Fastest Scan selection for SDS200 & 536HP

[rangers38]

I have about 15 local conventional programmed towns for my county installed on quick key 1 on my scanner. Additioanally, I have a P25 trunk system, and a DMR system. What would be the fastest way to set things up so all systems would scan the fastest?

 

[Ubbe]

Sort the channels in frequency order as big jumps in frequency steps makes scanning slower, especially in SDS100/200 scanners.

The trunked systems frequencies will be scanned until the squelch detects a carrier and then it tries to find a datasignal to decode. So set the control channel frequency first in the list as any voice channels eventually programmed in the list will slow down scanning if they are active with conversations. If it finds a control channel data in a site list it will skip the rest of the channels in that site list. Don't use the filter settings in the SDS200 set to auto as that will slow down scanning considerable.

/Ubbe

 

[rangers38]

I have the filters set to auto because on some sites the global feature does not work as well. So should I set them to normal?

 

[ctiller]

I have the filters set to auto because on some sites the global feature does not work as well. So should I set them to normal?

yes, Auto seems to slow things way down-on the SDS200 at least

 

[rangers38]

I have a town I am trying to monitor. It's a DMR system running RAS. I pick them up occasionally, but not consistent. I have heard Uniden ignores RAS on the SDS series & 536HP. I have tried different combinations of the filter settings but really does not make any difference. I have a discone antenna with LMR400. The site is only 8-10 miles away and I live on a really high elevation. Can't figure out why it's not a consistent signal

 

[jonwienke]

RAS won't affect the signal strength. If RSSI is fluctuating, you've got some kind of interference or something else is going on.

 

[jonwienke]

Auto seems to slow things way down-on the SDS200 at least

Auto tries all filter combinations on every channel, and slows scan down by a factor of 4 or so.

A better approach is to set the global filter to Normal, and then set Invert on specific problem frequencies. Or else the reverse--use Invert as the Global filter, and select Normal on specific problem children.

 

[Ubbe]

I have tried different combinations of the filter settings but really does not make any difference.

Did you try IFX as well? Some people say that changing modulation between NFM and FM instead of auto can make a difference.

It could be that there are too many interfering frequencies too close to the frequencies you are monitoring. If the DMR system are on VHF then it might help with an external FM broadcast trap filter. In USA it is 2-way radiochannels mixed in with cellular frequencies in the 700-900MHz band that could make it difficult if a celltower are too close to you.

You might get a clue what's going on if you program the frequencies of the DMR system as conventional analog only. Then you can listen for any type of interference or if the signal are plainly too weak. What does the values of RSSI, NOISE and D-ERROR say?

/DD

 

[Ubbe]

I have the filters set to auto because on some sites the global feature does not work as well. So should I set them to normal?

The filters OFF setting are the one that all other Unidens scanners are using. It gives the most sensitivity but might not filter out adjacent channels and interferencies as well as other settings. The receiver technology in the SDS scanners are more prone to interferencies and negative influencies from adjacent frequencies and Uniden then had to improve reception by introducing the filter setting.

I would suggest to start with the filter set to OFF. Then continue to test in the following order WIDE-NORMAL, WIDE-INVERT, NORMAL and finally INVERT. If nothing seems to help then do IFX to the frequency and try all the filter settings again. When the best filter have been determined you can set that to the site in trunked systems and the department for conventional channels, when you have moved the systems to a favorite list.

You'll need to use a display setting that show RSSI, NOISE and D-ERROR to help with the evaluation. You should try and get as low values as possible for NOISE and D-ERROR. The RSSI level are not critical to receive quality but could be helpful when testing different antenna positions and coax cables and things that affects the signal strenght.

/Ubbe

 

[rangers38]

Not sure what you mean with the IFX?
The system I am trying to monitor-
453.800 CC1 & 453.025 CC1
I have them installed as conventional as well as DMR

 

[Ubbe]

IFX are the intermidiate frequency exchanger that jumbles around the internal frequencies in the scanner so the filters might work in a different way with the interference problems you might have.

You have to enter the frequency in the IFX list in the profile in Sentinel or do it directly in the scanner by function+7 button. But you have to be stationary on the frequency to do it. Easiest way are to stop scan by pushing the chan button and enter the frequency and the chan button again. Then do fn+7 and it should turn on a ifx text on the display. You can turn the dial to step to the other frequency or enter the frequency directly and then the chan button.

To start scanning agian you do fn+system button.

/Ubbe

 

[rangers38]

Ubbe,

Thank you for your help. I figured it out after searching the subject. I tried it, and also tried different filters, no luck. I should mention that I live very close by a tower that has lots of county fire/ems/police etc. less than a 1/4 mile away. Is it possible that the DMR system I am trying to recieve is being silenced due to the tower? Also, I have it programmed as a DMR one frequency on a different scan bank. When I lock the channel, every a couple of times a minute I get full bars of reception, but no audio. Maybe the repeater?

 

[Ubbe]

I should mention that I live very close by a tower that has lots of county fire/ems/police etc. less than a 1/4 mile away. Is it possible that the DMR system I am trying to recieve is being silenced due to the tower?

Yes, that could be the problem. The SDS scanners are probably the worst receivers that Uniden have ever made. They have problems with nearby transmitters if they are too strong. Previous scanners didn't need any filter settings to perform well. But you have a BCD536 as well so try that?

Also, I have it programmed as a DMR one frequency on a different scan bank. When I lock the channel, every a couple of times a minute I get full bars of reception, but no audio.

It probably are some other frequency from that nearby tower that starts transmitting and the signal strenght indicator will trigger on that signal. You have to look at the NOISE and D-ERROR values to see if it is the DMR signal that fluctuates. If the RSSI indicates a stronger signal then the NOISE and D-ERROR should go down. If they instead increase then you have an interfering signal.

I forgot to mention one more thing regarding testing with filters and IFX to fight interferencies, that if you see signal strenghts of -70dBm and -60dBm and stronger then you could activate the attenuator that should drop the signal level by 20dB but interferencies usually drops much more and then interfere much less. You should have just as good reception with signal strenghts of -90dBm without any noticable noise on analog channels and without any annoying bit errors on digital signals.

/Ubbe

 

[rangers38]

I have had the same lack of reception with my 536HP for this system

 

[Ubbe]

Keep an eye on those RSSI, NOISE and D-ERROR values. What happens when you engage the 20dB attenuator on either scanner? The RSSI signal level should drop 20dB and if it doesn't it is some kind of interference issue. Programmimg the frequencies as analog only and listen to them could also reveal some crucial information that could help you.

/Ubbe

 

[buddrousa]

Compare the the DMR frequency 4xx.xxxx to all frequencies at the near by tower site and list them you may be trying to hear 460.100 DMR and the tower site has a frequency of 460.1250 and something like that will cause be headaches.

 

[rangers38]

I just got the scanner last week and am still finding my way around with it. I see the RSSI but don't know where the Noise or D-Error values would be in the display?

 

[jonwienke]

Select detailed display, and add them in the display editor in Sentinel.

 

[rangers38]

I looked in the sentinel under edit display, but don't see where you would add them?

 

[jonwienke]

They are options for most of the half-screen-width fields in the Detailed mode tabs.