SDS100/SDS200: Sds100 picking up two channels at once

[mikey1two]

Need help figuring out what’s going on here. I am scanning LA County Police dispatch (patch channels) and tactical channels here in Southern California. Analog channels in the 483-485mhz range. Multiple antennas tried all with the same result.

One particular channel is “L-tac 5” (483.4625) where if you are familiar with their system is basically a car-to-car. When monitoring this channel, I pick up the conversations, sometime very staticky and more than often overlapping with an unknown dispatch channel.
I say a dispatch channel because I hear the beeps that play when the officer is communicating with the dispatch.

Side-by-side with my 396, the 396 doesn’t pick up the “ghost” dispatch channel.

currently listening to 483.1625 perfectly clear …until that other “ghost” channel transmits then I get both. Again the 396 doesn’t pick up both.

LA City PD on p25, perfectly clear.

thanks

 

[KevinC]

Need help figuring out what’s going on here. I am scanning LA County Police dispatch (patch channels) and tactical channels here in Southern California. Analog channels in the 483-485mhz range. Multiple antennas tried all with the same result.

One particular channel is “L-tac 5” (483.4625) where if you are familiar with their system is basically a car-to-car. When monitoring this channel, I pick up the conversations, sometime very staticky and more than often overlapping with an unknown dispatch channel.
I say a dispatch channel because I hear the beeps that play when the officer is communicating with the dispatch.

Side-by-side with my 396, the 396 doesn’t pick up the “ghost” dispatch channel.

currently listening to 483.1625 perfectly clear …until that other “ghost” channel transmits then I get both. Again the 396 doesn’t pick up both.

LA City PD on p25, perfectly clear.

thanks

Try IFX and see if that helps.

 

[RFI-EMI-GUY]

Need help figuring out what’s going on here. I am scanning LA County Police dispatch (patch channels) and tactical channels here in Southern California. Analog channels in the 483-485mhz range. Multiple antennas tried all with the same result.

One particular channel is “L-tac 5” (483.4625) where if you are familiar with their system is basically a car-to-car. When monitoring this channel, I pick up the conversations, sometime very staticky and more than often overlapping with an unknown dispatch channel.
I say a dispatch channel because I hear the beeps that play when the officer is communicating with the dispatch.

Side-by-side with my 396, the 396 doesn’t pick up the “ghost” dispatch channel.

currently listening to 483.1625 perfectly clear …until that other “ghost” channel transmits then I get both. Again the 396 doesn’t pick up both.

LA City PD on p25, perfectly clear.

thanks

It could be intermodulation distortion, especially if one transmission seems abnormally loud. The solution? Attenuate signals or move antenna location, or use a better receiver.

 

[Ensnared]

Are the DPL tones the same? I will give you a little tip that has helped me monitor P25 systems, provided you have one in your Favorite list.

For saturated metro areas, I program, "Use site NAC" for all trunked system that list such. I tried this method in Houston, Texas and it worked great. Hope you get this figured out.

Cheers.

 

[Ubbe]

When monitoring this channel, I pick up the conversations, sometime very staticky and more than often overlapping with an unknown dispatch channel.

It's a RF problem with the receiver in SDS scanners. You'll have to try the suggested solution by using the attenuator, if the signal are strong enough or apply IFX to that frequency. I have the same problems at 460MHz and if I use IFX I only switch from one frequency bleeding into the one I monitor or another frequency when using IFX. The signal strength are -90dBm or weaker so I cannot use the attenuator. It's just happens to be a poor receiver in SDS scanners.

/Ubbe

 

[mikey1two]

Well it seems things just aren’t made like they were used to. Thanks for the quick replies and sorry for the late response back. I have gotten into the habit of toggling IFX and ATT on/off to better hear the conversation thanks to the replies.

I just got home from a western United States driving trip. Although the gps feature on these scanners were a great help when traveling, I mainly listen around home and unfortunately that doesn’t work well for me using this scanner. I’m disappointed at Uniden for having an known issue like this and 4 years later still selling it as is. And to top it off when was the last firmware update? There are improvement that could be made. Are they even trying to make their customers happy?
I doubt that I will buy another uniden scanner anytime soon if this is the quality that I will receive. I revon there are better alternatives out there that offer better support.
Thanks again for the replies,
-Mikey

 

[buddrousa]

The IFX is no different than the birdies were in the 1980's scanners

 

[Ubbe]

There's some huge birdies in the SDS100, the similar ones you see in the spectrum in SDR# when using a $10 SDR dongle. Remove the antenna and open the squelch at 156.000MHz, which is an often used channel in my country. The display also interfere at some frequencies so best to have it turned off during scanning and only light up automatically at conversations.

/Ubbe

 

[buddrousa]

But this has be a problem from day one when Microprocessors were first used but the IFX is a fix that helps with this problem and is a very useful tool.

 

[Ubbe]

That birdie at 156.000 cannot be fixed by IFX or any filter setting. There are a couple of those birdies in SDS100.

/Ubbe

 

[nacsr]

I have the same issue with 150.01