adacats
Scanner and Train Nerd
It is on the 996xt. The channel is 155.25 and is the university police and I live off campus and not in a residence hall. Priority is also not on. I will try leaving it parked on the channel and see what happens.
clicking on conventional channel
- Thread starter adacats
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Hmm,...
Any chance you could record the sound and send us the file to listen to?
Also, try parking on the channel as I suggested and then turning the squelch all the way down and the tone squelch off (no "PL", CTCSS or DCS - completely open). Listen for a minute or so and see if you hear anything odd other than the normal desired signal or the standard "rushing noise". There might be some low level interference on the channel, on that frequency or within 20KHz of it that is causing just enough interference so as to cause the scanner to stop on that channel when scanning. The only problem is that the CTCSS tone squelch SHOULD block that so I'm not sure. But it's worth a try.
If you tune around near that frequency, are there any other moderate or strong signals within 30KHz or so of that frequency? I'd search between 155.220MHz and 155.280MHz or even out further, say between 155.200MHz and 155.300MHz.
-Mike
Any chance you could record the sound and send us the file to listen to?
Also, try parking on the channel as I suggested and then turning the squelch all the way down and the tone squelch off (no "PL", CTCSS or DCS - completely open). Listen for a minute or so and see if you hear anything odd other than the normal desired signal or the standard "rushing noise". There might be some low level interference on the channel, on that frequency or within 20KHz of it that is causing just enough interference so as to cause the scanner to stop on that channel when scanning. The only problem is that the CTCSS tone squelch SHOULD block that so I'm not sure. But it's worth a try.
If you tune around near that frequency, are there any other moderate or strong signals within 30KHz or so of that frequency? I'd search between 155.220MHz and 155.280MHz or even out further, say between 155.200MHz and 155.300MHz.
-Mike
adacats
Scanner and Train Nerd
Here is an audio clip of what i am experiencing. Note it is a vox recording so there was a few seconds in between each static and click. Starts at the 1:00 mark. https://app.box.com/s/d3va0srxwe3ra8xcc4xu
That is something getting into the repeater itself. Could be any number of things, but kinda sounds like an extremely weak, distant station on the same freq and PL as the repeaters input. At any rate, this problem is on the Campus PD's end, and there really isn't anything you can do to stop it short of locking them out.
If you are close enough, you could try programming the repeater input frequency instead of the output. Depending on terrain and your antenna setup, you will need to be within 5 miles, likely less, in order to reliably hear their portables. Mobiles and bases can of course be heard slightly farther.
Couple of things -
First, that audio sample indicates you're listening to a P25 signal. Therefor, you can use a NAC to filter out all traffic on that channel except the signal you are interested in (similar to how a "PL" works for analog transmissions).
Second, that "clicking" sounds like some other signal either coming through on a mixed analog/digital repeater (it sounds like an analog signal with a CTCSS tone) or from another repeater on the same frequency. Again, if you can find the NAC used by the folks you want to listen to then you can filter that other stuff out just like with analog CTCSS ("PL").
I don't know what model scanner you are using so I don't know if you have NAC capability but if you do that should do the trick for you.
-Mike
First, that audio sample indicates you're listening to a P25 signal. Therefor, you can use a NAC to filter out all traffic on that channel except the signal you are interested in (similar to how a "PL" works for analog transmissions).
Second, that "clicking" sounds like some other signal either coming through on a mixed analog/digital repeater (it sounds like an analog signal with a CTCSS tone) or from another repeater on the same frequency. Again, if you can find the NAC used by the folks you want to listen to then you can filter that other stuff out just like with analog CTCSS ("PL").
I don't know what model scanner you are using so I don't know if you have NAC capability but if you do that should do the trick for you.
-Mike
adacats
Scanner and Train Nerd
The frequency I am listening to is a conventional 150 range channel, non p25. Im also using a Uniden BCD996XT.
The audio you recorded really sounded like P25! Maybe it is being simulcasted/multicasted from another P25 channel trunked or conventional?
-Mike
ecps92
Member
Certainly sounds P25 to me as well, with the clicks at the end of the audio being Analog
Dual Mode Rptr ?
Could they be patching a P25 channel into the Analog ? Is there a City/County/State TRS they might be on? patching to the Analog for Interop ?
Dual Mode Rptr ?
Could they be patching a P25 channel into the Analog ? Is there a City/County/State TRS they might be on? patching to the Analog for Interop ?
adacats
Scanner and Train Nerd
As far as I know, they have a single analog transmitter on top of their building. I guess it is possible campus police are using p25 as well, since the city police recently switched to that system.
Maybe that sample was of a patch from the city P25 system? It sure did sound like P25 (or some form of digital) audio to me.
Anyway, I'm guessing that the repeater may be a mixed mode (P25 and analog) conventional repeater or else an analog-only repeater with a near constant patch to a P25 (or other digital mode like DMR/Trbo) system (given the P25/digital sounding audio I heard).
Either way, the sounds at the end sound like they were coming through via the analog side as you could hear the low tones of the CTCSS and the static. Not much you can do about that unless they go all P25 then you could block it (the noise) with a NAC digital only setting (but you might then miss any analog traffic that may still come through).
-Mike
Anyway, I'm guessing that the repeater may be a mixed mode (P25 and analog) conventional repeater or else an analog-only repeater with a near constant patch to a P25 (or other digital mode like DMR/Trbo) system (given the P25/digital sounding audio I heard).
Either way, the sounds at the end sound like they were coming through via the analog side as you could hear the low tones of the CTCSS and the static. Not much you can do about that unless they go all P25 then you could block it (the noise) with a NAC digital only setting (but you might then miss any analog traffic that may still come through).
-Mike
Yep, the first minute of that recording is almost certainly P25, and not patched to an analog repeater either. Since they are not licensed for P25 (nor does the RR DB show P25), I had assumed the OP was scanning other things during the recording, and only the last few seconds were from the campus PD. If the recording was made while holding on the campus PD channel, then either they are using P25, or a co-channel user is.
When the campus PD channel is active with voice traffic, what does your scanner display in the lower right corner? Does it show "P25", "LNK", or an NAC code? Or does it show a CTCSS/DCS code or nothing at all?
adacats
Scanner and Train Nerd
Ok I see where the confusion is. The first minute is mixed between an agency using motorola and an agency using p25. Only listen to the part after the 1 minute mark. That is the static clicking on the conventional channel. Sorry for the confusion.
adacats
Scanner and Train Nerd
Here is another clip from that channel on my scanner. This is a vox recording so the non activity gaps are not there, but it is pretty close to how it sounded. A majority of this was in a 2 minute span. I don't think the officers and dispatch are hearing this, or they would have addressed the issue as it is pretty bad (and annoying). Any other ideas?
Here is a link to the audio clip:
https://app.box.com/s/gnmu2iyv1y9selwh6jz2
Here is a link to the audio clip:
https://app.box.com/s/gnmu2iyv1y9selwh6jz2
ecps92
Member
I have to agree with the last poster - it really sounds like it's the repeater getting keyed up. You can even hear the CTCSS tone in the background and, if it were general interference it would not likely have that tone on it. Whatever it is, it appears to be coming through the repeater so you can't really do anything about it. The users may be unable to address it immediately and simply are putting up with it.
If you really want to be sure, try using very different receivers with different designs to listen to the same frequency and see if they all get the same signals. I don't know what else to suggest to you.
If you know what the repeater's input frequency is you could try and see if you can hear the interfering signal on the input. It could be a real signal fundamentally on the input of the repeater or it could be a form of intermod created near or even within the repeater. Someone is likely working on it given how bad it is.
-Mike
If you really want to be sure, try using very different receivers with different designs to listen to the same frequency and see if they all get the same signals. I don't know what else to suggest to you.
If you know what the repeater's input frequency is you could try and see if you can hear the interfering signal on the input. It could be a real signal fundamentally on the input of the repeater or it could be a form of intermod created near or even within the repeater. Someone is likely working on it given how bad it is.
-Mike
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