Ramsey Electronics HR20, User Manual

Page 1: ...0 meter band easily retuned Front panel RF Gain Tuning and Volume controls Efficient LM 386 Audio amplifier drives speaker or earphones with a clean crisp audio Informative manual answers questions on...

Page 2: ...ADIO KITS HR Series HF All Mode Receivers QRP Series HF CW Transmitters DDF1 Doppler Direction Finder CPO3 Code Practice Oscillator QRP Power Amplifiers RAMSEY MINI KITS Many other kits are available...

Page 3: ...ion to the HR20 4 About Direct Conversion 5 Circuit description 6 Parts list 7 Schematic diagram 9 Parts layout 10 Assembly instructions 11 Initial testing 14 Alignment 15 Using your HR20 16 Troublesh...

Page 4: ...s Just follow the directions carefully All you need to know to successfully complete this receiver is contained in this detailed manual Enjoy your HR20 receiver RAMSEY HR SERIES AMATEUR RECEIVERS All...

Page 5: ...wn frequency with no need to mix or transform it with additional internal oscillators and amplifiers running at intermediate frequencies such as 455 KHz The advantage of this type of receiver is that...

Page 6: ...bump such radios and you will hear a thump or ring in the speaker or earphones Still another problem is that of AC line hum whenever an unregulated power supply is used rather than batteries The Rams...

Page 7: ...resistors brown black orange R5 R6 INDUCTORS 2 Shielded Coils marked 42IF 123 L1 L2 SEMICONDUCTORS 1 1N4002 Diode black epoxy style D1 1 SA602 IC U1 1 LM386 IC U2 1 6 2 volt Zener Diode small grey gla...

Page 8: ...become hot enough together to melt the applied solder so that it flows smoothly around the wire lead and on to the PC board trace Mount all electrical parts on the top side of the board provided This...

Page 9: ...HR20 9...

Page 10: ...HR20 10 HR20 PARTS LAYOUT DIAGRAM...

Page 11: ...m the antenna through C5 and R1 6 Install C13 a 27pF ceramic disc capacitor marked 27 or 27K 7 Install U1 the SA602 IC mixer oscillator The marked end of the IC band or dot must face the FRONT of the...

Page 12: ...small screwdriver or a knife Omitting this step will prevent the oscillator from tuning the 20 meter band 17 Install L2 shielded coil 18 Install C4 a 15pF ceramic disc capacitor C4 adds variable capa...

Page 13: ...1 Install C9 4 7 10 F electrolytic capacitor observe polarity 32 Install speaker jack J2 This jack is a 2 5mm type and mates with any 2 5mm plug as found on virtually all mini earphones 33 Install the...

Page 14: ...per directions and 9 volt battery antenna earphones or a small speaker Connect the following Fresh 9 volt battery Earphone or speaker Antenna or at least a random length of wire Adjust the three cont...

Page 15: ...iron slug Any kind of metal tip will affect the coil s true value so that the oscillator will run at one frequency with the metal instrument in the coil can and a completely different frequency by it...

Page 16: ...m the high end for LSB CW OPERATION A direct conversion receiver lets you hear equal sidebands on either side of the zero beat null of the exact frequency of the signal to which you are listening Ther...

Page 17: ...s developed in our HR series kits For example our FM receivers using the same LM386 audio IC deliver more volume These receivers however take advantage of IF amplifiers drift compensation and crystal...

Page 18: ...are an ideal point to get the DC voltage needed for the anode longer lead of the LED Plan where and how you wish to install the LED in your enclosure Locating the LED immediately above the on off swi...

Page 19: ...that L1 is oriented correctly and that C1 C2 C3 and C4 are installed in correct positions PROBLEM Loud AC hum or buzz SOLUTION If you are using the receiver with a battery or simply for listening i e...

Page 20: ...ontrols correct and adjustable inductors workable varactor tuning and the popular SA602 We know these receivers WORK as specified and that the ONLY reason any HR receiver will not work after the 1 2 h...

Page 21: ...eve a smaller variation in capacitance with the comfortable tuning of a knob Any resistor in a range from 500 ohms to 3000 ohms connected in series with the ground lead of R2 will set a limiting effec...

Page 22: ...e tuning knob on the front panel A logging scale is simply a set of numbers for adjusting a control For example 4 might represent 7 1MHz and 5 5 being 7 12MHz and so forth DIRECT FREQUENCY READOUT A n...

Page 23: ...itted by one of our customers Ramsey Electronics in no way warrants that this modification will achieve any particular ideal signal to noise ratio or audio frequency response but is does significantly...

Page 24: ...or else the audio circuits will cause oscillator instability Two alkaline cells in parallel or a 12 volt supply are recommended If the gain is too much use a resistor to reduce the voltage supplied t...

Page 25: ...HR20 25 CONSTRUCTION NOTES...

Page 26: ...chase Defective parts will be replaced promptly at our expense If you suspect any part to be defective please mail it to our factory for testing and replacement Please send only the defective part s n...

Page 27: ...due to construction methods To assist customers in such situations Ramsey Electronics Inc reserves the right to solve their needs on a case by case basis The repair is 50 00 per hour regardless of the...

Page 28: ...Assembly and Instruction manual for RAMSEY MODEL NO HR20 AMATEUR RECEIVER KIT REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solder Ramsey RTS12 Needle Nose Pliers Ramsey MPP4 or RTS05 Sm...