User manual RAMSEY HR20

[. . . ] HR20 Here's the ideal mini-receiver for catching all the busy action on 20 meters from your office, home or on trips!Small in size but BIG in features: · · · · · · · · · Easily tunes SSB, CW, RTTY and AM Smooth varactor tuning of any desired 250KHz segment of the 20 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 receivers, hookups and uses - enhances resale value, too!Ideal companion to the Ramsey QRP20 CW Transmitter Runs on a standard 9-volt battery Clear, concise assembly instructions lead you to a finished product that works FIRST time!Cases match all Ramsey products. HR20· 1 PARTIAL LIST OF AVAILABLE KITS RAMSEY TRANSMITTER KITS · FM10A, FM25B Stereo Transmitters · AM1, AM25 AM Transmitters · TV6 Television Transmitter · FM100B Professional FM Stereo 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 · MX5, MX-10 Mixers · MD3 Microwave Motion Detector · TFM3 Tri-Field Meter · STC1 Stereo Transmitter Companion RAMSEY AMATEUR RADIO 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 for hobby, school, scouts and just plain FUN. [. . . ] To check or `scan' a given band for SSB signals, tune your HR20 up from the low end for USB signals and down from 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. Therefore, when adjusting the frequency of your companion Ramsey QRP transmitter, be certain that you have in fact tuned to the other station's lower sideband. Because this receiver's oscillator is not shared with a transmitter, as in transceivers, there is no need for separate RIT (receiver incremental tuning). · ON THE AIR TRANS-RECEIVING Let's assume that you plan to use this receiver together with a Ramsey QRP transmitter, which provides an RF protected receiver antenna jack. While the receiver will be protected from RF damage from the transmitter, do not expect to monitor your own signal on this receiver while transmitting unless you are a QRP design expert and do not care about future factory service from Ramsey. Even with the circuit protection, the RF signal is just too much for the SA602. The transmitter signal overpowers the SA602, disrupting the internal oscillator. However, the receiver can handle the output of a crystal oscillator or VFO for frequency spotting purposes. 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 HR20· 16 SA602 audio output at the volume control, and switch in a pleasant oscillator pitch (keying sidetone) which is amplified to listening level by LM386. · SPEAKER OPERATION A fifty cent, two inch diameter speaker, lying naked on your workbench will give you a fair test of the speaker output capability. Speaker quality and welldesigned enclosures have their clear purposes!On the other hand, the LM386 indeed can deliver more audio output punch than is developed in our HRseries 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 controlled oscillators built into mass production sophisticated FM receiver ICs. A heavier drain on the HR20's battery by stronger audio will quickly result in chirpy signals and oscillator drift as well as the need for frequent battery replacement. Remember the SA602 circuits similar to the Ramsey HR-series generally call for sets of C or D cell batteries!For Experienced Builders more information regarding audio output is in the general notes. The simple design of the audio stage of the Ramsey HR20 receiver assumes preference for headphone or small speaker operation, low battery drain and general economy. HR20· 17 · MORE AUDIO POWER - ANOTHER WAY If you want to use your HR20 for casual band monitoring while you are busy across the room, in the shop, to share with a class or club or group and want LOTS more volume, try building up our very inexpensive Ramsey BN-9, 2 watt general purpose amplifier kit. Supply DC voltage to such an amplifier separately, using D-cells, a lantern or auto battery , or a well filtered power supply. · ADDING AN LED POWER ON INDICATOR For many people, a pilot lamp to indicate "power on" is more than a nice touch. [. . . ] All information required to properly build and test your kit is contained within the pages!DEFECTIVE PARTS: It's always easy to blame a part for a problem in your kit, Before you conclude that a part may be bad, thoroughly check your work. Today's semiconductors and passive components have reached incredibly high reliability levels, and it's sad to say that our human construction skills have not!All our kit parts carry the Ramsey Electronics Warranty that they are free from defects for a full ninety (90) days from the date of purchase. [. . . ]