Category Archives: Software Defined Radio

Ham Radio Workbench episode explores Diversity Reception

The SDRplay RSPduo

I just finished listening to the most recent episode of the Ham Radio Workbench with John Fallows (VE6EY) as a guest.

John is an SWL and Ham Radio operator and speaks at length about how he uses diversity reception to mitigate persistent local RFI (radio frequency interference).

If you have persistent issues with radio interference or if you’ve been curious about using diversity reception for mediumwave and shortwave DXing, I highly recommend listening to this episode. John has been known to frequent the SWLing Post and actually comes into the discussion primarily from an SWL’s perspective.

If you’ve tried diversity reception or a noise-cancelling system like the Timewave ANC-4+ in the past with mixed results, you’ll definitely benefit from listening to John’s best practices.

In addition, John points out that the excellent SDRplay RSPduo is a very affordable way to explore proper diversity reception.

How effectively can you mitigate RFI with diversity reception? Check out this video on YouTube queued up to the point where John does a live demo with his Anan SDR and loop antennas: https://youtu.be/vu8D87aVUTQ?t=2011 (I also recommend watching to full video presentation for even more detail.)

I’ve embedded the audio for the Ham Radio Workbench podcast below, but you can also find it along with show notes on the Ham Radio Workbench website.

Ham Radio Workbench is one of my favorite podcasts; if you like exploring a wide variety of technical topics, I highly recommend checking it out. It’s available on all podcasting platforms.

Also, check out John VE6EY’s YouTube channel and web site/blog.

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Radio Waves: Skyworks Acquires Silicon Labs, DRM Response to RW Article, CNN finds Radio Biafra, and Free Online Foundation Course

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Troy Riedel, Dan Robinson, and the Southgate ARC for the following tips:


Skyworks completes acquisition of the infrastructure & automotive business of Silicon Labs (Skyworks)

IRVINE, Calif.–(BUSINESS WIRE)–Jul. 26, 2021– Skyworks Solutions, Inc. (Nasdaq: SWKS), an innovator of high-performance analog semiconductors connecting people, places and things, today announced that it has completed its acquisition of the Infrastructure & Automotive business of Silicon Laboratories Inc. (Nasdaq: SLAB) in an all-cash asset transaction valued at $2.75 billion.

“On behalf of the entire Skyworks organization, I want to welcome the Infrastructure & Automotive team,” said Liam K. Griffin, chairman, chief executive officer and president of Skyworks. “In addition to a strong legacy of innovation and execution, the I&A business brings a highly diversified customer base that will enable our continued expansion into strategic end markets. Together, we will accelerate profitable growth in key industry segments, including electric and hybrid vehicles, industrial and motor control, power supply, 5G wireless infrastructure, optical data communications and data center.” Continue reading

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HFDY vs. Fire Brothers: Dan compares two Chinese Malahit SDR clones

Many thanks to SWLing Post contributor, Dan Robinson, for the following guest post and review:


Two Chinese Clones:   A Look at Noise Levels

Arriving recently here in the radio shack, were a Chinese clone under the name of “Fire Brothers” and another under the name HFDY.  I thought it would be constructive to note the key differences between these two clones, both of which are running Malahit 1.10c firmware, and post some video of a brief comparison.

A note in advance of any comments – I am primarily a HF listener so these comparisons do not cover frequencies above 30 MHz.  For those whose focus is on higher frequencies I recommend looking through the many comments on the Malahit Facebook group and Telegram by those who use these receivers in those ranges.

HFDY

  • Constructed of metal-like material (a correction from my previous articles that this is fiberglass of the kind used in printed circuit boards – thanks to Georgiy of Malahiteam for pointing this out)
  • Front speaker grille is gold color and appears to be metal but may be fiberglass as well – audio is quite good
  • Two top-mounted antenna jacks, one 50 ohm, the other Hi-Z (makes switching between HF and FM/VHF reception easier) with in-use LED indicators
  • Two high quality right side mounted black metal encoder knobs with large power button (clear printed Frequency/STDBY/Volume printed on panel)
  • Cabinet held together with TORX screws
  • 1.10c firmware
  • Receiver is elongated left to right to accommodate left side front-firing speaker, but is thinner overall and could be easily placed in a pocket though not recommended to prevent damage
  • Like every one of these SDRs, suffers from body sensitivity to touch which reduces signal levels unless some sort of additional ground is attached to cabinet
  • Internal flat-type Lithium battery of 3300 mAh though apparently capable of fitting up to 8000 mAh

Continue reading

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Dan adds updates to his Malahit SDR and variant reviews

Many thanks to SWLing Post contributor, Dan Robinson, for the following update to his previous post regard the DSP-2 and HFDY Malahit SDRs:


HFDY clone of the Russian-made Malahit SDR

Malahit and HFDY Updates

by Dan Robinson

HFDY CLONE:  As noted by a reader in comments, the Chinese-made HFDY leaves out a large portion of the military AIR band, with no coverage from 250MHz to 400MHz, or about 150MHz, whereas the Russian-made DSP2 only loses 20MHz from 380MHz to 400MHz.  This may be of concern for some readers, others not.

RUSSIAN DSP-2:  As users of the Russia-made DSP-2 may or may not have noticed, the current firmware shows SIX memory bank pages when there are only 5.  This appears not to have been discussed much on the Malahiteam Telegram group or elsewhere.  In response on this, Georgiy of Malahiteam says this “is normal and for our future features” so clearly there are future plans that we are not aware of.

CHINESE-MADE FIRE BROTHERS CLONE:  On September 21st, I took delivery of another China-manufactured clone, with a heavy metal cabinet, a vertical format with controls on top, and twin front-firing speakers.  Obtained via Alibaba, and branded as “Fire Brothers” this has a thick built-in telescopic antenna and a separate SMA jack which the maker describes as “[supporting] a better external shortwave antenna”

On Alibaba, prospective buyers of this receiver are given two options:  Type 1: 50KHz-2GHz without firmware updates supported, and Type 2 with support for updates.   The unit did arrive with 1.10c Malahit firmware with a 160 kHz bandscope width.

As noted above, this China-manufactured clone also blocks 200 mHz – 400 mHz and shows the Msi001 chip and STM32h743 and a claimed blocking figure of 85dB and  sensitivity up to 250MHz of 0.3?V = 10dB.  The battery is described as 5000 mAh and presumed to be flat type Lithium Ion.

The only thing included with this clone, which arrives in a plain black box marked “Fire Bros.Radio” is a USB-C cable.  That’s in stark contrast with the HFDY clone which comes in a high quality fabric zipper case, flexible whip antenna, USB-C cable, and a small metal stand.

The Fire Brothers manufacturer highlights the “high quality speakers” which not only fire out the front of the receiver, but also wrap around with openings on left and right sides of the radio.  My first tests show that audio is indeed quite nice, certainly equal to the Russia-made DSP-2, possibly an improvement on the HFDY clone which has a single front-firing speaker.

I’ll have more on this Chinese clone and some comparisons with the DSP-2, HFDY, and Afedri SDRs, in future articles here on SWLing Post.

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Mark’s Malahit DSP-2 notes

Many thanks to SWLing Post contributor, Mark, who recently shared the following comments in response to Dan Robinson’s excellent Malahit DSP-2 review series. Mark writes:

I’ve been playing with my new Malachit for a week now and I am very impressed. It’s got a superb receiver and last night I was pulling in several South American stations using the absolutely amazing Bonito MA305 with the longer whip, not the stock one, it’s around 30 feet up in a tree using H155 coax grounded at the base of the tree, this antenna really blows me away. Some of these stations are only 1Kw and the little Bonito was pulling them in very well indeed. I am in the country so have a very low noise floor and QTH is Ireland.

Yes I do have to turn the RF gain to 0 and use around 20db attenuation on Longwave but I know what I should be receiving here in Ireland on LW and by using attenuation it has no negative effect on LW. I do have a strong enough LW transmitter around 45-50 miles away which is probably having an effect here but if I compare it to my Tecsun PL-990x the Malahit completely obliterated the 990x on LW even with the attenuation on the 990x. Its performance on LW with external antenna is very poor even using one of the hidden features by Press and hold the [ 3 ] key for about 2 seconds, this does make a notable improvement to the 990x on LW and MW but the Malahit completely obliterates it on LW and External antenna. Of course the Malahit has no internal ferrite so without external antenna you won’t receive anything on LW or MW.

Continue reading

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Check out the new scheduler functionality in SDRuno V1.41

Many thanks to Jon Hudson with SDRplay who shares the following information about the latest release of SDRuno on the SDRplay blog:

Try out the new features in SDRuno V1.41 released today

SDRuno V1.41 was fully released today.  It includes the much requested full scheduler facility which allows you to set up numerous recording events for your RSP.  As well as providing all the expected calendar options (time of day, date, start and stop times, repeating options and so on), you can also set the ‘profile’ for each recording – this allows you to pre-set frequencies, bandwidths, demodulator options (AM/FM/USB/LSB etc.), choice of filters and antenna port selection.  Additionally you can choose the settings for connectivity to other third party software or the running of a specific plugin.

Added
• New Scheduler panel which replaces the old “Recorder” panel (launch using the SCHEDULER button in the main panel).
• A new autolayout to include the scheduler (for screen resolutions of 1920×1080 and above).
• Backup and Restore of the ini file settings (access via the main panel OPT menu)
• Screenshot button has been added to the SP1 title bar
• IQ wav files can now be used in plugins
Changed
• Autolayouts now take account of the taskbar location and size.
• Autolayouts have been improved to take account of higher resolutions.
• Saved workspace notification moved to the status bar.
• Memory Panel will now prompt to save any changes made when switching to another memory
bank.
Fixed
• Decimation and the LOLOCK state are now correctly saved and recalled within a profile.
• Main panel version tooltip now displays correct information.
• The step size could be set incorrectly when using non-FM modes and pressing any of the FM sub
mode buttons.
• ADS-B/DAB mode now handles when in both band-framed mode and also when the LO is locked.
• Bugs associated with wav file playback
• When loading a profile, the last used memory bank field will update correctly
• Saving a profile will now update the displayed loaded profile field correctly
Known Issues
• SP2 CWAFC drift issue (Zoom/window size/freq display)
• IF output mode disabled SP1 spectrum mouse clicks
• Occasionally if SDRuno is closed whilst a plugin is still running, it may not close properly. This may
necessitate a PC reboot to fix it.

You can find this latest version of SDRuno on our downloads system :https://www.sdrplay.com/downloads

Click here to continue reading this post on SDRplay’s website which also includes a number of tutorial videos.

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Guest Post: Mediumwave DXing in Botswana

Many thanks to SWLing Post contributor, Peter Wilson, who shares the following guest post and recordings from his listening post in Botswana:


Peter’s receiver is a Airspy HF+ Discovery SDR using SDR Console V3

MWDX from Australia and the USA received in Botswana

by Peter Wilson

Hello Thomas.

I moved my 16.2 metre random wire slightly farther away from the house, and installed a binocular balun and connected 20m of RG58 at the far end, not the “house end”.

Peter’s random wire antenna with binocular balun

Reception examples:

1500 USA WFED Washington DC 12790km

1152 AUS 6PB
ABC NewsRadio Busselton 8469km with ABC News ID

1600 B Radio Nove de Julho ID 7234km
Sao Paulo. Brazil. ID,
Web Address and jingle. Rinsed and repeated.
Portuguese: Radio Nove de Julho [English: Radio 9th July]

1026 kHz MOZ Emissor Provincial de Manica Chimoio 1057km.
A bit parochial but features the radio Mozambique song.

850 USA WTAR Norfolk, Virginia Fox Sports Radio ID 12700km

1296 6RN ABC Radio National. Wagin, Australia 10kW 8644km

558 AUS 6WA ABC Great Southern WA Wagin 8644km


Impressive reception from your home in Botswana! Thank you so much for sharing these recordings, Peter. You’ve certainly made the most of your random wire antenna!

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