Review and Comparison: Nooelec SMArt XTR and SMArtee XTR

Review and Comparison: Nooelec SMArt XTR and SMArtee XTR


Start with a legendary chipset, combine it with an advanced RTL-SDR platform, send three antennas and top it up with 2-year warranty: end up with a Nooelec SMArt XTR featuring the E4000. Yes, that E4000.



Before the RTL-SDR revolution in 2013, E4000 chipsets were common and cheap as chips; but the manufacturer (Elonics) went bankrupt, and prices skyrocketed as a result due to finite supply of E4000s.
Up until now, if you wanted an E4000, you could:
1) bet $40 on eBay that you get a genuine original, but even if you can find one for sale, it's safer to wager that P. Trump will receive a Nobel Peace Price,
2) send $40-ish to Nooelec for an XTR+ (bottom one in image), or
3) grab an Outernet dongle (middle one in image), which was only manufactured for a short time. Currently unavailable, so that's another train gone.


What's so special about the E4000 chipset?

Unlike common R820T/T2 chipsets, an E4000 directly converts the received signal without an intermediary stage, more technical info for those interested in Software Defined Radio using Matlab ... (free pdf download link) from page 11 onwards. In a nutshell: completely different approach to RF signal reception and processing.
Sensitivity. Excellent reception capabilities below 500 MHz during my tests; HB9AJG made independent comparative testing (pdf) back in 2003 using the original dongle and had similar observations. The R820T2 used in recent dongles is better than the R820T chipset used then, but despite considerable advancements in case design, efforts to lower noise and improving cooling, an R820T2 can be often behind an E4000 when the purpose is hearing a weak signal.
Both XTRs use the tried-and-tested SMArt case and architecture, both have a genuine E4000, -tee in the name means that the SMArteeXTR (from now on: "tee version" in text, that's the one with more letters in images) has bias-T, which means that receiver is sending power down the coax cable to power an external amplifier. That's the only difference between the two, so what you read here applies to either.

Money


The most expensive RTL-SDR dongle on the market. By a large margin.
SMArt XTR bundle costs $45 at manufacturer, or $47 on Amazon USA. Receiver only costs about 8 dollars less, but it's hard to imagine a scenario when omitting quality accessories is justifiable.
SMArt tee XTR bundle, that's the one with bias-T costs $48 at manufacturer or $49 on Amazon USA - buy this unless you prefer DC short antennas.
Shipping advice: Nooelec offers free worldwide shipping for orders over $50; so if you, say, add an 5dBi ADS-B antenna for $6 you're over fifty dollars, and that antenna will be usable on other frequencies as well.

Local Amazon stores are much more expensive than buying directly from manufacturer, e.g. Amazon UK charges $58 instead of $48 for the same bundle. Shop around.

First impressions


Delivery from States to Ireland took 5 days as usual, heavy bag, three antennas and industry-standard 2m RG58 50-Ohm cable. Receiver in separate plastic bag, yellow engraving and protector caps; case is identical to a SMArt without black paint, similar to Outernet's discontinued E4000 - no coincidence, that was also manufactured by Nooelec, but without thermal pads and accessories, think of it as trial run for SMart XTR. Caress brushed aluminum surfaces, engraved markings, and through-and-through quality - of all dongles on the market, SMArt XTRs are the best to touch, feel and look at.
Note to Hollywood: James Bond, Bourne, Jack Reacher or <name favourite hero or villain> will be authentic with any XTR saving the world.



Accessories are the same as those shipping with SMArts: three antennas, magnetic mount, quality coax cable, read the SMArt review for detailed info on accessories.
SMA female connector as it should be, almost all enthusiast-level accessories for Software Defined Radios use this screw-on and forget type, such as preamplifiers, upconverters, affordable mobile antennas and so on. Connecting to a wide variety of SMA gear was easy.

Bias-T


Constantly on with the -tee version, aimed for users with external preamps or other bias-T equipment, dongle protected by short-circuit resetting fuse. DC short antennas such as a QFH or loops, or J-poles are not exactly a vitamin pack for donge, use the regular XTR if planning using an antenna where you can trace wires from coax to braid with your fingers without interruption.
Outputs 3.3 Volts officially, measured 3.32 V:



Nooelec SMArtee showed 4.51V, rtl-sdr.com V3 topped out at 4.69V with same equipment, higher number is better, because LNA manufacturers state gain figures with 5V supplied. Uputronics Wideband Preamp (review) and LNA4ALL (review) worked.
Tuc-tuc, really? Any reason for 3.3V?

Software compatibility


Latest SDR# x86 rev 1666 recognizes tuner as an E4000. Latest release of SDR-Radio V3 2018-03-02_0828 (aka SDR Console) no issues, recognizes receiver properly after adding radio:



SDRPlay (download, my user guide) with ExtIO interface works seamlessly.
Android-based smartphone apps function right away, SDRTouch on the right, or watch TV easily:



Personally, I use SDRuno and, to a lesser extent, SDR Console, but SDRplay supports hot-swapping dongles and the majority of readers will be familiar with the interface, so screenshots are with SDR#.

Build


Both receivers are based on the SMArt architecture, cases and screws are cross compatible:



PCB surrounded by heatsink on one side and blue thermal pads on other, which are on with a vengeance, naught impossible to reliably reattach:



Gorge on image below, -tee on top, regular XTR on bottom:


Click image (3195x1216 pixels) above for full screen if you love poring over PCBs; -tee version is essentially an Outernet E4000 without IR receiver and with thermal pad, two things I disliked in the previous Outernet post.

Heat and power use


Doesn't get as hot as a SMArt or v3, ice cube compared to a Nano 3 (review), silver case won't soak up sunlight as much as a black dongle (khmm, regular SMArt again, khmm). Thermal pads seem to do a good job, grapewine and literature suggests E4000s use less power, a claim I couldn't test due to lack of equipment, thought power use seemed to be better than any other dongle for smartphone-based adventures, less battery drain with SDRTouch or when watching TV.
RTL-SDR receivers used for comparisons below are a Nooelec SMArtee, rtl-sdr.com blog v.3, Nooelec Mini 2+ Al, orange FlightAware Pro Stick with onboard LNA - in short, the four best general-use RTL-SDR dongles. All comparisons were done with the same equipment, be it filtering, external amplification or antenna used, only swapping receivers.

Waterfall, gain, tuning


Nothing you've seen before if used to R820T/T2dongles:



Massive hump in the middle, 200 kHz range out of 2.4 Mhz visible spectrum gone. Lovely. Turn on offset tuning, and/or correct IQ and it's gone (Under Cogwheel in SDR#, Radio Configuration => Advanced in Console).
Compared to rtl-sdr.com V3 on top, minimal gain on all receivers, medium strength local broadcast FM station, v3 bottom, XTRtee top:



Compared to Nooelec SMArtee on top:



Compared to Mini 2+ Al on top:



Gain adjustment is also different, any R820T/T2 (read: almost all dongles except EzCap 645) will incrementally show elevated noise floor with more gain applied, XTRtee one slider change 14.5 to 11 major difference:



Tuning is a (rewarding) pain, as you often can't see a signal which is there, especially on shortwave, nonetheless, headphones out and it's audible.
Overloads, badly with external amplification on a discone antenna, broadcast FM obliterates any other signal; I shouldn't see this in the middle of airband:


That looks like a nice WFM signal in the middle of some DAB interference; regardless of whatever it is, FM filtering (Flamingo FM or rtl-sdr.com FM bandstop) and/or an antenna which is less susceptible to noise pickup e.g. 1/4 ground planes are compulsory with added amplification, otherwise you can listen to FM everywhere, 178 / 215 / 290 / 480 Mhz as a taster, not restricted to those ranges:



It's an E4000-specific issue, neither a SMArt or V3 is so bad, swapping to a SMArtee:


It's hard to love an XTR.

Performance comparison


Nominally receives 65 MHz to 2300 Mhz, but with a gap around 1100 Mhz, so no ADS-B straight away - known issue with E4000s.
Audio quality on broadcast FM, airband, local utilities NFM, and with human voices are just... there... Arrived.
Loud. Depth and compassion audible, smooth and mellow, bottom-shelf thriftshop whiskey under the bridge or Jim Beam Honey with strictly one icecube. Testing was marred by my reluctance to plug in other receivers, a SMArt or v.3 sounds harsh in comparison, not that you can hear them, XTR is so much louder that I was double-checking volume settings.
Did I say XTRs sound good? Chilling out after work for the last two months with Bond's dongle, I was shaken, and definitely stirred come bedtime whether I should stay up and keep listening, or try another dongle.

Shortwave listening with a Ham It Up v1.3 Plus upconverter is rewarding, since 125 Mhz is added to received signal, right into the sweet spot of XTRs.

Made for airband: one room away resting, sorted for afternoon action as usual, then swapping to XTR on impulse - not changing any settings in software, suddenly Tower permission makes me jump off the couch. On a 1/4 ground plane cut for 125 MHz, I could hear handovers to UK control, a feat I could only accomplish with SDRPlays before.
Did testing on Cork ATIS (stable on 120.925 Mhz) from Lough Derg, 124 km as the crow flies, so electrically quiet as broadcast FM barely comes in, crossed zero for mobile phone signal strength, only audible signals are dairy cows digesting morning grass: V3, SMArt, Mini 2+ Al only static, orange Pro Stick whiffs of voice, both XTRs could copy with difficulty, RSP1A best, but I hadn't expected less.
Higher up: haven't tested weather sats, marine / local action bands fantastic, 400 Mhz range better than other R820T2 dongles. TV around 600 Mhz no hassle, no ADS-B, no surprise there - get a Pro Stick Plus (review, 19 dongle comparison for ADS-B) if aircraft position signals interest you. Couldn't test Gigahertz range reception, previous test on L-band for Outernet signals showed a V3 was superior versus previous incarnation of the SMArtee XTR, but again, not tested.

Recommended accessories


Add whatever you wish or can afford from the following list, Nooelec also sells a HF bundle with the XTR. Me, I would add the Rattlesnake kit for $20, end up with 6 antennas including two telescopics and two mounts on the table, covering nearly all eventualities at home or on the road. Two telescopics can be configured for weather satellites with Rattlesnake mount with ease, but that's a different review.

Alternatives


Nothing, really, as both XTRs are quite unique at what they do; however, $50 buys a wide variety of other gear.
Same cost: either a SMArtee bundle or V3 bundle with a bias-T LNA4ALL will run circles around any E4000 on VHF and above; an $8 generic with a Ham It Up v1.3 board gets you shortwave; or think about an orange FlightAware dongle with a Nooelec Rattlesnake kit. Possible permutations go on indefinitely, and I realize it's apples to a tractor, but over the fence, a Tecsun PL-310ET world band portable radio sells for $48 on Amazon, and that's no slouch either.



For DC to daylight complete frequency coverage with all bells and whistles, count together: 50 dollars for either XTR receiver with three antennas, then some more for the best upconverter called Ham It Up v1.3 Plus to get signals below 30 Mhz down to submarine level, then buy a Flamingo FM and AM broadcast filter for $15 each, top it up with a quality low noise amplifier - at least $30. An RSP1A for $99 plus shipping can do all of the above in one go, and then more, so my love of XTRs might not resonate with those readers who want an all-in-one.
One more dongle or the dongle to buy? This is the one for the discerning enthusiast, probably with existing equipment. Or the well-off ham crowd, who won't bat an eyelid at the price surrounded by Icoms, Yaesus, or more radios in the shack than years being married. If at all.

Would I buy one?


My brain and wallet says no. A SMArtee bundle is the best value dongle package right now, rtl-sdr.com V3 receiver only is peak of electrical engineering excellence, a FlightAware Pro Stick will have an onboard LNA. Add cost of accessories for HF, filters and preamps for a full system, and the SDRPlay RSP1A will be the only contender when rent is due. Still...
My heart says: without the slightest hesitation, I'd order a Nooelec SMArt XTRtee and suffer the $50 missing from the credit card. Finally, we got a dongle which not only mates beauty with performance and audio quality, but incorporates a legendary chipset on the latest RTL-SDR architecture.
Every single morning for the last two months, unconsciously, I pick either SMArt XTRs off the table, many, many weaknesses be damned. I just love hearing signals, and they're perfect for that job.





Update 1: minutes after post went online, a kind reader noted I haven't mentioned offset tuning, corrected, post updated with new printscreens.

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