VLF signal SAQ

24.12.2019 I received a weak signal in Kraków from TX Grimeton SAQ on 17,2 KHz.

SDR receiver fine work with Winrad software and other programs

My receiver contains three main blocks , I2S programmable synthesizer on Si5351 , digital demodulator , preamplifier on MOSFET.

Works on band 160m , 80m and 17m to 40m.

Several photos are below.

Alinco DJ-580 inside

Tube amplifier made by Warmar

A tube amplifier consists of three tubes: one ECC83 and two ECL86. It has two audio analog high impedance inputs. In order to control sound you can use two potentiometers: treble and bass. Audio output power of this one is a few watts. Output impedance to monitors is 8 ohm.

The amplifier with three way monitors has excellent sound , perfectly deep bass tones and mature high registers. Sound is detailed with wide stereo base.

Amplifier upgrade includes the following post:

Modernizacja wzmacniacza lampowego

Some pictures are shown below the original version.

 

 

Acoustic spectra for radio signal DAB and FM

Measurement of Spectra a signal using a Fast Fourier Transform FFT in the domain of time are performed in a finite time. In other words, the measured are portions of a waveform of the signal of the specified length. Fragments extracted cyclically subjected are to the FFT. Fragments the waveform on shores contains discontinuities because are collected at intervals. Discontinuities cause blurring to spectra. The spectra of the downloaded portions of the waveform are different from the spectra of the whole continuous the signal subjected to measurement. To reduce blur spectra signal is passed the signal through a time window. The Time window reduced spillage of energy in the domain of frequency. Measurements were made for spectra of acoustic signals DAB and FM. The signal was passed through a time window. Used were of the time window: Rectangular, Bartlett, Hanning, Hamming, Blackman, Blackman-Harris, Flat-Top. The time window it is function shaping the signal measured undergone FFT. In the domain of time, signal is as function of time and was multiplying with function describing by the time window. In the domain of frequency occurs weave these functions. The result of the signal is subjected to FFT.

 

See articles :     http://sp9mco.com/articles/

Acoustic spectra DAB and FM

TRX 10Rt na pasmo 80 m

Na schemacie dosępnym na stronie z poprzednimi moimi konstrukcjami amatorskimi regulacja m.cz. odbywa się przez regulację ARW. Można regulować wzmocnienie m.cz. tylko w pozycji (P) przełącznika ARW OFF . Potencjometr 470 k ohm. Wzmocnienie ARW jest tak dobrane, że w pozycji (K) przełącznika ARW ON nie ma potrzeby regulacji poziomu m.cz.