NooElec SMARTee XTR vs SMART Problem

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Prolands
Posts: 2
Joined: Fri Jul 13, 2018 12:41 pm

NooElec SMARTee XTR vs SMART Problem

Post by Prolands » Fri Jul 13, 2018 1:21 pm

Hello everyone!

TLDR: My NooElec SMARTee XTR performs much worse than SMART. I'm wondering if this is by design and if not can you help me troubleshoot it?

I've recently purchased two receivers from NooElec:
- SMART (the standard model, R820T)
- SMARTee XTR (supposedly the more-premium model with lower noise and extended range, E4000)

I've decided to compare both receivers like-for-like in 400MHz range. I've used SDR# on a Atom x5-Z8350 Windows 10 tablet. Both receivers were using a NooElec telescopic antenna from RaTLSnake M5 pack. Once one device was tested, SDR# was stopped, receiver unplugged from USB port, antenna re-screwed to new device and plugged into the same USB port. Both receivers were tested at sample rate of 1.024 MSPS and similar gain of 42 dB.

Results were disappointing. The more expensive and premium SMARTee XTR struggled to pick up the signals that SMART was able to find. Please see attached screenshots for comparison. I've chosen a constant signal at 442.325 MHz for testing. You can see that SNR or SMARTee XTR is at a level of ~36 dB, whereas SMART achieves close to ~64 dB. You can also see that the rest of the spectrum lights up like a Christmas tree when using SMART, whereas it's mostly quiet on the SMARTee XTR.

What gives?

- Is my SMARTee XTR faulty and I should get a replacement?
- Is this behaviour by design?
- Have I somehow damaged my receiver by swapping it with another to the same USB port?
- Should I be using a different antenna with each of the receivers?
- Is it possible that the USB driver is confused as to which device is plugged in and therefore making SMARTee XTR underperform? (R820T vs E4000 conflict?)

Appreciate your insight lads. New to the forum (hi!) and radio-related subject in general so go easy on me :)
Attachments
SMARTee XTR.PNG
SMARTee XTR.PNG (209.2 KiB) Viewed 386 times
SMART.PNG
SMART.PNG (239.13 KiB) Viewed 386 times

rtlsdrblog
Site Admin
Posts: 1788
Joined: Mon Nov 19, 2012 11:54 pm

Re: NooElec SMARTee XTR vs SMART Problem

Post by rtlsdrblog » Sat Jul 14, 2018 4:24 am

I wouldn't really call E4000 based dongles "premium" models. The only reason E4000 dongles are more expensive is because the chip manufacturer went out of business and so E4000 chips are rare now. The cheaper R820T2 is a technically superior chip and performs better in most areas. The only major advantage is that E4000 dongles have a larger upper tuning range.

That said the performance in most cases is similar enough not to notice, and I don't think you should be seeing that much difference. I don't have an XTR here, but I do have other E4000 dongles and they're fairly similar. The design isn't easy to screw up, so i'd wager that the XTR you have is faulty. Probably ESD damaged, or loose connections somewhere.

Prolands
Posts: 2
Joined: Fri Jul 13, 2018 12:41 pm

Re: NooElec SMARTee XTR vs SMART Problem

Post by Prolands » Sat Jul 14, 2018 2:55 pm

Thanks for the very insightful reply. Should help other people if they have a similar problem as there isn't much information out there about this dongle. Its being marketed as having higher sensitivity than tne R820T type (but I was not able to find comparisons).

I shall be returning mine for a replacement then! Cheers!

rtlsdrblog
Site Admin
Posts: 1788
Joined: Mon Nov 19, 2012 11:54 pm

Re: NooElec SMARTee XTR vs SMART Problem

Post by rtlsdrblog » Sun Jul 15, 2018 12:30 am

Sensitivity of the E4000 is a little better on the lower bands, but is barely noticeable.

HB9AJG did some measurements a while ago https://www.rtl-sdr.com/wp-content/uplo ... Tuners.pdf. That was written in 2013 with the R820T, and these days the newer R820T2 closes the sensitivity gap even more, and there have been improvements to the drivers as well.

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