Saturday, May 11, 2019

Some Candidates for the MW SDR DX-er


I’ve been a MW DX-er since my teens. Any other part of the radio spectrum is mostly tuned casually. Hence, I tend to evaluate my SDRs only by their MW performance.

A dedicated MW DX-er has some prerequisites for his or her receivers:
  • Sensitive enough to pull in signals in a low signal level environment.
  •  Robust enough to not overload easily when signal levels are high.
  • Access to software which can record and play back the entire MW band as efficiently as possible.


With the SDR being a “software defined radio”, it is true that software does define the radio experience. Software for the MW DX-er is worth a study of its own. However, at this stage, I thought it might be interesting to have a look at hardware that I have either tested myself, or that I think I know enough about to evaluate for MW DX-ing.


I even thought out a rather complex system for ranking the SDRs since they come in a large variety of price and performance levels. But the system relied on too many subjective factors, so for the time I settled for making an “Editor’s Choice” at the end of this article.

Software supplied with the hardware are listed in bold. Only Windows software versions are listed. Links to the SDR's home page and eHam.net review pages where available.

Name
Description
RFSpace CloudIQ

9 kHz-56 MHz. Ethernet. External 5V, 0.5A. Max sampling rate: 1807 kHz (1500 kHz tuning range), good for MW. Sensitivity -111 dBm. Good front end. Two antenna ports, software switchable. USD 630. Out of stock – discontinued? Available as used but scarce. Software: Spectravue, SDR Console. Receiver link. Eham review.
RFSpace NetSDR

0-32 MHz. Ethernet. External 5V, 1.3A. Max sampling rate: 2 MHz (1600 kHz tuning range), good for MW. Sensitivity -102 dBm. VHF/UHF add-on board optional. USD 1450 in 2011. Discontinued, available as used but scarce.  Quite large footprint. Software: Spectravue, SDR Console. Receiver link.
Expert Electronics ColibriNANO

0-55 MHz. USB. USB power (USB 2.0 is ok). Max sampling rate: 3 MHz, 1536 kHz (1230 kHz tuning range) is good for MW. Sensitivity -90 dBm, noise floor is on the high side. EUR 300. Available. Smallest SDR. Software: ExpertSDR2 (no IQ file playback!), HDSDR. Receiver link.
Microtelecom Perseus

0-40 MHz, USB. External 5V, 0.75A. Max sampling rate 2 MHz (1600 kHz tuning range) is good for MW. Sensitivity -103dBm. Good front end. EUR 800 in 2019, few available. Discontinued? Available as used but scarce. Software: Perseus, HDSDR, SDR Console, Jaguar Pro/Jaguar Lite. Receiver link. Eham review.
Elad FDM-S2

9 kHz-52 MHz + FM and 135-160 MHz. USB. External 5V, 750 mA. Max sampling rate 6144 kHz, 1536 kHz-option (1230 kHz tuning range) is good for MW. Sensitivity -106dBm. EUR 525, available. Software: FDM-SW2, SDR Console. HDSDR. Receiver link. Eham review.
Winradio G31DDC

9 kHz-50 MHz. USB. External 12V power. Max sampling rate 2000 kHz, 1600 kHz tuning range is good for MW. Sensitivity -106dBm. Robust front end. GBP 700, available. Software: Winradio (IQ recordings will not store/display date and time! No IQ recording scheduler!), HDSDR (current dll only supports bandwidth up to 1000 kHz, 800 kHz tuning range). Receiver link. Eham review.
Winradio G33DDC

9 kHz-50 MHz. USB. External 12V power. Max sampling rate 6000 kHz, 1666.7 kHz sample rate gives a 1250 kHz tuning range which is good for MW, but 32-bit sampling gives double-sized IQ files compared to other SDRs. Sensitivity -110dBm. Very robust front end. GBP 1600, available. Software: Winradio, more options than the G31DDC software, HDSDR (not tested, but known to be restricted to maximum 1000 kHz bandwidth). Receiver link.
SDRPlay RSP1A

1 kHz-2 GHz. USB. USB power, 180 mA. Max sampling rate 10 MHz, 1536 kHz option (1230 kHz tuning range) is good for MW. Sensitivity -101dBm but drops off on LW. 2 MHz lowpass filter gives reasonable front end. DAB notch filter. USD 109, available. Software: SDRUno, HDSDR, SDR Console. Receiver link. Eham review.
SDRPlay RSPDuo

1 kHz-2 GHz. USB. USB power, 180 mA (single tuner). Max sampling rate 10 MHz, 1536 kHz option (1230 kHz tuning range) is good for MW. Sensitivity not measured but likely similar to the RSP1A. Three antenna ports, Hi-Z port for SW/MW. 2 MHz lowpass filter gives reasonable front end. DAB notch filter. USD 280. Available. Software: SDRUno, HDSDR, SDR Console. Receiver link. Eham review.
Afedri SDR-Net

100 kHz-35 MHz. Ethernet (USB possible but too narrow IQ bandwidth). External 5V power, 370 mA. Max 2500 kHz sampling rate, 1333 kHz tuning range option is good for MW. Sensitivity -104dBm (overloads if gain is set too high), reasonable front end when gain is set low, otherwise poor. USD 260. Available. Software: HDSDR, SDR Console, various others. Receiver link.  Eham review.
SDRs not sampling the full MW band
Description
Airspy HF+
9 kHz-31 MHz + 60-260 MHz. USB. USB power, less than 0.5A (USB 2.0 port is ok). Max tuning range is 660 kHz. Sensitivity -112dBm. Very robust front end. USD 200, available. Software: SDR#, HDSDR, SDR Console. Receiver link. Eham review.
Seeed KiwiSDR

10 kHz-30 MHz. Ethernet. External 5V, 1.2A. No IQ sampling. Up to 8 simultaneous channels. Sensitivity -102dBm. Good front end. Can be set up as server. USD 300, less during Massdrop campaigns. Available. Software: None. Runs on any HTML-5 browser, like Chrome, Edge, Firefox, Safari. Receiver link.
SDRs not reviewed
Early Elad and RFSpace SDRs. SDRs with upconverters. SDRPlay SDRs lacking a 2 MHz low pass filter. Any SDR over USD/EUR/GBP 2000. SDRs typically unavailable. SDRs with no, or limited MW coverage.
In the pipeline
Not much, as per May 2019:
Elad FDM-S3 seems to be in its final stage before launch. EUR 950. Two software-selectable antenna ports?
Airspy HF+ Discovery is just around the corner. USD 100. One antenna port. Same sampling bandwidth as today’s HF+
RFSpace CloudSDR – ETA at Q4/18 has been changed to Q4/19. USD 900? Will we see it?

My Picks:

Low price range/entry level: The SDRPlay RSP1A. It is quite sensitive on MW, less so on LW, and may require some attenuation if the signal level is high. 2 MHz low pass filter helps. Several software options. Can double as a sensitive FM and DAB receiver with 6-8 MHz effective bandwidth, depending on PC. All for only USD 109. A steal.

Middle price range: Microtelecom Perseus. It is sensitive on MW and LW, good dynamic range and several third-party options including the bespoke Jaguar Pro/Jaguar Lite software which lifts the Perseus to the top of the sky. EUR 800 but limited stock, occasionally shows up on auction sites. A bit fiddly installation procedure. Others: Elad FDM-S2 (available, EUR 525), RFSpace CloudIQ (out of stock, maybe discontinued, USD 630). The Winradio G31DDC (available, GBP 700) will be a very good alternative if it gets full HDSDR support.

High price range: Winradio G33DDC. Very sensitive, and very good dynamic range. But a hefty price for the performance (GBP 1600), and proprietary software which some may like and some (like me) will not. Others: RFSpace NetSDR, only available on the used market (USD 1450 new). Good sensitivity and dynamic range, several software options.

If IQ recording of the entire MW band is not important, consider the ethernet based KiwiSDR. No IQ recordings, but up to 8 simultaneous channels (USD 300). Audio recordings are possible from all channels. Or the USB based Airspy HF+ with excellent sensitivity and dynamic range. Several software options, 660 kHz alias-free IQ recording (USD 200).

But you will likely discover that IQ recording of the entire MW band is important.


2 comments:

Ken Alexander said...

I have had 7 of those receivers. Still have CloudIQ, HF+, RSP Duo and KiwiSDR. CloudIQ is my favourite but poor frequency stability meant the end of my MW offset career. Still waiting for a GPSDO interface from RFSpace.

Stephanie Battaglino said...

I have three SDRs of the grouping Bjarne reviewed: the RSP2, HF+ and the Elad FDM-S2. In the RF Hell of the New York City metro area where I just moved from, the RSP 2 overloaded terribly, however the HF+ performed as if I was at the top of the world. Awesome sensitivity even right next to the 50Kw flamethrowers whose arays were within 5 miles of my location. Looking forward to seeing hkw they all perform in the much RF quieter California desert.