Airspy Discovery

Simon Brown



New owners – first impressions?


  • Like it
  • Hate it
  • Buying another
  • Taking dog for a walk


Simon Brown, G4ELI


Guy Atkins

Hi Simon,

The Discovery arrived here at my QTH near Seattle, USA this morning, and of course a brief test was in order. My DXing interests are foreign stations on MW, so I wanted to see how the Discovery performs close in frequency to strong local stations.

I gave the Discovery a brief and unscientific test at local noon. I was using both the FDM-DUOr and Discovery with Studio 1 software. I don't have an antenna switch on my desk at the moment so I quickly swapped the antenna manually between radios. I'm also not currently up for separate instances of Studio 1 (although it does that fine), so I restarted the software between each quick session, choosing the appropriate EXTIO file. This means there was some time for the weak signals to potentially fade between the quick A-B sessions. The medium wave band at midday is fairly stable though.
I immediately went to a couple of weak station frequencies that surround my local flamethrower (1 kW at 1.5 mi.) on 1450 kHz. The level of 1450 is about -35dBm on my ALA1530LNP Imperium. These stations on 1430 and 1460 are borderline-audible most of the day but with best reception in LSB or USB. Today I noticed that only 1430 was audible for testing, and it was bothered by splatter from 1450 as usual.
Both radios were run in the 768 kHz sampling rate, because that's the maximum out-of-the-box setting for the Discovery. Same mode, same bandwidths, same AGC, etc. were used of course. The FDM-DUOr demodulated 1430, providing weak but clear audio with some interference evident from the 1450 station. No attenuation was needed or adjustment of any gain setting. 
The Discovery nearly equalled the DUOr on this station (only a whisker of a difference, if any), although getting the same results was a bit "fiddly". I couldn't decide if using the automatic gain of the Discovery is best, or if using the manual gain setting is better. I'm leaning toward the auto gain feature...although it is hard to ignore the 20-30 dB difference in noise floor when using the auto setting. (The specific handful of manual gain settings of the Discovery which avoided overload resulted in a noise floor roughly equal to the FDM-DUOr's; but the auto gain feature raises the noise floor significantly along with the relative signal levels.) If I judged by ear only, and also looking at the S/N of 1430 kHz on Studio 1's I.F. display, then auto gain was better--with near-equal results to the FDM-DUOr. The DUOr was ever so slightly ahead of the Discovery in this difficult close-in strong signal test. With more experience with the Discovery I expect I'll be able to extract even better results.

Note that I've calibrated the level meter for the DUOr in HDSDR using an external signal source, but I've not done any calibration in Studio 1.
I tuned a few other weak daytime signals on MW and found it impossible to find any differences between receivers. Bravo, AirSpy! Considering the price difference this is an eye-opening performance turned in by the HF+ Discovery.  I look forward to night time tests, and serious coastal DXpedition tests in a few weeks. This will be the proof of the Discovery's abilities for me, seeking weak trans-Pacific medium wave signals with large directional antennas.

73, Guy


Got mine through China post 3 days ago.

Put it where my HF+ was, updated the firmware first and ... working flawlessly till then on HF

73 Jean-Marc

Taking also the dog (her name is Plume) for a walk :-)

Le 13/08/2019 à 19:41, Simon Brown a écrit :



New owners – first impressions?


  • Like it
  • Hate it
  • Buying another
  • Taking dog for a walk


Simon Brown, G4ELI


Angel M0HDF


I ordered mine in May (pre-order). It got here via airmail on Aug 20 with no issues.
I took it for a first “spin” to the local park with a small passive loop - 20m band this weekend. First impressions are good. Love it. More testing to follow. 

73 Angel



  1. Price.  Though I would not have mind spending more for a better enclosure (see below for dislikes).
  2. Performance.  From casual usage, I have no complaints about VHF performance.  My location is too polluted to test out HF properly.
  1. Enclosure.  The plastic enclosure is a step back from the metal enclosure of the original HF+.  Time will tell on how this affects durability around the antenna port and how it will survive accidental drops on a hard surface.  A metal enclosure also helps with keeping the device to stay in place and dissipating heat (see #2 below). 
  2. Heat.  It runs very hot.  At the antenna port, it becomes uncomfortably hot to the touch.  If anyone is interested, I can post temperature readings.
  1. Micro USB.  It would've been nice to have USB C without needing to orient the cable a certain way.
  2. Single antenna port.  Great for continuous browsing on a single whip antenna but external switching will be needed.

Larry Dighera

My Airspy HF+ Discovery, serial number 0xC8524E5D8B224A36, runs very
cool at 93.6* F (including the antenna jack) with firmware R3.0.2-BB.
Powered from a USB-2 port with a maximum current of 500 mA at 5 Volts
is only able to provide 2.5 Watts. So, the Discovery I wouldn't
expect the Discovery to get too warm. Mine only draws 270 mA or 1.35
Watts when in operation.

On Sat, 31 Aug 2019 16:55:51 -0700, "Winston" <@WinstonW>

2. Heat. It runs very hot. At the antenna port, it becomes uncomfortably hot to the touch. If anyone is interested, I can post temperature readings.


My current draw is 365 mA when operating with SDRSharp.  Firmware is R3.0.6-BB.  The hottest temp that I recorded is 121 F on the top of the enclosure and nearest the antenna port.  This is with a 24" telescopic antenna attached to the antenna port.  The temperature is lower when it is attached to and antenna via a coax cable and it seems like this is the best way to draw heat away from the Discovery other than to use an external fan.