dispatcher21
join:2004-01-22
united state | Why not use PL tones?
Why cant the radio guys just use PL tones to filter out the interference? |
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UHF
All static, all day, Forever
Premium,MVM
join:2002-05-24
clubs: | How does adding a PL tone make the interference go away? It doesn't. |
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TechieZero
Tools Are Using Me
Premium
join:2002-01-25
Wesley Chapel, FL
| reply to dispatcher21
said by dispatcher21  :Why cant the radio guys just use PL tones to filter out the interference? For fear of massive flame-age, you have a point. Maybe the Ham guys need to upgrade their methods if this is such an issue.
Not that I don't respect this activity, I think you guys are great.  |
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moonpuppy
join:2000-08-21
Glen Burnie, MD
 ·Verizon Online DSL
| said by TechieZero :said by dispatcher21 :Why cant the radio guys just use PL tones to filter out the interference? For fear of massive flame-age, you have a point. Maybe the Ham guys need to upgrade their methods if this is such an issue. Not that I don't respect this activity, I think you guys are great. No, he doesn't have a point as both of you don't know how PL tones work. All PL tones do is open the squelch of a receiver when it receives the right sub-audible tone. This is useful ONLY when multiple people are using the same frequency or sporadic interference.
BPL interference is trying to listen to a regular conversation next to a car running with no muffler.
Try again. |
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AmnChode
Premium
join:2001-03-27
San Antonio, TX
| reply to UHF
Exactly...PL tones/CTCSS doesn't filter interference. They filter out other traffic on the same channel. However, with the interference being caused, neither parties would be able to make contact (or at least be hindered in contact), thus making CTCSS null and void...
ie, CTCSS does not alleviate RF interference |
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dispatcher21
join:2004-01-22
united state
1 edit | reply to moonpuppy
I thought that what the problem was, sporadic interference? I did not know the interference was constant to the point of them not being able to communicate with their equipment. And yes, I know how PL tones work, we use them on our radios here and they filter out quite a bit of interfernece we get on our fire channel. With the PL tones off, we get a constant buzz and warble, we turn the PL tones on, the noise is completely gone. Whats causing the noise? We guess that its CSEPP across the river but the PL tones solve the problem for now till we can figure it out completely. |
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tenbase
join:2000-07-19
Alexandria, VA
| HF communications are very different from typical VHF/UHF communications. Squelch is rarely used (and is not even included as a feature in many HF transceivers), as many of the signals are very weak and close to the noise floor.
PL/DCS is really only useful for local VHF/UHF communications where relative signal strength is high and there is no need to pick faint signals out of the muck.
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I would kill everyone on this forum for a drop of sweet beer.. |
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AmnChode
Premium
join:2001-03-27
San Antonio, TX
| reply to dispatcher21
All the PL Tone does is tell the radio to "un-mute" when the tone is, for lack of better words, heard. Otherwise, the freq stays squelched. This works great if everyone uses the same freq, the same tone, and you can guarantee that you are in range of the contact without interference being an issue. It also keeps the radio nice and quiet when not being used.
However, when we are talking long distance contacts, which HAMs are more likely to deal with, you can't hear the contact or the tone over the interference, thus nullifying CTCSS tones. This is neglecting the fact that they would be searching for unknown contacts, to begin with. As such, they would not be squelching the radio purposely.
However, I believe what goes to the heart of the issue is that HAMs have to operate within specific guidelines and part of those guidelines is that they do not interfere with others traffic. Yet, at the same time, the FCC was allowing BPL to interfere with theirs, thus narrowing their radio spectrum even further. |
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moonpuppy
join:2000-08-21
Glen Burnie, MD
·Verizon Online DSL
| reply to dispatcher21
said by dispatcher21 :I thought that what the problem was, sporadic interference? I did not know the interference was constant to the point of them not being able to communicate with their equipment. And yes, I know how PL tones work, we use them on our radios here and they filter out quite a bit of interference we get on our fire channel. With the PL tones off, we get a constant buzz and warble, we turn the PL tones on, the noise is completely gone. Whats causing the noise? We guess that its CSEPP across the river but the PL tones solve the problem for now till we can figure it out completely. The interference of BPL is similar to what you are describing with CSEPP. Not only is it constant but much stronger and over a much greater frequency range.
As for the noise problem you are having, there are several possible reasons; bad transmitter, signals mixing, harmonics, etc. |
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MZR
join:2006-08-12
TX
| reply to dispatcher21
said by dispatcher21 :Whats causing the noise? We guess that its CSEPP across the river but the PL tones solve the problem for now till we can figure it out completely. Pager systems.... |
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TechieZero
Tools Are Using Me
Premium
join:2002-01-25
Wesley Chapel, FL
| reply to moonpuppy
said by moonpuppy :No, he doesn't have a point as both of you don't know how PL tones work. All PL tones do is open the squelch of a receiver when it receives the right sub-audible tone. This is useful ONLY when multiple people are using the same frequency or sporadic interference. BPL interference is trying to listen to a regular conversation next to a car running with no muffler. Try again. I wasn't claiming I know how "PL tones" work and my remark was a general one; as in Ham operators might have to step up to the challenges some way some how. |
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AmnChode
Premium
join:2001-03-27
San Antonio, TX | They are. They are trying to stop the interference. |
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