Re: Artefacts in new Airspy Discovery !? #sdrsharp #airspyhfplus #sdrconsolev3 #airspy


Larry Dighera
 

I have noticed moderator censorship of the Airspy Group also when
attempting to post this link:
http://www.ab4oj.com/sdr/airspy/airspy_hf_notes.pdf .

Personally, I believe this sort of censorship of factual information
posted to a public forum says volumes about the integrity of the
moderator(s). It is dubious that suppressing posts that contain valid
information will be effective in hiding truth from the public.
But when there is pride or prospective monetary profit involved, it's
remarkable the repugnant lengths to which entrepreneurs will stoop to
shield scrutiny of their revenue stream.

The oil, pharmaceutical, tobacco, and medical industries, to name a
few, come to mind ...

To the extent that such "moderation" reveals the true nature of the
censor, the public will know by such action the _true_ nature of the
individual with whom they are dealing.



On Mon, 26 Aug 2019 01:33:32 -0700, "Henry via Groups.Io"
<th444de=yahoo.de@groups.io> wrote:

b) Posting the subject in the Airspy group is not possible because the moderator there does not allow to discuss the matter. The corresponding posts, requests and comments were deleted or not allowed. We have tried!!!
From: "Guenter Fred Mandel" <dl4zao@gmail.com>
Date: Sun, 25 Aug 2019 07:13:45 -0700

Hallo Uwe,
i experienced similar results at my device if the antenna input is left open or terminated with a 50 Ohm Dummy load. You will find these occurances only if you careffully search the spectrum in the area of 5MHz and 14,5 MHz.

After some experiments i am now quite confident that these Signals are real RF spurs and no digital Artefacts. If you connect the Discovery to the Input of another SDR you probably receive the same Frquencies coming out of the Discovery.  I also could  confirmed the real existence of these small (less than -110dBm) RF Spurs with a sensitive Spectum Analyzer. Not a big issue at all for reception, because the exernal noise of an Antenna is much higher than these bumps.

The spurs do not disappear - as previously assumed - when a real antenna signal is present. With a Signal 50dB above noise floor from a Signal Generator applied, the spurs are still visible.

Besides these occurences, the Airspy Discovery is a great litlle device with tremendous reception quality. A lot of Bang for the Bucks

regards

Guenter

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