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The FDM-S1 is a Software Defined Radio (SDR) which can only be operated via a computer. It receives continuously from 20 kHz - 30 MHz and even up to 200 MHz in "oversampling mode". The software "SW1" offers the modes CW, LSB, USB, DSB, AM, SAM, DRM, FM and WFM. The tuning steps can be customized, as well as the bandwidth filters up to 24 kHz width. The maximum visible width of the spectrum is 3 MHz. Not to be forgotten is the spectrum recording function. All functions are software defined and can be enhanced or modified through software updates. The operation of the SW1 software needs a little getting used to. It is not as easy to use as the Perseus software. It offers many settings and configuration options. It is possible to import the the Eibi frequency list in CSV format. Of course other lists in the same format can be imported as well. It is also possible to directly download DX cluster frequency lists. The frequency list entries can be displayed in the spectrum as a function of the frequency. So you know what's going on at the tuned frequency. DRM (Digital Radio Mondiale) is decoded directly in the SW1 software. So you do not need any external software to receive DRM stations. What catches one's eye immediately, is the beautiful and responsive waterfall / spectrum display. It can be customized, but unfortunately it's not very easy. But usually you will not want to perform any big changes. Because it's nearly perfect in the original setting. A huge "plus" is the scalability of the waterfall / spectrum display. It adjusts to screen size and thus gives you a large display on a wide screen.  Tweaking the settings of the two manual notch filters is a bit cumbersome. But if you have some practice, it works quite well. Oh yes, an "auto notch" is also available. You'll be using it most of the time anyway. The SW1 software comes with a very effective noise reduction that is second to none. I have often used this function. It produces virtually no digital artifacts. Recently a noise blanker (NB) has been integrated. Although still a beta version, it works very well. But it can't beat the NB of the Perseus software. So, these were the most important features related to the software. I tested the version 3.15Beta.

How does it compare to the Perseus??

The Perseus costs almost twice as much as the FDM-S1. So is this a meaningful comparison? Yes, it is! The FDM-S1 is a good match for the Perseus. Regarding sensitivity and clarity they are very close. The Perseus has the lead by only a small margin, because its audio is a tad biased towards treble and thus more intelligible than the Elad. But just by a slight margin. Where the Elad has to make a few concessions is large signal performance. On my antennas, a 35m long wire and Fenu Loop / HDLA3, the S1 sometimes suffers from overload during the evening and night hours. The Perseus remains largely in the linear range. But the Elad can be retrofitted with an external preselector. Then it will probably be able to catch up with the Perseus.

The bottom line, I believe the Elad FDM-S1 is equal to the Perseus in most areas. Except in large signal performance. The SW1 software offers many configuration possibilities and DRM without external software. And a big plus for the SW1, it is freely scalable up to screen size!

Great performance at a fair price. Almost an insider's choice the ELAD FDM-S1!



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