Tuesday, 12 July 2016

Nooelec SMArt Review

Officially called Nooelec NESDR SMArt ($28 with antennas (link), $20 receiver only (link), the latest RTL-SDR dongle with improved features and the best accessory set ever offered for radio enthusiasts and newcomers to the hobby alike. That's my summary - it's really that good.
The price might seem steep compared to Chinese dongles available for less than $10 on eBay, but that topic has been thoroughly explored earlier (link).
Comparison with rtl-sdr.com dongle (called "Silver Dongle" in this post) is inevitable, especially as it costs $25 with antennas, or $18 receiver only (link). A detailed breakdown is at the end of the review.
Background information and testing notes in the Manifesto, underlined text are links, bring you to a new page in a new window. Click / tap images for full-screen glory.
The draft of this post has been sent to both manufacturers for a factual error check, many thanks for your input and support

First impressions

Bubble wrap envelope, shipping from USA to Ireland with USPS First Class took exactly one week.
The package is heavy, and even thick ziploc waterproof plastic bags exude quality, separately containing three antennas, magnetic mount with cable and receiver itself.
Two protector caps on the receiver, which will get lost in no time, but suggest "this is serious".
As a present, give it to anyone and s/he will be happy.

New dimensions

Problem: other RTL-SDR dongles and cases block a nearby USB port on laptops and on microcomputers such on the Raspberry Pi.
Solution: Narrower, deeper and shorter than any other dongle - barely wider than a USB port, compare it to the black/red USB drive on the left, or to blue generic chinese dongle on the right.

On a laptop or Raspberry Pi, two SMArts side-by-side is possible, and on a Pi 2/3, even the top port will be usable; transmitter for keyboard in the image, other USB connectors also go in.

A USB extension cable is recommended with RTL-SDR dongles,  'cause it will move the receiver away from nasty electronic noise coming from your computer. However, if you don't have one handy, prefer to use direct connection or plain lazy, the SMArt's USB-friendly narrow form works well: one more free USB port. That's a big deal if you only have three, like on most recent laptops.
The case is metal, brushed aluminum, feels and looks good, flat surfaced on four sides. Material is the thinnest of any metal dongle enclosure ever, such as the Silver dongle's, or Nooelec's own aftermarket extruded aluminum case for generic chinese dongles (that's the blue one, $15, link).

What's inside

Don't open the case unless necessary. Like receiving frequencies below 30 MHz with a wire, but more on that later.

Unscrew small screws at the USB port, then nut and washer at SMA connector (which are also a first on dongles), then slowly and gently pull out insides.
Large heatsink spans the flat side of the printed circuit board (PCB), two layers of thermal pads on the other side transfer heat to the metal case.

Blue thermal pads are on with super-sticky glue, don't ever remove them, original condition will be impossible to restore. Gorge on the image below, your unit will be 100 % the same.

The SMArt gets hot. Amazingly hot. Potato from the fire hot. Ambient temperature was scorching at an average of 62 Fahrenheit / 17 Celsius, far from Death Valley. I'd turn my mobile phone or tablet off. You get the point.
The SMArt ran fine without thermal pads and case for a day without hiccup, so I was slightly less worried. Nonetheless, I contacted the manufacturer.
Nooelec replied with the following information (I added filenames to images for clarity, no other alterations):

"The temperature dissipation is by design.  The goal is to move the heat away from the PCB and circuitry.  The more heat dissipated away from that area the better.  I've attached 2 example thermal images to exemplify.  Both are after 24 hours of active operation within the enclosure.

In the top view image, from top to bottom, is the smaller silicone pad, the larger silicone pad and the PCB.  The second image is just the bottom of the PCB with the heatsink affixed.

As should be fairly evident, the PCB temperatures are really quite low and about equal to the temperature of even the upper silicone pad.  Board-level temperatures are well below that of any RTL-SDR we have ever tested.  We are extremely confident in the long-term reliability based on our testing."

End of quote.

Antenna mount, cable, SMA connector

Mount base diameter has increased compared to previous Nooelec and generic dongle mounts.
Antenna screw is compatible with antennas supplied with any RTL-SDR dongle to date.
The magnet is so strong that it picked up the metal pan I use as a ground plane, which never happened before with any other RTL-SDR magnetic mount.
Standard radio coax cable (RG 58/U) with lower signal loss on paper than previous supplied cables, which you won't notice without lab equipment. If you need to extend it, identical cable is available worldwide - ask for "50 Ohm radio antenna cable" at your local shop, or order online.
You will notice cable length at 6.5 feet / 2m, long enough to reach. Mounts to date came with around 1 m cable, and that extra length is just the difference between placing the antenna in the window or taping it to the wall when traveling.
SMA connector at cable end means that accessories sharing that standard will be usable without an adapter.
Add all of the above together, and the whole contraption feels and functions like a proper magnetic mount. It's usable on a moving car, and I reckon $30 would be viewed as a good price for mount and antennas alone, if decision-making wasn't obscured by the "RTL-SDR dongle, so it must be **** veil in many heads. Check what $30 buys you at Ham Radio Outlet (link). 


Three supplied:
1. Telescopic, 6" / 15 cm to 23 5/8" / 60 cm, quarter-wave from 120 MHZ to 475 MHz, covers action bands and commercial FM broadcasts quite decently. Articulated joint, means you can fix the mount on a surface and turn the antenna vertical at the same time. It's a little short for shortwave, but will do an acceptable job on strong stations.
2. Medium size 10 3/4" / 27 cm (think longer edge of a sheet of paper) fixed antenna. Works OK for general use, like those times when frequency vs wavelengh calculations with telescopics are too bothersome.
3. Short 4.5" / 11.5 cm (think palm size) antenna, almost the same length as black ones coming with chinese dongles. Officially this is for 433 MHz use, does a good job with licence-free walkie-talkies.
All three fit into a laptop bag, and cover frequencies most users will likely encounter.

Go below 30 MHz

The SMArt works on HF frequencies with direct sampling. What's that?
Direct sampling means that received signal is not processed by electronic circuitry, it goes directly into the brain of the dongle - think of pouring beer into your ear and getting drunk. How much I love explaining complicated signal processing in a few words.
Works by pushing a small wire through the hole closer to the USB port, I use a jumper cable folded in half and some persuasion (read: "you're going in there"). If you never came across jumper cables, they can be ordered directly from Nooelec (link) or found in Raspberry Pi component kits.
Any small diameter wire will do, as long as there's a solid physical connection between wire and hole.

Software changes are necessary, in SDRSharp go to Settings (Cogwheel in top left corner), then click on Quadrature sampling, in drop-down list choose "Direct Sampling - Q branch".

The process has been around for years, and direct sampling holes for the same purpose can be found on the Silver dongle and on recent chinese generic dongles (walkthrough guide link). 
With 20 feet / 6.5 m ordinary household wire strung from a window, I received many stations from 183 kHz to 15 MHz, all without an upconverter.
Downsides? The signal enters the dongle's brain directly, just like a small amount of alcohol injected into the bloodstream will get you morbidly drunk, and the equivalent of six shots will kill you instantly. Similarly, this direct sampling mod can fry the dongle - you've been warned.
To ease your worries, know that direct sampling modded dongles are on the market for a while, and people been using them with good results. Don't expect upconverter-level performance, but you can get shortwave with some wire in a few minutes.

Configure your own

You can select other components from Nooelec to go with the SMArt (link). A Ham-It-Up upconverter (review link) for much better HF reception and a necessary SMA pigtail to connect stuff together is yours for $75.
Realistically, mark an enclosure (+$19) lest you wanna stare at a bare board and eventually break off the LEDs during daily handling, and definitely click on a Balun One Nine (+$9, review link) and barrel connector (+$3) to hear more with the same wire. That's a total of $106.
For a bit over hundred dollars, postman will drop one complete package to receive radio signals from all around the world. That's epic.


Antennas in the pack
function best with a metal surface under the magnetic mount. The larger, the better, nick a pan from the cupboard, place it in a window, smack the magnetic mount on top and you're good to go. For best results use an outdoor antenna, as high and free of obstructions as possible. Not always feasible, therefore if you live in an antenna-restricted environment, or don't want to listen to nagging neighbors, a metal pan in a window is a good compromise.

Also depends on software choice and settings, especially gain adjustment. If you're new to the game, play with software - a lot.
Using the included antennas, receiving a wide variety of signals is possible.
Commercial FM radio: no problem with any of the two larger antennas.
Airband: extended telescopic is perfect, airplanes talking to each other and ground control come in understandably.
Mid and Upper VHF: larger fixed antenna worked for the marine band and AIS signal reception, plus with many other local "action" frequencies.
UHF: the smaller fixed antenna is great for monitoring signals between 400-500 MHz, such as walkie-talkies.
ADS-B: the telescopic collapsed works well for airplane position signals. Extend it just an inch for even better reception, use free software to decode which speck in the sky does what (here's a link for the process), and marvel how much utility you got for the price of two cinema tickets.

Versus RTL-SDR.com dongle

Buy whichever package comes out cheaper for you, you won't go wrong with either.
Note: the rtl-sdr.com dongle used for comparison is not new. The $25 package with antennas is sold out at the moment - it's popular for a reason.
Receive performance: I couldn't see or hear a difference. Weak signals on shortwave with an upconverter still remain weak signals after swapping dongles back and forth. In the tunable range of RTL-SDRs I didn't see a significant enough difference to justify recommending one over the other on receive performance alone.
Direct sampling aka cheap shortwave: separate post link, both work with a wire through a hole.
Bias-T: aka sending power down the antenna cable for accessories. Not available with the Nooelec SMArt, requires a simple modification to the Silver dongle. For instance, if you want more local action and ready to fork out $30 for an LNA4ALL (link), the Silver dongle is a better choice. If you haven't heard of preamps before and think a discone is a kind of ice cream, go for the SMArt.
Case: both feature a metal case with thermal pads, brownie point goes to SMArt for USB-friendly shape.
Antennas: three is better than two, right? Not necessarily, as one middle-of-the road telescopic and two fixed loses out to one small and one huge telescopics in the adjustability stakes. However, the SMArt's telescopic antenna is perfect for ADS-B when collapsed and textbook-ideal for airplane chatter and morning radio when fully extended - it would be my choice if I could have just one antenna, but dismiss that nightmare aside and evaluate yourself what you use or would like to use your RTL-SDR receiver for. If you don't know, go for the SMArt and use supplied telescopic for everything. If shortwave reception is planned with an upconverter, and afraid hotel staff will notice the wire hanging out from your window, the Silver dongle comes with a huge 5 feet / 1.5m telescopic.
Magnetic mount and cable: No contest, the SMArt base and cable is quality, not an accessory to feel you got something for your money. Magnet is strong enough to pick up heavy metal objects, whole shebang stays on the car and won't fall of when going somewhere.
Reliability: The silver dongle is available for a while, a proven and tested performer, and the SMArt is new. Time will tell.
Warranty: Silver dongle - 6 months, SMArt - 24 months. I sincerely doubt you'll ever have to exercise a warranty claim with either manufacturer.
The choice is yours.

Other alternatives

Cheap chinese generic dongles: purely on price, read previous post (link).
Nooelec Mini + in aluminum enclosure: ($30, link): Uses previous generation R820T, no heatsink nor thermal pads nor usable antenna mount with cable. Performance difference between R820T and R820T2 is there (review link), some prefer the older R820T due to less distracting lines in waterfall. Case is strong enough to fight rabid dogs away, and it's a great modding platform due to large metal case for oil cooling and PC heatsinks.
SDRPlay ($150 or more, manufacturer link, my review link): a hyperspace jump compared to RTL-SDR dongles, both in performance and price. If you're thinking of spending this much, don't cheap out and order a SMArt package at the same time. There're a lot of projects for RTL-SDR dongles and significantly more guides, and even if you give the SMArt away to a grateful family member, the connector standard, mount, antenna cable and antennas will be perfectly compatible with the SDRPlay - which doesn't ship with any.


The Nooelec SMArt is the best buy RTL-SDR dongle package at the moment.
1. Receive performance is great, features make everyday radio easier and leave room for experimentation.
2. Magnetic mount with cable actually works.
3. Three usable antennas.
Unlike repurposed TV tuners, the SMArt is designed and engineered to perform as a radio signal receiver. Attention to detail is evident, from brushed aluminum enclosure through equipment-friendly cable and SMA connectors to direct sampling holes requiring no soldering.
All for $30. A ready-to-use software defined radio receiver package at this price point is nothing short of astonishing, and unparalleled at the moment.
The proven Silver dongle from rtl-sdr.com offers indistinguishable performance on most frequencies, and if you’re an advanced amateur and already have an antenna system and equipment in place, it’s hard to resist receiver only for $18.
Nooelec's NESDR SMArt is a great entry into the world of radio, and the first RTL-SDR package ever in which every component works as they should.
As of mid-2016, the SMArt is the dongle to buy.


  1. Thank you for a thorough review - I'm looking forward to trying my NESDR SMArt as soon as it arrives.

  2. Comments like this make me keep going!

  3. Great Review... just ordered!