Nooelec & External Clock Reference

[DMS11B]

I recently purchased two NooElec NESDR Smart XTR SDR - Premium RTL-SDR w/Extended Tuning Range, Aluminum Enclosure, 0.5PPM TCXO, SMA Input. RTL2832U & E4000-Based Software Defined Radios. These will monitor the new CRIS (California Statewide TDMA Phase 2) System, utilizing SDRTrunk.

I have yet to take one of the SDR's apart, does anyone know if these SDR's are capable of utilizing an external 10MHz GPS reference clock?


I did find this article, RTL-SDR Blog V.3. Dongles User Guide just not sure if the same applies to the Nooelec SDR's...

 

[thewraith2008]

The dongle like the RTL-SDR.com uses a 28.8MHz TCXO.
A 10 MHz reference cannot be used as a substitute for the internal reference clock.
The reference would be OK to check accuracy of SDR so long as it has a good PPM itself.

There is a video on youtube where a guy disassembles one to look at it, but he seems incapable of hold it in one position for any reasonable amount of time to get a good look at it.

In video it looks like two holes OP/ON (or QP/QN) are used for HP reception. (see here down the page a bit - for Nooelec NESDR SMArt)

Other information and installation guides here and here.

 

[redbeard]

No. And FYI you'd be better off with the non-XTR versions. The e4k tuners in the XTRs are not as good as the RTL tuners and really are best suited for the higher frequencies the RTL tuner can't reach.

You don't really need a better reference for simple trunk system monitoring, the TXCO built-in is pretty stable IMO. The cheapest SDR with reference input would be the Airspy R2. And it doesn't really need it either.

 

[AM909]

My experience with my TCXO dongles I wrote about here, and still is true 6 years later. 0.5 PPM is 400 Hz at 800 MHz, and plenty stable enough for P25's bandwidth. You shouldn't need an external reference.

 

[a417]

My experience with my TCXO dongles I wrote about here, and still is true 6 years later. 0.5 PPM is 400 Hz at 800 MHz, and plenty stable enough for P25's bandwidth. You shouldn't need an external reference.

I think the only realistic use case for me would be if I was trying to tie together multiple dongles for ATSC reception.

 

[Dirk_SDR]

You can easily calibrate the NESDR SMArt sticks e.g. with a GPSDO. I used the mini GPSDO of Leo Bodnar.