Noise from speaker

[exfirepro]

Rog,

I just discovered the N3 today myself, so can't comment until I get a chance to test one. IIRC the Nano 2 doesn't have a particularly great reputation in the SDR world, though I can't remember the details at present. I do know the one I suggested works, hence why I suggested it. It also uses SMA for the antenna, which would get round your disconnect worries.

Regards

Peter

[rogellis]

.
It looks like a nice unit - designed and built in the US.  And for aviation, we should not really be using the cheapest, especially if there is a chance of overheating on the inferior versions.  Hopefully the electronics are of a similar standard......

I have asked NooElec if they can produce a dongle and remote aerial as a package, as the aerials on their package are not suitable.  They will get back to me.

R

[Seanhump]

I've just ordered one of the single ones - https://www.amazon.co.uk/gp/product/B073JZ8CC2/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I'll let you know how it turns out ....

[Seanhump]

The Nano 3 arrived today..

Initial impressions are good - the build quality is very good, and the supplied heatsink / SMA-MCX adapter are nice touches ...
It's physically smaller than the 'stock' SDR so doesn't obscure the USB port it sits next to.

PAW has identified it straight away (shows as a NooElec NESDR Nano 3 in the home screen), and connection to the whip antenna brings in ADSB signals as you'd expect.

I'll try out various configs later tonight to see how it behaves with the USB extension and the tuned 1090Mhz NooElec antenna (though I have now 'tuned' my whip antenna, with noticeably better results...)

I'll leave it running for a while and see how hot it gets....

Scheduled to be flying tomorrow so I'll take it up with me and report back ...

[exfirepro]

Hi Sean,

My Nano 3 arrived today too..

I agree with your initial impressions, it certainly looks good quality and after plugging it in, mine was also immediately recognised as 'NooElec NESDR Nano 3' on the PAW Home Screen.

I have been running it at home with the standard PAW 1090MHz antenna and another SMA option and both performed as expected, so it certainly works fine.

It has been running for 12 hours now (without using the supplied heat sink) and although I haven't had any issues, my one concern is that it gets VERY hot - and the heat seems to be 'held' by the aluminium case and transferred through to the Pi USB block, which probably isn't good for the other components. It's now so hot in fact that I can only touch it for a few seconds without it actually burning my fingers!!

I will continue testing tomorrow with the heat sink attached.

Regards

Peter

[Seanhump]

HI Peter

I agree on the heat side of things, though more testing today with the Nano 3 in the short USB extension I'll be using removes the concern for the heat transfer to the Pi - So far there have been no issues using the Nano 3 with the USB extension and NooElec 1090Mhz antenna ...

Weather stopped any off airfield flying today so I didn't bother hooking the gear up in the cockpit for testing ....

[rogellis]

It has been running for 12 hours now (without using the supplied heat sink) and although I haven't had any issues, my one concern is that it gets VERY hot - and the heat seems to be 'held' by the aluminium case and transferred through to the Pi USB block,

Thanks for that, Peter.   I have asked the NooElec engineers if they would like to reply with any advice.    Unfortunately, my Nano-3s have not arrived as yet.   I was trying to organise a package deal with antenna.

Roger

[Seanhump]

The heat from the Nano 3 is sufficient for me to mount it outside on the V1 'All in one box' project ... and I've added the heatsink.

With the heatsink it's not so hot that you cant touch it anymore, but the extra space it needs means it wont fit inside !! (it's tight in there....)

I think the V2 one will need a slightly larger enclosure ... apologies for the quality of the pic ..

More to follow when it's finished .... (nearly there)

[rogellis]

I think the V2 one will need a slightly larger enclosure ...

I made a similar enclosure, as the PAW would not last on the back-shelf of a glider cockpit. 
No Nano to try yet, but will probably place it on a lead inside the enclosure.

R

[rogellis]

.
I had a reply from the NooElec engineer, who said:

It is a very good thing that the device is hot, as it means the heat is not concentrated into a single smaller area where it is likely to cause problems down the line.  Hopefully that makes some sense!

I presume this means that an insulated plastic casing to the chip might overheat the chip itself, rather than the casing, and ruin the chip.  The heat has to go somewhere.
​
.

Unfortunately it is a byproduct of the main chips themselves, which we cannot change as we do not manufacture them.  The best way to reduce power consumption is to use a host device with lower consumption (higher efficiency) and by ensuring the SDRs are not active when they are not being used.

By host device, I preume he means the aerial, so a tuned aerial would be better.   I will confirm this with him.

Ralph

[Ian Melville]

No, he means the RPi. As the SDR is required all the time, there is no power to be saved there.

[exfirepro]

Rog,

Presumably the engineer means...

My bold!
'Its a very good thing that the device is hot, as it means that the heat is [being transferred to the metal casing (and equalised there *), rather than being retained inside the dongle and] concentrated into a smaller area where it is likely to cause problems down the line [namely causing failure of internal SDR components].

I don't necessarily disagree with him as a general principle - especially taking account of his second comment (which Ian has already covered), but in our case it means that if we want to use this particular SDR Dongle with PilotAware, we need to ensure that the heat is not simply transferred to the Raspberry Pi - which is what happens in practice - from where it can potentially cause damage to components in the RPi or in the other attached dongles.

If you decide to use this device, I would certainly suggest fitting it on a USB extender, adding an extra heat sink and either mounting it outside your case, or modifying the case to incorporate a cooling fan (which you might be advised to do anyway as the case seems to have no obvious provision for cooling the RPi).

* Note: I suspect that the use of a metal casing to retain heat is deliberate to maintain a constant temperature inside the dongle, so that the crystal oscillator doesn't drift off frequency, - which is the whole point of a Temperature Controlled Crystal Oscillator (TCXO). If I am correct, we don't want to cool the dongle excessively either, as that could negate the effectiveness of the dongle.

Regards

Peter

[rogellis]

But in our case it means that if we want to use this particular SDR Dongle with PilotAware, we need to ensure that the heat is not simply transferred to the Raspberry Pi - which is what happens in practice - from where it can potentially cause damage to components in the RPi or in the other attached dongles.

If you decide to use this device, I would certainly suggest fitting it on a USB extender, adding an extra heat sink and either mounting it outside your case.

But is the Chinese dongle simply exporting its heat through the USB connector, instead of through its casing?  Logic would dictate that both dongles consume about the same power, and thus give out the same amount of waste heat, which has to escape somewhere. And if it is not exiting through the casing, it must be going through the USB.

If that is so then the NooElec is probably better, as it is dissipating the energy away from the R-Pi.   I do not have my NooElecs yet, so I cannot test this.  The NooElec engineer said that their dongle consumes 280 ma of power on average, or about 1.5 w.  Which is not very much, so I am surprised this results in such a high temperature.

Yes, by 'host device' the engineer did mean the R-Pi.  I did ask if there were any tweaks that could be made to reduce dongle energy consumption, but it appears not.  Even if less data is extracted from the dongle (like excluding weaker signals from contacts further away), it seems like the dongle will keep on doing its own thing. 
 
Rog

[Paul_Sengupta]

The "low power" dongle has a switched mode power supply rather than linear, and apparently takes 100mA less than the standard dongle.

But as for the Nano 3 and heat dissipation, what happens with the standard dongle is that the chip (the R820T IIRC) gets hotter. The standard dongle does get hot and does heat up the Pi to some extent, but not by that much generally, as the heat transfer through the PCB isn't that great. What the Nano 3 does is dissipate the heat away from the R820T chip, but that means everything else gets hotter.

This doesn't show the Nano 3, but it does show the heat signature from some of the other dongles.

https://www.rtl-sdr.com/tag/low-power/

[Seanhump]

The Nano 3 does run considerably cooler (you can actually touch it) with the supplied heatsink installed ...

I'm running mine on a short extension due to the space available in my case - that said, it also keeps it away from the Pi's USB ports ...