Best Filter

KO4IPV

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Working with a Uniden SDS100/. In the menu; Close call option / scroll down to Filter/ What is the best choice in that category Auto !
 

n1chu

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It’s a case of “Your results may vary”. The filters are there for you to try if you notice needed improvements or to just play around with them to see if they do make a difference. But the variables are too numerous to say one filter will work in all or most cases. (There may be one or two that do but I haven’t yet heard a general consensus to that effect yet.)

I remember someone stating it this way... Set up a filter and take some measurements, signal strength, etc. Then move that scanner to another location and take the same measurements. They won’t be the same-they can’t be because your location has changed... and with that, your choice if filters most likely will need adjusting to another filter or none at all.

I don’t use the filters but have played with them just to see if they might make a difference. Apparently I didn’t have any of the issues that caused Uniden to make them available for the end users so, in my case, they aren’t needed. But I don’t suffer from simulcast, which I believe is the main reason Uniden made the filters available. I could be wrong on this point. If I am, so be it. Maybe there will be other reports from those who notice an obvious improvement when filters are used.
 

Saint

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I basically listen to conventional. Does that make any difference, but wow just switched it in the off position and already see a difference thanks again
Yea I wasted a lot of time messing with these filters and I know there are a lot of people who find the filters work for them but it all has to do with your situation if they will work or not I find shutting them off the scanner scans faster also
Steve
 

Markb

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As has been posted here before numerous times, results from using the filters can vary and there is no set recommendation on what works when and where. You just have to try and see what works best in your situation. Simply turning the filters off may not be a good solution and can lead to disappointment. If you are getting interference (intermod) or other receive issues, you likely will need to try the filters and see if it helps, along with IFX.

Mark
 

Markb

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Also, it is important to note that the SDS series was built around handling simulcast distortion on LSM trunked systems. Conventional was apparently an afterthought, so that is where filters may become more useful as compared to a 7/800MHz trunked system.
 

Ubbe

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It's the exact same problem in all frequency bands and the reason that it might look like it is less problematic in 800MHz band are that most of the stuff are digital there and it's harder for a user to detect the problems. Either you hear a digital conversation or you don't. In analog you hear all the interferencies and notice the loss of sensitivity due to transmitters not even close in frequency that makes an impact on the receiver chips performance, which is the same regardless of transmission modulation and protocols used, it's the same RF signal that the scanner tries to receive.

/Ubbe
 

Ubbe

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The filter sits in the 1:st IF which is common to all frequency bands. It does nothing for the front end where the different frequency bands enter the receiver and are then mixed to either a 265MHz or a 380MHz IF frequency, depending of frequency band and if IFX are used.

Changing filter settings might help if you are interfered from other frequencies. It could be that the scanner looses sensitivity or other frequencies can be heard on frequencies that they do not belong on. There's a risk that you substitute one interference for another and do not notice any changes when trying different filters. The filter used are 10MHz wide so they pass a huge frequency range to delicate electronics that also regulate the receivers gain to try and reduce the possibility for any interference.

/Ubbe
 
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