SDS100/SDS200: No Sound/"Overpowering" System

[tvengr]

Try the IFX (intermediate frequency exchange). If there is a strong interfering signal that should solve the problem. Under the profile editor Miscellaneous tab, click on Review & Edit. Enter all of the frequencies for the 3 sites of the CDTA system. Write to scanner.

 

[Dexter2]

Both zip files won't upload here.

With Invert, its no signal bars, no DATA, no D-ERROR, and 22000 level NOISE
With Wide Invert, one or two signal bars, DATA, 26 D-ERROR, and 8300 level NOISE
With Off, full signal bars, DATA, 0 D-ERROR, and 400 level NOISE

I have a 30 second clip of transmission with Squelch on 2/Filter set to Off and very lucky to catch both voice and silence in the same video.

If I have Squelch on 1, the transmission comes in fine, but this new silence issue is what happens regardless.

I decided to look on here and see if there were other systems that use a very similar frequency which might have an effect.

 

[Dexter2]

PS. - Although at this very moment.

With Squelch on 1 and Filter set to off its, D-ERROR blank, NOISE has a level of 2000, no DATA, and full signal bars will either be present or flash, DATA will flash intermittently if not at all.

 

[tvengr]

If filters don't work, try the IFX and let me know if it does.

 

[Dexter2]

That included IFX.

 

[Ubbe]

when a transmission comes in (only on this system) it starts off fine, then the signals go to one or two bars and P25 Slot disappears, but I can still see the UID being they're literally talking, I just can't hear it.

Could it be that some of the voice frequencies are worse than others? Keep an eye on the frequency. When it says data it should be a control channel and when a conversations are followed it should show its voice frequency. Also set to ID search and set NAC to ignore to use as few restrictions as possible. If you only have two signal strength bars at best then it will be such a low signal that it will be easily interfered and you might have to use another antenna solution.

/Ubbe

 

[Dexter2]

Just added the frequency to the screen display. Currently, Squelch is on 2, Filter is Off, and NAC is set to ignore.

When DATA is shown and its three to full signal bars, D-ERROR is 0, and 400 NOISE the frequency is 859.1125

When DATA disappears and the bars are only one or two, and at times both or one will flicker the frequencies cycle through slow.

A transmission just came in and the frequency changed to 858.6875 as the TG popped up. During this time DATA/P25 Slot, TGID, and signal bars (one to two) flickered very fast. I then set squelch to 1, the TG then stayed on the screen, the UID popped up, but DATA/P25 disappeared and the signal bars stayed. A very faint air blowing sound came out.

What would an antenna option be? I've tried the original, this Remontronix? I don't understand why there's no issues with other systems that are on a wider scale.

 

[Ubbe]

When DATA is shown and its three to full signal bars, D-ERROR is 0, and 400 NOISE the frequency is 859.1125

You can't do any better than 0 for D-Error and 400 for Noise are the lowest when receiving a data signal as the scanner thinks that data are noise.

A very faint air blowing sound came out.

That's how it sounds when it cannot decode the data properly. Try IFX only to that 858.6875 frequency.

What would an antenna option be? I've tried the original, this Remontronix?

You'll need a bigger antenna that are focused on the 850MHz band. Maybe an external magnetfoot antenna for vehicles can be used, trying it at different places like in the window, on the microwave oven or some metal surface to try and improve ground. I don't have any 800MHz systems myself so cannot recommend what could be the best 850MHz antenna.

/Ubbe

 

[Dexter2]

I just took off the IFX for 859.1125a, on the Quick Search screen its a -45 signal and a consistent low faint air sound. When DATA appears the NAC ID flashes. Now I have Squelch on 2/3 and on three occasions when DATA disappears there was a loud squelch sound as if Squelch was on 0 or 1 for an analog system. I think the term is called open squelch. The other times it was just the faint air sound and no DATA.

On 857.0625, that same open squelch happens, BUT there is no signal AT ALL. Also, instead of DATA, this frequency says LINK, and I have only seen that word with the Police/EMS systems when they are talking. When LINK disappears that open squelch happens on and off very loud. Once I take it off, signal appears showing -45/-50/-55 and the word LINK appears, very rarely LINK will switch to DATA then back to LINK. When DATA appears, the NAC Site quickly flashes.

Lastly, on 856.7875 and 859.8125cn, there is nothing no signal, no DATA, no NAC, no LINK, nothing what so ever. Same thing after I take IFX off.

858.6875a is the only one with IFX now.

 

[maus92]

What system / site is being monitored. and from where?

 

[Ubbe]

, signal appears showing -45/-50/-55 and the word LINK appears, very rarely LINK will switch to DATA then back to LINK. When DATA appears, the NAC Site quickly flashes.

When those signal are that strong, enable the Attenuator. If the signal disappears completely or changes more than 20dB, should be around -65/-70/-75, then it's just interference from another system or site or frequency you are seeing and not the system your trying to monitor. Then it's time to fiddle with filters and IFX to try and get rid of those interferencies, which could be difficult.

When you have IDSearch on and NAC ignore it will actually show you what interferencies you have, but will be hidden from you if you use IDScan and NAC, which will make finding a solution much harder when not all information are shown to you. Then it could also be a cold solder joint problem that adds even more complexity into the mix. The SDS100 starts getting into deep problems when signal strengths go up un the -60dBm range and stronger, like your -45dBm signals will be devastating to the receiver chip, creating all sorts of RF problems.

It would probably be very useful to have a $20 SDR receiver dongle to see the whole frequency spectrum to know how much strong signals you actually have at your location.

/Ubbe

 

[buddrousa]

What if the frequency he is hearing is not the true frequency that is being transmitted.

 

[Dexter2]

Thank you for all of your responses and insight. Being that ID Search is on and NAC is set to ignore, how do you see the interferences or what the interferences are?

Everything disappears when I put Attenuator on, on any system that I have programmed. If I move the radio from my office to a back room, the system works a lot better, but regardless very rarely with Squelch on 2. If I have Squelch on 2, the TG's will flash when a transmission appears 80% of the time, I would guess 5 out of 75 transmissions would actually "stick" and come in normally. I find those five "lucky" transmissions take place usually outside of regular business hours. Which is why I was stumped that nothing changes outside, but if I go to one office building nearby, the radio works fine with Squelch on 2. Again, I never have any issue with no other systems I have programmed.

Not familiar of the SDR dongle, will have to look into it.

Looking at the frequencies on here, I was curious could it be what buddrousa mentioned, which would explain the "overpowering"?

 

[Ubbe]

Everything disappears when I put Attenuator on

If the signal disappears completely.....then it's just interference from another system

/Ubbe

 

[buddrousa]

Dexter2 how do you see over a wall that is taller than you?
RF signals are there it does not matter if it is the signal you want to hear or the interference.
Look at the interference as the wall that is taller than you.
Your next question is the radios the system users have.
Your scanner is $600 and wide banded their radio is several thousands of dollars and designed to only work where it is being used.

 

[Dexter2]

Totally get and agree. With that being the case, wouldn't I be experiencing more issues and/or malfunctions?

 

[buddrousa]

Yes and no it depends on what and where the interference is coming from.

 

[Dexter2]

Thanks. I do notice the difference in a room or even a hallway makes a big difference in its workings.

What does it mean what you see DATA but there is no signal bars very briefly?

I may have overlooked, how do you see the interference when you have ID Search and Ignore NAC set?