SDS100/SDS200: So what exactly are the filters, anyway?

[kruser]

Halloways facebook page has pictures of how the passband actually looks like in a SDS200 and what the different filter settings do to it.

/Ubbe

No good if you don't use facebook though

 

[W4EMS]

Link to his FB page?
FB Search was not productive.

 

[Ubbe]

No good if you don't use facebook though

I only joined FB to look at that specific page, nothing else and don't have any personal info submitted. I only get spam friend requests and investment suggestions on my FB start page.
Link are in message #12

/Ubbe

 

[bobruzzo]

Just reading this and as an amateur radio guy it would be nice to have at least a BASIC useful description of what these filters actually DO. In the least a ballpark setting THEN you can tweak as needed

 

[Ubbe]

As an amateur guy you know about IF shift and how you tweak it back and forth to get best possible reception. Uniden uses 4 different fixed settings of IF shift and are equally much a tweaking game until you find the best setting.

/Ubbe

 

[Anderegg]

I'm sure the internal details of how they made it work are proprietary and have no problem with that, but it sure would be nice if they officially said "here's what filter xx does and here's what the passband looks like."

I do like the idea of an icon on the display which graphically shows the filter passband.

Like buying a car with a bunch of controls and buttons on the dash, that say "mode 1" or "middle setting", but with no explaination of what they do!

For trunking, filtering is difficult to assess, because your dealing with a spread of frequencies, some may be affected differently than others by filters or interference. What I do, with my LSM systems, is identify the "problem" frequencies, you knwo, the ones that would be -50dBm buy 75 ERR rate, then make a conventional scanlist of just those frequenices, and throw various filters at them until they receive the least ERR. I also add ALL my problem frequencies to the IFX list, which probably helps the most, as it can turn a trunekd hit on said frequency from a blinking on and off name on the display, to an actual receive and lock of the talkgroup. I also use the same testing when determinign if I throw an attenuator at the system.

Paul