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   SR2

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21  

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4. Turn ON the receiver. 

 
After adjusting the volume to a pleasant level, you should hear some 
shortwave stations by turning the Tune Control, no matter how any of the 
adjustable coils happen to be set. 
While listening to any kind of station, whether broadcast or Teletype, etc.,  
use a small screwdriver to adjust the slugs in transformers T1 and T2 for the 
best-sounding reception. 
 
The Tuning Control covers varying segments of the bands selected by 
adjustment of oscillator coil T3. Adjustment of T3 anywhere between the full 
In 

position to the full Out position will give the user full range between the 
minimum and maximum frequency coverage set by C15 and C16.  
 
Both T1 and T2 must be adjusted with a non-metallic alignment tool such as 
is used in radio-TV service. If you do not have one, a suitable tool can be 
made by patiently sanding a screwdriver-like blade on the end of a wooden 
match stick, kabob skewer or small plastic crochet needle. Again, please be 
aware that a metal screwdriver blade will drastically increase the coil 
inductance and make adjustment quite difficult.  T1 and T2 are simply 
adjusted for strongest reception of any signal range that is tuned in. 
 
If you are without any kind of testing or frequency reference equipment  
whatsoever, the easiest way to start enjoying your SR2 is, with the Tune  
control set at its midpoint, slowly tune T3 with your alignment tool as though 
it were a tuning dial. Stop when you come into the middle of a group or 
cluster of foreign broadcast stations. Try tuning around these stations with 
the Tune control. If you like what you hear, readjust both T1 and T2 for best 

C16 = .001 

T3 Slug In 

T3 Slug Out 

C15 = None 

6.5—13.0 MHz 

9.0—18.3 MHz 

C15 = 47 pF 

5.1—7.9 MHz 

7.1—10.7 MHz 

C15 = 100 pF 

4.3—5.3 MHz 

6.0—8.3 MHz 

C16 = 100 pF 

T3 Slug In 

T3 Slug Out 

C15 = None 

8.4—14.2 MHz 

11.5—19.5 MHz 

C15 = 47 pF 

6.0—8.1 MHz 

8.5—11.0 MHz 

C15 = 100 pF 

4.9—6.3 MHz 

6.7—8.4 MHz 

Summary of Contents for SR2

Page 1: ...ne circuit is easy to build makes a nice one evening project Ideal scout school or club project Clear concise step by step instructions carefully guide you to a finished kit that not only works but yo...

Page 2: ...RADIO KITS DDF1 DopplerDirection Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CPO3 Code Practice Oscillator VLF1 Low Bander Low Frequency SWL Converter QRP Power Amplifiers RAM...

Page 3: ...t You Can Expect to Hear 4 Shortwave Listening as a Hobby 5 Circuit Description 6 Parts Layout Diagram 8 Block Diagram 9 Parts List 10 Assembly Instructions 12 Schematic Diagram 14 Shortwave Antenna I...

Page 4: ...in receiving broadcast stations due to the lack of superheterodyne design For example our popular Ramsey direct conversion receivers for the 40 30 and 20 Meter Amateur bands will also pick up AM broad...

Page 5: ...roadcast carrier that the carrier acts as a beat frequency oscillator BFO Even though this receiver can let you tune through several different HAM radio bands the signals are not likely to be intellig...

Page 6: ...ll schematic pg 14 shows the details concerning specific operation and component variable configurations Take a moment and examine the circuit block diagram found on page 9 The simplified signal flow...

Page 7: ...proper relationship between Fc and the LO exists the IF value will stay constant Due to the fact that the IF frequency stays the same all the time the Intermediate Frequency Filter can be very narrow...

Page 8: ...tomatic Gain Control AGC The gain control looks at the amount of signal level present at the output of the demodulator and varies the amount of gain the Amplifier has accordingly If there is a strong...

Page 9: ...ate F req ue ncy F ilte r A u dio S p e ak er S R 2 B lo c k D ia g ram L o ca l O scilla to r A G C D e m od S ig n a l S tren g th L E D A u to m atic G a in C o n trol R ece ive S ig n al S tren g...

Page 10: ...ectrolytic capacitor C26 INDUCTORS 2 1 H inductors looks like a resistor with brown black gold bands L1 L2 1 12 H inductor looks like a resistor with brown red black bands L3 2 Shielded can inductors...

Page 11: ...PC mount jack J1 1 Subminiature phone jack J2 1 9 volt battery snap connector 1 9 volt battery hold down clamp REQUIRED NOT SUPPLIED 9 volt alkaline or heavy duty battery Earphone small speaker or ext...

Page 12: ...f each step as understood and completed Some of the components require modification Examine the schematic circuit diagram and PC Board parts layout diagram as you proceed Use good soldering techniques...

Page 13: ...n NPN transistor marked 2N3904 This part is also oriented by the flat side so check your parts layout diagram for proper placement Bend the center lead out until it fits in the board and seat the part...

Page 14: ...SR2 14...

Page 15: ...SR2 15...

Page 16: ...cess We ll now move on to the RF section of your SR2 kit The next few parts form an input filter and mixer section to combine the RF input with the L O section just built The output of the mixer is th...

Page 17: ...red orange 43 Install T1 one of the shielded can inductors marked 42IF 103 44 Install R5 100K ohm brown black yellow 45 Install R6 10K ohm brown black orange 46 Install C28 01 F disc capacitor marked...

Page 18: ...r 104 62 Install U1 the LM358 8 pin IC Do not confuse it with the other IC read the chip marking carefully You will notice a notch band or dot on one end of the IC This should be oriented as shown on...

Page 19: ...ntenna and whether you think you may soon want to obtain a HAM radio license If the latter is true you may want to consult HAM radio literature and build the dipole or vertical antenna which you also...

Page 20: ...even a VHF scanner It s easy to build and a nice companion for your SR2 If you need more construction details on antennas check the book mentioned on page 6 or any introductory HAM radio book or the R...

Page 21: ...river like blade on the end of a wooden match stick kabob skewer or small plastic crochet needle Again please be aware that a metal screwdriver blade will drastically increase the coil inductance and...

Page 22: ...cuit is confirmed working standard signal tracing procedures should isolate any problem which will be either an incorrectly installed part a defective part or a bad solder connection Correct orientati...

Page 23: ...will find that the circuit board can be mounted nicely in a standard VHS videotape storage box which also gives room for a speaker or earphone storage and even a roll of antenna wire The controls are...

Page 24: ...mx 7 12 ITALY nx in EG re Columbus 2000 project ID 8 45 CHINA V of Russia relay Moscow Mailbag nx of Russia 9 02 IRAN nx re OPEC ID fqy sked 9 34 ISRAEL Kol Israel HB 2142 discussion US oldies 9 90 B...

Page 25: ...Notes Contributor MHz 18 96 SWEDEN Sweden Today special on Nobel prizes 18 96 SWEDEN Sweden Today article on burden of military spending on developing countries 18 96 SWEDEN Cinema Africa Film Fest b...

Page 26: ...SR2 26...

Page 27: ...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...

Page 28: ...ranty 27 Manual Price Only 5 00 Ramsey Publication No MSR2 Assembly and Instruction manual for RAMSEY MODEL NO SR2 SHORTWAVE RADIO KIT REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solde...

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