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40 METER (7.0 MHZ)
ALL MODE RECEIVER KIT
Ramsey Electronics Model No. HR40
Small in size but BIG in features:
• Easily tunes SSB, CW, RTTY and AM
• Smooth varactor tuning of any desired 250KHz segment of the 40
meter band, easily retuned
• Uses the popular SA602 IC chip for outstanding sensitivity and
efficient operation
• Front panel RF Gain, Tuning and Volume controls
• Efficient LM-386 Audio amplifier drives speaker or earphones with a
clean, crisp audio
• Informative m
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RAMSEY TRANSMITTER KITS • FM100B Professional FM Stereo Transmitter • FM25B Synthesized Stereo Transmitter • AM1, AM25 AM Transmitters • TV6 Television Transmitter RAMSEY RECEIVER KITS • FR1 FM Broadcast Receiver • AR1 Aircraft Band Receiver • SR2 Shortwave Receiver • AA7 Active Antenna • SC1 Shortwave Converter RAMSEY HOBBY KITS • SG7 Personal Speed Radar • SS70A Speech Scrambler • SP1
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Ramsey Publication No. MHR40 Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR HR40 AMATEUR RECEIVER KIT TABLE OF CONTENTS Introduction to the HR40 ................ 4 About Direct Conversion ................ 5 Circuit description .......................... 6 Parts list ......................................... 7 Schematic diagram ........................ 9 Parts layout .................................. 10 Assembly instructions .................. 11 Initial testing ...........
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INTRODUCTION: Our HR40 and HR80 models are thought of as “best for beginners” because Hams with a Novice or Technician licenses can operate CW in the 80 and 40 meter bands. If you like plenty of action and DX (long distance) communications, the 40 meter Ham band is the place to be. Almost 24 hours a day there’s something interesting happening on 40 meters. These are several groups of people who will enjoy this Ramsey HR40 Receiver: • Experienced Ham operators who want a simple extra re
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This receiver circuit is ideal for discovering just how simple a true “Communications Receiver” can be. That’s right- there is a BIG difference between the Ramsey HR40 and other simple short wave radio circuits we can try to build. Yet it is very easy to build. Our HR-series are by far the easiest to build of all the Ramsey kit receivers and therefore very nice for radio newcomers. Consequently, our manuals for the 40 and 80 meter receivers are written with beginners in mind, since both
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called “microphonics” which is a phenomenon where almost anything in the physical circuitry of the receiver can act as a sort of microphone or audio sound pickup. Touch or 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 Ramsey HR40’s use of the SA602 integrated circuit chip offers a circuit configuration that is as immune as any simple superhe
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PARTS SUPPLIED WITH THE HR40 KIT: CAPACITORS: 1 .001µF disc capacitor [marked 102, .001 or 1nF] (C3) 3 100pF disc capacitor [marked 100 or 101K] (C1,C2,C4) 3 .01µF disc capacitor [marked 103 , .01 or 10nF] (C5,C6,C7) 2 4.7 to 10µF electrolytic capacitor (C8,C9) 3 100-220µF electrolytic capacitor (C10,C11,C12) RESISTORS: 3 10K ohm potentiometers (R1,R2,R3) 1 270 ohm resistor [red-violet-brown] (R4) 2 10
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"LEARN-AS-YOU-BUILD" ASSEMBLY STRATEGY: To help you learn just what exactly is going on we'll discuss the purpose of most of the components or groups of components as we go along. Since we are trying to keep assembly of the board simple, we will not be able to fully describe each individual component’s function as you build, but Ramsey's "Learn-As-You-Build" kit assembly philosophy still stands. Check off each step as understood and completed. Examine the schematic diagram and
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HR40 • 9
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PARTS LAYOUT: HR40 • 10
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RECEIVER ASSEMBLY: 1. Install the RCA antenna jack, J1. Solder all four points. 2. Install C5, a .01µF ceramic disc signal coupling capacitor. This capacitor brings the signal up to the front of the PC board. Notice the long PC trace from J1 through C5 to R1 3. Install potentiometer R1, the RF gain control. Insert it into the PC board so that it seats firmly and is straight and even. Solder the three pins and the two mounting tabs. 4. Install L1(marked 421F-123), which tune
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capacitor is a first step in setting up the resonant frequency of the SA602’s internal oscillator, using the resonant LC circuit to be created along with C1, C3 and L1. 12. Install C1, 100pF disc capacitor (marked 100 or 101K). 13. Install C3, .001µF disc capacitor (marked 102 or .001 or 1nF). 14. Install L2, shielded oscillator coil (marked K6883 or K6886). 15. Install C4, 100pFdisc capacitor (marked 100 or 101). C4 adds variable capacitance of the varactor tuning networ
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29. 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. 30. Install the 9-volt battery clamp. Use a scrap component lead to loop through the two holes in the clamp and through the PC board. Solder the leads firmly to the board and to the battery clamp. Do not use too much solder on the clamp as this will cause the battery to sit too high and not seat securely. Congratulations! You have completed the assembly of you
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INITIAL TESTING OF YOUR HR40: You’re now ready to power up and test your HR40, but before you begin take some time to sweep off your bench of any loose component leads or solder splashes. A clean work area not only makes testing less frustrating but also less prone to problems. REQUIRED FOR INITIAL TESTING AND ALIGNMENT: A known frequency standard in the 10MHz range such as: • Crystal oscillator or, • RF signal generator or, • Grid Dip oscillator or, • QRP transmitter such as a Ramsey
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Alignment: Turn on whatever reference signal source you plan to use. This can be a regular transceiver keying a few milliwatts into a dummy load, a crystal oscillator or a signal generator. Or, you can look for a known signal that you have tuned in on another receiver. If you are without any reference signal whatsoever but have a reasonable antenna , you can use your familiarity with the 40-meter band to make a rough alignment of the receiver.If Ham radio and 40 meters are new to you, h
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USING YOUR RECEIVER: In your first tests, you might feel that tuning in CW and SSB stations by turning the control shaft seems tricky. Don't despair! The addition of a simple knob to the final version of your kit will result in more comfortable tuning right away. Also, the larger the knob, the easier the tuning is. Even smoother control can be accomplished by a vernier dial, which will also provide calibration marks. Finally, if you intend to use this receiver only for monitoring or workin
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A better operating arrangement will consist of a T-R switch, either a manual switch or break-in delay relay circuit. This switching circuit can disconnect the SA602 audio output at the volume control, and switch in a pleasant oscillator pitch (keying sidetone) which is amplified to listening level by LM386. The Ramsey Electronics Universal timer kit No. UT-5 is easily adapted as a sidetone oscillator. • SPEAKER OPERATION A fifty cent, two inch diameter speaker, lying naked on your workben
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you wish to install the LED in your enclosure. Locating the LED immediately above the on-off switch is ideal. The simplest way to make a neat installation is to drill a hole just sightly smaller than the diameter of the LED. Then, enlarge the hole a little bit at a time, just enough to let the LED be pressed in and held firmly. The resistor may be connected to either the anode or cathode side of the LED, but the anode must be connect to the + DC with the cathode connected to the nearest co
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TROUBLESHOOTING TIPS: PROBLEM: ALL signals are chirpy and unstable. SOLUTION: Sorry to have to say it , but this condition is only caused by a weak battery! Use a fresh alkaline cell. Any strong signal forces the audio circuit to rob voltage from the oscillator, which causes the instability. PROBLEM: Occasionally good but erratic operation. SOLUTION: Check very carefully for a poor solder connection. PROBLEM: Signals have an unpleasant hissing pitch. SOLUTION: Try a different set of hea
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GENERAL NOTES FOR EXPERIENCED QRP BUILDERS: We at Ramsey Electronics deliberately designed the HR-series of DC receivers to be easily available, affordable and buildable by any person willing to follow the assembly directions. To achieve this goal, the current models, with direct coupling of the SA602 to the LM386 operating with a gain figure of 50, use an amazing minimum of parts. If you know what you are doing with DC receiver design, we encourage you to use our HR-series for reliable bu
