Uahs Ir

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F/g. 3. Direct-printing readout of a GOES E operational message, showing the exce//ent printing clarity which is obtained.

lift the diode connected to point B in Figure 4.6 of the Handbook. Connect the 1 RIGGE R output to this point, and the monitor display will now trigger from the fax drum. In prac-hce( it is easiest to install an EXTERNAL TRIGGER jack to the back of the monitor, connec ted to the TRIGGER output of the FX-2E An SPST toggle switch (INTERNAL EXTERNAL TRIGGER) tan then be added so that you have switch-selection of either internal or external triggering The internal position fs used for norma! monitor operation or when the fax drum is not running (saving wear and tear on the horizontal deflection transistors ), while the external position is used to manually display and phase the fax. I o use the monitor in this fashion, you should reset the fax carriage and load paper as instructed. Start the drum, and switch the monitor to EXTERNAL I RIGGER. When the signal ts out of the noise, you can start the monitor sweep and operate the MANUAL PHASE switch of the FX-2E to move the line sync pulse (either visible or IR) to the left edge of the viewing area At that point, you can start the fax printing.

Operation as a Photographic Facsimile Recorder

The only electronic changes for photofax operation include the following:

2) Replace R8 with a lOOOhm pot, which will serve as a BLACK SET control.

i) Add a 15-mA meter m the switched 300-V line

4) Connect an R1130B glow modulator tube from the collector of Q1 to the

350-V bus, with the 15-mA meter in series Rewtre S201A so that the lamp is energized (connected to the 350-V line) with the switch in the PRIM position.

5) Reverse the diodes (D1-D4) in the deiector, delete R7, and replace it uith a 2200-0hrn resistor connected between the base of Q1 and the +12-V bus.

Refer to either the first edition of the Weather Satellite Handbook or the September and October, 1975, issues of 73 for construction of the light gun and its mounting to the carriage. I he phase-sensor reed switch will have to be reonented so that it closes just as the edge of the photographic paper passes the light gun lens.

With no video input, adjust Rtt (BLACK SET) tor a meter reading of 15 mA with S201 in the PRINT position. Full video drive (white li-vel] should then be applied and the WHITE SET control adjusted for a read ing of about 1 mA Resin-coated enlarging papers are recommended for printing, with Kodak Kodabrome RC being preferred (normal contrast grade) Black and white level adjustment should be altered in practice to produce good prints when I he paper is processed for 2 minutes in Koda^ Dektol developer Any (ommeruai fixer may be used, and youi should consult your local photographic supplier for Irays, chemicals, safelights, etc. 1 he aluminum foil strips and ground connections will not be required on the drum and can be omitted. When used in the photofax mode, the ret order must be operated m a darkroom with suitable safelight illumination to protect unexposed paper, 1 he paper can be cut to the required 7" x 7" in the darkroom.

Although the recorder will produce superb photographic prints, I Have not operated it in the photographic mode since first setting up the direct-printing version (see Figs. 2 and 3). The tax system is certainly somewhat more complicated a project than a CRT monitor, primarily due to the mechanical aspects ol the project Once finished, however, it should give you years of trouble-free service T he prototype of tht> photographic facsimile version has been in operation for over two years without a single problem, and there is no reason to assume that the direct-printing version will not have the same reliability Hie FX-2E system is virtually ideal in that it provides tor easy operation, low operating costs, immediate availability ot good-sized prints, superb resolution, and photographic image quality.®

Charies I Cohn WB9SKX 44> Rtdge Avenue Clarendon Hitis HWS14

Unplug It, Dummy!

safety for the traveling ham

For those recreational vehicles which have provisions for connecting to 110-volt outside power, there is always the risk of the owner forgetting to unplug the power cord before driving off. Human frailty and Murphy's Law being what t iey are. this is bound to happen sooner or later.

For us, the reckoning came one time when we had our camper van parked in our driveway while we were packing for a Trip. We had the cord plugged into our house power for pre-cooling the refrigerator. Getting off later than we had hoped, we took off in a hurry When we got to our first stop, we were horrified to find the socket from our extension cord fitting in the van power receptacle. The cord had pulled right out of its socket when we drove off, meaning it was lying in our driveway with the live ends exposed. Mindful of the neighborhood children who frequently play in our driveway, we put in a frantic long-distance call to our local police, informing them of the situation and asking them to do something about the hazard. Fortunately, no further harm came of it

To preclude any repetition of this fiasco, I installed a cord alarm m our van It is arranged so that a door bell rings if the ignition is turned on while the cord is plugged in You can install such an alarm in your RV for an expenditure of about SI5 for parts — less than the cost of a power cord that might be ruined by a drive-off It does the

Fig. L Wiring diagram of the cord alarm.

same job as a commercial alarm that sells for $50.

You will need the following three items: (1) An ordi nary door bell, installed near the driver's seat I chose a door bell rather than a buzzer in order to have a distinctive alarm sound that would not be confused with the seat-belt warning buzzer, [2) A bell transformer of the type designed to mount in a knockout hole in a junction box. Be sure to get a 10-volt transformer rather than a 16-volt type, which is for chimes. (3) A 12-volt dc relay (Radio Shack #275-208 or equivalent).

Attach the bell transformer to an unused knockout hole in the power control center or the junction box for the outside power receptacle, (Confinement of the 110-volt wiring to the inside of such a box makes for a very sate installation.) Connect the primary wires to the 1 U>volt power at the point where it enters the vehicle, with no circuit breakers or other switching devices intervening so that the alarm will not tail to operate because of a breaker or switch being turned off,. {Protection against short circuits in the transformer is given by the circuit breaker feeding the outlet into which the cord is plugged.)

Make a bracket for the relay socket out of sheet metal or aluminum angle and mount the relay in a convenient location. Wire up the system as shown in Fig. 1, soldering all connections to the relay socket. The transformer is connected to the bell in series with a pair of normally-open contacts on the relay One end of the relay coil is connected to chassis ground, and the other end is connected to a circuit that is energi/ed when the ignition is turned on Pick a circuit that is energized only in the "ignition" position of the switch, and not the "accessory' position For our Econoline van, a convenient connection point was the wire feeding power to the seat-belt warning system.

With these connections, turning on the ignition operates the relay and completes the circuit from the transformer to the bell so that it will ring if the transformer is powered by the cord being plugged in

What if you remember to unplug the cord but forget to stow tt? This alarm is foolproof but it is not claimed to be damn-fool-

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