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Maximum USB cable length

Question often comes up, Answer: 27 feet / 9 meters with RTL-SDR dongles:

For testing, I tried four separate RTL-SDR dongles in image above: v3, Nooelec Mini 2, Nooelec E4000 SMArtee and regular Nooelec SMArt.
USB connector cable is crucial, as mentioned in a previous post detailing stuff I'm happy with, blue 5 feet / 1.5 m USB connector with ferrites were used. Tried several USB connectors over the years, these worked best, 27 feet / 9 m connectors totaled 5 dollars off eBay.

Computers were a Lenovo and a ThinkPad, identical results, all computers provide 5V to USB devices, so host computer should not matter.

Noise pickup

Nope at these extreme lengths, in fact, better with once section of USB cable as receiver is moved away from computer, didn't see any noise pickup from 5 feet /1.5 m to 27 feet / 9 meters.

Try not to use coax below 20 feet / 6 meter

If distance between antenna and receiver is within these lengths, substitute coax with USB cables. Cheaper, and since signal received is immediately chewed into digital ones and zeros, there's no chance of electrical noise pickup by coax cable.
Doubtful? Check printscreens of various lengths, top image without any USB cable connection, then adding one section (5 feet / 1.5m) at a time.
Really, I can't see any changes between the second image from top (one section) and the last image on the bottom (5 sections).

RTL-SDR Dongles Image Gallery

Studio Photos of over 20 RTL-SDR dongles on the market:

More than 200 high-resolutions PCB, case and comparison images by clicking here.

Nooelec Ham It Up Plus upconverter / noise source

An upconverter lets you hear signals below the tuning range of RTL-SDR dongles, so signals less than 30MHz, that's the entire shortwave / medium wave / longwave spectrum will be audible with a suitable antenna. Works by adding 125 MHz to received signal, so a station on 3MHz will show up at 128 MHz, which falls into the tunable range of every RTL-SDR.

Plus in the name for $65 with free worldwide shipping means it contains a noise source for experimenters: antenna and filter tuning is possible out of the box if you have the knowledge and necessary equipment.

I use Ham It Up upconverters for years, so post contains references to predecessor called v1.3 BareBones, without Plus in the name, PCB board still available for $40 at manufacturer website. Official shop on Ebay also available, check that PCB board version is v1.30a2, and seller is nooelec:

We're still talking about the predecessor, which can be bought also for much more, ripoffs at $63 and $105 available:

That's a good sign, if something is in demand, opportunists will try, just use the Official Nooelec Order page to avoid spending more than necessary.

Official Prices

Ham it Up Plus in metal enclosure, subject of this review: $65 plus shipping from manufacturer.
Ham it Up Plus, PCB board only: called Barebones, $50 plus shipping from manufacturer.
Upgrading an existing Ham It Up is easy: enclosure kit for 1.3 and higher sold separately for $16, 125 MHz TCXO upgrade kit is a tenner, noise source kit is another ten dollars. If you got a v1.3 in a metal case you'll only need to drill one more hole to accommodate one more SMA connector, but at least Nooelec thought of punters who love soldering.

Ham It Up Generations

Let's look at differences, original version with surface-mounted 100 Mhz oscillator, the first I bought from Nooelec and reviewed five years ago, unpopulated noise source:

Version 1.3a1, you won't meet these any more, the basis for further improvements, fix 125 MHz oscillator, included here for identification, this is not the latest model:

Version 1.3a2, now what we call the Ham It Up v1.3, distinguishing feature from predecessor are addded screws for easier case mounting:

Version 1.30b1, the latest model also called Plus, easiest to categorize by two SMA antenna connectors above passthrough switch.


SMA female, package comes with barrel connectors to connect SMArt family, v3, SDRplays, AirSpy, nominally everything for enthusiasts.

Power options

Needs 5 Volts via USB Type B cable, which is not supplied, nor can be ordered from Nooelec, big thick square-ish cable for printers, probably used for dependability, USB-B connectors work, SDRPlay also fancies the standard.
Unfathomable, cannot understand, makes me constantly wonder why there's still no micro-USB port (read: Android smartphone charger plug), or mini-USB (bigger brother, GoPro or Uputronics). All above are 5V, more readily accessible, users can buy a smartphone charger paractically anywhere, whereas you gotta hunt for a printer USB cable.
Just in case, PCB got positive and negative inputs just in case you want to run it off a battery bank, properly labeled. Personally, I just run the upconverter off a $15 power bank, probably not as good as dedicated batteries, but certainly better than a switched-mode power supply or occupying USB port from host computer, and enables easy mobile operation.


Manufacturer site details two claims, quoting:

" Input, output and LO filters configured for substantial sensitivity and selectivity improvements" and "Ultra low-noise linear power regulator (LP5907), with voltage noise under 10 µVRMS!"

I can neither confirm nor deny those claims, what's clear is that in the sub 30 Mhz region the Plus is better than the predecessor; I tended to hear more with the Plus, often substantially more, to the point that a faint signal came in loud and clear - but it must be noted that shortwave reception is very much down to external factors such as atmospheric propagation, so look at the following knowing that switching upcomverters took 15 seconds, same station / dongle / everything:

Regardless of the possibility of tester error, with the same gain setting on the dongle, newer Plus has a noticeably noisier waterfall.
What's not tested: reception range supposedly extends down to 300 Hz, so it's theoretically possible to listen to time signals and other low frequency signals, stations I wasn't interested in as I had no equipment capable of receiving it, hence I have no suitable antennas for proper reception.
Noise source: well, I simply had no time to dwell into the quagmire of "How to use it?", at first glance, I'd need a directional coupler, and a few weeks off on a beach to soak up the topic and sunkissed margaritas, so this will have to wait. However, just like a sunroof or a towbar it's good to know the possibility is at hand should it be needed.

Worth it?

Certainly worth the extra few dollars over the regular version, if for nothing else, it's the latest Ham It Up with extra goodies.
Question gets a little complicated once we throw cost and the availability of higher-class all-in-one SDRs into the equations, and I mean the SDRPlay RSP1: total reception system cost including three antennas is around $140 with an RSP1A, but that's $140, not $50 for Plus board only.
If you already have an RTL-SDR dongle, true sub-30 MHz capabilities are $50 away, hint: order the Rattlesnake antenna pack for $15 and enjoy three antennas, free worldwide shipping and lots of interesting signals for years to come.

About Software Defined Radio and RTL-SDR


Software Defined Radio: computer or smartphone does signal processing, not individual and expensive components as with traditional radios. The cheapest way into radio reception, best bang for the buck.
RTL refers to chipset converting analog radio signal to digital form.
RTL-SDR dongles are digital TV tuners re-purposed for radio signal reception; with a special driver and free software, up to 2.4 Mhz worth of signals can be seen and heard - completely different experience than a traditional radio, where you only see and hear the tuned frequency. Think of looking at a waterfall through a telescope (Traditional Radio) or enjoying the whole scenery (Software Defined Radio).


Receive majority of human radio communications for cheap. Sky is not the limit; listening to the International Space Station orbiting 400 km above is an easy catch, plus more, popular uses:
- Listen to shortwave stations from other side of Earth,
- CB radio,
- VHF amateur radio,
- Broadcast FM, aka morning talk shows,
- Real-life weather satellite images as they come down from satellite, user image as an example,
- Voice of local utilities / security / taxi companies,
- Position reports from ships, trains and aircraft.
And so on, there are no gaps or locked frequencies with Software Defined Radio, no limit to what you can receive, hear, or decode.

How much?

Cheapest RTL-SDR receiver from China costs $8 from eBay, fantastic value if you're handy with wires for better reception. A better, and highly popular choice is's V3 bundle ($27, manufacturer, usually sells out on Amazon fairly quickly), however, antennas in that pack are designed for indoor use only, and you'll get much better reception with an outdoor antenna. To Dad, friends or any acquittance I want to talk again, I recommend Nooelec's SMArtee bundle ($32, manufacturer, Amazon USA) for overall quality, 2-year warranty, excellent customer support, and most importantly, long cable to place either of three antennas indoors or outdoors.

Many other RTL-SDR dongles are available for specialist purposes and different budgets up to $50, you get what you pay for.

What about software?

Multiple choices, all free, popular for Windows 7, 8, 10:
- SDR Sharp, or SDR#, easy to use for beginners with lots of plugins for particular purposes,
- SDRConsole for an Office-like environment, if you use Excel or Word on a daily basis you'll feel home in no time,
- SDRUno, bit of a learning curve (my guide here) to get the most out of any RTL-SDR receiver.
Alternatives for Mac or Linux exists, I use neither platform, so aficionados comment below what's good.

What can I receive? How does it look like?

Frequencies between 27MHz and 1700 Mhz are yours for the taking with an $8 generic dongle, insert a wire in 3 minutes (called direct sampling) and get shortwave signals (below 30 Mhz). If you don't know what's a Megahertz, think of your car radio, that receives between 88 to 108 Mhz, so reception capabilities are enormous with any RTL-SDR.
User interface of SDRSharp for example, you'd only see 96.4 on a traditional radio:

See a signal represented by a hump or line (lots of different types out there), click on it, hear signal. Left hand side allows fine-tuning for better reception. Surely, procedure involves learning how to use a particular software suite, but nobody starts with writing macros in Excel straight away, isn't it?
Smartphone apps look more or less the same.

Complicated? How does it work?

No. A complete novice will get to "happy days" status in less than an hour, and that's a pessimistic estimate.
1. Install software.
2. Connect three components together: computer, dongle, antenna, then
3. Place antenna close to a window, or outside if you can. Nick a metal cooking pan from kitchen if you can, place magnetic mount on that.
That's it, double click on software shortcut on Desktop, hear an invisible world.

Technical mumbo-jumbo

Complicated words such as impedance matching, wavelengths, ionospheric propagation, line of sight and so on are for enthusiasts, maybe you, definitely later on. Play with software, shorten or lengthen telescopic antenna, see what happens. If curious, google how radio signal reception works. Do your thing, exploring with success is the biggest reward.


No RTL-SDR can transmit, e.g. you can't talk to your buddy, mess up the neighbor's day by mimicking a car keyfob, or get in touch with buddy in Australia for $8. Skype, Viber, pick up the phone, get an UV-5R walkie talkie if wanna talk locally.
Some Software Defined Radios can transmit, we're talking many hundreds of dollars and in-depth software, programming and radio knowledge, sleepless nights of pure dedication.
If you really want to transmit, get in touch with your local ham radio society, easier and cheaper if you value your time.

I want to listen to the police, emergency services, firefighters

Not an easy task without some serious programming, and whilst it's apparently doable, easy and legal in the States, I have no interest, nor experience in the topic - what's the challenge with strong local transmissions anyway?
If police freqs keep you awake at night, you might be able to listen to them if they're analog, but most of the free world (drinkable water, McDonalds, careless walk home) gone digital ages ago. Not to mention, I heard from experience, emergency services are really boring.
If you're reading this from a less than fortunate region of the world where dictators reign, think twice, it's easy to end up on a lamppost, sent to a labor camp, or get stoned to death if you get caught.

WiFi, Bluetooth

No, RTL-SDRs are not WiFi or Bluetooth adapters.

I want to listen to cellphones or mobiles

Those frequencies are fully digital and encrypted, due to software limitations it's not really possible.

I want to receive digital TV

No problem, RTL-SDR dongles are primarily TV tuners, but due to different standards, the only RTL-SDR dongle which reportedly works in the USA is the ExCAP 645 - all others work for digital terrestrial TV, also called DVB-T, Freeview, Saorview, etc. Buy a $1 OTG cable and TV on an Android Smartphone is possible in less than 10 minutes:

Older (read: even $8 dongles) come with a remote.

I want to use RTL-SDR on my smartphone

No bother. Lots of apps exist for both Android and iPhone, visit your relevant platform store and search for "RTL-SDR", you'll be amazed.

I want to see aircraft position data.

You're not alone, called ADS-B, snapshot at my airspace as I write this, cheapest dongle with worst antenna on my windowsill indoors, can only get better than this:

Ordinarily, you get data of aircraft you can see with the naked eye with an $8 dongle straight away. If you want to reach out and increase range and data received, better gear is needed. I also love anything connected with aircraft, so this site has tons of info on ADS-B.

I want to listen to aircraft and pilot talk

Easy, specific frequencies for Tower / Approach / Ground can be found online within a minute, or seen in software without internet connection. For a taster how pilots and controllers sound like, go to the Live Air Traffic Control website.

I heard it's illegal

Receiving signals is tolerated in most developed countries as long as you don't act on the received information, to be on the safe side, ask around, read legislation, exercise common sense, or best of all, talk to local law enforcement. I've written extensively about the proper approach earlier.
Circumstances matter. Home town police did a courteous house call when I put a blatantly obvious huge antenna out on the roof, left within 10 minutes after being invited in seeing I'm a harmless radio enthusiast.
Please, do not use, operate or view any radio device in, at, near, or in close proximity to airports or aircraft without permission, unless you left home with the desire of four very twitchy policeman escorting your backside for a cavity search.

I got no money but want good receive performance

When I started all I had was $10 to spare and some free time, so had to go down the "make do" route. I still maintain, and deeply believe that money is not an issue, knowledge is. Having a slight clue what's happening from the very second radio wave hits the antenna to the joyful moment you see a transmission on screen has got more to do with the matter between your ears, not with equipment.
Order an $8 dongle, then in the two weeks until it arrives from Shenzen / Hong Kong: read, read, read. Speaking home, this page got lots of info, browse around, from easy mods to antenna positioning, or read posts on, or google away. Reddit group is open to anyone, manufacturers lurk around helping as much as they can answering questions, RTL-SDR Facebook group full of helpful folks, all the info you'll ever need is out there. If stuck, comment below, I'll do my best to help if you have a question.

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.

Review: Nooelec SMA Connectivity Kit

8 pigtails for Software Defined Radios and amateur radio equipment with standard SMA female connectors, 6" / 15 cm RG-58 cable with eight different connectors on the other end:

Costs $25 at manufacturer, same price on Amazon.

Conntinue reading ...

Good buys off eBay and Amazon

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Review: Nooelec Flamingo FM Bandstop Filter

Broadcast FM signals, such as regular car radio between 88 and 108 Mhz, are a major hindrance to other radio signal reception due to large amount of transmitter power used.
Nooelec's Flamingo FM Bandstop Filter is a solution, costs 15-16 dollars from manufacturer or Amazon USA plus shipping if applicable.

Continue reading ...

Filtered Amplified Coketanna with hard metal body and FlightAware Pro Stick Plus

Performance comparison versus a pro setup and build details.

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Building a Filtered Amplified Coketenna for ADS-B

Combine a proven, easy-to-do concept, the Coketanna discussed earlier, with the best performance RTL-SDR dongle for ADS-B and a filtered low-noise amplifier for great and affordable receive performance.

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