SDS100/SDS200: Slow decoding speeds

[Facsimile]

Does anyone else experience missing many/most conversations on conventional NXDN? I did a receive test with a Kenwood NXDN radio and my SDS100. Both radios have the same configuration. Same RANs, filters disabled, etc. I never realized that my SDS100 picks up maybe 10% what the Kenwood does. Originally I wanted to see the audio quality difference, which is minimal. But the receive/decode difference is unbelievably different.

Why?

I've also tried a few different antennas. And on top of that, received range is so much farther with the Kenwood that I'm starting to think there is something wrong with my SDS100. I'm talking like 2 or 3 more miles too. I am just shocked. Is this just how it is?

 

[Whiskey3JMC]

You're comparing two entirely different classes of receivers, a consumer scanner versus a professional radio. Of course the Kenwood is going to be more receptive on the band(s) it covers whether they carry NXDN or something else, that's a given. With that said, are you running the latest firmware on the SDS100 & experimented with different filter settings? (I'm aware you set filter to "off"). Also do you have said conventional NXDN programmed as a system (NXDN one Frequency Trunking) or as separate conventional channels?

 

[dmfalk]

The SDS100 is notorious for its poor reception, particularly on VHF. Often the best thing to do here is invest in a new, better antenna. Many of us have bought antennas from Comet, Diamond or Remtronics. They all beat the stock antenna.

That said.....

The SDS100 scans at about 80 channels a second. The screen refresh rate doesn't go that fast. The best thing you can do is adjust the various delay rates. I've set mine to 0, for just this reason.

 

[Facsimile]

With that said, are you running the latest firmware on the SDS100 & experimented with different filter settings?

Yes, latest firmware. I have not used the different filter settings only because I have never been able to find any documentation on them. With as long as I have had the scanner I never knew what I was missing out on.

Also do you have said conventional NXDN programmed as a system (NXDN one Frequency Trunking) or as separate conventional channels?

It's in as conventional NXDN as separate channels. Three total.

Often the best thing to do here is invest in a new, better antenna. Many of us have bought antennas from Comet, Diamond or Remtronics. They all beat the stock antenna.

I have three of the Remtronics antennas. They work great IMO.

The SDS100 scans at about 80 channels a second. The screen refresh rate doesn't go that fast. The best thing you can do is adjust the various delay rates. I've set mine to 0, for just this reason.

The scan speed isn't the problem - I thought it might have been at first. I can park both the scanner and Kenwood on the main active channel and wait. The Kenwood responds immediately but the scanner can take up to 5 seconds before I start hearing any voice/see any signal on the RSSI meter. It's not every time but I'd say about the majority.

I have tried being within 1000 feet of the repeater as well as a half mile away. Both scenarios the same thing will happen and this is without scanning. Just sitting on the repeater output.

 

[dmfalk]

Like I said, set all delays and wait times to 0. You can find out more on the Easier to Read SDS100 manual, here:

Easier to Read SDS100/200 Digital Scanner Manual

As for filters, this explains it all, in a handy PDF file:

https://wiki.radioreference.com/images/3/31/SDS100_SDS200_Filter_Settings.pdf

More about your SDS100 on the FAQ page:

SDS100 and SDS200 FAQ Page - The RadioReference Wiki

wiki.radioreference.com

And jus in case you didn't know it existed, there's a manual for Sentinel, too:

SDS Sentinel Software Manual

Setting the delays & wait times can speed up things. Plus, repeaters being what they are, are naturally delayed from source transmissions!

 

[Ubbe]

the scanner can take up to 5 seconds before I start hearing any voice/see any signal on the RSSI meter. It's not every time but I'd say about the majority.

Try and disable all features like priority scanning, CloseCall and those kind of things that operate in the background, interrupting a hold on a channel, that doesn't indicate on the display that its actually are on other systems/frequencies than what are displayed.

Then when having a hold on a conventional frequency you can change the IFX by doing Function+7 to totally change what intermediate frequencies that are used in the scanner. Then also try different filter setting, one at a time, to see if that improves anything. Filters are set to sites or conventional departments. If a filter are set to Global then it is the setting in the menu for "Settings/Global Auto Filter" that are used and might be easier to change than drilling down to the department and change it there.

But the Global setting will change all sites and department that are set to Global so once you have figured out what filter that works the best, if any, then set that to the site or department instead of its Global setting.

Also if the system you have issues with have a normally high signal strength, -80dBm -70dBm and even stronger like -60dBm then use the Attenuator setting for that site or department as the scanner can easily be overloaded and de-sense and loose sensitivity from other strong signals in the frequency band.

If a filter setting or Attenuator setting affects other channels in a department negatively then you'll need to move the system to a department of its own.

/Ubbe

 

[Facsimile]

I did a little test. I took my Kenwood, my laptop with DSDPlus, and my SDS100 and went about 1 mile from the repeater. The laptop and the SDS100 were attached to an external mag mount base with a Remtronics 920S antenna on it. For the control, I placed the Kenwood in the cup holder and confirmed that is received excellent quality audio and did not have any missed conversations. I then tested DSDPlus and experienced the same thing - good audio and no missed conversations. There was the occasional ERR that showed up on the voice calls but nothing concerning. Gain was set at right around 12 +/- 2ish.

I then attached the SDS100 to the same antenna setup that DSDPlus used and it could barely catch any voice calls unless they were more than 5 seconds long. I tried all of the filters using the Global setting and made sure it was applied correctly. I also tried turning on IFX. There were no differences in decoding noted. All other settings were already off - Close Call, priority scanning.

Also if the system you have issues with have a normally high signal strength, -80dBm -70dBm and even stronger like -60dBm then use the Attenuator setting for that site or department as the scanner can easily be overloaded and de-sense and loose sensitivity from other strong signals in the frequency band.

RSSI according to the SDS100 ranged from -62 to -77dBm but only showed up when (and if) it would decode. I also tried attenuation but that just made the scanner silent. Just to make sure I wasn't missing something, I factory reset the radio in hopes it would make things better but it did not.

Finally I tried the waterfall feature. It showed an ok signal with gain set to auto. I changed the gain manually and while it visually changed signal strength, it also changed the noise equally. One final thing I tried was setting the squelch to 0 so I could hear the digital noise. When it was audible, the NXDN digital sound would sound for about 5 seconds before the SDS100 would silence the sound and switch to decoded voice.

Fed up, I drove to within a tenth of a mile to the repeater, tried again with the same results.

 

[Ubbe]

I did a little test. I took my Kenwood, my laptop with DSDPlus, and my SDS100 and went about 1 mile from the repeater.

SDS scanners has only a 12,5KHz channel filter, the NFM one, as the most narrow one programmed in their DSP and not 6,25KHz that in some receivers are called SFM, Super Narrow FM.

If you try and receive a narrow 6,25 NXDN signal with a Uniden scanner it will struggle and most of the time have issues to try and decode the data. I have a couple of 12,5 NXDN systems and both my SDS100 and SDS200 sometimes have issues that when the data transmission stops it stays on the channel with an open squelch producing noise. So I believe there are some NXDN issues in the firmware. When using something like DSDPlus there are no such issues as I can set the channel bandwidth myself.

I have cruise ships visiting my area and some of them use a very narrow 6,25KHz DMR system that my Uniden scanners cannot decode properly, as they have no 6,25KHz channel setting, but works fine to decode using DSDPlus.

RSSI according to the SDS100 ranged from -62 to -77dBm but only showed up when (and if) it would decode. I also tried attenuation but that just made the scanner silent. Just to make sure I wasn't missing something, I factory reset the radio in hopes it would make things better but it did not.

The RSSI values only show when the squelch are open, so you'll probably need the squelch set to 0 to always see those values.

The attenuator reduce the signal by 20dB at 800MHz and at VHF it is 30dB. You should still be able to receive a signal with the attenuator on and a 20-30dB weaker level in strength, if the squelch are not preventing that.

SDS scanners signal strength indicator works over a large frequency range and not only from the frequency you receive, as it does in a conventional receiver. If you toggle the attenuator setting between enable/disable it should be a 20dB or 30dB difference in the RSSI value depending of frequency band, and if there's a different change in RSSI it means that the scanner are compromised from interference. It should be possible to manage that by using the filter settings but the filter are always 10MHz wide and its settings only move that 10MHz window to either side of the signal, so that you might block one interference but open up to another strong transmitter at the other end of the window.

/Ubbe

 

[I_Am_Infinite]

Thanks for the post I was wanting to get the nxdn key for my sds200 or even get another sds with it because there is at least one department id like to listen to.

Now im worried it might be pointless to get the key because its a vhf nxdn and it might not even be able to recieve it good like u are having

 

[dmfalk]

I repeat: adjust delays and wait times. This will improve hearing transmissions, as any delay, you might actually miss the beginning of a transmission, and wait times delay resuming the scanning, and you might miss out. It's not perfect (nothing ever is), but it does improve the enjoyment of these scanners. And yes, the default delays & wait times (usually a number of miliseconds) are not 0, and can make scanning not so enjoyable. This isn't the fault of NXDN, although they're working on some of those issues that do exist, but it does affect most transmissions, especially digital. This is why I always set the delays (especially digital delays) and wait times to "0".

Also, keep in mind that tried & true adage about scanning: the more you scan, the less you hear! Even with a scan rate of about 80 channels per second, if you have a big scan, it'll take a while to process.

I've never regretted having the NXDN & DMR keys activated.

 

[Facsimile]

I repeat: adjust delays and wait times. This will improve hearing transmissions, as any delay, you might actually miss the beginning of a transmission, and wait times delay resuming the scanning, and you might miss out. It's not perfect (nothing ever is), but it does improve the enjoyment of these scanners. And yes, the default delays & wait times (usually a number of miliseconds) are not 0, and can make scanning not so enjoyable. This isn't the fault of NXDN, although they're working on some of those issues that do exist, but it does affect most transmissions, especially digital. This is why I always set the delays (especially digital delays) and wait times to "0".

My delays and wait times are set to zero.

Also, keep in mind that tried & true adage about scanning: the more you scan, the less you hear! Even with a scan rate of about 80 channels per second, if you have a big scan, it'll take a while to process.

I don't have it scanning. It is parked on only one single conventional NXDN frequency.

Thanks for the post I was wanting to get the nxdn key for my sds200 or even get another sds with it because there is at least one department id like to listen to.

Now im worried it might be pointless to get the key because its a vhf nxdn and it might not even be able to recieve it good like u are having

I'm not bashing the SDS series. I was able to map out and submit this exact frequency and it's associated frequencies I am referring to using my SDS100 and SDS200. This was before I had DSDPlus. All I am trying to get at is that the SDS series may not be the best option for some NXDN uses as seen in my case. It can decode. There are just other quicker more reliable options in my experience. Based on what Ubbe said above, I tried a NXDN trunking system in my area that uses Nexedge96 and it has zero issues following all the private calls and dispatch.

If you get the key from Uniden for $50 I'd say it's worth it.

 

[I_Am_Infinite]

My delays and wait times are set to zero.




I don't have it scanning. It is parked on only one single conventional NXDN frequency.




I'm not bashing the SDS series. I was able to map out and submit this exact frequency and it's associated frequencies I am referring to using my SDS100 and SDS200. This was before I had DSDPlus. All I am trying to get at is that the SDS series may not be the best option for some NXDN uses as seen in my case. It can decode. There are just other quicker more reliable options in my experience. Based on what Ubbe said above, I tried a NXDN trunking system in my area that uses Nexedge96 and it has zero issues following all the private calls and dispatch.

If you get the key from Uniden for $50 I'd say it's worth it.

I didnt take it as bashing but you not getting the vhf nxdn conventional, because i wanted to hear traffic from lake of 4 seasons in northwest indiana, which it might not work well on and I cant throw 50$ to nothing, I realize some can and do but i cant.

I absolutely love my 200 and wud love to have another sds and most likely am going to when I save enuf. But I probably won't get that key, if I want to monitor that id probably go with something else.

 

[werinshades]

I absolutely love my 200 and wud love to have another sds and most likely am going to when I save enuf. But I probably won't get that key, if I want to monitor that id probably go with something else.

Well, I see Main Trading Company has the 150 on sale again this morning for $787/no tax or shipping so $787 total.. My friend told me his scanner arrived in perfect condition the last time, despite the "open box" advertisement. Then add the NXDN and DMR keys to that one.

 

[I_Am_Infinite]

Well, I see Main Trading Company has the 150 on sale again this morning for $787/no tax or shipping so $787 total.. My friend told me his scanner arrived in perfect condition the last time, despite the "open box" advertisement. Then add the NXDN and DMR keys to that one.

I do want the 150 so bad but i still gotta keep sa ing for good it