manualshive.com logo in svg
background image

AM25 

15  

 

ˆ

Winding L4. Locate one of the binocular ferrite cores and the enameled 
magnet wire. We will talk about winding complete turns through the core, 
a complete turn is a full wire course through one hole in the core and 
back out through the other hole. 

ˆ

63. Cut a length of wire 18 inches long and following the diagram shown, 
wind 2 complete turns through the core and form a loop 3/4 “ long. 

ˆ

64. Twist this loop fairly 
tight and continue winding 
another 8 complete turns 
through the core. Leave 
this wire end longer than 
the first wire, in this way we 
will have indicated that this 
is the side of the inductor 
that has 8 turns. If you 
wish, you can play it safe and color this wire with a black marker to really 
make it stand out. 

ˆ

65. Tin the ends of the wires on L4. Tinning means to ‘burn’ off the 
enamel insulation from the ends of the wire and to apply a coat of solder 
to the wire to allow a good solder connection. Simply puddle some solder 
on the end of your soldering iron and sit the wire in the hot puddle. You’ll 
see the insulation burn off and a nice coating of solder attach to the 
copper wire under the enamel insulation. Gosh, it takes longer to explain 
than to do it!  

ˆ

66. Position the wire ends so that the three wires are in line with the 
twisted wire pair in the middle.  

ˆ

67. Install L4, paying attention to putting the 8 turn wire end into the PC 
board hole nearest C1. The twisted wires go in the center hole and the 
remaining wire which was 2 turns goes into the hole near C18. It is vitally 
important that you properly install this part!   

ˆ

68. Winding L6. This inductor is similar to L4, but has a different number 
of turns. 

ˆ

69. Cut a length of wire 12 inches long and winding as you did before, 
wind 2 complete turns through the core and form a loop 3/4 “ long. 

ˆ

70. Twist this loop fairly tight and continue winding another 4 complete 
turns through the core. Once again, leave this wire end longer than the 
first wire to indicate that this is the side of the inductor that has 4 turns. 
The marker trick is OK to use here too. 

ˆ

71. Tin the wire ends and line them up as you did before with the twisted 
pair in the middle. 

ˆ

72. Install L6, the 4 turn end installs into the hole near L5, the twisted 
pair into the center hole and the 2 turn end faces R16.   

Figure 1

Figure 2

Содержание AM25

Страница 1: ...h for high school college or neighborhood radio station in use the world over Easily programmed via DIP switch to any clear channel on the AM broadcast band from 540 to 1710 KHz Operates on the same p...

Страница 2: ...IO KITS HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator QRP Power Amplifiers RAMSEY MINI KITS Many other kits are available for hobby school sc...

Страница 3: ...ic Diagram 7 Parts Layout Diagram 8 Parts List 9 Assembly Instructions 10 Frequency chart 18 Alignment Procedures 19 Troubleshooting 20 FCC Information 20 Antenna Experimenting 22 Ramsey Kit Warranty...

Страница 4: ...radio stations Re broadcasting received audio for shortwave or HAM radio use Listening aid for auditoriums churches or other events Short range experimentation We think that you will be very pleased w...

Страница 5: ...ng auto transformer L4 from Q8 and Q9 thus producing an AM output waveform This signal is then low pass filtered using C1 C7 and inductors L1 3 Notice that the audio information is applied at the powe...

Страница 6: ...from the VCO Voltage Controlled Oscillator and divides it by a number that we ll call N N is the frequency data that was sent by U2 and N is always equal to the desired frequency in megahertz times 10...

Страница 7: ...AM25 7...

Страница 8: ...AM25 8 PARTS LAYOUT DIAGRAM...

Страница 9: ...0 pF disc capacitor marked 0022 or 222 or 2200K C2 3 6 7 2 3900 pF disc capacitor marked 0039 or 392 or 3900K C4 5 2 4700 pF disc capacitor marked 0047 or 472 or 4700K C4 5 2 5600 pF disc capacitor ma...

Страница 10: ...atsinks 80 enameled magnet wire 2 4 40 x 1 4 screw 2 4 40 kepnut ASSEMBLY INSTRUCTIONS There are numerous solder connections on the AM25 printed circuit board Therefore PLEASE take us seriously when w...

Страница 11: ...tched ends of IC s and so forth 6 Solder all connections unless directed otherwise Use enough heat and solder flow for clean shiny completed connections 7 Trim or nip all excess wires extending beyond...

Страница 12: ...intain frequency exactly as programmed 12 Install C13 01 uf disc capacitor marked 01 or 103 of 10 nf 13 Install C14 another 01 uf disc capacitor 14 Install jumper JMP2 Simply use a small scrap of comp...

Страница 13: ...llow violet brown 28 Install Q10 2N3904 transistor Be sure to orient it correctly See the parts diagram for correct orientation 29 Install Q2 another 2N3904 transistor watch that flat side 30 Install...

Страница 14: ...mishaps Later stages of the transmitter require extra care so better to catch errors now rather than later 49 Install C19 001 F disc capacitor marked 001 or 102 50 Install R20 1 K ohm brown black red...

Страница 15: ...tion burn off and a nice coating of solder attach to the copper wire under the enamel insulation Gosh it takes longer to explain than to do it 66 Position the wire ends so that the three wires are in...

Страница 16: ...k brown 83 Install JMP3 using a scrap component lead wire 84 Install Q8 2N3904 transistor observe placement of the flat side 85 Install C17 01 F disc capacitor marked 01 or 103 or 10nF 86 Install C22...

Страница 17: ...ncy you wish to set your transmitter to It really is not sufficient to just check the AM band for an empty frequency using the AM radio closest at hand It is your responsibility to research what AM st...

Страница 18: ...entire circuit board Energizing the circuit board with solder bridges or misplaced components can damage your kit ANTENNA CONSIDERATIONS For many applications a 5 6 foot wire antenna connected to the...

Страница 19: ...6 close switched 128 16 and 2 A calculator comes in handy when you successively subtract the binary numbers 128 64 4 2 1 It really is quite easy and fun to find the right switches to close ALIGNMENT P...

Страница 20: ...o double check the assembly steps going backwards from the last step to the the first Bright lighting and a magnifying aid can be helpful in identifying soldering problems Use a methodical logical tro...

Страница 21: ...listeners have all the rights Your non licensed use of any device such as the AM25 has absolutely no rights at all over the rights of a licensed broadcast operator If your operation of the AM25 interf...

Страница 22: ...Here s a neat antenna idea the 1 1 2 PVC loading coil will fit nicely into 2 diameter PVC pipe Get a 10 foot length run the long antenna wire up through the pipe and over the edge a bit slip a PVC pi...

Страница 23: ...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 24: ...for RAMSEY MODEL NO AM25 SYNTHESIZED AM TRANSMITTER KIT REQUIRED TOOLS Soldering Iron WLC100 Thin Rosin Core Solder RTS12 Needle Nose Pliers MPP4 or RTS05 Small Diagonal Cutters RTS04 ADDITIONAL SUGGE...

Отзывы: