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Passbands of the DL2EBV bandpass filters

Below: Setting values of the DL2EBV bandpass filters in the SW2 software.
 

Below: DL2EBV bandpass filter ranges shown in SW2 software. Click on the image to enlarge.

Experiences with the S3 on long, medium and short wave (9 KHz - 54MHz)

The S3 is able to display a spectrum up to 24MHz wide. To make this possible, the S3 should be connected to a modern PC with enough RAM, fast processor and fast SSD. Otherwise, it can happen that the PC is overloaded and everything starts to stutter. This very large visible spectrum makes sense only for the short overview on the shortwave. You can't really work with it, because the single stations are not visible.

I compared the S3 several months with my reference SDR, the Winradio G33DDC Excalibur Pro. Most of the time I used the software that comes with the device. Reception-wise both SDR's give nothing to each other. Sensitivity and large signal behavior are similarly good, whereby the ADC clipping (overdriving of the AD converter) of the S3 was somewhat better than with the Winradio. The ADC clipping indicator barely lights up. However, only when the bandpass filters were installed and activated. Using the bandpass filters also makes the reception less noisy because the ADC only has to process a portion of the frequency spectrum.

Many comparisons from VLF to VHF brought the realization that Elad has done a great job with the S3! The reception differences to the Winradio G33DDC are zero! The only small difference is the audio playback of the two programs. But that relativizes itself after a short time of listening. When operating the S3 with the original SW2 software, it was noticed that there is no preselector bypass function on the software interface to be able to bypass the bandpass filters quickly! If one works with the spectrum width 24MHz, the bandpass filters must be deactivated first in the menu. Otherwise you will only see the bandpass range of the currently selected frequency. A cumbersome thing! Elad has already been pointed out. The SDR-Console V3 also supports the S3. However, the control of the bandpass filters does not seem to work correctly. Sometimes it works, sometimes it doesn't.

Pictures below: SW2 with 19.66MHz bandwidth. Preselector disabled. Software version 3.54.2

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The reception of FM (54 - 108MHz).

The S3 can also receive FM. From 54 - 108MHz the S3 works in undersampling mode. To avoid out-of-band interference, an FM bandpass filter is permanently installed. In the FM band, the 24MHz spectrum bandwidth can be used well. Thus one has overview of the whole FM band. Due to the larger transmitter bandwidth of the FM transmitters, the stations can be separated optically, to some extent from each other. For more precise tuning, the spectrum must still be zoomed in. The FM receiver is largely resistant to overload. No intermodulation was detected during the test phase with a discone and the Stampfl/Fenu active antenna for the upper frequencies. The receiver is absolutely DX-suitable and convinces with high sensitivity, low-noise and selective reception. The fast RDS function with detailed data output, helps quickly identify the station.

Frequency accuracy

My S3 has the "OCXO" Oven Controlled Crystal Oscillator built in as an option, which can also be calibrated via GPS. Because of the waste heat of the crystal oven, the S3 gets very warm. Yes, almost hot! So it is advisable to place the device in a well ventilated place. After reaching the operating temperature, the S3 has a frequency drift of less than 1Hz!!! The frequency is rock solid and meets professional requirements. For normal SWL requirements, the standard "TCXO" is absolutely sufficient.
 

Gnss (Global Navigation Satellite System)

The Gnss module in the S3 allows the reception of GPS signals with which the frequency of the oscillator is continuously calibrated. In addition, the Gnss module transmits data in the NMEA protocol (National Marine Electronics Association) via a ComPort to the computer to which the S3 is connected. With the Gnss data, position data (longitude and latitude), height above sea level, speed and others can be read and displayed on different programs. At the bottom of the picture you can see the u-center software. Depending on the possibility and location, different satellites can be received and decoded with it. At the time of recording, satellites from:
 

The extended Gnss functions are something for specialists and were only tested superficially.

Click on the image to enlarge.

Conclusion:

The Elad FDM-S3 is a top predator among SDR's! Currently there is no black box SDR that offers reception from 9KHz - 108MHz in top quality. Provided that bandpass filters are installed. The processing quality is top class and leaves nothing to be desired. In addition, the excellent FM reception, the advanced Gnss functions and the very fair price. The S3 should certainly be interesting for professional reception applications. The only shortcomings are the very high operating temperature with the built-in "OCXO" option and the missing bypass function for the bandpasses in the SW2 software.
The tip of the iceberg has become a bit wider. The S3 is on VLF, LW, MW and SW on par with the Winradio G33DDC and counts as of now to my reference devices!

Absolute top class.

posted 24.07.2022

Downconverter Module (DCM)

For reception above 108MHz, Elad has developed the Downconverter Module (DCM). This extends the frequency range up to 4000MHz. The S3 thus offers a continuous reception range from 9KHz to 4000MHz!
The DCM was announced in 2020. Due to the global corona crisis and the associated shortage of components in the electronics industry, its delivery was repeatedly delayed. Now the wait is over and the DCM is available. Albeit in small quantities. At the time of testing, the DCM had not yet been published on the Elad website.
 

The downconverter (DCM) with the switch board can be seen below. The switch board switches the receive path in S3 depending on the frequency when the DCM is active.

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As you can see from the pictures below, the DCM is very robustly built. The aluminum housing is milled from the solid and weighs 1kg. There is of course a reason for this. The higher the frequency, the better the RF shielding of the individual circuit boards must be.

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Blockdiagram from the DCM Front-End

 

Experience with the Downconverter Module

The DCM is offered by Elad as an option for the S3. It can be ordered together with the S3 or installed separately. However, Elad expressly recommends sending in the S3 for installation of the DCM. The reason for this was poor installation by the user. This led to malfunctions in the devices. So you need a bit of skill to install the DCM yourself. I installed the DCM and the switch board myself. For the whole thing to work, the DCM must be activated in the SW2 software. To do this, go to the settings under the "Advanced" tab. There you will find the settings "FDM-S3 Downconverter Module". Check the "Enable Downconverter & Serial Number" box and then click "Search". If the DCM is found, click on "Yes, Apply and Close". The DCM should then be ready.

 

Reception

I have been using the DCM for almost two years and have gained a lot of experience with it. I used the Dressler ARA2000 clone from Heinz Stampfl (HB9KOC) as an antenna. This replica worked much better than the old original. Heinz built the amplifier with the latest low-noise and large-signal-resistant amplifier chip. I rebuilt the actual antenna according to the old model. The frequency range of this antenna is 50 - 2000MHz. So it does not cover the entire frequency range of the DCM. Unfortunately, there were no other antennas available for the upper frequency ranges.
So let's start in the aeronautical band.
With the 24MHz sampling rate, the entire aeronautical band can be displayed. Interesting when you can see all the aircraft radio traffic. But it is not possible to work with this almost 20MHz wide spectrum/waterfall display. It is better to switch to a smaller sampling rate. E.g. 384KHz. This gives you a detailed overview of the transmitters. With the switchable and very low-noise preamplifier of the DCM, very weak signals can still be brought out of the background noise. Impressive! At no time did I notice any spillover from the underlying FM band. Regardless of whether preselection was switched on or off. On the comparator, the Airspy HF+ Discovery, I could hear and see faint VHF spillover at certain points.Further into the 2m amateur radio band. My reception is not good for this frequency range. It took a long time before I was able to record a few stations in this band. Thanks to overreach, I was even able to pick up a few stations in USB from Sweden. That worked very well. Unfortunately, the NFM playback of the SW2 software is a bad! The audio always sounds overdriven and makes listening difficult. Only with the equalizer can the overdriven audio be attenuated somewhat. Elad has known about this problem for a long time, but hasn't done anything about it yet.
The Airspy HF+ Discovery was again used as a comparison device. The reception of both devices was pretty much the same. The only difference was that the NFM playback of the SDR# software was much better than that of the SW2.

 

Below: The entire aviation radio band at a glance.

Weather satellites

The weather satellite band is just above the aeronautical band. To receive the Noaa satellites, for example, you don't even need a special antenna. With the ARA2000 replica, reception was surprisingly good when the satellite flew over the area.
 

Below: Noaa weather satellite reception.

 

DAB+ frequency band

Digital Audio Broadcasting, or DAB+ for short, broadcasts between 174 and 230 MHz. Although it is easy to receive, it is not audible! This is because the SW2 software from Elad does not offer DAB+ decoding. This is a great pity, as the DCM would offer this option.
 

Below: Part of the DAB+ frequency range.

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Over 230MHz

Unfortunately, I lived in a kind of "valley basin" that did not really allow reception of high frequencies. 70cm amateur radio and everything else above that was difficult or impossible to receive. You would have to live on a hill with a wide panoramic view for that. Due to the lack of a suitable residential location and the lack of special antennas for the GHz range, I had to end the test of the DCM.

Conclusion:

The downconverter (DCM) is an enrichment for the Elad FDM-S3 and is aimed more at specialists. The sensitivity and the large signal behavior were excellent during the entire test phase. Nevertheless, there were a few minor issues that affected operation and comfort.
The first thing I would like to see with this huge frequency range is a search function that allows you to scan a pre-programmed frequency range. In other words, a kind of scanner function. The competitor SDR# offers such a function as a plug-in. The other shortcoming is the audio playback in NFM mode. This is simply poor and should be corrected by Elad.
The DCM costs about the same as the FDM-S3.
Unfortunately, I was unable to give the DCM the necessary run-out to be able to test it at the very high frequencies.

Posted: 24.12.2023