Tag Archives: SDR

A review of the SDRplay RSP1A software defined radio

 

Today, SDRplay, the UK-based manufacturer of affordable software defined receivers, announced a new addition to their product line: the SDRplay RSP-1A.

The RSP1A joins the SDRplay product line of the RSP2 ($169.95 US), and RSP2 Pro ($199.95 US). The new RSP1A will retail for $99.00 US.

But what of this SDR’s performance?  In a nutshell: as of today, I’d contend that the RSP1A will simply be the best SDR value on the market. End of story. There is nothing I know in the $99 price bracket that can beat it.

How do I know this?  I can make this statement with confidence because I have been involved with real-world testing and evaluation of the RSP1A Alpha, Beta, and production models since May. I took the RSP1A with me to Canada this past summer for field recordings with my laptop, and I’ve also evaluated the RSP at my home. Like a number of other reviewers, I’ve been intimately involved with putting the RSP1A through its paces. And let’s just say I like what I’ve seen.

I actually do quite a bit of Alpha and Beta testing for manufacturers. While it’s time-consuming volunteer work and requires meticulous attention to minor details, it gives me an opportunity to have meaningful positive impact on an upcoming product. Manufacturers that actively involve enthusiasts in their testing phase tend to produce better-quality products on the first run. Better products, of course, mean a better radio market with options for those only now discovering the mystery––and fun––of radio as well as DXing.

Since the RSP1A is essentially iterative agility on behalf of SDRplay, the RSP1A was surprisingly solid even in its early release. And try as I might, there were very few issues I ever needed to report back to the engineering team. SDRplay took each item of feedback seriously, logged it, and followed-up. Over the course of the evaluation period, SDRplay improved their dedicated SDR application SDRuno, as well.

In essence, the RSP1A hardware now in production and shipping has been thoroughly tested and is ripe-and-ready for your radio adventures.

I have not compared the RSP and RSP1A side by side; running two instances of SDRuno on the same PC has been problematic. To my ear, when I’ve tested one after the other, the RSP1A serves up slightly better sensitivity, perhaps due to a slightly lower noise floor. Also the RSP1A frequency stability is much improved over the RSP1.

Specifically, the following upgrades have been made per SDRplay:

  • ADC resolution increased to 14-bit native for sample rates below 6 MHz, increasing to 16 bits with decimation
  • Enhanced RF pre-selection (greater filter selectivity plus 4 additional sub-bands compared to the original RSP1) for reduced levels of spurious responses
  • Improved LNA architecture with variable gain––the RSP1 had just a single gain step
  • Improved intermodulation performance
  • Performance extended to cover 1kHz to 2 GHz with a single antenna port.
  • Bias-T facility
  • Improved frequency stability incorporating a 0.5ppm TCXO (software trimmable to 0.01ppm)
  • Selectable broadcast AM/FM/DAB notch filters
  • RF shielding within the robust plastic casing

Performance

Suffice to say, this budget SDR delivers, and users will be wooed by its stellar performance.

I’ve spent 95% of my evaluation time on the HF and mediumwave bands and I’ve been impressed with the receiver’s sensitivity, selectivity, and AGC control. The audio fidelity is also highly customizable since it’s pumping audio directly through your PC’s system.

I haven’t spent any time above the aviation bands (higher than 140 MHz); I have, however, tested the RSP1A thoroughly on the FM broadcast bands and found it a solid FM performer. Note, too, that SDRuno’s built-in RDS decoder window provides quite a lot of data.

I’m also pleased that I haven’t noticed any front-end overloading––this, despite the fact that during travel, I’ve used it in the vicinity of some powerful broadcasters.

Comparing to benchmarks

I’ve compared the RSP1A to the Elad FDM-S2 ($500), WinRadio Excalibur ($900) and Microtelecom Perseus ($900).

The WinRadio G31DDC “Excalibur”

But let’s be clear, here: this is not an “apples-to-apples” comparison since the RSP1A is a fraction of the cost of the others, and is also a wideband receiver (1 kHz to 2 GHz). The only other SDR I own that has VHF coverage is the FDM-S2, which tops out at 160 MHz.

Pricier HF-focused SDRs have distinct hardware advantages––especially in terms of filtering––that give them an edge over budget wideband SDRs. Still, in my comparisons, the RSP1A holds its own quite well.

Compared to the WinRadio Excalibur, for example, this SDR came fairly close in terms of sensitivity.  The WinRadio’s synchronous detector––which I consider to be the best in the business––was indeed more stable than that of the RSP1A. The RSP1A sync lock could falter a bit during a weak signal’s QSB dip compared with the Excalibur.

But again, HF SDRs in the league of the FDM-S2, Excalibur, and Perseus have the luxury of designing receiver architecture around a much smaller portion of the spectrum. If you are a hard-core DXer looking for uncompromised performance on the HF/MW bands, then you should invest in one of these benchmark SDRs. I have, and I’d never give one of them up.

With that said, even though I have these amazing benchmark SDRs at my disposal, I still purchased the original RSP1 (then at $159 US) years ago. Why?  For one thing, it’s more portable than the Excalibur or Perseus as it requires no external power supply (like the excellent FDM-S2, the RSP derives its power from the USB data cable). Additionally, I do like to play with frequencies above 50 MHz from time to time. The RSP offers up an all-in-one RF toolbox at a very affordable price. I don’t hesitate to throw the RSP in my pack and take it anywhere I’m travelling. If it gets damaged or lost, I’m only out $99––not $1,000.

Again, RSP1A’s bang-for-buck simply blows my mind.

Side note: I do wish someone would develop an accessory outboard filter box that could be implemented with budget wideband SDRs, thus providing, in a sense, a hardware “upgrade.” Something like the Elad SPF-08 preselector box designed for the FDM-S2

Any cons?

This review has been overwhelmingly positive because, frankly, the RSP1A is challenging to find fault with. Of course, if it carried a price tag of $600-900, I’d be much more critical of its performance as compared with my benchmark receivers in that same price class. I’d fully expect a robust preselector system, a bullet-proof front end, and performance that could match or surpass the benchmarks.

But for just $99? You simply can’t get that kind of hardware for that cost.  So SDRplay engineering cleverly pulls every bit of performance out of their receiver by focusing on their SDRuno application, which is optimized for this receiver.  And for that reason, it’s in a class by itself.

Admittedly, when SDRplay first introduced their application, SDRuno, I wasn’t the biggest fan. I found it rather quirky and a little cumbersome to use. SDRuno has come a long way, though; SDRplay has continuously improved it, and today, I prefer it to HDSDR and SDR console. SDRuno is much less cumbersome to use than it used to be, and the default window arrangement is pleasing (though I’d still like SDRuno windows to lock and act as one window as I flip through programs on my Win 10 PC). I even prefer SDRuno to Elad’s application in terms of ease of use.

If more AF/IQ recording features are added (virtual receivers, for example) it could even become my application of choice.

The great thing about the SDRplay RSP series, however, is that they’re supported by so many third-party SDR apps. If you don’t like the one you’re using, there are numerous others to chose from. SDRplay takes an affirmative stance that their hardware should be usable on as many platforms with as many applications as possible. Kudos to them.

Here’s a question I know I’ll be asked…

“I just purchased the RSP1. Should I upgrade?”

Good question! As you might guess, my answer is fairly simple and depends on your particular needs:

If you’re happy with the RSP1 and see no real benefit in the RSP1A upgrades above, don’t bother upgrading. Seriously…enjoy what you have! The RSP1 is still a sharp, capable, versatile little SDR and fully supported by SDRplay and its community. I’ve worked some incredible DX with mine over the past few years, and love it.

If you like the sound of the RSP1A and would appreciate the upgrades listed above, then go for it! After all, it’s only $99! Consider this: the price is less than that of my recently reviewed Digitech AR-1780 portable and less than the venerable Tecsun PL-660. Even with a modest external antenna, it will perform circles around these rigs.

If you need an excuse to justify the upgrade to the RSP1A, consider doing what I’m planning to do: give your RSP1 to a friend or someone interested in the hobby. Or, donate it to your radio club as a raffle prize. Then too, of course, you can snag a decent price for it by selling it on eBay or QTH.com.

Summary

While a little busy, I do enjoy the combined spectrum display option on SDRuno.

If you can’t tell, I’m most impressed with this latest offering from SDRplay. I can recommend it with confidence because you simply can’t beat the performance and features for the price.

If you’re considering the RSP1A as your first SDR, you’ll be happy to know SDRplay’s Mike Ladd has also amassed a healthy number of SDRuno instructional videos on YouTube as well. If you start with the first video, by the end of the series you’ll be adept at using SDRuno. Couldn’t be easier.

Think of it this way: The RSP1A is the sporty-but-affordable compact car of the SDR world. It delivers performance well above its comparatively modest price and is fun to operate. In terms of DX, it gets you from point A to point B very comfortably––and quite affordably!

With just $99, there’s no reason you can’t join the world of SDR––the RSP1A is a very accessible, very intuitive SDR start your exploration of the radio spectrum.

Click here to view the RSP1A at SDRplay’s website.

SDR pioneer Dr. Vanu Bose dies at 52

Photo credit: Vanu Inc.

(Source: Southgate ARC)

Software Defined Radio pioneer Dr. Vanu Gopal Bose passed away on November 11, 2017 aged 52

In 1998 he founded Vanu Inc. which pioneered the commercialization of software-defined radio and was the first company to receive FCC certification of a software-defined radio in 2004.

The firm’s technology, which grew out of Bose’s graduate research at MIT, increases the role of software in operating the radio-based component of wireless communications networks, including those used for cellphone communications.

His company had recently deployed over 40 Community Connect base stations in Puerto Rico to provide cellular service in the wake of two devastating hurricanes.

Read the Boston Globe story
http://www.bostonglobe.com/metro/2017/11/12/vanu-bose-pioneer-cellular-wireless-infrastructure-dies/mK9MjcOEiuPIOovhCGUHFJ/story.html

“Virtual Radios” by Vanu Gopal Bose, et al 1998. One of the original MIT SpectrumWare papers
https://archive.org/download/VirtualRadios/VirtualRadios-VanuBose.pdf

2003 Guardian newspaper article Radio active revolution
https://www.theguardian.com/technology/2003/jul/10/onlinesupplement2

Connecting the last billion
https://www.technologyreview.com/s/609009/connecting-the-last-billion/

Airspy HF+ SDR Now Available to Order

As reported recently on the SWLing Post that the Airspy HF+  would be available “really, really, really soon”, the rumor has become reality–this new SDR receiver is for sale on Airspy’s main sale site www.Itead.cc.

The direct link for purchase is: https://www.itead.cc/airspy-hf-plus.html.  The price in US dollars is a very reasonable $199.00, considering the high performance evident by the few test units “in the wild” recently.

There was an initial $50-off coupon code available first come, first served this morning for the first 100 orders. These were snapped up quickly; I was fortunate to make it into that limited group and I saved $50 each off a couple of HF+ units. My intent is to pair them up for full coverage of the medium wave band–while recording I/Q WAV files)–using two receiver “instances” within Studio 1 or SDR-Console software. (The alias-free bandwidth of the HF+ is a modest 660 kHz, a trade-off this receiver makes to deliver high performance at a low price.) I expect a EXTIO DLL file to be available soon for use in EXTIO software like Studio 1 (or the EXTIO version of SDRuno which I also use).

I plan to be comparing the HF+ to my current Elad FDM-S2 SDR; based on specs and early user reports, it should be a tight race.

UPDATE: I’ve learned that the shipping timeframe for the HF+ is the beginning of December (approx. three weeks). There is also a U.S. distributor who is kindly offering a similar $50-off deal: https://v3.airspy.us/product/airspy-hfplus/

Simon Brown, author of the popular SDR-Console software versions, closely compares the Airspy HF+ ($199 USD) against a RFspace NetSDR ($1449 USD w/o options): http://www.sdr-radio.com/Radios/Airspy/AirspyHF

Who else is planning on an Airspy HF+ purchase? What are your monitoring interests you plan to use it for? Please comment below and share your thoughts with other SWLing Post readers!

 

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

Airspy’s latest: The Airspy HF+ SDR

SDR manufacturer, Airspy, has a new product shipping “really really really soon” (per their website). The Airspy HF+ promises improved frequency agility through the use of high-performance passive mixers with a polyphase harmonic rejection structure. Airspy states that no external band filters are required as they are with many budget SDRs.

There are many other improvements over their previous iterations. Here’s the product information copied from the Airspy HF+ page on Airspy’s website:

(Source: Airspy)

The Software Defined Radio revolution brought great flexibility in VHF and UHF reception. Today we offer the best wide band receivers which address these needs. We also provide a high performance extension for weak-signal wide band reception on HF – something other competing solutions fail to address efficiently.

Airspy HF+ is a paradigm shift in high performance HF radio design. It is a joint effort between Airspy, Itead Studio and a top-tier semiconductor company to build a state of the art SDR for HF and VHF bands.

Like most high-end HF receivers, the HF+ uses very high dynamic range ADC’s and front-ends. But unlike the current offerings in the market, it also brings more frequency agility by using high performance passive mixers with an excellent polyphase harmonic rejection structure. No external band aid filters are required like the lower end HF receivers, which makes it the ideal companion for light portable high performance operation.

Both the architecture and level of integration achieved in this design allow us to bring top performance reception at a very affordable price.

All the major SDR software is supported. Check the download page.

State of the Art SDR streaming technology!

We concentrated state of the art DSP and networking techniques into our SpyServer software to allow multiple users to stream high quality IQ data from the same receiver at the same time. No compromises in the quality were made like it is usually done in Web SDR interfaces. You get actual IQ data you can process with your plugins and extract the last bit of information out of it.
The server software is highly scalable and can run on computers as small as the $7 Orange Pi Zero to top end 64bit servers with multiple cores/cpus, including the popular Raspberry Pi series.

HF Tuner

Airspy HF+ achieves excellent HF performance by means of a low-loss band filterhigh linearity LNAhigh linearity tunable RF filter, a polyphase harmonic rejection (HR) mixer that rejects up to the 21st harmonic and multi-stage analog and digital IF filtering.
The 6 dB-stepped AGC gain is fully controlled by the software running in the DSP which optimizes the gain distribution in real time for optimal sensitivity and linearity. Harmonic rejection is a key issue in wide band HF receivers because of the large input signal bandwidth of the input signal. The output of the IF-filter is then digitalized by a high dynamic range sigma delta IF ADC for further signal processing in the digital domain.

VHF Tuners

Excellent VHF performance is also achieved by using optimized signal paths composed of band filtershigh linearity LNAs with a stepped AGC, a polyphase harmonic rejection mixer and IF filters optimized for their respective bands.
The amplifier gain is switchable in 3 dB-steps and fully controlled by the AGC running in the DSP. The RF signal is converted to baseband by a high linearity passive mixer with a polyphase harmonic rejection structure. The low-IF signal is then converted into the digital domain by the same IF ADC used in the HF chain.

IF Sampling

The IF analog to digital converter (ADC) is a 4th order multi-bit noise shaping topology; it features very high dynamic range and linearity. The IF-ADC sampling rate is determined by a control algorithm running in the embedded DSP. This advanced technique adjusts the sampling rate depending on the tuning frequency with the goal of avoiding the disturbances and spurs generated by the switching discrete-time sections of the IF-ADC.

Digital Down Converter

Once the IF signal is digitalized, the high sample rate I/Q stream is then frequency translated and processed with cascaded CIC and FIR decimation stages. After every stage, the sample rate is reduced and the resolution increased. The final signal at the output has 18bit resolution and an alias rejection performance of 108 dBc. The data is then scaled to 16bit and sent to the Micro-Controller for streaming over USB.

Architectural Advantages

The main advantages over techniques from the legacy super-heterodynes up to the now mainstream direct sampling is that the whole receiver chain is well protected against out of band blockers while still relaxing the RF filtering constraints, making it simple and cost effective.
The natural filtering of the sigma-delta ADC combined with the excellent linearity and sensitivity of the analog chain reaches an unprecedented level of performance and integration.

Use it over the network!

Connect as many SDR applications as needed to the HF+, over the Internet or in your own local network with near zero latency thanks to the new SPY Server software.
This setup basically brings all the flexibility of Web based SDRs while still benefiting from the full power of desktop applications. The IQ data is processed in the server with state of the art DSP and only the required chunk of spectrum is sent over the network. What is sent is the actual IQ signal, not compressed audio. This means you can use all your favorite plugins to process the IF, eliminate noise and perform heavy lifting of the signals as you are used to do with locally connected SDR’s.
We have a tradition of building multi-tools, so we made sure the SPY Server runs on 32/64bit Windows and Linux on Intel and ARM processors without any compromises. Low cost Raspberry Pi 3 and Odroid boards are in the party.

Technical specifications

  • HF coverage between DC .. 31 MHz
  • VHF coverage between 60 .. 260 MHz
  • -140.0 dBm (0.02 µV / 50 ohms at 15MHz) MDS Typ. at 500Hz bandwidth in HF
  • -141.5 dBm MDS Typ. at 500 Hz bandwidth in FM Broadcast Band (60 – 108 MHz)
  • -142.5 dBm MDS Typ. at 500 Hz bandwidth in VHF Aviation Band (118 – 136 MHz)
  • -140.5 dBm MDS Typ. at 500 Hz bandwidth in VHF Commercial Band (136 – 174 MHz)
  • -139.0 dBm MDS Typ. at 500 Hz bandwidth in the upper VHF Band (> 174 MHz)
  • +15 dBm IIP3 on HF at maximum gain
  • +13 dBm IIP3 on VHF at maximum gain
  • 110 dB blocking dynamic range (BDR) in HF
  • 95 dB blocking dynamic range (BDR) in VHF
  • 150+ dB combined selectivity (hardware + software)
  • 120 dB Image Rejection (software)
  • Up to 660 kHz alias and image free output for 768 ksps IQ
  • 18 bit Embedded Digital Down Converter (DDC)
  • 22 bit! Resolution at 3 kHz channel using State of the Art DDC (SDR# and SDR-Console)
  • +10 dBm Maximum RF input
  • 0.5 ppm high precision, low phase noise clock
  • 1 PPB! frequency adjustment capability
  • Very low phase noise PLL (-110 dBc/Hz @ 1kHz separation @ 100 MHz)
  • 2 x High Dynamic Range Sigma Delta ADCs @ up to 36 MSPS
  • No Silicon RF switch to introduce IMD in the HF path
  • Routable RF inputs
  • Wide Band RF filter bank
  • Tracking RF filters
  • Sharp IF filters with 0.1 dB ripple
  • Smart AGC with real time optimization of the gain distribution
  • All RF inputs are matched to 50 ohms
  • 4 x Programmable GPIO’s
  • No drivers required! 100% Plug-and-play on Windows Vista, Seven, 8, 8.1 and 10
  • Industrial Operating Temperature: -45°C to 85°C

Typical Applications

  • High Performance Networked HF/VHF Radio
  • Ham Radio (HF + 2m)
  • Short Wave Listening (SWL)
  • AM DX
  • FM DX
  • VHF-L TV DX
  • Remote Telemetry Radio Receiver
  • Low Bands IoT

Supported Operating Systems

  • Windows Vista, 7, 8, 8.1 and 10
  • Linux
  • *BSD
  • OSX

Supported Hardware

  • Intel compatible PC
  • Raspberry Pi 2 and 3
  • Odroid C1, C2 and XU4
  • Many other Single Board Computers (SBC)

Minimum hardware requirements

  • 1GHz Pentium or ARM
  • 1GB of RAM (to run your own OS, HF+ barely needs 1MB of memory)
  • High speed USB 2.0 controller

Supported Software

Developer API

  • Open source, multi-platform user mode driver libairspyhf on github

No price point has yet been made public–at least, none that I have discovered. Of course, we’ll post shipping and pricing details when they become available. Follow the tag AirSpy for more. Check out the Airspy website for full details and documentation.

U Twente antenna damaged

Many thanks to SWLing Post contributor, Dan Robinson, who shares the following item from BCL News and Richard Langley:

Antenna of Twente SDR receiver damaged // Bclnews
http://www.bclnews.it/2017/10/06/antenna-of-twente-sdr-receiver-damaged/

The antenna was damaged yesterday during a storm. As posted on the WebSDR website:

“The antenna currently is not working properly. After a preliminary repair of rain/storm damage on October 5, it seems reception has faded away again during the night. We’ll try to fix this soon, weather and spare-time manpower permitting.”

(Richard Langley via dxld yg)