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The main technical data of the V2D

Block diagram of the Arinst V2D

The V2D is a tuner based SDR. It works with the powerful digital tuner chip "R820T2". This chip is used in many black box SDR's. To my knowledge, the V2D is the first portable SDR receiver to use this chip. Actually the chip R820T2 was designed for the frequency range 40MHz - 1000MHz. But by a special circuit the frequency range can be extended significantly.
Roughly speaking: By upconverting and downconverting the large frequency range 100Khz - 2800MHz is generated.

A look under the hood

If you loosen the eight small screws on the side of the case, you are granted a view into the interior of the device. Actually, no big surprise, the V2D is neatly built. The display is attached to the motherboard with two screws. If you remove these two screws, the display can be removed very easily. In doing so, I made a positive observation. The display is a 4" IPS LCD module, which can be bought in many online stores, should this ever break, it is cheap to get. The battery is located under the display. For the top view, I removed the covers of both shielding boxes.

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Functions of the V2D

The V2D has a large number of functions that need to be mastered and also understood. The pictures below show most of them. If you press the on/off button twice in succession or pull up the main screen with the stylus, the menu with the settings appears. The currently opened page is highlighted in blue.

Image origin: Arinst

On the "Band" page, the receive frequency, operating mode, bandwidth, NB, antenna impedance and tuning steps are set by tapping the frequency display.	Under "RF path control" from the Band page, the simple (Basic) gain control can be called up.
Under "RF path control" from the Band page, you can access the advanced gain control.	On the "Display" page, the width of the baseband and the width of the IF1 spectrum are entered. The spectrum settings (Chart Settings) are also located there.
Under Display at "Chart Settings" the spectrum and waterfall settings of Baseband, IF1, IF2/MPX and Audio can be made.	The Device page houses the settings for display brightness, display off time, power on mute, center tuning mode, change of tuning knob direction, language switching, dark/light theme, mouse port activation, switching to PC mode and display of firmware, serial number, etc.
On the "Sound" page the NR, AGC, Notch Filter, Squelch and the Equalizer are operated with presets.	The setting options of the Noise Reduction. (NR)
The notch filters are freely configurable.	An important filter is the noise blanker.
The "Presets" page houses the 125 (5x25) alphanumeric memories. All parameters are stored.	Main display menu. Here you can compose the main display. The display is scalable.

The operation of the Arinst V2D

At the time of testing, there was no user manual for the V2D. Therefore, I have listed a few basic functions and procedures here.

-- Most settings are made via the touch display. To do this, use the included touch stylus.
    If you tap and hold the stylus on the three small dots at the bottom of the display and pull it up a bit, the mode menu appears. Here
    the operating mode, bandwidth, AGC, NR, NF (notch filter) and for WFM the RDS decoding are displayed. For the main menu the three small
    points are pulled up further. Pressing the on/off key once also opens the operating mode menu. Pressing it a second time opens the main menu.

-- On the right side of the V2D there is a rotary knob with a push function. If you press the rotary knob, a small menu appears on the right edge of the screen.
    The following settings can be made via this:

-- To quickly go to direct frequency entry, press and hold the frequency display for one second.
-- If you want to set the squelch level, press/hold the S-meter and move the red line to the appropriate position below the noise threshold. Squelch
    off: Press/hold on the S-meter.
-- The same (press/hold) applies to most other settings such as AGC, NR, etc.
-- On the main display between the spectra there is a small square with a gray background. Pressing/holding this will take you to the main display menu.
    Here the arrangement and the function of the different spectra can be defined. Moving the square also scales the display.
-- If you press the on/off button twice in quick succession on the left side of the device, the display is switched off. Pressing it once switches it on again.

The V2D also offers a feature that no other portable receiver offers! The operation with a computer mouse. The mouse is connected to the USB-C socket. If you don't have a mouse with a USB-C connector, you should get an adapter.
Wired mouse work without problems. But wireless mouse with a 2.4Ghz USB dongle also work! However, not every wireless mouse works. Until now, only a Russian product that the manufacturer sent me for testing purposes worked. The wireless mouse "OKLICK 525MW". If you are lucky, you can find these OKLICK mouse at AliExpress. The best will be, one works with a wired mouse. All settings as well as frequency tuning can be done with the mouse. Pressing the mouse wheel opens the small menu as seen above.
But normally the V2D is operated with the combination of touch input pen and rotary knob.

Firmware Update

To add new features and to correct software bugs, the firmware of the V2D can be easily updated. For this purpose, Arinst offers the free software "Arinst Virtual Lab", which can be used to perform the updates. After installing and starting the software, the V2D is detected, its data is read and compared with the database at Arinst. It is automatically detected whether the firmware on the V2D is outdated. If this is the case, the update procedure starts. Afterwards the device is restarted automatically. The update takes less than two minutes.

Basic Experiences & Findings

Because the V2D has an elaborate gain control, I first had to figure out how to deal with it. There is a "Basic & Advanced" setting option. The "Basic" mode offers only the attenuator setting and a simple 15 step low noise amplifier setting. The "Advanced" mode offers the additional setting option for the mixer.
After some tests in different frequency ranges it was clear that the "Basic" mode was sufficient to be able to go on reception at the existing stationary antennas. The V2D has a manual as well as an automatic gain control. The automatic control (AGC) in the "RF path control" section was not used because of the too high gain on long, medium and short wave because it brings too much level. The receiver then noises too much, quickly reaches its limits and produces intermodulations.

Five configurable notch filters are available to suppress whistling tones. The user must estimate the pitch himself and enter the value in Hertz (Hz). There is no visual representation of the notch filters on the spectrum. This is cumbersome and takes time to adjust. Here an auto notch would be the better variant. Often the annoying whistling tone was gone while still searching for the right setting.

The noise reduction (NR) offers five sliders. It works decently after careful adjustment. Reducing it to a single slider would simplify the adjustment procedure considerably.

The noise blanker works quite well and can largely suppress grazing fence impulses. With three controls, it can be adjusted relatively quickly.

The 125 memory locations are very useful. In addition to the frequency, operating mode and bandwidth, all settings that the receiver currently has, are stored. This means that before saving a frequency, you scale the spectrum/waterfall, set the mode, bandwidth, tuning steps, gain, AGC, etc. as you like. Everything is then stored in the memory and can be labeled alphanumerically. If you recall the memory, everything is restored as it was stored. Unfortunately, it was not possible to save the memory contents on the PC at the time of testing, should they ever be lost due to a firmware update.

The V2D has some audible interference on long, medium and short wave. These interferences come mainly from the display or its control.

When a weakly incident station sits between strong stations, it is often masked with a noise bell. This indicates "reciprocal mixing". The cause is the sideband noise of the receiver oscillator. The sideband noise of the receiver oscillator mixes with the strong signals. This effect often occurs on medium and short wave.

The V2D in receive mode at stationary antennas

After several weeks of familiarization and some bug feedback to the manufacturer Arinst, a serious test could be performed. Because I had no suitable comparison receiver in the same class at hand, I took the premium SDR Elad FDM-S3, because it has a similarly large frequency range. Admittedly, a tough competition for the V2D.
The hardware and specs of the V2D leave a largely good impression. Now it will turn out how it will behave on powerful antennas. In the test phase, the following antennas were in use:
- Reuter RLA4E/Fenu cross loop
- Datong AD370 active dipole horizontal
- NTi Megadipol MD300DX Vertical
- ARA 2000 clone from Heinz Stampfl for the range up to 2GHz

Below are audio comparisons between the Arinst V2D and the Elad S3.
Second 0 - 10: Arinst V2D
Second 10 - 20: Elad S3
One exception: When comparing Italy Cable Timesignal:
Second 0 - 34: Arinst V2D
second 34 - 68: Elad S3

To hear the subtleties I recommend to use a good headphone.

Long wave
We start at 171KHz. Here Medi-1 from Morocco is a good choice. On 171KHz the station comes in very strong at the NTi MegaDipol MD300 in the evening hours. The MegaDipol brings the V2D to its limits. The gain has to be adjusted back a bit. In AM synchronous (AMS) mode, the audio is free of the typical AM crackle. On the Elad S3, the station comes in clearer and with a little less noise. With BBC-4 on 198KHz the case is the same.
 

Medi 1-171khz-V2D-S3-SAM-8khz

BBC 4-198khz-V2D-S3-SAM-8khz

Medium wave
In AM mode, the typical fast fading of the station can often be heard. If you switch to AMS and set the audio AGC correctly, the fading and crackling is almost gone. The clarity of the signal delivered by the V2D is practically as good as that of the Elad S3. With the quasi-stepless bandwidth adjustment, one always has the appropriate bandwidth available. With increasing signal strength in the evening hours, a special effect becomes noticeable. If you hear a weak station between two strong stations, the weak station is covered with noise. This is "reciprocal mixing". This effect can be mitigated somewhat by turning down the gain. If there are no strong stations near the receive frequency, the V2D behaves perfectly. The bandwidth filters are steep enough to listen with 6-8KHz bandwidth in the evening hours. The built-in equalizer with its presets can be manually adjusted to suit listening habits. Especially with strong stations like Radio Romania on 1152KHz with 20KHz bandwidth, it invites you to linger there. The sonority that the V2D delivers here is already great. On a good active speaker or headphones well understood. The Datong AD370 delivered the best results here.

RNE Radio Nacional-738khz-V2D-S3-SAM-8khz

Radio Romania-1152khz-V2D-S3-SAM-20khz

Lyca Radio-1458khz-V2D-S3-SAM-10khz

Above medium wave
In this frequency range, Dutch, Greek and Serbian radio pirates can be received very often in the evening and night hours. These stations usually come with unstable transmission frequency and have suboptimal modulation. The V2D masters the prevailing reception situations without major problems. With AMS one or the other station can be made more audible. A bit further up, coastal radio stations send their weather messages in USB. These could also be recorded well. In this area the V2D got along best with the Datong AD370. It has a moderate receive level and less noise because it is horizontally oriented. So far, no large signal interference could be detected.

Dutch Pirat-1620khz-V2D-S3-SAM-6khz

Greek Pirat-1700khz-V2D-S3-SAM-6khz

Lampedusa Radio-1876khz-V2D-S3-USB-2.7khz

Shortwave
In the 80m band we meet radio amateurs. The V2D brings in the sideband operation consistently very good results. Even with air weather station Shannon Volmet on 3413KHz in USB, hardly any differences to the S3 are audible. The audio reproduction, the flexible bandwidth selection and the frequency accuracy, leave nothing to be desired here. The difference to the Elad S3 which is frequency calibrated via GPS is hardly noticeable. Arriving on shortwave, we linger a bit in the 60m tropical band. Radio Rebelde on 5025Khz is very good to receive around 2am. Only that the signal in the lower sideband is disturbed by the well known RTTY signal. Switched to USB and with 4KHz bandwidth, the station can be enjoyed quite pleasantly on the V2D. On the Elad S3, the station is equally good to record. Here you can see how important and useful the manual gain control is. If I had left this situation to the automatic gain control, the station would have been completely noisy and there would be intermodulation products. A little later on the same frequency and in AM sync, the V2D brings the station flawlessly. The synchronous demodulator is very stable and never lost sync at any time. It also has a wide capture range. A few kilohertz further down at 4885KHz, Radio Clube do Para from Brazil slowly makes itself heard. Here hardcore DX reception is the order of the day. On the Elad S3 the station is just at the turf. A few Portuguese words are already to be understood. In this difficult situation the V2D has to pass. The station can be heard but not understood. A bit above the 41m band Voice of Korea is broadcasting. The station comes well with the V2D. Unfortunately the station is a bit noisy compared to the S3. In the vicinity of strong signals you often have to reduce the gain so that the V2D does not overload. A rare guest on the frequency 8879KHZ is Mumbai Radio, an airband radio station from India. No differences to the S3 can be heard. On exactly 10MHz, among others, Italy Cable broadcasts the time signal. Because of the beautiful classical music, always nice to linger. Large differences are to be noticed also here none. At Radio France a small surprise. In this comparison, the V2D noise a trace less than the S3. Then further into the 17m amateur radio band. In this comparison, the reproduction quality is again equal. And already the end of the classic shortwave is reached. The beacon DK0TEN on 28257KHz is always good to test the selectivity of the filters. Here the V2D can't quite keep up. The steepness of the filters does not come up to that of the S3. But this is not a big surprise. The digital bandwidth filters of the V2D have only 500taps. Those of the S3 at least 1500taps. So significantly steeper-edged or sharper. The sharper the bandwidth filters are, the higher the processor load.
Reciprocal mixing" was also noticeable on shortwave as soon as strong signal levels were near the receive frequency.

Shannon Volmet-3413khz-V2D-S3-USB-2.7khz	Amateurfunk-3785khz-V2D-S3-LSB-2.7khz	Radio Rebelde-5025khz-V2D-S3-USB-4khz
Voice of Korea-7570khz-V2D-S3-SAM-8khz	Mumbai Aero-8879khz-V2D-S3-USB-2.7khz	Italy Cable Timesignal-10000khz-V2D-S3-USB-2.7khz
Radio_France_Int.-15300khz-V2D-S3-SAM-8khz	Amateurfunk-18161khz-V2D-S3-USB-2.7khz	Amateurfunk Bake-28257khz-V2D-S3-CW-0.1khz

The upper frequency ranges
The upper frequency range of the V2D goes up to 2800MHz. Therefore, this range was only "tested", because it would go far beyond the scope of a test report.
In the FM broadcast band, the V2D brings good to very good reception performance. It is also Dx-suitable by the selection of the bandwidth filters. Unfortunately, RDS doesn't work that well. The decoding works well with strong incoming stations, as soon as the signal strength decreases, it doesn't work so well anymore. The audio playback via the built-in speaker is more for when you don't have an active speaker or headphones at hand. It doesn't sound convincing, which of course also has to do with the V2D's small case size. Overloads I could not determine during the operation at the active antenna fortunately none. In the vicinity of FM stations , i.e. in urban areas, the situation might look different. In the civil aviation band, the V2D surprised with good reception. Here, the gain had to be raised to have enough level. The same in the 250MHz range. In this range transmit Satcom military satellites, which are often used by Brazilian and Russian radio pirates for their private purposes. The V2D received surprisingly well in this range. I was able to follow some conversations without understanding a word of them. To be able to test the frequencies above, there was partly a lack of usable signals and partly a lack of special equipment.

The Arinst V2D controlled via PC
Thanks to the driver that Arinst provides for free, it is possible to control the V2D via a Windows computer. Unfortunately, I found that only HDSDR worked properly with the V2D. The SDRUnoEXTIO version 1.22 also worked, but crashed often for reasons unknown to me. Probably because the program is outdated and no longer 100% compatible with Windows 10. SDRSharper, a clone of SDR#, is quite nice, but also had its problems and froze now and then.
 

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The Arinst V2D in outdoor use
The V2D is a portable receiver because of the built-in battery. So I started to hunt for waves outside the domestic fog. Equipped with the V2D, telescopic antenna and earphones I went out into the open. The used telescopic antenna Diamond SRH789 is from the length, perfectly designed for the V2D. To use the full receiver sensitivity, the antenna input must be switched to "HI-Z" (high impedance) in the settings of the V2D.
The V2D is sensitive enough to receive BBC4 on 198KHz at the telescopic antenna during the day. On the medium wave around 15:00 stations were also receivable. Among them RAI on 900KHz and Radio Gold on 1548KHz. Of course, you have to experiment a bit with the gain control to get the best results. One thing I have noticed after a short time: The automatic gain is set much too high, even for outdoor use on the telescopic antenna. As a result, the receiver noises much too much. With the manual gain setting I drove much better. This optimized the reception wonderfully. There are a total of 15 levels to choose from. One of them is the automatic. The reception on shortwave was even better because of the stronger signals. Just listening to strong incoming stations is really fun with the V2D. Especially when you look at the wonderful, scalable display. The reception of SSB stations, whether amateur or utility, was excellent. The V2D sits very accurately on the frequency. Even ECSS reception, listening to AM broadcast stations in SSB, was no problem at all. There were no differences in audio when switching sidebands.
After lingering on shortwave for a while and under a critical tester's eye, I noticed that something was not quite clean. In almost regular intervals were partly strong interferences to hear and on the spectrum/waterfall to see. Unfortunately, the V2D does not differ in this matter from other portable receivers with large display with spectrum display. The interference found is generated by the display! Now I also realized why you can turn off the display by pressing the on/off button twice. To get rid of the interferences. Means, if one wants to receive interference-free, the display must be switched off. That clouded the joy.
Back at home, I unscrewed the device to see if I could somehow dampen the interference. At first glance it seemed hopeless. But at second glance, I noticed that the edges of the case were painted over. The places, where the tinned side parts come on it. Because of the overpainted edges, there could not be good RF shielding. So I removed the paint from the edges and screwed the unit together.
A second test showed that the interference was about 10dB less. They were still audible, but significantly less. Unfortunately, my little intervention was not a cure-all. There were areas where the interference was still equally strong.
 

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Conclusion:
The Arinst V2D is almost a "dream kit." It offers amazingly good reception on long, medium and short wave without immediately overload. And that at domestic active antennas. When working with the manual gain control, one largely saves intermodulation products and noise. The function variety is enormous and qualitatively on a high level. At that point you notice how Arinst has made an effort. Above shortwave, the V2D can also convince. What it lacks here is a search function (scanner).
The case is robust and of good quality. But unfortunately there is criticism here. The housing shells were painted in places that should not be painted! The painted flanks of the housing worsen the shielding effect significantly, which is noticeable with strong interference in reception, one operates the V2D with telescopic antenna. Especially in the FM range, the interference is very strong. Not only that. In the development of the V2D was much too little attention to decouple the display to prevent interference radiation in the receiving branch. The approx. 4h battery life was unfortunately never reached. After just under 3 hours of operation was the end.
Otherwise, the V2D is great fun. Especially with a external antenna.
Arinst proved to be a very committed manufacturer when it came to correcting bugs in the software and implementing suggestions.

postet: 22.01.2023