need some information about sdr

[bonk83]

what would i need to use sdr for a scanner in the 151 to 159mhz and trunking systems p25,dmr,nxdn and possibly pro voice i'm been searching for what i would need i didn't really understand it i will appreciate all the help

 

[mandcaff]

your best bet would be to get a couple rtl sdr .com usb sticks, unitrunker and dsd+.you would need some type of vac (virtual audio cable) there are differnt types some free some you have to pay for, thats all you would need.

 

[bonk83]

your best bet would be to get a couple rtl sdr .com usb sticks, unitrunker and dsd+.you would need some type of vac (virtual audio cable) there are differnt types some free some you have to pay for, thats all you would need.

do i have to buy the unitrunker and dsd+ software are they different usb sticks for different frequencies and trunked systems

 

[BM82557]

do i have to buy the unitrunker and dsd+ software are they different usb sticks for different frequencies and trunked systems

Unitrunker is free - website is Unitrunker

DSDPlus is free - website is https://www.dsdplus.com/

VB Audio cable is free - website is VB-Audio Virtual Apps

 

[bonk83]

this is probably going to be a stupid question since it is virtual are they actually a cable

 

[bonk83]

this is probably going to be a stupid question since it is virtual are they actually a cable

 

[M105]

this is probably going to be a stupid question since it is virtual are they actually a cable

No it is not a physical cable. It is a software audio device that shows up in your volume control/mixer like your speakers and microphone. It allows you to run an audio stream between programs. For example if you want your tuner program like Unitrunker to send its received audio to DSD+ you would set unitrunker to use the virtual cable as its output and set DSD+ to use the virtual cable as its input. It is like connecting a virtual wire between unitrunker and DSD+.

A typical application would be to connect unitrunker to DSD+ with a virtual cable and then listen to DSD+ output on your speakers.

I use VB Cable and donated a few bucks to the author. It is a handy little piece of work.

 

[SteveSimpkin]

Here are several tutorials:
https://www.rtl-sdr.com/listening-trunked-radios-one-rtl-sdr/
https://www.rtl-sdr.com/comprehensive-video-guide-to-trunking-and-digital-voice-with-the-rtl-sdr/
https://www.rtl-sdr.com/sdrtrunk-setup-and-use-tutorial/

 

[paulmohr]

I use VB cable for my screen capture and streaming software to patch in my Blue Yeti mic. Along with OBS and Reaper.

Still waiting for my SDR to get here from China lol. Tracking says it is in the US now so it shouldn't be long.

 

[bonk83]

are they a specific sdr usb stick to get dmr and nxdn and vhf and uhf frequencies

 

[SteveSimpkin]

are they a specific sdr usb stick to get dmr and nxdn and vhf and uhf frequencies

No. All SDR USB stick receivers should cover the range of VHF/UHF frequencies typically used for business and public safety services. Most SDR-RTL receivers have a frequency range of 24 – 1766 MHz. Some models will also allow operation below 24 MHz.
What model did you buy?

 

[bonk83]

i didn't buy one yet i was needing some suggestions on what to get

 

[SteveSimpkin]

I have two of these and have been very happy with them.
https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/

 

[bonk83]

the (RTL2832U) can it receive weak signals from far towers

 

[paulmohr]

that is the one I have coming in the mail, I only ordered one though. I am not really looking to follow trunked system with it. I got mine more for looking for really strong signals that might be interfering with my regular scanner and doing some antenna testing. And just to play with in general.

 

[M105]

the (RTL2832U) can it receive weak signals from far towers

It is still a radio receiver and I find that the SDR dongles have decent sensitivity. Like any radio what it receives relies heavily on the antenna to which it is connected. If your scanner radio will receive the "weak signal from far towers" on your current antenna then most likely so will your software defined radio.

 

[SteveSimpkin]

the (RTL2832U) can it receive weak signals from far towers

In general, these SDR-RTL sticks are very sensitive.
As to receiving signals from towers far away, that depends on a lot of other variables including how far away the tower is, your antenna characteristics, where your antenna is mounted (higher is usually between), interference from local RF sources, the terrain between your antenna and the tower, the type of coaxial cable used to connect your antenna to the SDR, etc.

 

[bonk83]

i have a centerfire vhf/uhf multiband antenna with 75 feet of rg11 the antenna is 20 feet high my elevation is 672 feet they are mountains to the northwest and the elevation goes down below

 

[M105]

i have a centerfire vhf/uhf multiband antenna with 75 feet of rg11 the antenna is 20 feet high my elevation is 672 feet they are mountains to the northwest and the elevation goes down below

Sounds good. The dongles were originally TV tuners and accept 75 ohm impedance nicely. You can use TV splitters. Again, if your scanner receives it your SDR probably will too.

 

[bonk83]

do i need sdrsharp are is that the samething as the usb stick