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G8MNY  > TECH     14.08.26 16:12l 88 Lines 2729 Bytes #8 (0) @ WW
BID : 1950_GB7CIP
Read: GUEST
Subj: Ferrite Ring Demo circuit
Path: JH4XSY<N3HYM<IW2OHX<GB7CIP
Sent: 260814/0710Z @:GB7CIP.#32.GBR.EURO #:1950 [Caterham Surrey GBR] $:1950_GB
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.

                 ﾚﾄﾄﾄﾄﾄﾄﾄﾄｿ           ﾚﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ
                 ｳ 100MHz ｳ           ｳ ANALYSERｳ
                 ｳ SCOPE  ｳ           ｳ ADAPTOR ｳ
ﾚﾄﾄﾄﾄﾄﾄﾄﾄｿ       ｳ Y1  Y2 ﾃﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｴ 0-90MHz ｳ
ｳ SQUARE ｳ       ﾀﾂﾄﾄﾄﾄﾄﾄﾄﾙ           ﾀﾄﾄﾄﾄﾄﾄﾄﾂﾄﾙ
ｳ  WAVE  ｳ _____ Tｳ  _____    Test     _____  ｳ
ｳ  OSC   ﾃ(_____)ﾄﾁﾄ(_____)ﾄﾄ>ﾄﾄLﾄﾄ<ﾄﾄ(_____)ﾄﾙ
ｳ  1Hz-  ﾃﾙ  50ohm Coaxes ｳ    /~\    ｳ
ｳ 50MHz  ｳ                ｳ    \_/    ｳ
ﾀﾄﾄﾄﾄﾄﾄﾄﾄﾙ                ｳ           ｳ
                          ﾀﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙ

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_ｳ
      ｳｳ
      ｳｳ       S Q U A R E   W A V E   S P E C T R U M
-10dB_ｳｳ
      ｳｳ  ｳ
      ｳｳ  ｳ  |
-20dB_ｳｳ  ｳ  ｳ  ｳ  ｳ  |
      ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  |  |
      ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  |  |
-30dB_ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  |  |
      ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ
      ﾀﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁ>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_ｳ
      ｳ
      ｳｳ      SHORING OUT THE L WILL SHOW
-10dB_ｳｳ      ITS EFECTIVNES ON A 50� SYSTEM
      ｳｳ
      ｳｳ  ｳ
-20dB_ｳｳ  ｳ  ｳ
      ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ
      ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ
-30dB_ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  |  |
      ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ
      ｳｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ  ｳ
-40dB ﾀﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁ>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_ｳ
      ｳ
      ｳ
-10dB_ｳ
      ｳ        Any interwinding capacitance will
      ｳｳ       bring back the higher frequencys.
-20dB_ｳｳ
      ｳｳ
      ｳｳ  ｳ
-30dB_ｳｳ  ｳ
      ｳｳ  ｳ
      ｳｳ  ｳ  ｳ
-40dB ｳｳ  ｳ  ｳ
      ｳｳ  ｳ  ｳ  ｳ
      ﾀﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ>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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