Tag Archives: DXpedition

Results: AirSpy HF+ vs Elad FDM-S2 Weak Signal Comparisions

Looking north toward Cape Lookout, Oregon, near the site of my SDR receiver recordings. Photo courtesy of Wikimedia Commons.
In my original article 10 days ago, I set up a SWLing Post reader poll to let you give your opinion on which shortwave recordings within four pairs of audio files provided the most intelligible result. The recordings were intentionally noisy, low-level signals to help us discover–through critical listening to the files–if there is a clear favorite between the AirSpy HF+ or the Elad FDM-S2 receivers. Of course, there were only four pairs of recordings…not a very large sample size.

However, 34 readers of the original article took the time to listen and respond, so let’s get to the numbers, shown in these graphs:

Interestingly, the responses above seem to point to:

  • Two recording pairs tied in the results (50% / 50%) or were very close (HF+ 52.9% / FDM-S2 47.1%)
  • The FDM-S2 led one recording pair by a large margin (67.6% / 32.4%)
  • The HF+ led another recording pair by an equally large margin (67.6% / 32.4%)

Taken as a whole, no obvious winner emerged, although one might conclude the HF+ has a slight edge due to its lead in the “very close” recording pair of 7.230 MHz.

One thing is clear–the AirSpy HF+ is a surprisingly good performer for its price of $199 USD! For many enthusiasts this will be all the SDR they need.

As a final note, I’ll mention that the AirSpy HF+ used for the tests was totally stock. I have not yet performed the “R3 Bypass” mod nor the firmware update to my HF+ units. The simple R3 Bypass, discussed at length on the AirSpy Groups.io forum, significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues. For more on this modification from a MW DXer’s perspective, read Bjarne Mjelde’s insightful article at his Arctic DX Blog.

Thank you to all the readers who took the time to listen to the SDR recordings in this comparision and register your opinions.

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

Digging in the Noise: Weak Signal Audio Recovery with the AirSpy HF+ and Elad FDM-S2

I’m currently spending the better part of a week at Cape Lookout State Park on the Oregon coast, with a great view of the ocean through tall evergreen trees. This is one of my favorite parks in the Pacific Northwest, especially when DXing during the blustery winters from one of the nice cabins at Cape Lookout.

The view from the beach near my cabin; the turbulent waves were a precursor to the gale force winds at the park during the night of the 23rd!

Although I’m at the park for trans-Pacific medium wave DXing, I’m also comparing receivers, both SDRs and portables. This morning I sought out a few weak shortwave signals, pitting the Elad FDM-S2 SDR ($529 USD) against the AirSpy HF+ ($199 USD). I have a pair of the HF+ receivers to cover all of medium wave (as the FDM-S2 easily does). Many SWLing Post readers already know that the upstart HF+ trades bandwidth to gain high performance in order to keep the price reasonable.

My antenna used for the following recordings was a small “Flag” antenna using a Wellbrook Communications FLG100LN module and a 2K ohm variable potentiometer for termination. The design uses crossed tent poles in an “X” formation to support the wire loop. This design travels easily in a compact package; I have Dave Aichelman of Grants Pass, Oregon to thank for this very useful “tent pole loop” implementation of the Wellbrook FLG100LN.

The Wellbrook-based antenna functions superbly, and its low-noise design helps hold down QRM from the nearby cabins (which unfortunately have been “upgraded” recently with noisy cold fluorescent [CFL] light bulbs). The area around the Cape Lookout cabins used to be superbly low noise and suitable for radio listening, but now it is more of a challenge than before. The Wellbrook FLG100LN is perfect for the situation though; Wellbrook ALA1530LN  Pro and ALA1530S+ 1-meter loop antennas work commendably at the park too.

The Wellbrook FLG100LN module with a home brew RFI choke in-line

A 2K ohm variable potentiometer is protected from the elements in a small plastic bag. The “pot” is adjusted for the best nulling of medium wave stations off the back side of the antenna’s reception pattern.

The “tent pole loop” antenna is strapped to a fence railing with ultra-strong Gorilla Tape to keep the 7-ft. square loop vertical.

On with the recordings…

For the FDM-S2 and HF+ comparisons I used the SDR-Console V3 software. Every parameter was identical for the receivers–sampling bandwidth, filter bandwidth, AGC, mode and so on.

Take a critical listen to the weak signals recorded with the SDR receivers, identified as only “Radio A” and “Radio B”. A link to a poll is at the end of this article; please indicate which recording of each pair has the most intelligible audio in your opinion, and submit your choices when you’ve made up your mind on each audio clip. After a week or so I’ll post the results of the voting, and identify the receivers.

9.615 MHz, LSB, Radio A


9.615 MHz, LSB, 
Radio B (note: the same male announcer heard in clip “A” begins at 00:14 in this “B” clip)

 

9.730 MHz, USB, Radio A


9.730 MHz, USB, 
Radio B

 

7.230 MHz, S-AM, Radio A


7.230 MHz, S-AM, 
Radio B

 

9.860 MHz, S-AM, Radio A


9.860 MHz, S-AM, 
Radio  B

 

Note on 7.230 MHz recording: this was an interesting frequency, as the signal was tightly surrounded by a very strong local 40m ham radio LSB station as well as a strong China Radio International signal. There were other strong amateur and broadcast stations within 30-50 kHz of 7.230 MHz, also. This A-B test more than the others may indicate receiver performance in a strong RF environment on a crowded band.

Ready for the poll? Register your votes at the Google Docs form below:

https://tinyurl.com/ya38wj69

In a week to 10 days I’ll post the results in another article. NOTE: I haven’t provided a “both sound the same” choice in the poll to encourage you to ‘dig deep’ into the audio and listen critically–to find something that stands out in one clip versus the other.

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

Exotic shortwave DX copied in Rio Capim, Northern Brazil

The beautiful Capim River in a land of Jaguars, Tarantulas and occasionally, wonderful shortwave DX

Hi there, I returned from my third trip to the Rio Capim area of Pará, Northern Brazil about 5 weeks ago, having been out there for exactly a month. Now, whilst this was strictly a business trip I always make time to tune around the bands, mostly shortwave, in the hope of copying some interesting DX. My previous two trips were reasonably successful; however, I didn’t really hear anything new – just lots of Tropical Band – and tropical stations with much greater signal strength and clarity. Part of the problem is one of which most of us suffer from – the dreaded local QRM. Even in the depths of the rain forest noise is present from building electrical systems (particularly lighting) and other equipment. In my first attempt to escape the noise on this trip I ventured out of my accommodation building (basically a very large hut) to the wire fence that separates us and the larger fauna (although having said that, the monkeys and everything else that lives in the area appears to have no difficulty scaling a 6 foot fence – funny that! ). Anyway, ultimately, you’ve really got to want to hear something special quite badly to venture out. I suppose it could be the definition of hard-core DX! I tried this only once because as I was copying a very nice signal from Radio Guinea on 9650 kHz, I found myself about 2 feet from a Tarantula Hawk Wasp dispatching a very large spider (check out the very brief video on my YouTube channel). That was me done for alfresco DXing in the jungle.

Bonito’s USB-powered MegActive MA305 E-field antenna up a tree…performed superbly in Brazil

Fortunately, I was lent a 4-wheel drive truck for the duration of my visit and so I decided to find a quiet location to park up and listen to the radio – therefore only having to venture outside (at night) to place my antenna. One evening after dinner I got in the truck and drove around the site for a while until I found a location, effectively on the edge of the jungle that was mostly very quiet. Perfect…as long as I didn’t end up as something else’s dinner. I took the super-compact USB-powered Bonito MegActive MA305 antenna with me on this trip because I’d already tested it at home on DXpeditions and in Crete and thus I was confident as to how superbly well it would perform in a quiet location. To supplement my antenna choices, during the first weekend, I made the 90 km drive to the nearest town and bought, amongst other supplies, a 40 metre length of speaker wire and a 3.5 mm jack connector to make a temporary long-wire antenna.

In my experience, there are roughly 3 tiers of Tropical and Tropical Band DX on short wave. There’s the bottom tier of stations which with a decent portable and a few metres of wire can be readily heard in the UK on a Dxpedition – and at home with a magnetic loop antenna, for example and a good quality table-top receiver or SDR. Amongst this group of signals I would include Rádio Clube do Pará, Brazil on 4885 kHz,  Radio Difusora Roraima on 4875.3 kHz, Emisoras Pio XII 5952.5 kHz, Radio Santa Cruz, 6134.8 kHz etc. etc. On the next tier are tropical stations that are really difficult to hear in the UK – but can be heard with good propagation and good equipment. This group includes Radio Aparecida  on 6135.2 kHz particularly, Rádio Educação Rural on 4925.2 kHz, Radio Tarma Internacional on 4774.9 kHz, Rádio Evangelizar (formerly Radio RB2) on 6040.7 kHz etc. There are many more examples from these two groups I could use, but you get the picture. Lastly, there is a tier of stations that are very rarely or never heard in Europe, irrespective of equipment or propagation. Often these stations operate with low TX power which makes them extremely difficult to copy anyway – and that leads to ambiguity farther as to whether they are even on-air. Furthermore, some of these stations broadcast very irregularly, which makes copying them even more of a lottery.

My mainstay travel receiver, the brilliant Eton Satellit..two-time veteran of South American DXing

In this context, a month in Northern Brazil was a useful timescale for surveying the Tropical Bands and geographically tropical stations for the presence of very rare signals. Fortunately, over many hours of listening in Rio Capim with the Eton Satellit and mostly the Bonito MegActive MA305 antenna, I manged to record six signals that are very rarely heard outside of South America. The list of stations follows below, complete with the antenna arrangement. Further below you will find embedded reception videos and text links to the same videos on the Oxford Shortwave Log YouTube channel. Please take the time to watch the videos and note the comments made by some of my subscribers with local knowledge. In particular, Rádio Gaúcha and Rádio Canção Nova on 4825 kHz are very irregular broadcasters and therefore I was fortunate to be in the right place, at the right time to copy their signal. More luck came my way with the reception of Radio Sora de Congonhas on 4775 kHz – made possible because of a total power cut on site, reducing noise effectively to zero (I was indoors at the time). I, personally, never heard anything else other than Radio Tarma, Peru on or around 4775 kHz – itself something of a rarity, except when conditions are very good.

In conclusion, I have to say, once again, the DXing credentials of the Eton Satellit and the Bonito MegActive MA305 USB-powered antenna are clearly demonstrated here. The perfect travelling companions for the serious DXer and broadcast band listener alike, I had no issues getting through security at any of the airports and their combined weight is unnoticeable in a fully loaded backpack. I definitely recommend both products. It’s also worth noting that if you’re travelling to a relatively remote location, even with modest equipment, you might be able to copy rare signals that will provide good information to the rest of us trying to hear those same signals from 1000’s of km away. I will be returning to Rio Capim early in 2018 and I’m seriously considering taking my Perseus SDR with me. A superbly sensitive and selective receiver with noise reduction that actually works, it opens up the possibility of even more exotic DX on that trip.

As always, thanks for watching/listening/reading and I wish you all excellent DX and Season’s Greetings. 73!


   The list of exotic catches and antennas utilised:

  • Radio Apintie 4990 kHz, Suriname – Bonito MegActive MA305
  • Radio Cançao Nova 9675 kHz Sao Paulo – 20 metre long-wire
  • Radio Verdes Florestas 4865 kHz, Cruzeiro do Sul – Bonito MegActive MA305
  • Rádio Gaúcha 11915 kHz, Porto Alegre – Bonito MegActive MA305
  • Radio Sora de Congonhas 4775 kHz, Congonhas – Bonito MegActive MA305 antenna
  • Rádio Canção Nova 4825 kHz, Cachoeira Paulista – Bonito MegActive MA305

 

Click here to watch on Oxford Shortwave Log YouTube channel

 

Click here to watch on Oxford Shortwave Log YouTube channel

 

Click here to watch on Oxford Shortwave Log YouTube channel

 

Click here to watch on Oxford Shortwave YouTube channel

 

Click here to watch on Oxford Shortwave YouTube channel

 

Click here to watch on Oxford Shortwave Log YouTube channel

 


Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

DXing in a large suburban garden with the Eton Satellit & Bonito MegActive MA305 antenna

Hi there, the garden at my house is pretty small and as a consequence, I am very limited in terms of what antennas I can usefully employ. You can’t position anything further than about 10 metres from the brickwork and to compound this, we are surrounded on all sides by neighbours in close proximity. All very nice people, but all very noisy – electrically speaking lol. I simply can’t get far enough away from these sources of electrical noise to achieve excellent SNR.

The solution to my problem was ultimately a Wellbrook ALA1530 magnetic loop, but prior to that I used an end-fed random wire, the performance of which deteriorated as the months went by as the ubiquitous blanked of local QRM continued to increase. Eventually, I was forced outdoors, well away from my town – effectively catalysing my forays into the Oxfordshire countryside on DXpeditions. That first experience of listening to the radio on shortwave, in the absence of any QRM was enlightening to say the least and of course, subsequently, DXpeditions have become a mainstay of my listening activities. However, despite enjoying some great DX successes out in the woods, one has to be realistic about how often it’s possible to leave the house just to listen to the radio. This led me to the purchase of the Wellbrook ALA1530 magnetic loop. It proved to be a triumph of electrical noise mitigation and an absolute necessity in copying transatlantic medium wave signals in such a noisy and compact space. A total game-changer. The brilliant performance of the Wellbrook eventually led to me purchase a second, cheaper active antenna; the E-field Bonito Boni Whip and in turn, that purchase led me to the MegActive MA305, kindly supplied by Bonito themselves for objective testing.

Have DXing kit, will travel…everything you need in a small flight case…

You might remember my initial tests at home confirmed, as expected, that E-field antennas don’t work well in electrically noisy environments (except at LW frequencies in my experience) but outdoors, away from noise, they are superb. I have a number of reception videos on my YouTube channel – Oxford Shortwave Log which clearly demonstrate identical performance of the Bonito MegActive MA305 antenna and Wellbrook ALA1530 magnetic loop out in the woods. So, what if you’ve got a large garden in a suburban area that allows you to be just far enough from sources of electrical noise…how much of a difference does it make to the noise floor of your receiving equipment? Can E-field antennas such at the Bonito MegActive MA305 do the job? Furthermore, how well does a random wire work in a larger garden?

 My MegActive MA305 antenna system for mobile DXing…and another use for a washing line…

I was fortunate enough to know someone who owns a house with a large garden, quite close to my QTH (a 10 minute walk) and who was more than willing to let me set up my DXing equipment and sit around until the early hours of the morning, listening to and recording various signals on my Eton Satellit. In preparation, I set up the Bonito MegActive MA305 antenna and hung the radiating element on the washing line – sounds ridiculous but actually worked very well, placing it about 2.5 metres above the ground. I also set up a 40 metre longwire, which at its closest point, was still approximately 25 metres from the house, and 30 metres from the neighbours. This post will focus on the performance of the MA305; a subsequent post will detail the performance of the longwire.

The large garden I ‘borrowed’ for my DXing session with the Bonito MegActive MA305 antenna

Suffice to say, the MegActive MA305 performed admirably during my first listening session. In the middle of the afternoon I copied a very strong signal from The Voice of Korea around 15:44 hrs UTC on the 25 metre broadcast band, followed at 17:10 hrs UTC with a superb signal from The Voice of the Broad Masses 2, Eritrea, on the 40 metre ham band. Later on in the evening I copied Radio Mail with excellent modulation, CHU Canada with voice announcements (almost impossible at home), Myanmar Radio with an untypically strong signal and XEPPM Radio Educación from Mexico City with a signal I would normally expect on a DXpedition-proper with a large antenna.

My conclusions to this experiment are simply that E-field antennas can work in a suburban environment, if you are able to site them far enough away from adjacent sources of electrical noise. I don’t have empirical data on this, however, I can confirm that 10 metres proximity is too close at my QTH and 30 metres is sufficiently far away at this test location. One has to assume the houses nearby are similarly equipped to mine with electrical appliances that generate electrical noise. Thus, if you’re interested in a very well-priced, compact antenna and you live in an urban or suburban environment with access to a large garden/ outdoor space, an E-field Boni Whip or MegActive MA305 might well be suitable – and you’ll have a superb portable antenna for those listening sessions away from home!

Finally, I should mention the Eton Satellit. Much-maligned in certain quarters when it was first introduced into the market, it continues to demonstrate superb DXing credentials. I won’t forget some words of wisdom from a friend of mine and fellow DXer, with more than 3 decades of experience in listening to the bands on HF. He told me that Judging from his own experience with some of the original Grundig Satellit models of the 1980s and early 90s (namely the 400, 500 and 700) he was quite sure that the Eton Satellit is a considerably better DX performer than those vintage sets, that offered great sound for casual listening to international broadcasters, but didn’t perform too convincingly on weak DX signals. The Eton Satellit has been a revelation and I’m pleased to have played a small part in turning around the rather widely held view that it was less than worthy of the Satellit branding.

Fresh out of the box, the Eton Satellit has surpassed all my expectations…

Please find embedded reception videos below and text links to the Oxford Shortwave Log YouTube channel. My next post on this subject will cover the performance of a 40 metre longwire in this large garden environment. Thank you for reading/watching/listening and I wish you all great DX!


Click here for video on Oxford Shortwave Log

 

Click here for video on Oxford Shortwave Log

 

Click here for video on Oxford Shortwave Log

 

Click here for video on Oxford Shortwave Log

 

Click here for video on Oxford Shortwave Log

 

Click here for video on Oxford Shortwave Log

 

Click here for video on Oxford Shortwave Log


Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.