a signal level that's lower than any carrier squelch setting, and way too low to pull any intelligence out of, yes, it's entirely possible that the audio will unmute at a lower level in a receiver that's set up for standard decode unmuting than one set up to unmute through the squelch setting. Doesn't have a thng to do with whether you can read the signal or not, but it in effect gets a reaction from the receiver that carrier squelch won't allow. STD/STD unmuting/muting combo is the one that produces the greatest sensitivity levels, and in that case, the signal "goes farther."
Just as an aside, I have demonstrated this effect on the test bench many times to reinforce my contention that certain base station applications, especially repeaters, need to employ the AND/OR or the AND/STD unmuting/muting combo. Mobiles I leave to operator preference.
Last edited:
Hi all,
Re: Joe M.:
"...CTCSS/CDCSS could actually go a little farther than CSQ if you want to split hairs. Any should work as long as you can make out the audio on a signal, and if you can't make out the audio, there is little use for the signal anyway. There are some receivers that are also intentionally set so that this is the case. The squelch is set tight so local users can use a system CSQ, but to get more distance you have to encode the correct tone/code. This is usually in the ham band this happens."
Let me elaborate some. Many ham repeaters use comercial equipment and are operated by communications professionals and engineers. One club I used to belong to was one such and in the guide book it was suggested that users turn off the CS completely and use only the PL receive. This affords maximum sensitivity under difficult conditions, however the man is right, if you can't copy the intelligence the signal carries there's no point in straining your ears.
"The squelch is set tight so local users can use a system CSQ, but to get more distance you have to encode the correct tone/code."
This was exactly the case in point, however transmitting the tone kicked in a receive preamp so naturally the repeater's receive was greatly enhanced. This of course has nothing to do with why users were encouraged to use PL receive exclusively, located in Manhattan NYC the repeater's signal was subject to severe local conditions which weren't present in other areas. This is akin to my experience using HTs to communicate at special events which often have difficult conditions all thier own. I found out for myself that PL squelch will open when carrier squelch will not and misses calls. I don't expect you guys listening to your scanners at home will experience such conditions so for you it's a moot point, but take your portable in the field and you'll notice the difference.
Hey "Equal Opportunity Offender", do you think we have them sufficiently confused now? You got me, until know I thought hysteresis was an unwanted characteristic of an iron core contributing to the Ix of a transformer. I'm surprised you didn't describe it as the "flywheel factor", possibly due to your reluctance and thier leakage inductance, distributed capacitance or possibly reactance or resistance. Even with my high transconductance I'm confused. Let's just consider hysteresis as an excitable monkey if you know what I mean mho. (;->)
Re: Joe M.:
"...CTCSS/CDCSS could actually go a little farther than CSQ if you want to split hairs. Any should work as long as you can make out the audio on a signal, and if you can't make out the audio, there is little use for the signal anyway. There are some receivers that are also intentionally set so that this is the case. The squelch is set tight so local users can use a system CSQ, but to get more distance you have to encode the correct tone/code. This is usually in the ham band this happens."
Let me elaborate some. Many ham repeaters use comercial equipment and are operated by communications professionals and engineers. One club I used to belong to was one such and in the guide book it was suggested that users turn off the CS completely and use only the PL receive. This affords maximum sensitivity under difficult conditions, however the man is right, if you can't copy the intelligence the signal carries there's no point in straining your ears.
"The squelch is set tight so local users can use a system CSQ, but to get more distance you have to encode the correct tone/code."
This was exactly the case in point, however transmitting the tone kicked in a receive preamp so naturally the repeater's receive was greatly enhanced. This of course has nothing to do with why users were encouraged to use PL receive exclusively, located in Manhattan NYC the repeater's signal was subject to severe local conditions which weren't present in other areas. This is akin to my experience using HTs to communicate at special events which often have difficult conditions all thier own. I found out for myself that PL squelch will open when carrier squelch will not and misses calls. I don't expect you guys listening to your scanners at home will experience such conditions so for you it's a moot point, but take your portable in the field and you'll notice the difference.
Hey "Equal Opportunity Offender", do you think we have them sufficiently confused now? You got me, until know I thought hysteresis was an unwanted characteristic of an iron core contributing to the Ix of a transformer. I'm surprised you didn't describe it as the "flywheel factor", possibly due to your reluctance and thier leakage inductance, distributed capacitance or possibly reactance or resistance. Even with my high transconductance I'm confused. Let's just consider hysteresis as an excitable monkey if you know what I mean mho. (;->)
n4voxgill
Silent Key
i know a woman that had a hysteresis
PL / CSq / DPL...
My goodness....I've been working since 1977 with systems WITHOUT PL, with PL, now DPL....ALL of how well you can or can't hear depends on the quality of the involved equipment, the WEATHER, how well your repeater, transmitter, mobile, portable is MAINTAINED....Take a portable, bad weather, you can't talk from the city limits... Good weather, a portable, you might be able to talk from the NEXT county !!!! Its RADIO. Never the same two days in a row (at least around here !!!!) Steve
My goodness....I've been working since 1977 with systems WITHOUT PL, with PL, now DPL....ALL of how well you can or can't hear depends on the quality of the involved equipment, the WEATHER, how well your repeater, transmitter, mobile, portable is MAINTAINED....Take a portable, bad weather, you can't talk from the city limits... Good weather, a portable, you might be able to talk from the NEXT county !!!! Its RADIO. Never the same two days in a row (at least around here !!!!) Steve
N_Jay said:
OK. Frequently, the squelch is set just above the threshold, or maybe a little tighter if there is still too much noise on the signal for the user's taste. CDCSS/CDCSS decoders (especially CDCSS) can decode well into the noise at the point where the signal actually has very little intelligible audio left, and that point is usually well below what most people set the squelch at. It is sometimes even lower than what you CAN set the squelch at due to hysteresis.
As a communications professional, you should have seen this many times as well where a signal is decoded by a CDCSS decoder and the signal is just too noisy to hear.
Joe M.
kb2vxa said:
The case I'm talking about uses an OR squelch gate. If the decoder decodes the correct tone/code, it activates the repeater OR if the (tight) CSQ logic sees a signal strong enough to break the squelch, it will activate the repeater. This is a way to eliminate weak CSQ signals yet still allow the repeater to be used by 'locals' in CSQ mode. It's commonly called Dual Squelch.
Now, as for your example of CTCSS licking in a preamp, that makes no sense. IF the signal is below the decoder level, it won't benefit from the preamp at all. Or are you saying it took a strong enough signal to 'kick' the repeater and then the preamp kicked in to make the signal less noisey?
Joe M.
Hi again,
"The case I'm talking about uses an OR squelch gate."
You're taking me back to the days of learning the difference between gates, or, nor, and, nand, if, maybe, sometimes, not, and tied in knots. Uh, I guess you can call it dual squelch at ten paces, turn and fire the repeater, choose your squelch weapon. "Give it dynamite and give it DEATH!"
It's too early in the evening for me to get slap happy, what's WRONG with me?
"Now, as for your example of CTCSS licking in a preamp, that makes no sense. IF the signal is below the decoder level, it won't benefit from the preamp at all. Or are you saying it took a strong enough signal to 'kick' the repeater and then the preamp kicked in to make the signal less noisey?"
Sort of, when dual receivers are used one is selected with a voter. It's done with PL/anti-PL so the voter has but one choice with no chance of confusion. Naturally the PL receiver is the one with the preamp so for all practical purposes the presense of a tone activates the preamp. Does it make sense now?
"Its RADIO. Never the same two days in a row (at least around here !!!!) Steve"
Calm down man, give me a moment to gather my senses and let my ears stop ringing.
Ah, that's better. Enhanced propagation aside I have noticed 6M signals with plenty of QSB where there should be none, margial signals will often fade in and out unexplicably. 2M signals tend to be rock solid while 1.25M ones fade up and down. 70cM ones are mostly rock steady but weaker repeaters will fade right out at the time you're in the middle of an important QSO but when you're just chatting it's 5/9. It's Murphy you know, it's MURPHY! He knows better than mess with my new scanner, or is it he only likes to mess with me when I'm transmitting?
"Who listens to radio? Only two hundred and fifty million people, that's all."
An old PAMS spot.
"The case I'm talking about uses an OR squelch gate."
You're taking me back to the days of learning the difference between gates, or, nor, and, nand, if, maybe, sometimes, not, and tied in knots. Uh, I guess you can call it dual squelch at ten paces, turn and fire the repeater, choose your squelch weapon. "Give it dynamite and give it DEATH!"
It's too early in the evening for me to get slap happy, what's WRONG with me?
"Now, as for your example of CTCSS licking in a preamp, that makes no sense. IF the signal is below the decoder level, it won't benefit from the preamp at all. Or are you saying it took a strong enough signal to 'kick' the repeater and then the preamp kicked in to make the signal less noisey?"
Sort of, when dual receivers are used one is selected with a voter. It's done with PL/anti-PL so the voter has but one choice with no chance of confusion. Naturally the PL receiver is the one with the preamp so for all practical purposes the presense of a tone activates the preamp. Does it make sense now?
"Its RADIO. Never the same two days in a row (at least around here !!!!) Steve"
Calm down man, give me a moment to gather my senses and let my ears stop ringing.
Ah, that's better. Enhanced propagation aside I have noticed 6M signals with plenty of QSB where there should be none, margial signals will often fade in and out unexplicably. 2M signals tend to be rock solid while 1.25M ones fade up and down. 70cM ones are mostly rock steady but weaker repeaters will fade right out at the time you're in the middle of an important QSO but when you're just chatting it's 5/9. It's Murphy you know, it's MURPHY! He knows better than mess with my new scanner, or is it he only likes to mess with me when I'm transmitting?
"Who listens to radio? Only two hundred and fifty million people, that's all."
An old PAMS spot.
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