SDS100/SDS200: Electrical Performance Specs for SDS100

We have not been able to find these,either @ Uniden or any of their resellers. For all other Uniden models their electrical specs are readily available. Uniden has made certain claims about the SDS100's sensitivity & selectivity specs but provided no posted or written confirmation. If these are available, it would be greatly appreciated that someone point me in the right direction. Thank U.

Try searching this site and you should find a table posted by Upman comparing the 436HP to the SDS100. Sensitivity was one of the things in the table. This was shortly before the SDS100 was available.

Upman also has made a number of observations about how each should perform in comparison to each other in a number of different situations.

I don't recall ever saying anything at all regarding selectivity. As to sensitivity, I've said it will be either better or worse than the BCD436HP, depending on frequency and environment.

Did multiple searches, found a couple of mentions but still no table of RF performance specifications for the SDS100. I would hope Uniden would provide these in a table form for easy reference. If U have a link to these, pls post it. Thanks.

MCode said:

Did multiple searches, found a couple of mentions but still no table of RF performance specifications for the SDS100. I would hope Uniden would provide these in a table form for easy reference. If U have a link to these, pls post it. Thanks.

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http://forums.radioreference.com/uniden-prospective-owners/368953-sds100-vs-436-a-4.html#post2935122

Note that the performance specs in that table could have changed due to firmware updates made since that post. Some may be better and some may be worse, depending on frequency and RF environment.

UPMan said:

Note that the performance specs in that table could have changed due to firmware updates made since that post. Some may be better and some may be worse, depending on frequency and RF environment.

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That's not very helpful.

Sensitivity specs don't change with RF environment, they are what you measure in the lab under test conditions, real world sensitivity may change due to blocking.

Why not publish a proper spec with sensitivity and dynamic range?

I was using the "popular" perception of sensitivity, which as you note does change depending on RF environment.

Because the spec can change based on future firmware changes.

UPMan said:

I was using the "popular" perception of sensitivity, which as you note does change depending on RF environment.

Because the spec can change based on future firmware changes.

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OMG

"Popular perception", really?

You and I know there are proper ways to specify RF performance, these statements make me wonder what you trying to hide?

I know you are tweaking firmware but this sounds like you are still designing it.

Um...not trying to hide anything. Actually disclosing more than I have to and will stop now since it so distresses you.

UPMan said:

Um...not trying to hide anything. Actually disclosing more than I have to and will stop now since it so distresses you.

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Amused more than distressed.

This so called "popular perception" of sensitivity only happens due to poor design where a receiver can't handle strong RF environments, suffers blocking and appears deaf.

woodpecker said:

http://forums.radioreference.com/uniden-prospective-owners/368953-sds100-vs-436-a-4.html#post2935122

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Many thanx for the specs table..

But now I am shocked on how bad some of the SDS100 RF specs are..
@ every frequency the sensitivity specs for the 436 are "significantly better" than the SDS100..
When U check the max column, some are 3X worst. It seems that the "worst" column must be the unit's limit specs which in the CE biz are typically defined as worst case for unit release by the factory during mass production. It appears the wider this tolerance is the increased possibility of getting a unit with "subpar" performance.
IMHO..
When purchasing the SDS100 @ its higher cost, I would have thought that besides the updated features of display and later protocols, the RF specs should be better than the 436. Regarding firmware updates, I would think that is for improving unit operation, battery life not RTF performance. Regarding selectivity, this spec in my opinion is also crucial, especially if there a high-powered signal on an adjacent frequency that can bleed over..

Remember that a Pro-2006 scanner have a bad spec of something like 0.6uV sensitivity but most users swear by that it is their most sensitive scanner. An Icom R2/R10 receiver have great specs at something like 0.15uV but in most cases will in real life have the worst sensitivity of your scanners. The SDS100 will not be the best RF performer and are focused on solving the simulcast issue. It has a chip with programmable specs and if Uniden would state some specs and they later change them to adapt to the real world, some users might claim that it is out of specs and demand their money back.

I only wish that Uniden would change the attenuator option to instead be a city/suburban selection to switch between highest sensitivity in a forgiving RF enviroment and a lower sensitivity that handles demanding RF enviroments better. I agree with another poster about having user selectable parameters to really be able to finetune and then store to these two modes. As it is now you have to load two different firmwares to get a similar type av adaption to your own RF enviroment.

/Ubbe

UBBE I read on here where a SDS100 owner sent his back because it has already had 5 FW updates and the owner thought that meant the SDS100 was rushed to market and did not want the scanner.

MCode said:

Many thanx for the specs table..

But now I am shocked on how bad some of the SDS100 RF specs are..
@ every frequency the sensitivity specs for the 436 are "significantly better" than the SDS100..
When U check the max column, some are 3X worst. It seems that the "worst" column must be the unit's limit specs which in the CE biz are typically defined as worst case for unit release by the factory during mass production. It appears the wider this tolerance is the increased possibility of getting a unit with "subpar" performance.
IMHO..
When purchasing the SDS100 @ its higher cost, I would have thought that besides the updated features of display and later protocols, the RF specs should be better than the 436. Regarding firmware updates, I would think that is for improving unit operation, battery life not RTF performance. Regarding selectivity, this spec in my opinion is also crucial, especially if there a high-powered signal on an adjacent frequency that can bleed over..

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Specs are great, but real life is where it matters. Compared to my 436HP, I don't see much difference in the SDS100, except the latter is able to scan a simulcast system effectively. I've read others have issues with the SDS, and I'm guessing it comes down to their environment.

Specs are crucial element of the product as they provide a level of comparison between comparable products, also for their respective ranking given pricing.. But sensitivity is not the only "spec", SNR (signal-to-noise) gives an better indication of sensitivity vs. noise level. As having a sensitive tuner but then a noisy RF stage the noise can/will cover up the signal. I fully understand that Uniden may not want provide these in the operation manual but at least should disclose on their website. I appreciate the feedback. Thanks.

Every electronic device have internal noise. You can see it as the bar you have to clear in high jumps. More internal noise will raise the bar and the signal has to be stronger to clear the bar and continue to the next stage.

The first amplifier in a scanner will be exposed to RF that also will increase the internal noise and raise the bar. How much will depend on the quality of the amplifer and the amount of RF that the amplifier get exposed to. Scanner specs always show the best value measured in a lab without any kind of external RF noise that could interfere. You can compare that with diesel gate in a way that you can never achive those figures in real life.

/Ubbe

Ubbe said:

Every electronic device have internal noise. You can see it as the bar you have to clear in high jumps. More internal noise will raise the bar and the signal has to be stronger to clear the bar and continue to the next stage.

The first amplifier in a scanner will be exposed to RF that also will increase the internal noise and raise the bar. How much will depend on the quality of the amplifer and the amount of RF that the amplifier get exposed to. Scanner specs always show the best value measured in a lab without any kind of external RF noise that could interfere. You can compare that with diesel gate in a way that you can never achive those figures in real life.

/Ubbe

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1st of all, in any good, quality tuner there is an built-in noise floor from the electronics circuits itself. Thats why I mentioned previously that SNR can be more pertinent than just a good sensitivity spec. Besides the tuner's noise floor U have incoming noise, such as a pulse type and here the tuner front end must separate noise from an incoming transmission signal. If U check out a quality tuner be it a hi-fi FM tuner or communications receiver the brand will disclose a multiple of tuner specs including SNR, quieting slope, selectivity, THD, uV @ a specified standards level. My disappointment with Uniden was when I couldn't find any specs on the SDS100. I understood the SDS100 was SDR type design, and uses an overclocked ADI Sharc processor. As I have experience with the CommRadio CR1A which is also an SDR design and covers the various high frequencies and ultra-hi-frequencies from 100MHz up to 500MHz. And I had significant interest in the SDS100 but wanted more technical info before putting down the $. I didn't want to buy the SDS100 and then later find out its RF performance was subpar.

I did find various threads on this site explaining how the SDS100 compared to 436 or 536 but in most instances there was no science and/or actual measurements to verify the subject RF performance capability of the SD100. I also understand the advanced protocols available for the SDS100 but those were not my primary interest. I greatly appreciate all of the feedback that various guys posted. Thank U.

MCode said:

Specs are crucial element of the product as they provide a level of comparison between comparable products, also for their respective ranking given pricing.. But sensitivity is not the only "spec", SNR (signal-to-noise) gives an better indication of sensitivity vs. noise level. As having a sensitive tuner but then a noisy RF stage the noise can/will cover up the signal. I fully understand that Uniden may not want provide these in the operation manual but at least should disclose on their website. I appreciate the feedback. Thanks.

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That's not correct, you measure the SNR to determine the sensitivity, the standard measurements for NFM are to measure the microvolts of RF required for 12dB SINAD (Signal+Noise+Distortion divided by Noise+Distortion) and for AM 10dB S/N ratio.

Another important spec is the SFDR, spurious free dynamic range, anything can be sensitive but if it overloads easilty it won't matter how sensitive it is.

The SDS100 has a cheap sattv tuner like a $10 dongle, they are designed for 6-8 MHz bandwidth DVB reception where signals are normally moderate strength and relatively constant. If you turn the gain up too much the in band intercept points fall through the floor and it will overload like hell, if you keep the gain too low it will appear deaf. Its difficult with AGC to get the gain right, it really needs to be user adjustable like a dongle. This is probably why Uniden won't publish a spec becuase they haven't finished fiddling around with it.

These cheap tuners make mediocre cheap receivers, Rafael Micro are known to have wide variations and poor yields which you can get away with when buidling a $20 satellite receiver.

woodpecker said:

That's not correct, you measure the SNR to determine the sensitivity, the standard measurements for NFM are to measure the microvolts of RF required for 12dB SINAD (Signal+Noise+Distortion divided by Noise+Distortion) and for AM 10dB S/N ratio.

Another important spec is the SFDR, spurious free dynamic range, anything can be sensitive but if it overloads easilty it won't matter how sensitive it is.

The SDS100 has a cheap sattv tuner like a $10 dongle, they are designed for 6-8 MHz bandwidth DVB reception where signals are normally moderate strength and relatively constant. If you turn the gain up too much the in band intercept points fall through the floor and it will overload like hell, if you keep the gain too low it will appear deaf. Its difficult with AGC to get the gain right, it really needs to be user adjustable like a dongle. This is probably why Uniden won't publish a spec becuase they haven't finished fiddling around with it.

These cheap tuners make mediocre cheap receivers, Rafael Micro are known to have wide variations and poor yields which you can get away with when buidling a $20 satellite receiver.

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Thanks for ur response..
But as I posted previously measuring an RF tuner's sensitivity is complex and the noise floor/distortion are pertinent plus the output filters used for spec measurement should be defined. The crucial factors are gain, spurious, harmonics, image frequency rejection, return loss, phase noise, group delay, frequency stability, TOI. So just providing just a hyped sensitivity spec which is often created by the marketing department are meaningless without proper backup. But then again having the experience and supporting lab equipment is required to give the subject tests merit.
What I would like to see would be a comparison table performed by an independent calibration lab comparing multiple scanner models vs. the SDS100 @ various frequencies, multiple protocol modes.
Then an objective comparison could be done. As presented now there are simply too many variables of mixed opinions and personal experiences. Don't read me wrong, I greatly appreciate the feedback by the SDS100 users explaining their "use cases" but would like to see more objective, substantiated measurement data.