SDRTrunk Dongle Question

[DewAddict]

I've been running SDRTrunk for quite some time now with an RSPdx (8 mhz bandwidth) and it works quite well. I got to thinking and was wondering what setup would work better for receiving the most traffic as possible on a larger P25 phase 1 system here in SE Michigan. Should I use multiple (3 or more) RTL-SDR dongles, each with low bandwidth or (2) RSPdx units with the 16 mhz total bandwidth? The reason I ask is that I don't really understand how it does the trunk-tracking and if multiple dongles allow better tracking over having one or two, very large bandwidth devices.

Hopefully I explained my question well enough.

 

[Enforcer52]

Tell us what system and what tower(s), that makes all the difference, number of frequencies on the system, and their megahertz spread. 16 mhz maybe overkill, depending on the system.

 

[Whiskey3JMC]

Use this calculator to determine how many SDRs you'll need to cover the spread of each site

 

[DewAddict]

Sure, no problem.

This one

 

[Enforcer52]

Using the calculator that @Whiskey3JMC suggested you would need 3 RTL-SDRs to cover the needed frequencies. Or 2 RSPdx.

A lot cheaper to go with the 3 RTL-SDRs at around $40 each.

 

[DewAddict]

Using the calculator that @Whiskey3JMC suggested you would need 3 RTL-SDRs to cover the needed frequencies. Or 2 RSPdx.

A lot cheaper to go with the 3 RTL-SDRs at around $40 each.

Ok, good to know. I only have 2 USB ports on the laptop I use, do the dongles work ok with a powered USB hub?

 

[Enforcer52]

Ok, good to know. I only have 2 USB ports on the laptop I use, do the dongles work ok with a powered USB hub?

Yes a good powered usb hub is definitely needed, I run 8 sdrs on this powered hub.

https://www.amazon.com/gp/product/B0CKQY84RT/ref=ox_sc_saved_title_2?smid=A25874M2IJ00ZT&psc=1

 

[DewAddict]

Thanks for the help.

 

[jtwalker]

With 5 dongles you may be running into a few potential issues:
1) splitting your antenna signal 5 ways will cause degradation of rf signal without some kind of active splitter, or using 5 separate antennas;
2) usb power - may not have enough electrical power to drive 5 dongles with powered hub;
3) usb throughput- your usb hub in your pc may not have enough bandwidth to handle 5 dongles.

 

[jtwalker]

With 5 dongles you may be running into a few potential issues:
1) splitting your antenna signal 5 ways will cause degradation of rf signal without some kind of active splitter, or using 5 separate antennas;
2) usb power - may not have enough electrical power to drive 5 dongles with powered hub;
3) usb throughput- your usb hub in your pc may not have enough bandwidth to handle 5 dongles.

#2 was supposed to be “without” powered hub

 

[boatbod]

With 5 dongles you may be running into a few potential issues:
1) splitting your antenna signal 5 ways will cause degradation of rf signal without some kind of active splitter, or using 5 separate antennas;
2) usb power - may not have enough electrical power to drive 5 dongles with powered hub;
3) usb throughput- your usb hub in your pc may not have enough bandwidth to handle 5 dongles.

#3 can be an issue with a single wideband sdr also. It's best to have a higher spec cpu to handle all the bit shuffling.