Any SDR “Experts” that can help me out?

[alertpage]

Get rid of the USB Extension cables - they are the problem. We are capturing all 3 sites from St Paul with 6 dongles and stock antennas. I have found those USB Extension Cables interfere somehow and we have removed them from all of our setups.

 

[mmtstc]

Anecdotally, I agree with this as well. I have always struggled with reception when using an extension. USB hubs haven't been an issue though. I have both a USB-C and a USB-A hub and they both work great. One has a 6 foot cable, the other has a 2 foot cable.

 

[kb5udf]

Cheap, thin, and presumably unshielded usb extension cables can be problematic, but thicker higher quality ones I purchased from amazon work fine.

 

[Robdobb]

I agree with @kb5udf i have about 70 or so dongles throughout a lot counties in Minnesota. one of my biggest issues was using Windows just because java is horrible with SDR-Trunk so now all of my towers run Linux, Also the antenna setup the RaTLSnake M6 V2 on amazon works fairly amazing.

​

I have the same antenna, works great!

 

[janeksp6]

Cześć wszystkim! Próbuję dopracować moją konfigurację SDR, ale wygląda na to, że wciąż brakuje mi wielu transmisji, a odbiór jest nieco nieregularny. Miałem nadzieję, że ktoś, kto wie o wiele więcej ode mnie, mógłby udzielić mi porady na temat mojej konfiguracji i dać mi wskazówki lub wskazówki, jak mogę ją ulepszyć. Mam teraz siedem kluczy sprzętowych, na których działa SDRtrunk w systemie Windows na 9. piętrze w centrum Saint Paul. Nie rozumiem Linuksa. Zapłacę za Twój czas i wiedzę. Z góry dziękuję!

signguy10 Zmniejsz Sample rate A w Bandwith Outh na 96000 dla pasma 88-108 MHz

 

[janeksp6]

In sample rate reduce A in Bandshift outh to 96000 for 88-108 MHz band

 

[VexingRaven]

I'm a bit late but wanted to chime in as I see a few issues in this thread.

• Number of radios: You don't need dedicated radios for each system, you only need sufficient total bandwidth to cover the spectrum used by all of the systems combined. 1 radio can receive an effectively unlimited number of calls across an unlimited number of systems, as long as they all fall within its bandwidth. It may help to draw out the radio spectrum and all the channels used by the systems you're covering, and figure out how many radios you need.
• USB ports: You may be exceeding the total USB bandwidth and number of USB host controllers available. USB hubs do not increase either of these things, and are not helpful for connecting SDRs to a computer as an RTL-SDR running at full bandwidth is basically saturating a USB 2 port all by itself, especially if you're running them at 2.8 or 3.2MS (2.4MS is a bit more lenient). You will want to stick to directly connecting 1 SDR per physical USB port for best results, and having more than 3 or 4 SDRs on one system is probably going to have poor results because there's a limited number of USB host controllers. It's best to have as few radios as possible while still covering the bandwidth you need to avoid running bottlenecks which are not obvious due to the logical layout of the USB controllers. If you have both USB 2 and USB 3 ports, try spreading them evenly between the USB 2 and 3 ports. Most systems only have one USB 2 host controller, even if they have a large number of USB 2 ports. Similarly, all of the USB 3 ports may share a single USB 2 controller behind the scenes which is ultimately still limited to USB 2 speeds. If you want more, you might need to add a PCI-E USB card.
• Operating System: I haven't really heard of anyone having issues using SDRTrunk on Windows. I personally did it for years without a problem, and many of the users of the SDRTrunk discord have quite elaborate setups on Windows as well. You can try Linux if you want but it would not be my first thing to try.
• CPU performance: You haven't mentioned your system specs at all, you might be trying to do too much on your CPU depending on its specs. Channelizing 7 SDRs worth of bandwidth can be a strain on the CPU if it's an older system, as could decoding too many calls at once. Keep an eye on CPU load.

In general, you may want to try scaling down... Start with 1 system and 2 SDRs, see if you are missing any calls there. Once you're confident in that, then you can add more systems and add additional SDRs as required by bandwidth. Going straight to running so many SDRs on so many systems makes it hard to figure out where the issue lies as you could have an issue with any of your SDRs, or an issue with the scale of the system as a whole.

 

[signguy10]

How can I increase the amount of USB controllers? Just adding more cards?

I'm a bit late but wanted to chime in as I see a few issues in this thread.

• Number of radios: You don't need dedicated radios for each system, you only need sufficient total bandwidth to cover the spectrum used by all of the systems combined. 1 radio can receive an effectively unlimited number of calls across an unlimited number of systems, as long as they all fall within its bandwidth. It may help to draw out the radio spectrum and all the channels used by the systems you're covering, and figure out how many radios you need.
• USB ports: You may be exceeding the total USB bandwidth and number of USB host controllers available. USB hubs do not increase either of these things, and are not helpful for connecting SDRs to a computer as an RTL-SDR running at full bandwidth is basically saturating a USB 2 port all by itself, especially if you're running them at 2.8 or 3.2MS (2.4MS is a bit more lenient). You will want to stick to directly connecting 1 SDR per physical USB port for best results, and having more than 3 or 4 SDRs on one system is probably going to have poor results because there's a limited number of USB host controllers. It's best to have as few radios as possible while still covering the bandwidth you need to avoid running bottlenecks which are not obvious due to the logical layout of the USB controllers. If you have both USB 2 and USB 3 ports, try spreading them evenly between the USB 2 and 3 ports. Most systems only have one USB 2 host controller, even if they have a large number of USB 2 ports. Similarly, all of the USB 3 ports may share a single USB 2 controller behind the scenes which is ultimately still limited to USB 2 speeds. If you want more, you might need to add a PCI-E USB card.
• Operating System: I haven't really heard of anyone having issues using SDRTrunk on Windows. I personally did it for years without a problem, and many of the users of the SDRTrunk discord have quite elaborate setups on Windows as well. You can try Linux if you want but it would not be my first thing to try.
• CPU performance: You haven't mentioned your system specs at all, you might be trying to do too much on your CPU depending on its specs. Channelizing 7 SDRs worth of bandwidth can be a strain on the CPU if it's an older system, as could decoding too many calls at once. Keep an eye on CPU load.

In general, you may want to try scaling down... Start with 1 system and 2 SDRs, see if you are missing any calls there. Once you're confident in that, then you can add more systems and add additional SDRs as required by bandwidth. Going straight to running so many SDRs on so many systems makes it hard to figure out where the issue lies as you could have an issue with any of your SDRs, or an issue with the scale of the system as a whole.

How can I increase the amount of USB controllers? Just by adding more cards?

 

[VexingRaven]

How can I increase the amount of USB controllers? Just by adding more cards?

You can add more USB cards, but you probably don't need it.

 

[wogggieee]

How can I increase the amount of USB controllers? Just by adding more cards?

Use an SDR with wider bandwidth. It will simplify things too. Something like an Airspy can cover the bandwidth of three rtl-sdrs

 

[signguy10]

Computer specs