Re: Appologies for basic newbie questions....

John Freeman

I don't think any apology is needed.  I have similar questions with a similar struggle to find answers.  No real "problems", and I have enjoyed my new FDM-S2 for 3 months, kept up with beta SW2 releases, and consider it an amazing device.  No previous SDR experience but like to think I have some understanding of radio and digital processing.  The manual tells us how to change many settings, but it does NOT help us understand what the system really does, and what the settings really mean.  Maybe I need a pointer to basic SDR references?  But I wish we had a Principles of Operation, and/or a Best Practices guide, along with an updated User Manual.

For example, I finally got my EF-SWL antenna installed in the attic, replacing a 20 foot wire strung in side.  I get MUCH better reception, but with the wire, I was always able to eliminate ADC Clipping warnings by enabling the attenuator.  With the EF-SWL, I was not able to eliminate those warnings, I guess the signal is just stronger.  However, I accidentally discovered that the warnings diminished when I set the HW config to a lower bandwidth, 1.23 MHZ to 307 KHZ.  OK, great, but a) should I even care about that clipping warning?  b) Is it better to reduce or filter the RF some other way to reduce it?  I liked working with the wider bandwidth, but can live with 307KHZ if that is "better".  c) what causes the clipping?  I guess it makes sense that narrower BW just means less signal total so less chance of clipping?  And I believe "clipping" means the ADC digital output is hitting its max output value.  But maybe I have it wrong. d) sometimes during the day I just can't eliminate the clipping, should I do something about it?  What?

What do the Noise Blanker and Noise Reduction really do?  I have tried them, sometimes they seem to help, sometimes seem to add more noise.  How should they be used, what cases, when?  Is this related to the noise floor I see in the display, which ranges from -65 to -120 db on different bands and atten settings.  Is that normal, unusual?  Attenuator reduces both signal and noise, is that a good thing, and the idea is just to get below clipping?

What does Auto Notch really do?  It almost never really helps, and adds distortion, while manually setting a notch seems to work pretty well in most cases when needed. 

I tried some recordings recently for the first time, and was getting a file created, then immediately closed, 0 size.  Finally figured out that checking Disable Out of Space made the recording work!  Why?  There is plenty of space on my disk.  (Win 7 environment). No clues, and I don't know if there is a log somewhere that reports out of space that would have helped me to find this or not.

LO and Tuning can be locked together, or changed separately.  Why would I want to lock them, or not?  How do I decide?

Thanks for any replies, I don't mean to complain, as I said, its a great device, just overwhelming, and marginally documented.


---In elad_sdr_en@..., <rogeriuw@...> wrote :

I have an Elad FDM DUO and FDM SW2 software.

I am not completely inexperienced with SDR setups as I have currently a Flexradio 5000A and PowerSDR

software which I have used for some years. Also Winradio SDR receivers

Is there any BASIC information as to what the Elad setup will actually do?

I have printed the manuals for the FDM DUO and the FDM SW2 but nowhere can I find the basics of the system.

The manuals are very, very poor in comparison to the Flexradio manuals.

Where does one find out the basics???


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