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Last Updated
03/31/2019
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Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION. |
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AMATEUR RADIO ACCESSORIES sa AMATEUR RADIO TRANSMITTER ACCESSORIES xx AMATEUR RADIO Amplifier cooling system uses a muffin fan, cardboard box and a length of clothes dryer vent hose. Improving the vacuum relay QSK in s.s.b.-VOX operation. A voltage-regulated, high-current 13.8 volt power supply that allows a 12-volt d.c. 2-meter amateur radio to be operated from 110-volt a.c. Voltage regulator circuit to power a Tempo S-1 from an external 13.8 v.d.c. source. A solid state RIT (receiver incremental tuning) switch is the heart of a quiet c.w. break-in system. Improved spot capability for the Drake T-4XC and R-4C while using the vacuum relay QSK. Add forced air cooling to the Heathkit HP-13 mobile power supply. An outboard volume control for your receiver. Designed for use with high-impedance headphones. Est. cost: $5. Construction details for an "instant" repeater control which can be carried in your pocket, used with any modern transceiver, and requires no additonal power supply. A universal tuning reminder. A simple add-on device for your transceiver that will remind you to retune when you change bands. Build a threshold gate for use between c.w. receiver and speaker. This signal-to-noise ratio enhancer can exceed 40dB. How to build a general-coverage (1.8 MHz through 30 MHz) receiver preselector. How to build an emergency alert tone decoder which will sound an alarm should a particular tone be detected for the required length of time. Living with the lead-acid battery. How they work and how to use lead-acid (automobile) batteries to power amateur radio equipment. How to build an X-Y display for c.w. and single-ended RTTY TU (interface) signals. A three component oscilloscope adapter is all that is required. An easy to build 2 meter preamp and gated noise source. Frequency control readout device allows a blind ham operator to determine the frequency via three mechanical pointers. How to build a c.w. filter for the novice operator. Part 1. Est. cost: $15. How to build a c.w. filter for the novice operator. Part 2. Contruct a low-noise gallium arsenide field effect transistor (GaAsFET) preamlifier for 420 MHz. A high-resolution tuner for a VHF/UHF receiver or transmitter uses a simple phase-locked-loop method. Build a switched capacitor bandpass CW filter. Includes separate bandpass controls, a frequency control, and an output volume control. Convert a 15-minute tape cassette into an endless tape loop. Ideal for recording and transmitting "CQ's". Consolidated control console. Analyze what controls and switches have to be manipulated to operate a ham radio station. Then, find a way to consolidate (combine) the controls into fewer controls for more convenient station operation. How to build a low-budget wooden operating desk. Top measures 24"x48". Est. cost: $32 The handy-pack, a self-charging heavy duty battery pack for your handi-talkie will provide up to 3 days of power for field operations. The project consists of 7 individual 1.2 volt cells and a two-level charging circuit to allow normal charging and continuous trickle charging. The practical aspects of charging nickel-cadmium batteries are discussed. Rig rack is built from a 24"x48" piece of plywood to hold a Heathkit 101 rig, but can be adapted for any other model. Use a TV demodulator to monitor your amateur band receiver while watching television at another location. Control box for HF transceivers features a remote PTT (push-to-talk) switch, extendable microphone, microphone preamp and equalizer, sidetone, and remote headset volume control. Convert a rugged plastic carrying case (originally used for a soldering gun) to carry a 2-meter handheld radio and accessories. The case also incorporates a ground plane and telescoping whip antenna to improve transmit range. A simple, effective, inexpensive approach to receive and/or transmit audio equalization. Adapting the Radio Shack "Stereo Parametric Equalizer" for amateur radio use. Build a portable operating setup for QRPers. Plywood box (17"x9"x9") holds all of your small-size QRP gear for transporting or mobile use. The evolution of an HF suitcase station. Some ideas for a portable station built around an IC-735 transceiver and accessories all stored in a strong photographic-equipment case with a volume of less than 1 cubic foot. Portable operation via battery power. Using deep-cycle lead-acid batteries to power amateur radio equipment for field use. Includes tips on caring for these batteries. How to revamp your operating position. Dimensions for building a table, cabinets and cubicles to house your ham radio equipment. A remote base controller for the ICOM 2AT, 3AT, or 4AT. An inexpensive way to incorporate a synthesized remote base in your repeater or base station. Est. cost: $45. Backup bonanza. Build a simple switchbox to transfer the antenna, speaker, key and microphone from one transmitter to another by pressing a single button. How to build a new operating position. Equip a four-leg table with a two-shelf rack which hold your amateur radio equipment and keeps the cords out of sight. Rack is made from a single sheet of plywood. Using photovoltaic panels, batteries and regulators to power amateur radio equipment (transceivers, node controllers, etc.) The Vackar high-stability L-C oscillator. Built as a shielded modular unit for a HF amateur-band receiver. HF-band (high-frequency) preamps. Pros and cons about using a preamplifier ahead of the station receiver. Includes a schematic for a practical two-stage, 20-dB low-noise preamp and a circuit for bypassing the preamp when transmitting. Some receiver design aids. Methods for employing simple two-section HF bandpass filters at the front end of any homemade receiver. Building simple isolation interface devices to connect transceivers to amplifiers. An easy-to-build, thermochromic RF power indicator. How to convert a "Duracell" throw-away 9-volt battery tester strip into an RF power indicator for handi-talkies. Build a 455 kHz tunable BFO (beat-frequency oscillator) for receivers that use Collins-Rockwell mechanical filters. How to keep an emergency back-up radio station battery charged. Battery is automatically disconnected from power supply unit when not in use and automatically charged when in use. Tips on providing DC power to portable (roving) ham radio setups. Looks at batteries, generators, automobiles, etc. A $10 phone patch. S-Niner, a tunable, high-gain RF preamplifier covers ham, shortwave and citizens band. Gives 18-30 dB gain Wooden cabinet (rack) to hold ham gear. "Varactor Super Band Spreader" uses solid state diodes that work like and are used as variable capacitors. Tables show how much bandspread can be obtained. Est. cost: $4. The FET S-Niner, an RF preselector (preamplifier) tunable from 3.5 to 30 mc in two bands. Improves receiver sensitivity. Ham station switch box performs four functions. (1) Connects antenna to either transmitter or receiver while (2) simultaneously controlling the standby functions of the transmitter or receiver. (3) Provides a side-tone when you send CW and (4) feeds low-power signal into the receiver so you can find your signal on the receiver dial. High-gain tunable RF preamplifier covers the international shortwave and ham bands between 5 and 30 mc. Provides over 40 dB overall gain. Est. cost: $16. Simple phone patch for ham radio operators. Autopatch selector for radio amateurs. Remotely-controlled device is used to activate up to 16 different devices upon receipt of the proper DTMF (dual-tone multifrequency) codes sent by a UHF transceiver. Primary use is to select from more than one UHF transceiver when interfacing to a telephone line. A battery-powered regenerative preselector using a high-gain field-effect transistor (FET) will boost weak signals about 40 dB before they reach your receiver. One diode and capacitor added to any AM detector will nearly double the output. Can also be used on CB, shortwave or crystal sets. Novice hams may want to install a CW filter on their receivers to improve selectivity. Some tips. HertzMarker will sound off with a sharp tone each time you tune through a preset bandspread on your tuning dial. This simple transmitter, set near your receiver, will generate the tone. Get better selectivity with an amateur radio receiver with this active audio filter. This bandpass filter can be adjusted to Q values between 1.4 and 15. Its center frequency can be adjusted from 375 to 1500 Hz. "On-the-air" sign lights up whenever you press the push-to-talk button on your amateur transmitter. Does not require a direct connection to the transmitter. Simple circuit will emit an audible beeb every ten minutes. Used by ham radio operators to remind them to identify their station. Build and install a scan delay feature in the ICOM R-7000 multiband communications receiver. Bringing a computer into the amateur radio shack. Tips on selection, applications, avoiding RFI, etc. A 6-meter preamp for $7. Zener receiver muter. Mechanical filter sharpens bandwidth for optimum reception of AM, CW, SSB, and CB. Clatter stopper. A simple detector circuit which prevents momentarily strong RF pulses (clatter) from reaching a speaker. Such clatter usually occurs when a nearby transmitter is keyed. Single-control preselector improves the sensitivity of a low-cost (under $100) general-coverage receiver. Relay turns on a tape recorder motor whenever the signal being monitored is being received. Impulse noise suppressor can be added to any SWL, Ham or CB receiver. Adding a 10-minute "beeper" to a digital clock reminds ham operators to identify their station. Active filter sharpens CW reception. Provides 6-dB selectivity of less than 100 Hz. Uses an op-amp in the circuit. Est. cost: $15. Selective call receiver monitor turns on the CB audio only when a special signal is received. Using an agreed-upon channel, the caller and receiver have electronic devices to send and receive the special signal. Est. cost: $50. Amateur radio modulation monitor circuit shows when negative-peak modulation hits 50, 80, and 100 percent. Preamplifier connects between antenna and a two-meter amateur-radio receiver. Passive noise limiter circuit that is inserted between the audio output of a receiver and the earphones. It contains both series (threshold) and shunt noise-limiter configurations. Improving reception in crowded VHF/UHF ham radio bands by using a wave trap or a half-wavelength shorted transmission line stub. Tunable bandpass filter circuit for use in the 40-meter band. Design and build a front end (preamplifier) for your shortwave or VHF/UHF receiver. This circuit utilizes the MAR-x series of monolithic microwave integrated circuit (MMIC). Design and build a ham-band variable frequency oscillator (VFO). Use it to control the frequency of transmitters, as the local oscillator that tunes a radio receiver, or as a signal generator to perform tests and measurements on radio equipment. Part 1. Design and build a ham-band variable frequency oscillator (VFO). Part 2. Explanation and importance of some accessories to amateur radio receivers. Filters for QRM radios that can help prevent overload from local AM and FM broadcast stations. Two circuits shown. Build a versatile DTMF tone pad accessory for your radio transceiver. Est. cost: $20. VLF (very-low-frequency) and LF (low frequency) ham-radio bands. (1) Simple VLF/LF-to-HF converter circuit lets you receive these bands on either 3.5 to 4 MHz or 4 to 4.5 MHz. (2) Soup up your receiver with this VLF/LF preamplifier circuit. Call-Alert. Eliminate the constant chatter on your favorite CB channel or 2-meter repeater. The audio is blocked until the correct touch-tone sequence is received. Est. cost: $49 (decoder) and $23 (encoder). Rollaway ham shack. A cabinet on casters holds all the ham gear for one amateur. Use a dual voice coil speaker to receive signals from two different receivers. Levels can be preset so that one signal source is reproduced as a background level and the second signal comes in much louder and overrides the background signal. Either signal circuit can be shut off. Est. cost: $10. VHF extender connects between antenna and receiver and can be used for any 4-megacycle-wide segment of the spectrum between 30-mc and 170-mc. | |||||||||
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