Gebruiksaanwijzing /service van het product HR20 van de fabrikant Ramsey Electronics
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20 METER (14 MHZ) ALL MODE RECEIVER KIT Ramsey Electronics Model No. HR20 Here’s the ideal mini-receiver fo r catching all the busy action on 20 meters from your of fice, home or on trips! Small in .
HR20 • 2 P ARTIAL LIST OF AVAIL ABLE KI TS RA MSEY TRA NSMIT TER KITS • FM10A, FM25B Stereo Transmitters • AM1, A M25 AM Transmi tter s • TV6 Telev ision Transmitte r • FM100B Profess.
HR20 • 3 HR20 AMA TEUR RECEIVER KIT Ramsey Publication No. MHR20 Price $5.00 TABLE OF CONTENTS Introduction to the HR20 .................4 About Direct Conversion .................5 Circuit description ...........................6 Parts list .......
HR20 • 4 INTR OD UC TIO N: If you like plenty of action and DX (long distance) communications, the 20 meter Ham band is the place to be. Almost 24 hours a day there’s something interesting happening on 20 meters.
HR20 • 5 This receiver circuit is ideal for discovering ju st how simple a true “Communications Receiver” can be . That ’s right- there is a BIG diff erence between the Ra m sey HR20 and other simple short wave radio circuits we can try to build.
HR20 • 6 Advantages of any Direct Conversion receiver include: • It is simple, and therefore economical and easy to build • It is quite sensitive even with a simple antenna • Its tuning oscillator co uld even be set up to serve directl y as a transmitter VFO in a simple transceiver setup.
HR20 • 7 PARTS SUPPLIED WITH THE HR20 KIT: CAPA CIT ORS : 1 15pF ceramic disc capacit or [m arked 15 or 15K] (C4) 1 27pF ceramic disc capacitor [mar k ed 27 or 27K] (C13) 2 36pF ceramic disc capacitor [mar k ed 36 or 36K] (C1,C2) 4 .
HR20 • 8 "LEARN-AS-YOU-BUILD " RECEIVER 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.
HR20 • 9.
HR20 • 10 HR2 0 PART S LAY OUT DIA GRAM.
HR20 • 11 RECEIVER ASSEMBLY: 1. Install the RCA antenna jack , J1. Solder all four points. 2. Install C5, a .01µF ceramic disc signal coupling capacitor . Th is capacitor brings the signal up to the front of the PC board. Notice the long PC trace from J1 through C5 to R1.
HR20 • 12 are marked by polarity and must be installed in the proper dire ction. You’ll see that one side of the capacito r has a black band and is m arked w ith a ‘-’ sign. This is the negative side, the ot her side is the posi tive lead. Make sure you in sert the p ositive lead into the ‘+’ marked hole on the PC board.
HR20 • 13 25. Install the 9-volt battery snap connector, making sure that the red (+) and black (-) leads are co rrectl y installed . 26. Install C7, .01µF disc capacitor (marked 103 or .01 or 10nF). 27. Install C8 , 4.7-10µF e lectrol ytic capacitor.
HR20 • 14 INITIAL TESTING OF YOUR HR20: You’re now re ad y to power up and test your HR20, but before you begin take some time to sweep off your bench of any loose c omponent leads or solder splashes. A clean work area not o nl y makes testing less frustrating but also less prone to proble m s.
HR20 • 15 Align men t: Turn on whatever re f erence signal source you plan to use. This can be a regular transceiver keying a few milli watts 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 receive r.
HR20 • 16 USING YO UR RECEIVER: In your first tests, you might f eel 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 w ill result in more comfortable tuning right away.
HR20 • 17 SA602 audio output at the vo lum e control, and switch in a pleasant oscillator pitch (keying sidetone) which is amplified to listening leve l b y LM386. The Ramsey Electronics Universal timer kit No. UT-5 is easily adapted as a sidetone oscillator.
HR20 • 18 • MORE AUDIO POWER - ANOTHER WAY If you want to use your HR20 for casual band monitoring w hile you are busy across the room, in the shop, to share w ith a cl ass or club or group and want LOTS m ore volume, t ry building up our very inexp ensive Ra msey BN-9, 2 watt general purpose amplifier kit.
HR20 • 19 TROU BL ES HOO TI NG TIP S: PROBLEM: ALL signals are chirpy and unstable. SOLUTION: Sorry to have to sa y it , bu t this condit ion is only caused by a weak battery ! Use a fresh alkaline cell. Any strong signal forces the audi o circuit to rob voltage from th e oscillator, which cause the instability.
HR20 • 20 GENERAL NOTES FOR EXPERIENCED QRP BUILDERS: W e at Ramsey Electronic s deliberately designed the HR-series of DC receivers to be easil y available, aff ordab le and builda ble b y any person willing to follow the assembly di r ections.
HR20 • 21 BANDSPREA D AND TUNING R ANG E: The easiest way to enjoy finer tuning , if you plan to use your receiver only for checking your favorite segm ent of the band, is to ad just the oscillator coil so that your desired segment f alls within the second half of the rotation range of the tuning contro l.
HR20 • 22 FR EQU EN CY S T ABIL I TY: A kilohert z of drift is not a big deal in FM circu its or a short wave broadcast configuration, but ANY freq uency instability is ann oying when trying to recei ve CW or SSB. The varactor - controlled Lo cal Oscillator is indeed a VFO, and therefore needs all the consideration given to any VFO circuit.
HR20 • 23 another way of getting bandspread for y o ur favorite frequencies. Finally , it may be necessary to operate the counter on battery power only; connection of an AC adapter might introduce considerable hum into the receiver.
HR20 • 24 The ‘-’ side of the new capacitor is connected to the circuit trace leading to t he volume control. Mount this capacitor as close to the body of the new LM386 as possible.
HR20 • 25 CONSTRUCT ION NOTES:.
HR20 • 26 The Ramsey Kit Warranty Please read carefully BEFORE calli ng or w riting in about y our kit. Most problems can be solved without contacting th e factory. Notice that this is not a " fine print" warrant y. We want y ou to understand your rights and ours too! All Ra mse y kits will work if assembled properly.
HR20 • 27 3. F ACTOR Y REP A I R O F A S SEM BLE D KI TS: To qualify for Ramsey Electronics factory repair, kits M UST: 1. NOT be assembled with acid core solder or fl ux. 2. NOT be modified in any manner. 3. BE returned in f ully-assembled form, not partially ass embled.
HR20 • 28 HR20 AMATEUR RECEIVER KIT Quick Reference Page Guide Introduction to the HR20 . ............... 4 Circuit description ....................... .... 6 Parts list .............................. ........... 7 Schematic diagram ................
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