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.

SDRconnect - The Server

Went on a quick 24-hour trip to Kongsfjord on the  28th and 29th (Ascension Day’s a holiday in secular Norway), and—finally—spring had arrived! Much welcome, after April and most of May turned out colder than usual… actually colder than February.

Main reason for the trip was checking up on the electrician’s work—a long-awaited upgrade from ungrounded outlets to grounded ones. With all the gear we’ve got running, swapping some of the doubles for quadruple outlets just made sense. Funny thing, the weekend before, I noticed one of them felt warm to the touch, and when I had a proper look, one of the leads was brittle and about to give out. So yeah, the timing couldn’t have been better! A burned-down KONG-HQ wouldn't be a pretty sight.

The Four The Better

I’ve had a bit of a play with the SDRconnect server in earlier posts, like this one.

I haven’t seen much discussion on the SDRPlay's groups.io reflector about the pros and cons of using the SDRconnect server. Maybe the nRSP-ST is the way to go if that’s the route you’re considering—or maybe people just aren’t that interested. There’s plenty of frustration over how slowly SDRconnect is developing, but barely anyone seems to mention the server functionality. Watching from the sidelines, it’s fascinating how reluctant people are to move from SDRUno to SDRconnect—just goes to show how hard it is to break old habits. Fun fact: SDRUno actually started out as Studio One (or "1") back in late 2014. Cost €149 and needed a USB dongle to function. And wow, were people furious.

Back to SDRconnect Server—I’m definitely not a fan of SDRPlay’s interface choice. That character-based CMD window takes me right back to my pre-Windows 3.0 days, and trust me, those were NOT the good old days. With all the configuration options available when setting up the server, it’s far too much hassle if you want to do anything beyond the default settings. Thankfully, Jon Hudson at SDRPlay put together a video showing how to create a batch file, which makes things a bit easier—but still far from ideal.

"Calling CQ MSDOS, listening...."

So, for personal use, what is the advantage of using the Server, instead of RDP-ing to the actual host? Because any hardware from SDRPlay except the -ST needs a physical PC at the server end anyway. Since I have five Perseus/Jaguar sessions running, RDT is my only option. Especially since I save several TB of data every week. I would need a lot more capacity on my internet connection to save IQ recordings to my client PC, and capacity = money.

One could argue that it's faster to connect to a server. Yes, but... we're talking about a  few seconds, aren't we. And sure, it's free, while many free RDT programs don't offer audio. But some of them do! And that the first client controls all receiver options while the other users can only tune within any band span the first user has decided makes it nowhere near an alternative to the KiwiSDR.

That said: Configuring the server setup is very straightforward. Of course, you need to enable Port Forwarding in you router. But then, your ISP will likely change the IP address at regular or irregular intervals, rendering the config setup unuseable unless you have a DDNS service. And to top it off, at some parts of the world there is CGNAT. Make an internet search about it, if you haven't read my first post.

In summary, I struggle to understand why I should use the SDRconnect Server. Maybe that's why there is so little talk about it on the user forum?

To wrap up this post, a couple of photos from Wednesday evening, 22:30-ish, at opposite directions (NNW vs. SSE)

(Soon to be) Midnight Sun

KAZ Antenna Construction Zone

End Of Season - Preparing For Summer DX!

So, it’s the 10th of May, and the snow cover is considerably thicker than it was in March—who would have thought? At last, we’ve had a couple of days where the temperature climbed above 5 degrees Celsius, with completely clear skies to boot! The photo below was taken at 20:30 local time, just a week away from experiencing 24-hour daylight. Incidentally, the pole you see may soon support two KAZ antennas as part of a project I’m working on. As for summer DX, the focus will shift to chasing FM signals using a few SDRPlay RSPdx units and two FM antennas.

Today, I retrieved the KONG beverages — only two out of five managed to endure the harsh winter unscathed. A few indoor hardware replacements have already been completed, as we opted to swap out the consumer-grade TP-Link router for a professional model from Teltonika. In times like these, with tariff threats looming on one side and an influx of Temu garbage on the other, it was refreshing to support the growing Buy European campaign and buy a product made in Lithuania!

More as it happens.

Perseus22 SDR - Are We Getting Somewhere?

 At long last, version 1.4 of the Perseus22 software is here—almost exactly five months after version 1.3 dropped. You can check out the updated release notes here. My biggest issue with earlier versions was the basic IQ recording and playback options, but that’s finally sorted—though the scheduling feature could still use a bit of work. The biggest surprise? You can eventually be able to access Perseus22 files using other software!

My original review of the Perseus22 is here. Although it’s based on version 1.1, not much changed in terms of improving my SDR experience in versions 1.2 and 1.3.

Now, let’s see how the IQ recording feature holds up this time around.

Starting an IQ recording:

Before, you had to enter a file name before starting a recording—just like the old Perseus software. Not anymore. Well, you still can if you want, but if you pick 'Time to Use in Filename' in Settings, you can kick things off straight away with a date- and timestamped file name. You’ve got the option of using your local time (probably based on your PC settings) or UTC. You can even add a file label to the file name, like I’ve done in the image below.

Just a heads-up: the maximum recording time is capped at 60 minutes, which, to me, doesn’t make much sense if you’re aiming to record an entire night.

Playback of an IQ recording:

Another huge step up from version 1.3! The playback bar is nice and long, making it much easier to slide the cursor with accuracy. You can drag it back and forth on the playback bar and keep an eye on the time displayed just above it. But I don't think it's a good idea that the timer (highlighted in yellow in the image) shows local time. When we’re DXing, we clearly want UTC—not local time! It’s not such a big deal if you’re in Europe, but it’s bound to cause confusion if you’re several time zones away.

Navigation is pretty well thought out. I’ve already mentioned the sliding cursor on the playback bar. The 'VCR' controls—Play/Pause, Stop, and Loop—are all easy to understand. The Fast Forward and Rewind controls skip ahead or back by 1/10th of the file length with each click. For very long IQ recordings, it can be tricky to pinpoint the exact spot you want to check. It would be better to have an option to jump 10, 20, or even 60 seconds at a time.

The A and B controls let you set a loop within the recording, and they’re simple to apply and remove. If you’ve set a loop, you can use the Save control to save that loop section as a new IQ file. The downside is you have to name that file manually—it really should have been date- and timestamped like the original file. Still, the idea is solid.

Overall, recording and playback has seen major improvements compared to the earlier version of the software. To be fair, it started off as quite basic

Scheduled IQ Recordings

The scheduler has a pretty traditional design, clearly geared towards DX-ers who record IQ files casually rather than methodically. The only recurrence option available is "Daily," which feels quite limiting. Adding an "Hourly" option would’ve been a massive improvement. As it stands, you’ll end up spending loads of time setting up hourly top-of-the-hour recordings with this scheduler.

Mind you, if you’ve set up and enabled all the entries, make sure to hit that "Run" button in the bottom-right corner. Don’t forget!

Calibration

Some of you might remember that I wasn’t impressed with the calibration options in previous versions. Well, that’s now been improved—and in quite a clever way. There are two options: you can either use a DAB+ MUX signal (available in most of Europe and certain other areas), or go for a signal you ‘trust,’ like WWV on 10 MHz. Many Jaguar users, for instance, set up a Bodnar mini-GPS to 'transmit' just outside the MW band (e.g., 1705 kHz). The manual option is still available though.

According to Elad, the .p22 file header has been updated to 64 bytes, making the files compatible with third-party software. In fact, the latest version of WavViewDX is already working with Perseus22 files!

API?

No word whether an API will be offered or not. 

Another KONG-HQ Visit (And Some Nice Daytimer Openings Recently)

From the amount of snow on the ground, this could very well be early May.

The Friday drive from Vadsø was in bright sunshine, at least until sunset 45 minutes before arrival, and with temperatures just below freezing most of the way. Around 90% of the road was bare - the remaining 10% was pure ice! Studless tyres required some careful driving.

Both OJS and I had some hard drive trouble, now hopefully fixed for the remainder of this season. March 4 and 5 saw some interesting daytimer openings, mostly towards Ohio at around 23:30Z. Noted here were:

• WVCX-KY 1160 (no sign of Chicago)
• WTLC-IN 1310
• WMAN-OH 1400
• WBNS-OH 1460 (no sign of Des Moines)
• WBCO-OH 1540 (no sign of KXEL. That's 500 watts day power)
• WQCD-OH 1550 (neck-on-neck with Windsor)
• WXGT-OH 1580 (no sign of CKDO) 

Not much of a winter...

Tomorrow Saturday I will be heading towards my old home town Berlevåg for a cordial visit before returning to Vadsø. Here's the evening view towards east. It makes me wonder what kind of DX the coming night has in store for us. Maybe another daytimer opening?

The bright star is Arcturus, a red giant sitting about 37 light years away. Its size? Massive—25 times the radius of our Sun!.

WavViewDX - Probably The Most Versatile Playback Software Today

 So, this is it - the brainchild of German DX-er Reinhard Weiß:

Waterfall from12 hours of continuous recording + some more (zoomed beyond time and frequency edges for clarity)

I hadn't heard about WavViewDX (hereafter WVDX) until late January. It turns out it's fairly new. Reinhard mentioned to me that it started off solely as a viewer in late 2021. Plans to include a player began a year later. Work on an integrated import/analyser commenced in the summer of 2024, and development has been rapid since then. After 12 years of using Jaguar, I'm very much into the "What you see is what you hear" concept. We older individuals tend to prefer linear TV and radio, and it seems the same applies to DX-ing: Linear (live) DX. However, with IQ recordings, we can pick and choose! DX on demand! All we need are the tools to select our DX. Tools like Jaguar, WVDX, Carrier Sleuth, the enhanced SDR Console Navigator, and possibly others are very helpful if we want to review long runs of IQ recordings.

WVDX can import a wide variety of IQ files: Perseus, Jaguar (Perseus), SDR#, SDRconnect, SDR Console, Winradio RXW, Winradio DDC, Linrad single channel, Linrad dual channel for phasing, and my old favourite, SpectraVue! More are likely to be added. The available step sizes (as of today) are 10 kHz, 9+10 kHz or 5 kHz. 

The MWList Logbook and Databases are incorporated, and logging to MWList is straightforward.

WVDX is available for Linux and Windows down to Win7.

Jaguar users will be familiar with the waterfall shown above. Of course, you can also make a detailed spectrum view for every frequency. Below is one from 1320 yesterday:

5 hours + on 1320 (uncalibrated) and the MWList integration with Logbook

A detailed spectrum is done for one frequency at a time. If you’re using an external HDD and a slow CPU like I do, it can take a long time. You can compromise on details to speed it up. A fast CPU and an internal SSD will be way quicker than the 22 minutes I used for a 3-hour spectrum with 0.1 Hz resolution, 30 minutes time resolution and 10 Hz width. Here are your options:

If you opt for the rightmost values above, you're probably in for a long wait if you're not using a fast CPU and SSDs.

Luckily, the data gets saved for later and reloads quickly. Jaguar, on the other hand, processes spectra in the background (livescan) while recording, so that's a bonus.

Now, Jaguar (and Perseus) files are single files. Software like SDR Console and SDRconnect can use RF64 files, which can be massive. Here's an example from SDRconnect of a 90+ minute, 46-GB recording:

Recorded with RSPdx-R2 and SDRconnect

Navigating in time and frequency in the waterfall and spectrum is dead easy—just point and click, and it responds instantly. Might be a bit tricky to get the exact time, though. Traditional tuning is done with the right (upwards) and left keyboard arrows. Beware that only 5, 9 or 10 kHz step sizes are available. There is a Manual Tuning option in the More menu as well, where you can insert a frequency of your choice. There are loads of keyboard shortcuts available too. The spacebar starts and stops playback. Modes are selected with A for AM, S for SAM, F for FSAM, L for LSB, and U for USB. Just to name a few.

If you're into offsets, WVDX offers a choice of one or two calibration frequencies. We use a Bodnar mini-GPS that transmits on 1705 kHz, and after enabling auto-calibration in Jaguar, the resulting IQ files are spot on in WVDX. The Perseus SDR is known to drift quite a bit if ambient temperatures change, and the temperature in my radio room at the KONG HQ has varied between 3 and 12 degrees Celsius the past few days, with huge variations in the Perseus frequency response.

Since it's still early in development, there will be a few functions and GUI solutions that could be improved. After a "buggy" period, the current version 1367 seems pretty stable. All in all, I'd say it's a brilliant alternative for those who want to "DX on demand," almost regardless of their hardware choices.

And there is even a user manual! And a web page!

First Visit to the KONG-HQ in 2025!

So, guess what? This is my first trip to KONG-HQ since late November! Even during my Christmas holiday in nearby Berlevåg, I didn't manage to swing by. "Good weather" and "Weekend" just couldn't get their act together until today.

Not that I really needed to. Despite some wild weather, there haven't been any power outages, so our PCs and Perseus have been chugging along just fine. While I was there, I swapped out two of Ole's hard drives and hooked up a Sonoff plug to one of my desktop PCs.

The 170-km drive to Kongsfjord was pretty chill, with mild snow showers and calm winds tagging along. I was bracing myself for a trek through deep snow from the parking lot to the house, but nope! The wind had blown all the loose snow away, so I ended up walking on a nice, crunchy snow crust from the latest thaw (there's been a few), barely leaving any footprints

Very little snow left as I walked towards the KONG-HQ

A well-known motif for my readers. The sea lyme grass isn't even close to being covered by the snow.

Yikes! The plastic shovel I grabbed from my car was no match for this crust. And the steel shovel? Buried... under the crust! Took me a while to dig it out...

+1 Celsius today. January's cold spells have been few and far between. Oh, and the sun officially made its comeback a week ago. "Officially" because the plains to the south keep it out of sight. But hey, it's nice to have lighter days. Any day now, it'll show up.

And while I'm at it - it might be a while until my next post - I hit up a thrift shop in Vadsø last Thursday and found this gem! Well, actually two!! This is the David Andersen Type 551 portable radio. With the lid on, it looks just like another suitcase. Made in 1954, it sold for NOK 427, which in today's money is half the price of an iPhone 15 Pro Max! No clue if they work 70 years after - probably not - but I'm still tempted. By the way, the thrift shop is called Det Hvite Hus, which, of course, translates to that funny farm in DC.

The David Andersen portable radios. Looks like they have been takes well care of.  Interesting to note that even the NDB section was marked (Radio-navigasjon, I suppose I don't have to translate that).

More as it happens (but it may be spring by then).