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QST

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– Devoted entirely to Amateur Radio     www.arrl.org 

  

  

January 2016    3

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Photos by the author.
ARRL member Don Dorward, VA3DDN, has 

been a licensed Amateur Radio operator since 

2002, with basic and advanced certification. He 

graduated Ryerson Electronics Technology in 

the Gerber files available at no cost to any-
one who would like them. There are also a 
limited number of finished PCBs available 
at my cost plus postage. Contact me by  
e-mail for details.

1963. His career positions included manage-

ment of R & D, ISO9001, and ISO13485 Quality 

Systems, Regulatory Affairs, in the areas of 

technical support for electronic components 

and materials, environmental testing and instru-

ment calibration, automotive electronics product 

development, switch mode power supply de-

velopment, medical electronics, UL/CSA and 

EU product safety testing and certification, and 

EMI compliance. Don developed programs for 

accelerated life testing methods such as HALT 

and HASS, in-house training for Quality Sys-

tems, ESD prevention, and IPC Workmanship 

Standards for the Acceptability of electronic 

equipment. He is the inventor on two patents, 

and retired in 2006. Don is a Life Member of 

IEEE, Radio Amateurs of Canada, and Ten-Ten 

International. You can reach him at 

va3ddn@

arrl.net

Reprinted with the permission on ARRL. Copyright © ARRL 

January 2016, QST p59

Summary of Contents for SM-20

Page 1: ...270 Ω R5 100 Ω Kr Kg R4 4 7 kΩ R2 3 3 kΩ C1 C2 0 01 D1 1 2 3 Q1 BC547B Q2 BC547B 16 V 2 2 μF 8 V 5 V R5 0 red wire To Radio PTT yel wire com gnd blk wire 1N5819 Bi color red grn LED or two separate LEDs in parallel C1 capacitor 2 2 mF 16 V tantalum C2 capacitor 0 01 mF 50 V ceramic D1 Schottky diode 1N5819 LED1 see text bi color 3mm LED Jameco 94553 or Digikey 160 1058 ND Q1 Q2 NPN transistor BC54...

Page 2: ...ads and finished with larger shrink tubing over both wires If you opt for two separate LEDs bend the leads at right angles about 0 2 inches from the LED body as seen in Figure 2 Next po sition both LEDs with their leads pointing at each other in a soft jawed vise at the desired distance apart I used 0 75 inches Tack the leads together with a drop of solder then position and solder the color coded ...

Page 3: ...485 Quality Systems Regulatory Affairs in the areas of technical support for electronic components and materials environmental testing and instru ment calibration automotive electronics product development switch mode power supply de velopment medical electronics UL CSA and EU product safety testing and certification and EMI compliance Don developed programs for accelerated life testing methods su...

Page 4: ...ional Information Note Pin out outline of Q1 Q2 as shown on pcb matches 2N4401 2N3904 BC547B 2N2222 may require mounting 180 deg Please verify pin out of the transistors you have per manufacturer data sheet ...

Page 5: ...Please note the illustration of the bi color LED in the QST drawn circuit above is incorrect It should be as shown below Revised Jan 23 2016 VA3DDN Kg Kr ...

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