Bulletproof Home Security System
An easy lo assemble and install kit that offers options not normaHy found in other alarm systems Hidden switch mounts under ihe dash Kit has provisions for sensors and remote control switch Programmable time delays for exit, entry and alarm periods Basic hook-up uMtzes dome tight circuit activating when doors are openec The alarm will arive a siren or pulse horn at a 1H2 rate. Not prone to false alarm due to reliable CMOS circuit ry. No external switch required' Complete kit with easy to follow instructions and
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Two hardware input and three user-function output switches are available. The outputs control external devices such as power amps, etc. The inputs can be used for temperature or burglar alarm sensing, an SWR alarmh etc. For example, you couid write a macro that upon detection of a high SWR would disconnect the power ampH give a digital voice announcement warning the control operators of the failure, and have the repeater switch to a memory fite that requires CTCSS access and a unique courtesy tone
( VEHICLE INTRUSION ALARM (J An easy to assemble and install kit that ofteis options not normally found c tn oinei alarm systems. Hidden switch mounts under the dash. Kit nas i provisions for sensors and remote control switch Programmable time Ji delays for exit, entry and alarm periods. Basic hook-up utilizes dome lignt Ji circuit activating wnen doors are opened. Tne afarm wifl dnve a siren oi Q pulse horn at a 1HZ tale. Not prone to false alarm do to reliable CMOS Q circuitry. No external switch required1 Complete kit with easy to tollow
In 1962, during a series of high-altitude weapon tests, a 1.5-megaton bomb called Starfish was detonated 250 miles above Johnston Island in the Pacific Ocean. Instantly, lights winked out and burglar alarms rang all over Hawaii, over 600 miies away Such an effect from so small a device was unexpected and began the first real look into the EMP problem.
MFJ Enterprises, Inc. is introducing its new MFJ-701 RFI-free Choke kit thai eliminates RFI (radio frequency interference) problems that affect TVs, radios, stereos telephones, VCRs, computers, PA systems, burglar and fire alarms, test equipment, modems, monitors, and other electronic devices
Another doohinky that the kids will get a big kick out of is this ten circuit transistor kit. This can be assembled in a few minutes and then, by means of changing the plug-in wires in the printed circuit board, you can make the circuit into a two stage AM radio, a light operated relay, a wireless broadcaster, a code practice oscillator, an electronic switch, a two stage audio amplifier, a body-capacity burglar alarm, a voice operated relay, or an electronic flasher. A card fits into the center of the board showing where to make the connections for each circuit. Costs 15.75 from Allied Radio. Better order quickly and give the U.S. Mails time to deliver before Cringle is due.
The circuit shown in Fig. 1 wasn't really meant to be a lightning detector -originally it was part of a burglar alarm we built and installed some time back. But the first night we had a lightning storm all the bells and whistles went off and the neighbors . , , well, anyway, here we have a lightning detector that works quite weiL
The letter writers object to Surviving the Unthinkable ' an article which appeared in the May 1982, issue of 73, which suggests EMP-hardening of am* ateur installations. The writers seem to feel that it is possible to avert a calamity by remaining unprepared. By that reasoning, lo prevent fires we should get rid of fire extinguishers and fire departments to prevent burglaries we should avoid using locks.
The existing repeater-to-UHF audio interconnects should be reourted through the intercom trigger relay so that the UHF control repeater hears only the action at the site in the event of a burglary. Fig. 2. The existing repeater-to-UHF audio interconnects should be reourted through the intercom trigger relay so that the UHF control repeater hears only the action at the site in the event of a burglary. If you use this technique, you'll have to remember to reposition the switch to the ALARM spot when yoifre ready to leave (he site otherwise youll hear nothing when the burglar makes his appearance- Every repeater site has its own individual weaknesses from the standpoint of burglary susceptibility. Since my site had but one door and no windows, my problems were minimal, I simply installed a magnet on the door and a magnetic reed switch adjacent to it on the wall. If your site has more than one door, or a window or two, you'll want to install a magnetic reed switch at each possible...
CARRIER-CURRENT COMMUNICATION is not new. Utility companies have used this technique for com trol, telemetering, and communication over highvoltage lines since the early 1920s.1 Most nonutility users, however, operate on the low-voltage, 120 240V lines. University campus radio systems have often used the power lines for campus-wide broadcast-band programming. Other devices that use carrier-current communications include cordless telephones, intercoms, music systems, appliance controllers, and burglar alarms. Recently, local area networks (LANs) that communicate over the power lines have become commercially available.
The life expectancy of a good ham mobile rig left unattended in a car on the streets of New York is about 20 minutes. In Chicago it is about 40 minutes - and almost an hour in Boston, on the averagj . It is prudent to make every effort to protect your investment, not only with some sort of alarm system, but with the best locking device you can get - something that wiM keep the rig in the car even if a burglar manages to get into it and they can manage.
My personal interest in the Hal I-Effect sensor was in understanding the linear device * though switching sensors are very important contributors to many project applications. In fact, Hall-Effect switching sensors were used in some computer printers to sense the end of carriage travel They also work well in burglar alarm window and door movement detection in addition to a multitude of other uses.
For several years now i have used a Micronta 63-8B6 24-hour timer that was sold by Radio Shack many equfvaient models are available almost anywhere. These days there is a big market for these devices in home security to turn your house lights on and offj and some of the more elaborate models can be programmed for different on and off times each day over a period of a week or more.
This basic system is a single-channel digital system and, although limited in its capability, is perhaps one of the most common telemetry systems. Systems of this type usually use telephone lines to transmit contact closure information. Examples are the remote fire and burglary alarms offered by numerous protection and security firms, These security systems offer door entry and fire monitors which activate a relay which, in turn, sends a current down a telephone line to activate a light or audible aiarm at a police station or security office.
For instance, maybe 15 years ago I recommended that hams interested tn making a few extra bucks could do worse than get into selling alarm systems for homes and commercial buiidings. I heard from quite a number of hams who took my editorial seriously and went into the business part time to start, but soon found it far more remunerative than their old job. Many did very well. Well, that same business is still out there, waiting for anyone with some gumption to get into the business, Today only 8.6 of private homes have alarm systems. You couldn't ask for an easier market
On the one hand l get letters from readers ,vho thank me for getting them into new businesses such as home security, computers, and so ont telling me that I provided the impetus to get them going and that they've done well. Indeed, many have become wealthy. But 'hen still get letters saying that some poor reader can't afford a subscription, Now, with alf that money out there just waiting to be grabbed, how can anyone be short of cash Okay, if we are going to monitor a repeater aft the time so that we will hear the alerting call when it comes through, we are going to have to put in some sort of automatic alarm system. And if we are going to interest many hams in participating, it is going to have to be relatively inexpensive.
This cavity oscillator is intended for wideband FM This is compatible to the So'fan burglar alarm units with the ex* ception that the Gunn diode ts operated from fixed voltage. The varactor in the cavity is a variable voltage capacitance diode (varicap), and shifts the frequency as the voltage to it is varied from 0 to 10 volts Construction cost is minimal for the Gunn diode and waveguide parts The varactor is, however, somewhat expensive if you can't find it surplus. Possibly a brief history of 10 GHz units might be in order. Normally, for low cost operation 10 G Hz G J nn transceivers were constructed using a SolFan or similar type burglar alarm, or a door opener microwave device. Cost was about 5 lo 20 each, with availability in most larger cities. The primary difficulty with the simple Gunn trans-