hi any help please best filter settings on sds 100 especially uhf scanner initial setting and then individual deprartments groups etc im working on it but still get high squelch noise levels interference and hard to hear transmissions .
SDS100/SDS200: sds100 filters
- Thread starter joerobb23
- Start date
There is no “best”, it’s whatever works for you in your RF environment. I have global filter set to OFF on my SDS scanners and find this gives me the best performance.
There’s a few differing approaches you can take. I started with everything turned off. (It took a while because some settings were on as the default setting.) Since the filters were released for end user use in an effort to combat simulcast problems, which I didn’t have, I went through my scanners and turned all the filters off… In an effort to determine if maybe the default settings had some filter set to on and it was hiding the simulcast problem. Since I didn’t notice any differences after I turned everything off, I just left them off. Those filters were never meant for the end user anyway. They were for the bench techs to use when they diagnosed a problem such as simulcast but certainly not limited to correcting the simulcast issue. It’s my understanding when the simulcast issue had radios being returned for corrective action, Uniden realized the influx of scanners sent in for repairs could be reduced by releasing the filters and turning all of us into beta testers. A smart move actually, after it was realized the simulcast issue is very location specific. If we moved the scanner just a few feet we’d get differing results and since the bench techs back at Uniden couldn’t test the scanner where it was to be put into service it is up to us. You may find a good setting for a particular digital trunked system that’s giving you troubles and the guy next door sees something different. It’s the nature of the beast I guess. But if you are not experiencing any simulcast issues, think yourself fortunate. You don’t have to look for alternate filter settings.
By default, everything should have the value “global” for filter which means use the default, scanner-wide value.
External antenna, to get it away from noisy power supplies, led lights, WiFi signals.
Scanner has IFX setting also if you hear interference from an adjacent frequency.
Scanner has IFX setting also if you hear interference from an adjacent frequency.
Mostly, it’s on you to identify where the noise is generated. It could be a household device or a bad transformer on a telephone pole down the street. You can do the following ONLY if you know what you are doing-if there’s any doubt in your mind, do not follow what I write.
If you have a battery powered scanner you might try turning off the main at your circuit breaker panel. This cuts off all power to the house so first be sure there’s nothing that absolutely needs power all the time, (other than clocks on your stove or oven) or devices that need a manual reset and won’t resume normal operation until that is done. If the noise goes away, it’s something in your house that’s causing the noise. You can then turn the main back on and start turning off individual circuit breakers in an effort to narrow down where the offending device making the noise might reside. If that doesn’t do it you could take a walk away from your house and see where the noise level is greatest. It may be a transformer on a pole or the guy next door, a good reason to remain on a friendly basis with your neighbors!
If you live next door or in close proximity to commercial businesses they may be the cause.
If you live in an apartment complex or a duplex home that only has one electrical panel, don’t go turning off ANY power until you check with them, ALL who may be affected by a power outage caused by you… there are medical devices such as dialysis machines that, when running, need to keep running. (The device may or may not have battery backup, or the backup battery may be defunct.)
It’s a crap shoot but without the proper testing gear at least it’s a start. Your local utility company may have a free service where they send out an investigator if you suspect the noise is coming from the power lines.
Ubbe
Member
Filter settings are not at all connected to simulcast issues. They are for trying to stop signals from other frequencies to interfere and mix with your reception.
The initial problem are a low quality receiver solution and the use of too wide filters that are 10MHz wide when they need to be as narrow as possible down to 100KHz but those are impossible to manufacture and even much wider ones are super expensive.
The 85 cent receiver chip are designed to be used with already amplified signals from a satellite dish or to receive high signal level FM broadcast signals and high level terrestrial TV signals. To be able to use the receiver chip in a scanner its gain need to be maximized and Uniden also put in a preamplifier in the scanner to make it as sensitive as other scanners.
In most user cases the receiver are constantly overloaded which creates intermodulation where one signal frequency can be heard on many other frequencies. SDS100.mp4
Unidens filter settings are a IF shift function that moves the 10MHz wide bandpass filter up or down in frequency. If it gets shifted up in frequency the lower edge of the 10Mhz filter are moved closer to the frequency you are monitoring, that will filter out any signals that are lower in frequency but will also open up to more signals above the frequency. That's the Normal and Invert settings. The filter can also be moved halfway up or down in frequency, that's the Wide settings. If the filter isn't moved at all and you receive your frequency at the middle of the filters 10MHz range then that are the Off setting for the shift function as any normal scanner uses.
How you are suppose to use the filter settings are if you monitor a 850MHz signal and you have a strong local signal at 855MHz that then could interfere with your reception making it distorted or even making the receiver loose sensitivity. If you enable a filter settings that shift the 10Mhz filter down in frequency, it will stop to receive signals above 851MHz and that interfering signal at 855MHz will no longer be received and can no longer interfere. But then you could have an equally strong local signal at 841MHz that now starts to interfere. Then you choose the wide filter settings that only shift the filter halfway and both the 855MHz and 841MHz signal will be outside of the filters range where it pass signals to the receiver.
It's a global filter settings in the scanner where you set a filter type and that type will be used wherever Global have been set as the filter type for trunked sites and conventional departments. If you change the filter in the Global setting it affects all settings that use Global as their filter.
For sites and departments you can choose to use individual filters, Off, Normal, Invert, Wide Normal, Wide Invert and Wide Auto and Auto, that will not be affected from what filter you have set in Global.
To actually evaluate what filter to use, if any, are easiest with digital signals. You set a field in the display to show Digital Error Count and you watch that number while receiving and try to get as low number as possible when testing different filter settings. In a site it could be the control channel frequency or any of the voice frequencies that are interfered and when changing a filter to fix a bad reception of one frequency it could make it worse for other frequencies in that site.
For analog you have to listen to the audio quality and also set a display field to show Noise. You want as low noise level as possible and a clean signal but you can only go by the noise number when there are no one talking, it has to be a silent carrier as any audio modulation will make the numbers go up. For analog the filter affects all frequencies that belong to that department, so fixing one problem could create another problem at another frequency.
/Ubbe
The initial problem are a low quality receiver solution and the use of too wide filters that are 10MHz wide when they need to be as narrow as possible down to 100KHz but those are impossible to manufacture and even much wider ones are super expensive.
The 85 cent receiver chip are designed to be used with already amplified signals from a satellite dish or to receive high signal level FM broadcast signals and high level terrestrial TV signals. To be able to use the receiver chip in a scanner its gain need to be maximized and Uniden also put in a preamplifier in the scanner to make it as sensitive as other scanners.
In most user cases the receiver are constantly overloaded which creates intermodulation where one signal frequency can be heard on many other frequencies. SDS100.mp4
Unidens filter settings are a IF shift function that moves the 10MHz wide bandpass filter up or down in frequency. If it gets shifted up in frequency the lower edge of the 10Mhz filter are moved closer to the frequency you are monitoring, that will filter out any signals that are lower in frequency but will also open up to more signals above the frequency. That's the Normal and Invert settings. The filter can also be moved halfway up or down in frequency, that's the Wide settings. If the filter isn't moved at all and you receive your frequency at the middle of the filters 10MHz range then that are the Off setting for the shift function as any normal scanner uses.
How you are suppose to use the filter settings are if you monitor a 850MHz signal and you have a strong local signal at 855MHz that then could interfere with your reception making it distorted or even making the receiver loose sensitivity. If you enable a filter settings that shift the 10Mhz filter down in frequency, it will stop to receive signals above 851MHz and that interfering signal at 855MHz will no longer be received and can no longer interfere. But then you could have an equally strong local signal at 841MHz that now starts to interfere. Then you choose the wide filter settings that only shift the filter halfway and both the 855MHz and 841MHz signal will be outside of the filters range where it pass signals to the receiver.
It's a global filter settings in the scanner where you set a filter type and that type will be used wherever Global have been set as the filter type for trunked sites and conventional departments. If you change the filter in the Global setting it affects all settings that use Global as their filter.
For sites and departments you can choose to use individual filters, Off, Normal, Invert, Wide Normal, Wide Invert and Wide Auto and Auto, that will not be affected from what filter you have set in Global.
To actually evaluate what filter to use, if any, are easiest with digital signals. You set a field in the display to show Digital Error Count and you watch that number while receiving and try to get as low number as possible when testing different filter settings. In a site it could be the control channel frequency or any of the voice frequencies that are interfered and when changing a filter to fix a bad reception of one frequency it could make it worse for other frequencies in that site.
For analog you have to listen to the audio quality and also set a display field to show Noise. You want as low noise level as possible and a clean signal but you can only go by the noise number when there are no one talking, it has to be a silent carrier as any audio modulation will make the numbers go up. For analog the filter affects all frequencies that belong to that department, so fixing one problem could create another problem at another frequency.
/Ubbe
As Ubbe/ pointed out, the filters apparently have nothing to do with correcting simulcast issues, which dashes the assumptions I have made concerning why Uniden had released the filter settings to the end users. (Uniden may have given us the filters in an effort to appease those who were suffering from simulcast but that’s another story, more about marketing than correcting an issue. All that I wrote was assumed to be correct because most all of the threads relating to Uniden allowing us to use them (at the time they were released) came from those experiencing simulcast issues. And since there was no posts that I saw which discounted that, I ran with it as gospel. Sorry for the misinformation. And thanks to Ubbe/ for correcting my miss-speak.
ka3jjz
Wiki Admin Emeritus
We have a complete - and I do mean complete = writeup on the SDS filters linked in our FAQ viz
wiki.radioreference.com
for anyone that cares to read through all of the posts and file. As you can see, it has been the subject of much discussion in the past
Mike
SDS100 and SDS200 FAQ Page - The RadioReference Wiki
for anyone that cares to read through all of the posts and file. As you can see, it has been the subject of much discussion in the past
Mike
Mike, I expect you refer to only RR posts relating to filters when you say “complete”. Apparently I gleaned erroneous information from one of the other forums (possibly Facebook?) as I have found no mention of simulcast in the “complete” compilation you have listed, and mistakenly regarded it as “gospel”, which /Ubbe took issue with (justifiably so) just recently. I was working under the mistaken understanding the filters were released by Uniden in an effort to combat simulcast issues on the SDS series. (I had confused the simulcast issue on the BCDx36HP to also affect the SDS series, and the filters were offerred in an attempt to eliminate/reduce it.) Thanks to /Ubbe I have since discarded that erroneous train of thought!We have a complete - and I do mean complete = writeup on the SDS filters linked in our FAQ viz
SDS100 and SDS200 FAQ Page - The RadioReference Wiki
for anyone that cares to read through all of the posts and file. As you can see, it has been the subject of much discussion in the past
Mike
Is it my understanding the switch to SDR in the SDS series has eliminated the known simulcast problem with the BCDx36HP series? Or does the SDS series also have the simulcast problem (maybe not as severe)?
ka3jjz
Wiki Admin Emeritus
When I say 'complete', this is a reference to capturing most every thread we've had on the subject of filters. AFAIK I read somewhere that Uniden actually didn't want users to know about them (oddly enough)
The SDS scanners from all reports handle simulcasting much better than the other scanners, including the x36HPs.. Look to the many other threads of folks using them in simulcast areas for proof
Mike'
The SDS scanners from all reports handle simulcasting much better than the other scanners, including the x36HPs.. Look to the many other threads of folks using them in simulcast areas for proof
Mike'
Uniden Just would not tell you what each filter did for whatever reason...
It's a try them and see what works for you type of senario...
ok thank you just discovered i cant pick up new jersey state pd im only 3 miles from mahwah picking up rockland p 25 phase 2 fine always got njsp great anyone have any ideas are they encrypted?
No, they're clear
But uhh...question was asked by the OP who created the thread. Not sure how that's hijacking but I digress
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