4.7 GHz

[moonbounce]

So today I was looking to see if I could find any signals north of 1300 MHz, to cut a long story short, I did.
Up in the 4.75 GHz I have discovered 3 channels, all DMR. I thought that maybe they were an image frequency but I don't think image frequencies should be up in the GigaHertz band. One sounds like it maybe a taxi service or something like that and, the other I am not sure yet.

I found this interesting as I shouldn't pickup any signals up in 4.7 GHz, but there they are. I was using an SDRSharp version and DSD+Fastlane and 12.5 stepping. This is in the London area. Anyone with any ideas?

Moonbounce++

 

[mciupa]

What emission is shown with that frequency?

 

[moonbounce]

What I hear is a dispatcher and vehicle, mentioned going to Vic Hospital. The other channel is some kind of buisiness.

Stepping is 6.25 kHz, and finding more active DMR channels.

 

[Aviator747]

What are you using as your RX, HackRF or something?

 

[moonbounce]

What are you using as your RX, HackRF or something?

I am using a Terratec dongle not the E4000 type.

 

[mikewazowski]

Definitely an image of something.

 

[moonbounce]

Here is a screen shot.

 

[jwt873]

I did a quick TAFL search for stations operating between 4.0GHz and 4.2GHz within 100km (60 miles) of the London area. There are none.. Canadian Radio Spectrum Licence Search

As mikwazowski says, you're most likely hearing some sort of images.

 

[moonbounce]

I did a quick TAFL search for stations operating between 4.0Ghz and 4.2Ghz within 100km (60 miles) of the London area. There are none.. Canadian Radio Spectrum Licence Search

As mikwazowski says, you're most likely hearing some sort of images.

Yup I would agree with Mike also, just never figure signals to repeat themselves so far out of band.

I will have to do some searching to find the image frequencies, I am recognizing it as maybe from the 400 MHz area.

Moonbounce

Another screenshot using NXDN.

 

[Aviator747]

I know I get images, intermod, in other bands when I crank the gain up on my RTL V3.

 

[moonbounce]

Definitely an image of something.

Good point, so I turned the RF gain way down and the AGC but the signals are still there as strong as ever, I don't understand it.