SDS100/SDS200: Intermediate Frequency Exchange IFX
- Thread starter JASII
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Changing the Intermediate Frequency is worth a try if you find this;
After you have programmed your scanner one of the frequencies programmed just happens to be the same as a known “birdie” frequency, a frequency generated within the scanner that will cause the scanner to stop scanning, it’s thinking it landed on an active frequency. Choosing a different Intermediate Frequency will allow for the scanner not to stop on the old Intermediate Frequency.
After you have programmed your scanner one of the frequencies programmed just happens to be the same as a known “birdie” frequency, a frequency generated within the scanner that will cause the scanner to stop scanning, it’s thinking it landed on an active frequency. Choosing a different Intermediate Frequency will allow for the scanner not to stop on the old Intermediate Frequency.
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That depends on how bad the original interference is. It could range from "minor improvement" to "OMG!"
ecps92
Member
and I've seen others where it has.
See posts 21-23 where the user was getting NWS on a NON NWS frequency
Ubbe
Member
It depends of if you have any receive issues and what type of issue. Generally speaking when you receive a 100MHz signal it is mixed down to a lower frequency, lets say 10MHz, that are more easy to handle in the receiver. The oscillator signal in a receiver, lets say 90MHz, are added to the receive signal and creates a third frequency, the IF, that then are 100-90=10MHz and the receiver can then use a better quality filter at 10MHz.
But that 90MHz oscillator will also produce an equal strong signal from an 80MHz input signal, 90-80=10, and if there are a transmitter there it will be received as good as the one at 100MHz.
The IFX function can then switch the oscillator to be 110MHz and 110-100=10 so that the 100MHz signal are still received just as good but the 80MHz one will be mixed to produce 110-80=30MHz which the 10MHz filter will not let thru.
Most Uniden scanners, at least the most expensive ones, use two different IF frequencies, lets say 10MHz and 15MHz, using two different filters that increase production cost but the IFX function can then also make a switch between the 10MHz and 15MHz filters to change the relation of what unwanted frequencies that will be received.
When it comes to Unidens SDS scanners they use a chip that are its whole receiver that can be bought for 70 cent from Alibaba, if you buy only one. This chip has a lot of internal interference signals that appear as the unwanted receive signals but are several hundreds more and creates a higher risk that any of those hundreds of signals will mix with signals at the receive input and interfere with your reception. So IFX will have a higher use in SDS scanners.
/Ubbe
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Seeing you can set this up in Sentinel Software I would think it is saved but I have never had to use this feature.
tvengr
Well Known Member
The frequencies set to IFX are under the Miscellaneous tab in the Sentinel profile editor. I don't see any settings for IFX in favorites lists.
You can prove it out by trying it. My guess is yes, they will be saved. But I, like others, haven’t seen a need, and haven’t tried changing it. But my guess is once changed, the radio will back it up during the shutdown prosess. So, change the IF, power down the radio, and then back on. Now go and see if it took. If it did not, try saving it BEFORE you turn the radio off.
Ubbe
Member
No. Those programs are favorite list editors and the IFX settings are a table that are used in the profile settings, and neither ProScan nor ARC have profile editors.
/Ubbe
ARC has 4 offerings relating to Profiles, “Open Profile”, “Save Profile”, “Save Profile As”, “Change Profile Name” …under the File tab. Doesn’t that constitute a profile editor? I am missing your meaning…
tvengr
Well Known Member
I haven't looked at the profile in the ARC536 software. If it is like the other ARC software, profile has a different meaning. A profile is a list of files which you can open up all at once rather than having to open each file individually.
Thanks. I wasn’t aware…
Ubbe
Member
It's a bit unfortunate that ARC uses profile to name it's favorite settings. It's easy to mistake it for Unidens profile settings that are a totally different thing that include every setting in the scanner except favorite lists.
/Ubbe
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