detect and display std & non-std DPL's?

[Hoot]

I'm looking for something that will detect and display the DPL or CTCSS being used on a given frequency regardless of whether it's a moto std PL or not. i'm willing to buy whatever is necessary to make this work.

i already have a uniden BC796D and several motorola CDM 1250's that have discriminator outputs, and a laptop running win95 that i use for my CPS programming. i'm either looking for a 'black-box' type of decoder with an lcd screen or software that will run on the laptop. anything that works on all squelch codes, not just the standard ones. thanks in advance.

 

[Al42]

There are boxes that will detect and display PL frequencies, but only the standard ones. (There's no such thing as a "non-standard" DPL code.) The only thing that will "detect" a non-standard PL tone is a frequency counter, and you'll need one that can count to (and display) 0.1 Hz with a gate time of 1 second or less - not a cheap item. (0.1 Hz is 10 seconds, so it takes some really cute circuitry to be accurate to 0.1 Hz and do it in a second or less.)

 

[Voyager]

There are boxes that will detect and display PL frequencies, but only the standard ones. (There's no such thing as a "non-standard" DPL code.) The only thing that will "detect" a non-standard PL tone is a frequency counter, and you'll need one that can count to (and display) 0.1 Hz with a gate time of 1 second or less - not a cheap item. (0.1 Hz is 10 seconds, so it takes some really cute circuitry to be accurate to 0.1 Hz and do it in a second or less.)

Actually, there is, or at least there was. D053 was not a standard code nearly 20 years ago. I think now, it is.

There are also many 'codes' that are not used because they duplicate other codes when shifted in time. Some are also not used because they are close to that difference.

Joe M.

 

[Hoot]

There are also many 'codes' that are not used because they duplicate other codes when shifted in time. Some are also not used because they are close to that difference.

those are exactly the codes i'm interested in. i understand the reasons behind why the non-standard tones are undesireable, but i need to be able to distinguish chatter from some frequency pirates. i can listen on open squelch, but it gets a little overwhelming with everything going on. i'd much rather find the pirate's non-standard code, program that into my radio, and give a closer listen.

seems like all the black-box decoders will only do a list of 106 or 112 DCS tones. i'm sure it's possible to decode all the tones if you receive a good sampling of the transmission. wonder why nobody makes one that does it.

 

[Voyager]

There are also many 'codes' that are not used because they duplicate other codes when shifted in time. Some are also not used because they are close to that difference.

those are exactly the codes i'm interested in. i understand the reasons behind why the non-standard tones are undesireable, but i need to be able to distinguish chatter from some frequency pirates. i can listen on open squelch, but it gets a little overwhelming with everything going on. i'd much rather find the pirate's non-standard code, program that into my radio, and give a closer listen.

seems like all the black-box decoders will only do a list of 106 or 112 DCS tones. i'm sure it's possible to decode all the tones if you receive a good sampling of the transmission. wonder why nobody makes one that does it.

I think the original list was 104 codes, and that was expanded to 112 (which includes the 053 code I mentioned used to be non-standard).

What makes you think they are using a non-standard DPL? Most radios won't take them in the programming. Some earlier models only took the original 104.

Joe M.

 

[Hoot]

i'm thinking they're either using a non-standard tone or open squelch because we used a service monitor and it couldn't detect a valid squelch code. i'd imagine that they'd wanna have some kind of PL on their end too so they wouldn't have to listen to us all day. ...and they seem to key-up during the middle of our transmissions which implies they don't hear us. they're only about 15 miles away and i'm putting out about 75W from a 300+ foot building. i'm sure my signal is getting to them just as much as theirs is getting to me.

they aren't actually accessing my repeater as it has a zetron tone panel on it, but they're transmitting on our repeater's output frequency and actually overpowering it even from that distance. if they're talking while we're talking, it's just a heterodyne mess and you can hear them clearly for 2 seconds after our transmission has ended but the radio's hang-time is still open, especially if the heterodyne interference distorted the turn-off code. sometimes they even break through our squelch on their own which might be because it's a non-standard tone and our radios decoded it wrong.

i don't know much for a fact, i'm just guessing at alot of this, but they're definately on my frequency whether or not they're using a standard PL, non-standard PL, or none at all. i'm just trying to get some good intel on them to submit to the fcc with my complaint. from what i've been told, if i had to wait for the fcc to track down an unknown offender, i'd be old and gray before anything was done. i figure if i already knew the who/what/where, all they'd have to do is call the guy and flex their official muscle. ($$$$$)

 

[mancow]

Just for what it's worth the Bendix/King radios will do non standard tones. You just punch in whatever you want in the tone fields.

mancow

 

[Voyager]

i'm thinking they're either using a non-standard tone or open squelch because we used a service monitor and it couldn't detect a valid squelch code. i'd imagine that they'd wanna have some kind of PL on their end too so they wouldn't have to listen to us all day. ...and they seem to key-up during the middle of our transmissions which implies they don't hear us. they're only about 15 miles away and i'm putting out about 75W from a 300+ foot building. i'm sure my signal is getting to them just as much as theirs is getting to me.

they aren't actually accessing my repeater as it has a zetron tone panel on it, but they're transmitting on our repeater's output frequency and actually overpowering it even from that distance. if they're talking while we're talking, it's just a heterodyne mess and you can hear them clearly for 2 seconds after our transmission has ended but the radio's hang-time is still open, especially if the heterodyne interference distorted the turn-off code. sometimes they even break through our squelch on their own which might be because it's a non-standard tone and our radios decoded it wrong.

i don't know much for a fact, i'm just guessing at alot of this, but they're definately on my frequency whether or not they're using a standard PL, non-standard PL, or none at all. i'm just trying to get some good intel on them to submit to the fcc with my complaint. from what i've been told, if i had to wait for the fcc to track down an unknown offender, i'd be old and gray before anything was done. i figure if i already knew the who/what/where, all they'd have to do is call the guy and flex their official muscle. ($$$$$)

All things considered, just mention that they are not using a standard CDCSS code which you believe may be interfering with your equipment and is not "good engineering practice" (use that exact 3-word phrase)

You aren't using 131.8 or 136.5 Hz CTCSS, are you?

Joe M.

 

[Hoot]

You aren't using 131.8 or 136.5 Hz CTCSS, are you?

Joe M.

no, i'm not using any of the easily tripped tones, in fact we use DPL. i'm just taking a wild guess that the pirates are too.

 

[Al42]

in fact we use DPL. i'm just taking a wild guess that the pirates are too.

Why guess? Look at their signal (in your receiver - before filtering) with a scope and be sure.

 

[Voyager]

in fact we use DPL. i'm just taking a wild guess that the pirates are too.

Why guess? Look at their signal (in your receiver - before filtering) with a scope and be sure.

Better yet, just look at it on the service monitor. You should be able to tell if it's got a DPL signal.

They COULD be using LTR, too. That won't show up as a DPL signal.

Joe M.

 

[loumaag]

Better yet, just look at it on the service monitor. You should be able to tell if it's got a DPL signal.

You must have missed this bit:

i'm thinking they're either using a non-standard tone or open squelch because we used a service monitor and it couldn't detect a valid squelch code.

 

[Voyager]

Better yet, just look at it on the service monitor. You should be able to tell if it's got a DPL signal.

You must have missed this bit:

i'm thinking they're either using a non-standard tone or open squelch because we used a service monitor and it couldn't detect a valid squelch code.

Nope. In fact, that's why I suggested the SM rather than scoping a receiver. The SM display would be much easier to do (since it's there).

He said it couldn't detect a valid squelch code. That (to me) means that the SM simply could not recognize the waveform against whatever codes are stored in it. That doesn't mean that the waveform was evaluated by a human to see if there is a DPL waveform present. That would be very easy to see - standard code or not. Remember, CSQ was not even ruled out.

Joe M.