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G8MNY  > TECH     08.10.18 11:00l 96 Lines 3063 Bytes #3 (0) @ WW
BID : 40964_GB7CIP
Subj: Ferrite Ring Demo circuit
Path: ED1ZAC<ED1ZAC<IZ3LSV<IK6ZDE<I0OJJ<GB7CIP
Sent: 181008/0852Z @:GB7CIP.#32.GBR.EURO #:40964 [Caterham Surrey GBR]

>From g8mny%gb7cip.#32.gbr.euro@i0ojj.ampr.org Mon Oct  8 10:55:00 2018
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>From: g8mny@gb7cip.#32.gbr.euro
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From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                                  (New Apr 10)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

Being involved with ham training, I have been doing all the techical demos
including AM & FM (Sigen), but I was ask to do a SIMPLE demo of ferrite rings
ability to reduce QRM to & from leads.

                 旼컴컴컴커           旼컴컴컴컴
                  100MHz             ANALYSER
                  SCOPE              ADAPTOR 
旼컴컴컴커        Y1  Y2 쳐컴컴컴컴컴 0-90MHz 
 SQUARE        읓컴컴컴켸           읕컴컴컴쩡
  WAVE   _____ T  _____    Test     _____  
  OSC   (_____)컨(_____)컴>컴L컴<컴(_____)켸
  1Hz-  쵬  50 Coaxes       /~\    
 50MHz                      \_/    
읕컴컴컴켸                           
                          읕컴컴컴컴컴

The oscillator can first be used to demonstrate the square wave shape on the
scope (Y1) & also on the spectrum analyser harmonics of a square wave (Y2).

  0dB_
      납
      납       S Q U A R E   W A V E   S P E C T R U M
-10dB_납
      납  
      납    |
-20dB_납          |
      납              |  |
      납                      |  |
-30dB_납                            |  |
      납                              
      읒컴좔컨컴좔컨컴좔컨컴좔컨컴좔컨컴좔컨컴좔컨컴>Harmonics
       1  3  5  7  9  11 13 15 17 19 21 23 25 27 29 31

Then via a 1 turn ferrite ring.
 
  0dB_
      
      납      SHORING OUT THE L WILL SHOW
-10dB_납      ITS EFECTIVNES ON A 50 SYSTEM
      납
      납  
-20dB_납    
      납          
      납                
-30dB_납                        |  |
      납                              
      납                              
-40dB 읒컴좔컨컴좔컨컴좔컨컴좔컨컴좔컨컴좔컨컴좔컨컴>Harmonics
       1  3  5  7  9  11 13 15 17 19 21 23 25 27 29 31

Then via a 8 turns on the same ferrite ring.

  0dB_
      
      
-10dB_
              Any interwinding capacitance will
      납       bring back the higher frequencys.
-20dB_납
      납
      납  
-30dB_납  
      납  
      납    
-40dB 납    
      납      
      읒컴좔컨컴좔컨컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴>Harmonics
       1  3  5  7  9  11 13 15 17 19 21 23 25 27 29 31

This works for large rings that you can put over mains leads, or even tiny
cores to be wired in series with Mic signals etc.


See also my tech buls on "Clip on QRM Probe", "Reducing Electronic RF QRM"
"Spectrum Harmonic Demo circuit", "Scope RF Trick", "Tuned Circuit Scope Demo"
& "Oscilloscopes".


Why don't U send an interesting bul?

73 de John G8MNY @ GB7CIP



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