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VERSION                                 DATE                                              NAME                 

 

English                                    31/10/12

                     

Dipl.-Ing. R.Menn

    

Page

 9

  
 

Switching to the waterfall display shows the spectrum as follows. The CW type sidebands can be seen, but the 
coloring is quite distracting.   
 

 

 
 
 
 
We now shift the color table so that the signal can be interpreted better (+62). It’s still the same signal, but we 
“desensitized” the receiver by shifting the color table so that only the peak signals are coded in a color and the 
noise stays in black.  
 

 

 
 
 

Further  shifting  the  color  table  (+79)  lets  now  the  waterfall  display  the  dash  and  dots  quite  clearly.  Any  other 
signal other than the peaks are suppressed. 

Summary of Contents for RDR50

Page 1: ..._____________________________________________________ Author Dipl Ing R Menn Receiving Examples Digital Communication and Measurement Receiver Transceiver RDR54 50 Version English First posted 31 10 2...

Page 2: ...eception of a shortwave station with a strong interference in one sideband Page 6 4 SHANNON Volmet 5505kHz with interference Page 7 5 Reception of an NDB and decoding the stations ID using the waterfa...

Page 3: ...the Collins R390A URR and rare TELEFUNKEN E 52b K ln are among my daily receivers An ICOM 8500 was used for reference in the 2m band I nevertheless find that the Reuter RDR54 deserves a place in this...

Page 4: ...l can be seen well and an optimal listening experience can be guaranteed Demodulator AM E nvelope 10 kHz Bandwidth AGC limit 50 dBm medium strong station The station was received using a loop antenna...

Page 5: ...ing signal In the upper part of the spectrum you see a dominant whistler a typical small interference signal which will be heard as a loud constant tone Using the sharp edged Notch Filter we can blank...

Page 6: ...ed in the early morning hours in Europe The lower sideband has a relatively wide interference which we can eliminate in a couple of ways First we can use the SYNC mode and simply chose the Upper Side...

Page 7: ...andwidth As you can see the signal is displayed quite compressed but the interference hump can be seen well In this setting the audio of the VOLMET is completely dominated by the interference Using th...

Page 8: ...ish 1 0 31 10 12 Dipl Ing R Menn 8 5 Reception of an NDB and decoding the stations ID using the waterfall diagram In Europe you can receive a lot of NDBs non directional beacons in the upper LW band A...

Page 9: ...pe sidebands can be seen but the coloring is quite distracting We now shift the color table so that the signal can be interpreted better 62 It s still the same signal but we desensitized the receiver...

Page 10: ...r SB SB SB 6 CW reception and decoding For the CW signal which is usually very weak a combination of some of the RDR54 s unique features can be used to make the signal more intelligible First we use o...

Page 11: ...Page 11 This will result first in a gargling sound if we continue the dashs and dots will be literally punched out of the noise which will make the CW signal very easy to understand Again we use the...

Page 12: ...DR s spectrum display Turn down the loudspeaker s volume completely Connect the RDR s headphone out to the soundcard input of your PC or laptop In case of the latter the settings for microphone sensit...

Page 13: ...tions spaced only 5kHz apart from another Voice of America VoA broadcasts around 16 UTC on 15580 kHz from Botswana Radio Exterior de Espa a REE with a much stronger signal on 15585 kHz A true challeng...

Page 14: ...eband bandwidth set to 5000 Hz VoA reception using DSB and a Passband shift of 4000 Hz to cut out the REE signal completely Note that the bandwidth needs to be adjusted afterwards also 9 Reception of...

Page 15: ...ut out completely by using the Synchronous detector and USB as an option Then we can use the notch filter for the somewhat broader HET tone 3 and narrow the bandwidth just so that we just cut out the...

Page 16: ...intelligibility of this difficult signal 10 Reception of weak signals close to the noise ground on 2m Reception of signals in the 2m band is always a challenge The atmospheric noise in this band is s...

Page 17: ...it function for the very same purpose In the FM demodulating modes wide and narrow you can raise the Gain Limit to a point where the squelch operates to cut off the noisy audio output Adjust the Gain...

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