SDS-100 Reception Quality (Multiple Antennas)

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dmullen1373

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Hey guys,

I just received my SDS100 (I spend nearly $775) the other day and the reception quality is horrendous. I have a GRE Pro-96 that literally blows this thing out of the water. I'm in LA so I know the RF situation has to be polluted and make receiving difficult - but my 96 does it with no problem.

I basically hear real faint traffic that I know is being transmitted another frequency - for example, my sheriff's office uses about 15 dispatch frequencies and several others for tactical. During scanning, my scanner will stop on a tactical and I'll hear a call go out really faintly. It's super annoying. I've tried setting the squelch to 15 and it still does it. I still have a couple weeks to get my money back and I'm seriously considering it.

What do y'all think? For the kind of money I put out, I expected a lot better!
 

Ubbe

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SDS scanners use a SDR receiver chip that have more or less the same performance as a $10 SDR dongle receiver. The difference are that the chip in the SDS also has high end features like 4k UHD video handling and other things that cannot be used in a scanner. In some locations where the RF situation are problematic it will be almost impossible to use a SDS scanner due to the overload and intermod issues with these kinds of SDR chips.

The receiver chip has an automatic gain adjustment that looks at all signals in a wide spectrum and adjust the gain to suit the strongest signal. It means that a strong signal could make your weak signals too weak and they could dissapear completly and cannot be monitored any more.

/Ubbe
 

Kaleier1

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What frequencies is your sheriff's office using? I have an SDS200 which is the base/mobile version and it is great for simulcast and 800/900 MHz trunked systems but bad on VHF and UHF conventional. Lots of intermod and frequencies bleeding over each other.
 

jonwienke

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Set the global filter to Normal, and pick Invert for the frequencies that still have interference, or enable IFX.
 

dmullen1373

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What frequencies is your sheriff's office using? I have an SDS200 which is the base/mobile version and it is great for simulcast and 800/900 MHz trunked systems but bad on VHF and UHF conventional. Lots of intermod and frequencies bleeding over each other.
Thank you for your response - they're at about 482 MHz and are all conventional analog. If the signal is strong, the radio performs really well. I had similar issues with the 436HP, but not nearly like this. The 396xt that I had did really well so I'm trying to swipe one from eBay but am also considering sending this thing back. I don't have and P25P2 stuff out here that I care about so I may just do that. I appreciate you guys' thoughts and insight.
 

werinshades

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Thank you for your response - they're at about 482 MHz and are all conventional analog. If the signal is strong, the radio performs really well. I had similar issues with the 436HP, but not nearly like this. The 396xt that I had did really well so I'm trying to swipe one from eBay but am also considering sending this thing back. I don't have and P25P2 stuff out here that I care about so I may just do that. I appreciate you guys' thoughts and insight.
Try changing the modulation to FM on analog, change volume offset to +2 or +3 to compensate for the audio loss, and the filters can be set Globally, by site and by department. If most systems are working on one specific filter setting, use that globally. If a certain system is coming in poorly, try the above suggestion. I've been doing this since I first received the scanner, and others that I've suggested this to also reported positive results. Like you, I'm in a high RF environment of Chicago, and CPD is currently using a 460Mhz. analog systems.
 

Kaleier1

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Thank you for your response - they're at about 482 MHz and are all conventional analog. If the signal is strong, the radio performs really well. I had similar issues with the 436HP, but not nearly like this. The 396xt that I had did really well so I'm trying to swipe one from eBay but am also considering sending this thing back. I don't have and P25P2 stuff out here that I care about so I may just do that. I appreciate you guys' thoughts and insight.
Yeah that's to much money to spend for UHF conventional that doesn't work well. If the SDS series did conventional VHF and UHF well I would say keep it for future proofing but the way it is now it wouldn't make sense. I have to use my $129 Alinco DJ-MD-5T Dual band handheld transceiver to monitor FRS and GMRS. Some say the reciver is direct conversion so is not good but I don't find a problem with it and it is much better than the SDS200.
 

maus92

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My SDS reigns supreme on P25 simulcast - the GREs cannot handle it at all. The SDS also does OK with VHF conventional. Depends on what you need. Just about everything in this region is simulcast.
 

gmclam

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My SDS is keeping up just fine with all the GRE models I have listed below and others I don't have listed. However, I have it connected to my antenna system where I've filtered out all the (high powered) undesired stuff I reasonably can. And on systems where the GRE models suffer from simulcast, the SDS shines.
 

Australia4001

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Ive used uniden all my life ..

I tried 3 sds units , returned them all ,
Next was the older 436 , a little better reception,
Next I tried the Whistler trx series , wow is the word that comes to mind.

My area situation requires a sensitize scanner , so the trx it was , the difference between hearing something and not in my neck of the woods ,


I still keep the 436hp for strong signals, it just not my go to scanner
 

dmullen1373

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My SDS is keeping up just fine with all the GRE models I have listed below and others I don't have listed. However, I have it connected to my antenna system where I've filtered out all the (high powered) undesired stuff I reasonably can. And on systems where the GRE models suffer from simulcast, the SDS shines.
This sounds awesome. I've played around with the filtering settings but I'm still getting bleed-over - and this is with any antenna I've tried. I tried what the gentleman suggested above but nothing has worked. Can you share your settings?
 

maus92

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If your area has P25 simulcast, the SDS is the choice. If it doesn't, then most any scanner will do. The GREs that I owned were too sensitive for the analog simulcast in my area, requiring ATT to be switched on and off constantly (I use my radios in mobile mode) to prevent distortion. And I've mentioned earlier that the GREs stank on P25 simulcast.
 

gmclam

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This sounds awesome. I've played around with the filtering settings but I'm still getting bleed-over - and this is with any antenna I've tried. I tried what the gentleman suggested above but nothing has worked. Can you share your settings?
I haven't yet learned about how these filters work in the SDS. What I've done is add old-fashioned physical filter inline between my antenna and multi-coupler. At minimum you want to remove AM & FM broadcast signals, as they are the strongest. Here's a cheap filter that I use to do that.
 

dmullen1373

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Hey guys,

So I've tried everything here. I've enabled IFX and tried varying combinations of Invert, Wide Invert and Even Auto (which I've read slows down scanning tremendously) and I still get intermod on several of these 482-484MHz frequencies. My county fire department dispatches on a 470Mhz frequency and the issue happens down there, too. If I attenuate the frequency, of course that fixes it but then some of the weak frequencies are way weak. I've tried what seems to be like everything but the issue still exists.

This can't possibly be normal for an $800 scanner - or is it? Is there anybody in LA who's trying to listen to LASD on an SDS100? I'd LOVE to hear of any tricks or tweaks to make things better! Thanks in advance!
 

Ubbe

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This can't possibly be normal for an $800 scanner - or is it?
No, it's not normal for a $800 scanner but it is normal for Unidens SDS scanners due to the receiver hardware used in them.

/Ubbe
 

maus92

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If you don't need P25 simulcast receive functionality, then you don't need an SDS radio, although I have no issues receiving VHF conventional with mine. I cannot speak for UHF since it's not commonly used in this area anymore (replaced by 7/800 mostly P25 simulcast) thus we need an SDS, and it performs flawlessly. Has the price gone up? My SDS100 was $650.

I should add that I only used a Remtronix 800 antenna.
 
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dmullen1373

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If you don't need P25 simulcast receive functionality, then you don't need an SDS radio, although I have no issues receiving VHF conventional with mine. I cannot speak for UHF since it's not commonly used in this area anymore (replaced by 7/800 mostly P25 simulcast) thus we need an SDS, and it performs flawlessly. Has the price gone up? My SDS100 was $650.

I should add that I only used a Remtronix 800 antenna.
I get it. Los Angeles is standing up a Simulcast system and I figured let's be on the cutting edge! No it was about $800 with the extra battery and charger, case, and Remtronix 800 antenna...
 

dmullen1373

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No, it's not normal for a $800 scanner but it is normal for Unidens SDS scanners due to the receiver hardware used in them.

/Ubbe
Is there a chance, sir, that FW can adjust sensitivity or possible help curb this in the future? Or should I just walk away before I get even more frustrated? I'm not asking you to predict; I'm just asking if that type of tweak to the receiver can be made via firmware. Thanks for your insight.
 
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