KONG51 - Day Three

 We awoke to a wet Sunday morning with temps just above freezing. But only a gentle breeze outside! I had set a dough of bread on Saturday afternoon, and it had a good night's rise. Another two hours of shaping and resting followed before a two-hour final proofing started at 08:30. At noon, the bread was done. 

And this is it.

Propagation-wise - no rise there. Very poor conditions overnight, consistent with propagation forecasts so only the usual dominants were heard. Maybe the best catch (thorough check not done yet) was KGIW-CO 1450, heard both on the 340 beverage and at alt-Loran.

After our usual Cappucino and Caffé Latte routine, I went out for quick walk and took these photos.

Sun and sun dog

Sebulonbukta - The Sebulon Bay. Kongsfjord in the distant, centre of photo.

The KONG HQ

DX Starts Here! (pt. I) - start of the 340-deg beverage.

DX Starts Here! (pt. II) - start of the 310-deg beverage.

KONG HQ and the hamlet Veines (left). 310-deg starting point visible.

The hamlet Veines

Facing NW - Antenna support belonging to the 310- and 340-deg beverages.

Just after 12 we drove to the alt-Loran site to collect the SSD with last nights recordings, replace the battery and set down a new grounding rod with termination at the far end. We didn't have to, since after a bit of searching in the "swampy" area we did in fact find the old grounding rod - albeit without the terminiation. That fixed, we drove back to the KONG HQ in sleet showers.

Dinner! Ole the farmer brought with him some products from his area, such as Umami (huh?), Jalapeño & Cheddar, and Bratwürst sausages. Served with a paste of almond potatoes and carrots, Heinz ketchup and Idun mustard. Maybe we should have had beer with this, but being who we are we chose red wine, a Bellerouche Côtes du Rhône 2023.

Sausages...from left, Bratwürst, Jalapeño & Cheddar and Umami, which unexpectedly won the first price!  

More importantly, these products are local (to Ole, not me). In dire times like these, locally produced alternatives should always be preferred, even when more expensive.

Weather: Calm, some sleet and rain showers in the afternoon but otherwise dry. Just above freezing, peaking at 3 Celsius. Tomorrow's forecast is sunny but windy, up to 4 Celsius but cold overnight.

So, with this image of the western horizon at 17:20 local, it's time to finish off another report from the Arctic.

KONG51 - Day Two

Windy and rainy morning at the KONG HQ, 2 Celsius. I woke up at 05 local (03:00 UTC) and noted that trans-polar signal levels had increased steadily since 22:00. Even as late as 15:00 today there were a few signals on the band. The first ID-ed NA station (of interest) of the DX-pedition was WLRS New Albany IN 1570 at 01:00, but around 22:30 we lost several stations that powered down from their day power before we could catch any ID. Some of the other stations noted in my logbook were KPRZ-CA 1210, KORT-ID 1230 (audible for several hours!), WMMB-FL 1240, KMBY-CA 1240, KXRO-WA 1320 and WRHC-FL 1550.

Sunrise...

Afterwards, signals zig-zagged in strength and provided little of interest. 

The main objective for Saturday was to get the alt-Loran beverage site up and running. Fiddling with small screwdrivers etc. in rain, gale-force winds and just above freezing is not our favourite pasttime, so we tried to wait out the weather until it was "as good as it gets" before driving off. Apart from a nasty rain shower we timed it pretty well, and began the return drive just after sunset. Not quite done yet, tomorrow we need to repair a faulty far-end grounding with its terminating resistor, but that should be an easy fix. The initial impression is that it's working very well already. We will see after we have collected the recordings tomorrow morning and compared them with the KONG beverages.

Kjølnes Lighthouse, near the alt-Loran site

Pacific stations were heard early today, Tonga-1017 with marine weather forecast around 10:30. Radio Majuro-1098 and Gold FM from Fiji on 990 were also very strong until China's sunset spoiled the Pacific party like so many times before.

One interesting catch was the looping announcement on AFN's stations in Japan on 1575 kHz at 11:00, that due to the government shutdown, the AFN radio channel had been temporarily suspended, followed by a long pilot tone. We tried to figure out if this was the case with AFN's Korean stations on 1440 as well, but interference from STV Sapporo was too strong. A check later on 1575 kHz at 16:00, AFN seemed to be back to normal (?) programming with ABC news followed by automated pop music with canned announcements - typical for overnight programming.

Dinner! Yes we admit, we love a good meal. And we are not fans of heat-and-eat meals. Today is salmon day. Sushi-grade salmon loins marinated in balsamico crema, olive oil, dried herbs, spices, garlic and ginger root. Baked in the oven for 8 minutes at 200 Celsius. Served with tagliatelle and pesto with parmesan cheese, and chopped bacon. Good shit, especially when served with Calles Riesling.

Salmon looking forward to some heat treatment

Dessert:The whipped cream was excellent. The Tokaji wine was delicious. The Apricot with Almonds cake - uhm...maybe we should have opted for something else. But the Disaronno was great!

We have already discussed the weather - a favourite point of conversation among Norwegians. To sum it all up: Windy and rainy early in the day, calmer and less rain in the afternoon and a maximum of 4 Celsius.  Now at almost bedtime, calm, mostly dry and 2 Celsius. The forecast for Sunday is calm winds, occasional light rain and 2 Celsius.

KONG51 - Day One

First day of KONG51 - and 50 years since the first MW DX-pedition to Kongsfjord, in late December 1975!

This time we're only two  - Bjarne and Ole Forr  - as OJ Sagdahl couldn't come this time. I picked up Ole at the bus stop in Varangerbotn after an 11-hour trip on his part, before proceeding by car to my KONG-HQ in rather wintery conditions, at least on higher altitudes. Just before we met this semi truck in a steep descent, it was seconds away from a reindeer massacre as a herd of 20-30 reindeer decided to cross the road in front of him. Worse yet: A few seconds further ahead and we could have been part of it. Close call!

Photo: Ole Forr

Anyway! We arrived safe at the KONG HQ at around 16:30 local (14:30 UTC). Not much more to do except make ourselves comfortable, and enjoy the first KONG51 dinner - home-made fish gratin with white wine from Calles Riesling. For dessert we enjoyed chocolate pudding and custard, and some Disaronno Amaretto.

Some aurora was observed in the evening. Not much, and we're happy with that, but here's an image from the eastern sky.

Conditions are so-so. The Japan opening at 20:00 UTC brought little of interest. We do note however that Canada is already audible on 1230 kHz and that is (maybe) a good sign.

CBC Churchill MB (left) and CBC Iqaluit NU visible

Weather at the KONG HQ: 2 degrees Celsius, light rain and moderate winds. Tomorrow's forecast: Same, same.

Tomorrow, we plan to erect a 1000-metre beverage antenna at the alt-Loran site 30 km away from here, complete with a PC, Perseus SDR, 5G mobile connection and a 12V battery. It may be cold, it may be wet.

KONG HQ - Only Days Away From The KONG51 DX-Pedition

So, we're approaching mid-October and it's becoming increasingly chilly. Still no white to be seen though, neither on the plateaus nor at sea level. By next weekend we may see maximum temperatures of 2-3 Celsius and rain, with possibly even colder conditions later on. This autumn has been anything but normal so far.

We do enjoy the good weather though, so much that on Saturday I decided to take a trip from home to check out things and bring some food supplies. Two of the beverages were a bit "saggy", so I tightened the ropes at the far end to add some height. On the photo below you will see two wires; the closest is one of the (dual) beverage antennas pointing 340 degrees to the western part of North America. A few metres away is the single-wired beverage running to the eastern/central part. I think it "lands" just east of Chicago. Further away around the bend are two of the supports for the other 340 wire.

Beverage Antennas

What also needed attention was the "alt-Loran" kit, comprising an Intel NUC PC, a Perseus SDR, 2-TB SSD, Bodnar Mini-GPS, 12V battery and a modem and external antenna for 4G/5G communication. The Jaguar software needed an update, so we're now ready to deploy a 1000-metre beverage antenna next Saturday. We are excited, because conditions are so much better than last autumn.

Hard-Core Remote DX-ing

Several uncommon stations were heard Saturday night and morning, like KSVC-UT 980, KRKS-CO 990, KJJC-UT 1230, KEIN-MT 1310, KLFD-MN 1410, KJCK-KS 1420, KFOO-CA 1440 and KOBO-CA 1450.

I had some hopes for Sunday morning's DX, but the rise in the Polar K-index and solar wind brought much less exciting DX and higher noise levels.

To end this post, two photos illustrating the contrasting weather. First, a pre-sunset photo of my neighbourhood on Saturday. Next, from a rainy Sunday morning's sunrise. We'll be back on Friday afternoon, October 17.

What A Great Start Of The Season!

Last year's start of the season wasn't dismal. It was awful. Yes, we were near or at solar maximum, but it sounded to us like the ionosphere had gone into meltdown. Conditions gradually improved a bit, but it was a lousy year for long-distance MW reception.

The contrast to this year couldn't be greater! And we're not that far away from solar maximum!

September has been a very good month for us, especially up north. Inspired by the conditions, I decided to try to lean in a bit more with my loggings approach. So, I set myself a goal: By the end of each month I will make, and publish, a preliminary log from the Smøla and KONG locations. They are my loggings only, my teammates are much more active, hear more and publish their loggings elsewhere.

Here is the September Log. Please note that I only log stations of personal interest. Stations heard day in and day out are omitted. Like hundreds of AM stations in North America, all high-powered stations, basically everything from China, and more.

Radio logs can be sorted in many ways. This log is sorted by frequency.

Let's see if I can keep up the pace until April! I'd be surprised if I do.

Last Sunday I  had to make a quick trip to Kongsfjord. Below is a photo from the starting point of the 310 beverage antenna. That snaky thing going towards my house is the 150-metre coax run.

The photo was taken at 15:23 local and the sun is already quite low, just a week after equinox. But hey! No snow!

KONG 50 - Preps For A New Season At The KONG HQ

Friday 12-SEP

The 50th KONG DX-pedition! Who would have known, back in January 1997, when we had our first KONG. My goodness, we've come a long way.

We were gathered late afternoon on Friday the 12th, when Ole and OJ arrived from Andøya after a stop-over in Kiruna, Sweden. I had been on-site since Thursday afternoon doing what I do best - preparing the dinner, baking a bread and doing some light-hearted antenna work. Some internet issues were partially solved.

This is a proper bread

So...dinner: The traditional fish soup, comprising fish (aha!), chopped carrots, potatoes, seleriac and leek, and of course a red chili for a bit of bite. For dessert we had chocolate pudding with custard - a rather common choice for us. Calles Riesling with the soup, Grappa with the dessert.

Bjarne (left), Ole and OJ. The roses on the table is a definite first in our KONG meetings. Was it in honour of the anniversary?
 

View to the west after sunset

Quite a windy day, gusting at 20 m/s  but only a light breeze in the evening. The temperature maxed out at 20 degrees Celsius, itself almost unheard of in mid-September at this latitude. The minimum temperature was 14!

Saturday 13-SEP

Followed by a view to the northeast before sunrise!

Weak signal levels from North America overnight on the 310-degrees beverage antenna, with only the common stations at readable levels. Smøla HQ recordings were a bit more exciting for me, with WALG Albany GA heard on 1590. The day before, the rather common WAUB Auburn NY dominated that frequency.

My ISP was here on Friday and set up a new fibre box from Zyxel which for most of their customers will double as a router. I had ordered they put it in bridge mode because I have a well working RUTX10 router from Teltonika "inside" of the fibre box. But they didn't do that, did they? It became very obvious that they hadn't, so that had to be fixed. So, we configured the Zyxel for bridge mode, reset, and everything was fine. But when I tried to log on to the RUTX10, I ended up at the Zyxel device! With the Zyxel down I was able to access the RUTX10, only to find out that it was set in bridge mode! But why??? Anyway, I decided to not pursue the matter any further, and let the RUTX10 be connected to the Zyxel. Why? The case is that I have lots of Sonoff devices here that need to speak to Wifi. They can not connect if the wifi password requires special characters. The Zyxel router however does not accept a wifi password without special characters. Go figure.

Most of the rest of the day was spent outside erecting, repairing and configuring the 50-degrees and 340-degrees beverages. The 50-degrees is complete, (or so we thought, see Sunday) the dual, staggered 340 wires are up but some final adjustments, such as grounding and weatherproofing will be done Sunday.

After a windy and cloudy start, the wind calmed and the clouds disappeared so with temperatures close to 20 Celsius we could work in shirt-sleeves.

Dinner! Fried and oven baked pork tenderloins, fried and baked small potatoes, with a salad of broccoli, chopped celery stalks, red grapes, sweet cherry tomatoes, finely chopped red onion and a dressing made of red wine vinegar, olive oil and a little touch of sugar. Chocolate pudding again for dessert. An old friend of ours, a 2023 Belleruche Côtes‑du‑Rhône red wine joined us for the main course, and one of the most exclusive brands of grappa, Grappa di Brunello, kept us company for the dessert. 

Dinner!

Late afternoon I also set another dough of bread, It will need 12-14 hours to rise, so that's a story for...

Sunday, 14-SEP

Up at 06:30, I just managed to save the dough before it collapsed! Then followed two hours with light massage between 30-minute rests, and a two-hour final proofing before going into the oven. Good result.

The 310 and 340 beverages delivered very well overnight! Their directivity properties were proved (again), as 1450 kHz gave us WMFJ Daytona Beach FL on the 310, and KFIZ Fond-du-Lac WI on the 340.

The 50 beverage however appeared to be in a bad state. The miserable reception required some fault finding, and finally some adjustments late in the afternoon lowered the noise floor by a whopping 15dB or more. Result! 

The morning was crisp, calm and chilly, a welcome change from previous days. During the day the temperature rose to around 16 Celsius, in the evening around 12. The coming week will see gradually lower temperatures, and some rain. Since September is known to be a rainy, cold and windy month, we're extremely satisfied with this weekend's weather.

View from the HQ. Goosanders resting in the bay before heading towards southerly winter locations.
 

And then, the last dinner this time: Baked cod loins on a bed of pre-baked root vegetables along with red onion, bits of bacon and cherry tomatoes. The cod was baked with Sriracha salsa from Wildfire, an excellent spicy touch to the excellent fish. Served with rice. The selected wine was Kim Crawford Sauvignon Blanc from New Zealand.

Salsa Cod

For dessert we had the rest of the chocolate pudding, along with some Grappa. Later on we checked the MW band on the 50 degrees beverage. The band was awash with Japanese stations and a few Australians as well.

This will be the last post from us until it's time for the KONG51 log, starting the third week of October. Ole and OJ will drive south at 06:00 tomorrow and will visit DX-ers in Sweden along the way. For me it's a 2.5 hour drive back to work.

Receivers and antennas

Antennas: 

50-degrees, 520 metres. Directed towards northern parts of Asia and the Pacific. Western Europe on the backlobe.

310 degrees, 275 metres. Directed towards eastern North America.

340 degrees: 2 x 340 metres, staggered. Directed towards western North America.

Receivers: 9 Perseus SDRs (3 each). Preamps and splitters. Software is Jaguar Pro, version 10 or earlier.

Preps For A New Season At The Smøla HQ

As many will know, the KONG crew also operate beverages and SDRs at Smøla island, southwest of Trondheim. It was time for our annual trip to the island. Smøla is flat, it's boggy and surrounded by treacherous waters. Visitors were Bjarne and OJ Sagdahl. Unfortunately, only two of the "Gang of Three" could make it there as Ole Forr was busy with other appointments. Our host at the site is radio amateur Rolf. 

A lovely site for DX-ing!

DX equipment needs maintenance. In this case, the 315‑degree beverage had suffered a gain loss, so it was clearly in need of repair. The PC I had deployed there — a relatively new Dell MFF — was experiencing LAN connectivity issues and required replacement. One of OJ’s Intel NUCs was also suffering from overheating. And, as it turned out, there were a couple of nasty surprises waiting for us as well.

Thursday AUG-21

The taxi picked me up at 04:30 local time for a flight from Vadsø via Alta and Tromsø, south to Trondheim, where OJ was waiting at the airport. After a while, we drove through heavy rain showers towards the 18:45 ferry crossing and arrived on site around 20:00. We had brought along some amazing sushi from Trondheim. With dinner done, we settled in with a few beers and Rolf's excellent AV system to watch Roger Waters’ Us + Them before calling it a day.

Sushi, with IPA from Hogna

Friday AUG-22

Time to inspect the beverages and the transformer/preamp boxes. Both the 290‑ and 315‑degree beverages need to cross a narrow strait that falls dry at low tide. The 290 appeared to be fine, although we didn’t check the far end until later. The 315, however, had suffered a break and needed repair.

Back at the antenna starting points, we had a nasty surprise — both boxes containing the transformer and preamp had been taken over by ants! Not a pretty sight. Fortunately, they hadn’t caused any damage to the hardware inside.

Cozy ant condo

My Dell MFF was replaced with a refurbished Intel NUC PC, and OJ’s extremely hot‑running NUC was swapped for a newer model.

We also replaced the power supply for a device not used by us, which had been causing a lot of RFI. The new one seems to be much quieter — result!

As at the KONG HQ, we do enjoy a good meal. Dinner that day was six (two each) 150‑gram Angus beef burgers, flavoured with Chili Ginger topping from Wildfire, topped with Gruyère cheese, and served with fried onions and a salad.

The REAL Burger King

We had a Scarpa Piemonte red wine with the burgers, followed by a few beers and a bit of grappa and gin afterwards. It was hard to stay awake, so although we watched most of Remember That Night — David Gilmour live at the Royal Albert Hall — we had to pause the rest until the following day.

There were occasional rain showers throughout the day, but the winds were calm and the temperatures pleasantly mild, around 10 to 12 °C

Saturday AUG-23

Time to deploy the anti‑ant boxes! I had brought along a couple of S‑sized DriBox units, rated to IP55. Unfortunately, we couldn’t fit both the transformer and the preamp inside, so the transformer went into the DriBox and the preamp into the cleaned — and hopefully well‑sealed — old box. Future upgrades may include M‑sized DriBoxes, since the super‑small ants seem to find their way inside in the unlikeliest of places.

In the afternoon, when the tide was low, we repaired the broken 315‑degree beverage antenna. While the fix is temporary (the wire will likely be replaced next year), we believe it should last through the coming winter. The effect on the band signal was immediate and most welcome.

Standing at the point where the 315 broke, facing SSW (the 290 crosses the strait somewhere...).

Dinner! Salmon fillets marinated in a mix of chopped ginger and garlic, balsamico crème, olive oil, lemon juice, and a herb-and-spice blend from Wildfire called Harvest. Baked in the oven at 200 °C for seven minutes — though six would have been perfect. Served with plenty of pasta tossed in pesto. Good stuff!

We paired the salmon with a Leitz Riesling, and afterwards retreated to Rolf’s AV room with a couple of beers to watch Yacht Rock on HBO Max — an amazing story about the music and musicians that shaped our youth. We then finished the evening with the last part of the David Gilmour concert, featuring guest stars such as Graham Nash, David Crosby, and David Bowie.

Salmon fillets and pasta with pesto

Cloudy, still a few hefty showers but mostly dry. Not much wind. 10-12 Celsius.

Sunday AUG-24

Fixing things took less time than expected, so we enjoyed doing very little, apart from the usual routine — checking the overnight recordings (nothing new). We noted that Radio Northern Star has resumed broadcasting on 1575 kHz. For anyone curious about how it sounds, here is an MP3.

Rolf had to leave early, so we ferried him to his car. Later, we went to the boathouse where all our radio gear is stored and carried out further equipment checks, including a last‑minute repair to the far‑end grounding of the 315‑degree beverage. We seem to have eliminated any RFI that could affect reception — very happy with that.

Sunday dinner was simple: salmon and pasta leftovers from Saturday. For dessert, we had sourdough bread with Roquefort Papillon.

It was a cloudy Sunday, with the sun peeking through for just a few minutes. Otherwise, it was dry and calm.

We’ll leave Smøla tomorrow Monday around noon. I have an appointment with my son Henning for go‑kart racing in Trondheim in the afternoon. Should I survive, I’ll catch a plane to Bodø later and spend two more days there on work‑related matters. Below are some photos from the area.

Some of the receivers at the Smøla HQ.

Smøla. Flat. Boggy. The odd high-voltage line.

Crossing of the strait in low tide

End point of the 290-degrees beverage

View from the starting point of the 290-degrees beverage

Tall masts (with warning signs)

Exploring the ATS-Mini: A Pocket-Sized Receiver with Big Aspirations

A recent Reddit post sparked my curiosity about an ultra-compact, budget-friendly radio known as the ATS-Mini—also referred to by its technical title, the V3 AMNVOLT Mini SI4732 DSP Radio Receiver. It's quite a mouthful, but its description is certainly accurate.

I purchased the unit from AliExpress for just USD 23.71, and despite its modest price tag, it claims support for a wide range of frequencies:

• FM: 64–108 MHz with RDS

• LW: 153–500 kHz

• MW: 520–1710 kHz

• SW: 1730–30,000 kHz

FM reception was surprisingly good - with RDS PI and text

SI4732: A Familiar Core

The heart of the receiver is the SI4732 DSP chip, commonly found in many low-cost radios, including the Tecsun PL-990 and XHDATA D-808. These retail for around USD 300 and USD 100, respectively—making the ATS-Mini a notable bargain.

Despite its compact dimensions (80×34×19 mm, 58 grams including battery), the device is packed with functionality. It includes an ESP32 microcontroller with Bluetooth and Wi-Fi capabilities—features rarely seen in radios of this size and cost.

Community Impressions and Durability Concerns

The online reaction has been mixed. While some users report their units failing shortly after purchase, others praise the device’s capabilities when it works properly. As with many community-developed hardware projects, quality control varies, but the enthusiasm is unmistakable.

Real-World Testing at KONG HQ

As with all new receivers I get my hands on, I first measure sensitivity. Using one of my longwire antennas, I compared it to the SDRPlay RSPdx and found it performed admirably—receiving similar signals with only some differences in audio quality.

It also handled adjacent-channel interference fairly well. Encouraged, I brought out my signal generator to push the device further.

Small...Smaller...Mini!

Technical Performance

• Sensitivity: Surprisingly strong, measured at around −100 dBm (~2 µV) for most of the frequency range.

• Low-frequency sensitivity roll-off: Present, but expected in this price bracket.

• FM sensitivity: Not formally measured, but reception of weak Finnish FM stations was comparable to more expensive gear

• Strong signal handling is somewhat on the poor side: Saturation began at −47 dBm (S9+30) and became total at −27 dBm (S9+50); roughly 20 dB behind more robust receivers. I used a method where I set up a feed from a signal generator 200 kHz away from the tuned frequency for this test.

Alternative layout, emphasizing signal levels

Battery Performance

The ATS-Mini is powered by an 800 mAh Li-Ion battery, rated at 3.7V.

It appears that certain hardware revisions suffer from rapid battery discharge, including notably high drain even while the device is not in use. Under typical usage conditions, the battery ought to last between six to eight hours, depending on the configuration—although enabling Wi-Fi will undoubtedly reduce this runtime. I managed eight hours and thirty minutes from a full charge to complete depletion with Wi-Fi disabled.

After recharging, I powered down the device and left it for twelve hours before switching it back on. During that period, the battery voltage had dropped from 4.13V to 4.11V, which I believe falls within acceptable limits. Another 14 hours later voltage read 4.10V. Furthermore, when the unit first arrived—after spending a couple of weeks in transit—it still retained a respectable level of charge. That leads me to believe my particular unit isn’t defective. However, numerous users have reported experiencing issues to the contrary.

Features and Functional Highlights

Despite limitations in signal handling, audio quality and durability, the ATS-Mini offers:

• Multiple reception modes including SSB. Yet, Synchronous AM is missing.

• RDS support for FM

• SMA antenna input, 3.5mm audio output, and USB-C charging

• Wi-Fi connectivity with support for access point mode

• Flexible firmware with multiple UI themes

• EIBI database support (still hit-or-miss for me)

The radio has no bandstop or bandpass filtering, making it effectively “wide open” and susceptible to overload in strong-signal environments.

Open-Source Ecosystem

What sets this receiver apart is the thriving community behind it. Developers and enthusiasts—many from GitHub—are actively enhancing both hardware and firmware:

• Enclosure and stand designs via downloadable CAD files

• A variety of tuning knobs

• Documentation for mods and firmware updates

• A growing library of shared knowledge and experimentation

While the user interface and jargon can feel daunting at first, this is part of what makes the project special: it's not just a product, but a collaborative effort.

Open for hardware mods! Not by this guy though... I've seen videos of people doing modifications with a soldering iron. Amazing.

Final Thoughts

Though it lacks the versatility of an SDR with wideband sampling, the ATS-Mini excels at what it sets out to do. It’s a simple, effective, and surprisingly capable receiver, ideal for travel or experimentation—just remember to bring a proper antenna.

For a device that costs less than a dinner out, its value is driven not just by the hardware itself, but by the passionate community improving it every day. It is a part of the radio hobby I haven't paid much attention to. And while the ATS-Mini is not the solution for hard-core MW DX-ers like myself, it will surely have a market.

Can Switching Power Supplies Be Quiet?

Over the years, there has been considerable discussion among DX-ers surrounding switching power supplies, particularly due to their tendency to generate radio frequency interference (RFI) affecting radio reception. German DX-er Werner Karn prompted me to revisit a manufacturer I had previously tested, after sharing on the Perseus reflector that his Perseus22 was being powered noise-free by a medical-grade 9V supply from Mean Well.

I had, in fact, evaluated Mean Well supplies many years ago during my quest for a suitable solution for my KiwiSDRs. While they performed reasonably well, they weren’t entirely noise-free, which led me to the tongue-in-cheek conclusion that “they meant well” but hadn’t quite hit the mark. It turns out, however, that Mean Well offers supplies in varying grades of quality. The one I had tried was an “industrial grade” GST-type unit, whereas Werner had opted for a “medical grade” GSM-type 9V model.

This piqued my interest, so I ordered a selection of 5V, 12V, and 19V models—the latter intended to replace a rather noisy PSU for a Dell micro desktop PC, affecting the lower shortwave bands. I’ve now tested all of them, and there's no sign of RFI whatsoever.

From what I can observe—literally, judging by pre- and post-test waterfall displays—none of the units produces any detectable noise across the frequencies we care about, i.e. 0–30 MHz, and especially MW.

They all look alike, so I had to add a bit of extra voltage info...

It’s my view that manufacturers of DC-powered devices tend to favour low-cost power supplies to keep expenses down, especially since end-users rarely pay attention to such details. Even reputable makers of commercial-grade routers like Teltonika adopt this approach. Yet quality supplies needn't cost the earth. A 4A, 9VDC medical-grade PSU suitable for the Perseus22 sells for around €20 each, roughly 1% of the radio’s retail price, and significantly less when purchased in bulk.

I’m not suggesting Mean Well is the sole producer of low-noise switching power supplies. I simply lack the time or resources to comprehensively survey that market. Still, the medical-grade GSM-type units I’ve acquired are as quiet as a traditional linear power supply.

Just a heads-up if you’re planning to order one (or several): the default DC connector is a 2.1 mm barrel plug (2.1×5.5 mm). They also offer adaptors for various other connectors at very fair prices—usually under €0.50. Also note that you’ll need a separate mains cable with a C7 connector—commonly known as a “figure 8” or “shotgun” plug. The plug converter guide looks like the image below.

See link above for better resolution

Mean Well is a Taiwanese firm. That may be of interest if you take geopolitical factors into account when making purchase decisions—I know I do. Yet, the actual product is made in China. So, there you go.

The HydraSDR RFOne – Is It Really Just Another Airspy R2?

 I was made aware of the HydraSDR RFOne on a Reddit forum recently. There was mention on the forum about the similarity with the Airspy R2, and that the HydraSDR proprietor Benjamin Vernoux had been working with Airspy’s Youssef Touil. And indeed, when I compared the images of the board, they were “suspiciously” similar. So, what is the RFOne? An Airspy R2 rip-off or clone, or a novel product?

Vernoux and Touil had indeed collaborated on the Airspy R2, with Vernoux focusing on its hardware design. The project started in February 2013, according to Airspy’s own comprehensive “About” page.

So, what are the similarities and differences between the two?

They both cover 24 to 1800 MHz, have a 12-bit ADC and sample up to 10 MSPS. Also, they both use the LPC4370 microprocessor. And of course, the size of the board.

Contrary to the Airspy, the RFOne uses the R282D tuner instead of the R820T2. According to my sources, both tuners have pros and cons, but the R282D is said to consume less power, and has built-in filtering. One post on X (formerly known as Twitter) may suggest that the RFOne has a better signal to noise ratio on FM. However, the test was done indoor with almost no other signals present. The results in a typical multi-signal environment need not be the same.

The test was done using SDR++ software. Since newer versions of SDR# are proprietary for Airspy’s own SDRs, I don’t expect the RFOne to run on SDR#. There will likely be support via dll for HDSDR. If it will be able to run on SDR Console is not clear.

Another difference is a much larger enclosure, which can house up to three boards. And the USB connector is USB-C instead of Micro-USB. The three boards-in-one do not seem to be interconnected in any way, as each has its own antenna port and USB-C connector.

According to HydraSDR’s post on X (formerly known as Twitter), it will sell for “less than 200 USD”. This would usually mean USD 199… while Airspy sells the R2 for USD 169 via Itead in the US (EUR 232 incl. VAT in Germany).

I bought an Airspy R2 together with the upconverter Spyverter for HF and MF use in 2017. The Spyverter added no value at all, because I experienced signal overload all the time. As this report reveals, I was underwhelmed.

So, on July 2^nd at 17:00 CEDT, we will know about availability and price.

Sources: Airspy, rtl-sdr.com, X (formerly known as Twitter), and my friendly AI.