Band Allocation (older newbie question)

[EA Rob]

I have a question about 300 MHz - ~ 400 MHz band allocation. Specifically; why am I receiving stereo commercial radio in the aforementioned band? There seems to be a simulcast for almost every station in the "FM Radio" band, however not necessarily in the same order. Using SDRsharp, I can see the spectral masks buttressing the primary broadcasting signal, as would be in the FM ( 87MHz -108MHz), and with the same (or better) clarity. Is this the HD Radio frequency allocation?

 

[LeapFrog]

So you are listening with an SDR?
Sounds like you are experiencing commercial broadcast bleed-over, likely due to the receiver becoming overloaded by the strong local broadcast signals.

Consider an "BROADCAST FM BAND-STOP FILTER" (band-rejection filter) for the SDR, this may stop the issue. (But I also could be way off base, I don't know much of the bands)

This filter rejects signals between 88 – 108 MHz with around 50 dB or more attenuation. A broadcast FM band-stop filter is very useful for use with SDRs as in some areas broadcast FM signals can be so strong that they overload the SDR, causing very poor performance in other bands. You can tell if this is the case for you if you see images of BCFM stations or interference that looks like a WFM signal at other frequencies when you turn up the gain.

Best Regards
-LeapFrog

 

[Captain Kilowatt]

So you are listening with an SDR?
Sounds like you are experiencing commercial broadcast bleed-over, likely due to the receiver becoming overloaded by the strong local broadcast signals.

Consider an "BROADCAST FM BAND-STOP FILTER" (band-rejection filter) for the SDR, this may stop the issue. (But I also could be way off base, I don't know much of the bands)


Best Regards
-LeapFrog

That is exactly what the problem is. Too much signal going in and messing with the internal RF amp resulting in all kinds of image frequencies across the spectrum.

 

[Road Squawker]

Here ya go

 

[EA Rob]

Thanks guys! I do indeed have the components to build something for now. So going down the RX rabbit hole, I've decided to attempt to install GNUradio with my shiny new SDRplay RSP1 on a Linux ubuntu vm. Everything installs, but for some reason the RSP 1 is not connecting to the GNUradio app. Any suggestions? My wife is going to kick my ass if I continue to stay in the basement for hours on end. I'd like the ass-kicking to at least be worth the time. (i.e. having a working GNUradio / SDRplay hardware interface)

 

[LeapFrog]

So going down the RX rabbit hole, I've decided to attempt to install GNUradio with my shiny new SDRplay RSP1 on a Linux ubuntu vm. Everything installs, but for some reason the RSP 1 is not connecting to the GNUradio app. Any suggestions?

VM as in virtual machine?
If so, you may have troubles interfacing the SDR hardware through the virtual machine, usually this is related to the hardware's driver software not "making the connection" through a com port or something i.d.k. but you are asking the physical machine to host the device, then create a virtual machine, (with it's own simulated hardware) and expect everything to freely pass between the actual hardware into the v.m. onto the GNUradio front end without issues; that's a lot imho .

I don't know if you have Linux actually installed on your machine, but if you decide to try GNUradio on windows, here is a link. I found it easier to install the driver software for my RTL-SDR on a windows computer.

If it was me I would dual-boot windows and Linux, if you cannot live without windows.
I think on a native install (not a linux live disk or virtual machine) that you wouldn't have this issue as long as the driver installed correctly (and it's the correct driver for your SDR).

I haven't found the time to futz with Linux, and the driver issues killed it for me so I run SDR# software (free) on Windows with my RTL-SDR.

73

 

[EA Rob]

VM as in virtual machine?
If so, you may have troubles interfacing the SDR hardware through the virtual machine, usually this is related to the hardware's driver software not "making the connection" through a com port or something i.d.k. but you are asking the physical machine to host the device, then create a virtual machine, (with it's own simulated hardware) and expect everything to freely pass between the actual hardware into the v.m. onto the GNUradio front end without issues; that's a lot imho .

I don't know if you have Linux actually installed on your machine, but if you decide to try GNUradio on windows, here is a link. I found it easier to install the driver software for my RTL-SDR on a windows computer.

If it was me I would dual-boot windows and Linux, if you cannot live without windows.
I think on a native install (not a linux live disk or virtual machine) that you wouldn't have this issue as long as the driver installed correctly (and it's the correct driver for your SDR).

I haven't found the time to futz with Linux, and the driver issues killed it for me so I run SDR# software (free) on Windows with my RTL-SDR.

73

So part of the problem, much to my chagrin seems to be my inexperience. I can get the SDR to operate in a windows environment with the OEM software (SDRplay) & other software i.e. SDRsharp. After attempting to use GNUradio in Linux ( unsuccessfully ) I took your suggestion and installed the software (GNUradio etc..) from the link you provided. (thanks! BTW) I'm figuring if I can become familiar with GNUradio in windows (where it should work), I would then be better equipped to understand the nuances / configuration of the software when I migrate to the more versatile Linux environment. The issue seems to be (in addition to the above) either how the variables are set in the osmocom Source, or some additional files that could be missing. Is there a way to test / ensure connectivity between the GNUradio software and the SDRplay API library? Thanks for your help thus far. I'll try to inflict less ass pain moving forward..

 

[LeapFrog]

I can get the SDR to operate in a windows environment with the OEM software (SDRplay) & other software i.e. SDRsharp.

The issue seems to be (in addition to the above) either how the variables are set in the osmocom Source, or some additional files that could be missing. Is there a way to test / ensure connectivity between the GNUradio software and the SDRplay API library? Thanks for your help thus far. I'll try to inflict less ass pain moving forward..

Hi EA Rob,

I am not familiar GNUradio software or your type of SDR, it seems you already have the correct drivers installed in Windows; as you describe using it with SDR Play / SDR#.

As for getting your specific SDR to work with GNUradio on windows (or Linux), I don't know if SDRplay RSP1 is even compatible with GNUradio. (In a "plug-n-play" manner)
Check this list.

I do know that if you can code a driver for specific hardware, then you can make just about anything work, as long you have the source-code for the software.
(Like how GNUradio is opensource, as others are)

This level of "programming" goes beyond my skill set, I know these terminal commands:
"sudo su"
"sudo apt-get install"
"sudo apt-get update"
lol obviously I'm no Linux guru, I play around with Live boot dvd's every now and again.
Sorry, I wish I could help you more with this, but that's about all I know on the subject.

Best Regards.
-LeapFrog