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AF1 

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 51. Install R3, 47K ohm [yellow-violet-orange].  

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52. Install R2, 750K ohm [violet-green-yellow]. 

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53. Install R5, 100K ohm [brown-black-yellow]. 

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54. Install R7, 49.9K ohm [yellow-white-white-red]. 

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55. Install C14, .01 uF disc capacitor [marked .01 or 103 or 10nF]. 

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56. Now we’ll install the two MF8 switched capacitance bandpass filter 
IC’s. If you prefer to use an IC socket, you may install one if you wish. 
Be aware, however, that our techies find more repair problems due to 
sockets than due to chips burned out from overheating with a soldering 
iron. Be extra careful not to “bridge” the printed circuit traces together.
Notice that one end of the chip is marked with a dot, notch, or band. Be 
sure to orient this end as shown in the parts diagram. 

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57. Install R23, 1K ohm [brown-black-red]. It mounts 
standing up. 

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57. Lastly, we have to wire the power “on” indicator 
LED. LED’s are polarized, so be sure to orient the long 
lead as shown in the diagram. The leads will slide 
through the holes on the top of the switch contacts. Be 
sure to leave enough lead length on the diode so it can 
“poke through” the front panel. 

 
CONGRATULATIONS 
 

You have just completed your AF1 CW audio filter unit.  Take a well 
deserved break now. Give your eyes a rest. When you return, be sure to 
check over your work on the     
entire circuit board.  Energizing the circuit board with solder “bridges” or 
misplaced components can damage your kit. Five minutes well spent now 
can save hours of troubleshooting time and dollars in expensive replacement 
components. 
 

SETUP AND OPERATIION OF THE AUDIO FILTER 
 

We know that your itching to use your audio filter, so here are the testing 
instructions to verify the operation of your filter. 
  

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Connect a suitable power supply (12-14 V AC or DC) to the power jack. 

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Connect an audio source (an audio function generator does nicely, but 
you may use the actual rig you’re going to connect your filter to, provided 
you are capable of receiving a 400 - 1000 Hz tone). 

Long 
 
Lead 

Содержание AF1 CW AUDIO FILTER

Страница 1: ...t Utilizes state of the art switched capacitor bandpass filter IC s Four selectable bandwidths 750 Hz 500 Hz 250 Hz and 100 Hz all with digital accuracy Adjustable filter center frequency for convenie...

Страница 2: ...ce Meter RAMSEY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator QRP Power Amplifiers RAMSEY MI...

Страница 3: ...5 Parts list 6 AF1 Assembly instructions 8 Schematic diagram 10 Parts Layout diagram 11 Hook up configurations 13 Troubleshooting 14 Ramsey kit warranty 15 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR RAMS...

Страница 4: ...ter the received audio to only allow a single CW tone to be heard That s where the Ramsey AF1 filter comes in to help The audio filter board creates an audio frequency bandpass filter to remove the un...

Страница 5: ...ascaded to provide sharper filter characteristics a Q LOGIC binary input to set the filter bandwidth an adjustable internal oscillator to provide the center frequency for our filter and an extra op am...

Страница 6: ...8 3 100K ohm resistors brown black yellow R5 6 12 1 750K ohm resistor violet green yellow R2 1 49 9K ohm resistor yellow white white red R7 1 147K ohm resistor brown yellow violet orange R9 1 294K oh...

Страница 7: ...steps First we install parts in physical relationship to each other so there s minimal chance of inserting wires into wrong holes Second whenever possible we install in an order that fits our Learn A...

Страница 8: ...dphone jack Notice the seven pins protruding from the bottom of the component Be sure that none of these connecting pins have been bent over before installing J2 Solder all connections Next we ll begi...

Страница 9: ...signals from the bottom to the top side of the circuit board and then back to the bottom side again 17 Grab some more scraps of leads form and install JMP2 3 4 Hey this is better than recycling if we...

Страница 10: ...cement diagram 26 In the same manner install diode D2 another 1N4148 Note that the polarity of this diode is reversed 27 Install C4 1 uF disc capacitor marked 1 or 104 28 Install R8 47K ohm yellow vio...

Страница 11: ...AF1 11 AF1 PARTS LAYOUT DIAGRAM...

Страница 12: ...sure to orient this end as shown in the parts diagram 38 Install C1 1 uF disc capacitor marked 1 or 104 39 Install R6 100K ohm brown black yellow 40 Install C6 10 uF electrolytic Check polarity when...

Страница 13: ...sure to orient the long lead as shown in the diagram The leads will slide through the holes on the top of the switch contacts Be sure to leave enough lead length on the diode so it can poke through th...

Страница 14: ...commands and you did it yourself TROUBLESHOOTING INSTRUCTIONS While we had hoped that it wouldn t come to this if you re having trouble with your kit here are a few suggestions Use a methodical troub...

Страница 15: ...be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronics project kits are packed with pride in the USA If you b...

Страница 16: ...for RAMSEY MODEL NO AF1 CW AUDIO FILTER RAMSEY ELECTRONICS INC 590 Fishers Station Drive Victor New York 14564 Phone 585 924 4560 Fax 585 924 4555 www ramseykits com REQUIRED TOOLS Soldering Iron WLC...

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