DX-440 AM/FM Direct Entry Communications Receiver (200-0221) Operation - Part 1 Faxback Doc. # 17502 You can use the DX-440 to wake you up to your favorite station everyday. And before you retire for the evening, you can set the timer so that the radio turns itself off after an interval between 10 and 90 minutes. Make the following settings with the power off. SETTING THE ALARM 1. Press the TIMER button so that the display shows the current timer setting (or 0:00) and STANDBY remains. NOTE: The time setting disappears after five seconds, but STANDBY remains. 2. While STANDBY is flashing, press UP or DOWN, or use the tuning knob, to set the desired timer setting. NOTE: *STANDBY stops flashing, if you do not change the time within five seconds. If tis happens, you must return to the previous step. The timer uses a 24-hour clock (13:00 is 1:00 P.M.) 3. When the correct timer setting is displayed, simply wait. In about five seconds, STANDBY stops flashing. A few seconds later . A few seconds later, the display returns to the clock mode with STANDBY still displayed. NOTE: As long as STANDBY is displayed, the DX-440 comes on each day at the time you set. 4. If you want to stop the DX-440 from coming on without changing the timer setting, press TIMER so that STANDBY does not appear on the display. 5. To check the timer setting, press TIMER so that STANDBY and the timer setting are displayed. If the DX-440 is already in the STANDBY mode, you must press TIMER twice to accomplish this. USING THE SLEEP TIMER To have the radio turn itself off after a period of 90 minutes or less, proceed as follow: 1. Press the SLEEP button. The display shows SLEEP 90 in the upper right hand corner. 2. If you want fewer than 90 minutes playing time, press the SLEEP button again. Each time you press the button, the playing time reduces by 10 minutes. To turn off the radio before it normally turns itself off, press the POWER button. SPECIAL TUNING TECHNIQUES AND CONTROLS In addition to the standard tuning operations described previously, use the following controls for special operations. RF GAIN CONTROL This control adjust the receiver's sensitivity. For short wave and FM reception, rotate the control to the MAX position, this provides the maximum sensitivity. When you listen to the MW, standard AM band, or LW band through external, rotate the control only as far as needed to obtain a good signal. If you turn the knob further you might hear a distorted signal. For weak stations, rotate the control to the MAX position. If you encounter interferance, adjust the control in both directions until you get the best compromise between your station and the interferance. AM NARROW/WIDE SELECTIVITY SWITCH Some station transmit their signal so that very little space exhist between their airspace and the station next to them on the band. If, while tuning, you encounter interference, caused by the signal from an adjacent station, press the button for the band you are listening to and select the NARROW position. The interference is muted. For full reception leave the switch in the WIDE position. If you plan to listen to Morse code, referred to as CW (continuous wave), set the BFO switch to the IN position. If you encounter too much noise as you tune, set the AM NARROW/WIDE switch to the NARROW position. USING HEADPHONES While not in control,you might consider using headphones to obtain the best reception. Many stations broadcast marginal signals. Only headphones can capture the subtle difference between the signal from such stations and the surrounding noise often encountered at night. Be sure that then headphones terminate in a 1/8 inch plug. Insert the plug into the PHONES jack on the side of the radio. When you plug the headphones in, you silence the speaker. Because the radio can receive stereo FM, when you listen to FM stereo broadcast, be sure your are designed for stereo operation so that you can obtain the full benefit of this feature. USING THE LOCK CONTROL Use this to prevent unauthorized use of the radio or to ensure that any station you might be monitoring remains tunes in. When you move the LOCK switch to the IN position, you disable the POWER button and the tuning controls. If the radio is on when you use the LOCK switch, you cannot turn off the radio or change the current frequency. To release the LOCK function, set LOCK switch to the out position. SPECIAL SSB/CW RECEPTION TECHNIQUES Many station transmit unmodulated telegraph transmissions in the shortwave band. To receive these special Morse code characters, the radio uses a special circut, a beat frequency oscillator, to modify the transmitted signal so that you can hear it. This particular type of transmission is called continuous wave (CW) transmission. Many stations transmit voice signals with a suppressed carrier in the single side band mode. (SSB), part of the radio transmission spectrum that lies to the side of the primary frequency signal. Amateurs tend who transmit voice below 10MHz use the lower side band (LSB). Above 10 MHz, they use the upper side band (USB). Commercial utility stations generally use the USB. A carrier has to be to make these signal audible. TO RECEIVE CW 1. Turn on the radio 2. Extend the antenna fully straight up. 3. Set the BFO switch to on. 4. Rotate the BFO PITCH control to the midpoint. 5. Rotate the RF GAIN control to the MAX position. 6. Press the AM button to select the AM band. 7. Tune in the CW station using the tuning knob, or enter the frequency using the direct access buttons. 8. Adjust the CW tone using the BFO PITCH control. 9. Reduce strong signals by using the RF GAIN control. This also reduces interference and noise. TO RECEIVE SSB VOICE 1. Turn on the radio 2. Extend the antenna fully, in a straight up position. 3. Set the BFO switch to the IN position. 4. Rotate the BFO PITCH control to the LSB position for stations below 10MHz or to the MAX position. 5. Rotate the RF GAIN control to the MAX position. 6. Press the AM button to select the AM band. 7. Tune in the SSB station using the tuning knob, or enter the frequency using the direct access buttons. 8. Rotate the BFO PITCH control to adjust the signal quality. 9. Rotate the RF GAIN control to dampen strong signals. This can improve signal clarity as well. NOTE: Before choosing another band, set the RF GAIN control to the MAX, and move the BFO switch to the OUT position. USING THE SHOULDER STRAP 1. Insert about five inches of the end of the strap into the hanger. 2. Pull the free end of the strap upward, and insert the end into the lower edge of the strap buckle as shown in Figure 1. 3. Pull at least three inches of the strap through the buckle. Then bring the end of the strap beneath the upper buckle. Refer to Figure 3 4. Pull the free end taught. Be sure that at least two inches of strap extend from the upper end of the buckle. Slip the extra strap beneath the belt loop. To remove the shoulder strap, follow Figures 5, 6, and 7 to reverse the procedure. CHOOSING AN ANTENNA The radio uses a telescoping antenna and internal ferrite bar antenna for reception of signals between 150kHz and 1620 kHz. These antennas provide acceptable reception for most stations . However, if you use an external antenna, you can receive more signals, and the signals you receive will be better. FM BAND Use a set of VHF-TV rabbit ears. Those made for TV-FM coverage can help get better performance on the FM band. Use an outdoor FM antenna. This type, specially designed for optimum FM performance, requires rooftop (or simular location) mounting. Use a combination TV/FM antenna. NOTE: To use an external antenna, equipped with 300-ohm twinlead, connect the twinlead's terminals to a 300-ohm to 75-ohm matching transformer, Cat. No. 15-1253. Then insert the 75-ohn connector of the transformer into an F-to - RCA adapter, Cat. No. 278-252. Finally, insert the RCA type plug of the adapter into the RCA antenna jack of the receiver. Be sure to move the antenna switch to EXT. AM-SHORTWAVE BANDS For AM reception, you can use many different types of antennas. Unfortunately, no single antenna can effectively cover the entire frequency range of the DX-440, from 150kHz to 29999 kHZ. A general purpose shortwave antenna, such as Cat, No. 278-758, can provide better reception than either of the built in antennas. However, if you want the best possible reception on one specific band, your antenna must be a certain length. Refer to the following charts. The first chart indicates the length if wire required for optimum performance on the specified band. The second chart gives you the required length of wire to receive the amateur radio operator's bands. Frequency Antenna Wire Length (feet) 150 kHz - 500 kHz 1440 lengths generally 520 kHz - 1600 kHz 441 impractical to erect 1600 kHz - 4500 kHz 153 4500 kHz - 12000 kHz 57 12000 kHz - 29000 kHz 22 Wave Length- Ham Band Antenna Wire Length (feet) 160 meter 246 80 meter 117 40 meter 66 20 meter 33 15 meter 22 TO CALCULATE ANTENNA LENGTH FOR A SPECIFIC FREQUENCY You can determine the exact length of wire you need for a specific frequency using the following information. The, obtain bare copper wire, stand-off insulators, and and an appropriate length of lead-in wire. Be sure to use a static discharge unit to guard against lightening damage. For complete information, refer to THE RADIO AMATEUR HANDBOOK, published by the American Radio relay League. This formula results in a half-wave antenna. Length of a 1/2 wave antenna= 468000/Desired Frequency (kHz) For example, to pick up internal shortwave signals in the 19 meter band, 15100 to 15350 kHz, pick a representative frequency, such as 15350 kHz. the formula becomes 468000/15350 = 30 1/2 SYSTEM GROUNDING To ensure the best reception, always connect a ground wire to the external antenna jack. Connect the single wire lead-in to the center terminal of the RCA plug. Connect a suitable earth ground to the outer terminal of the plug. A suitable earth ground can be a clamp to a metal water pipe or a copper rod driven several feet into the earth. Radio Shack sells a copper ground rod (Cat. No. 15-530) and the appropriate hardware. BAND ALLOCATION To avoid interference and confusion, certain portions of the radio spectrum have been set aside for specific purposes. Perhaps the most familiar example is the 540-1600 kHz standard AM broadcast band. Ham radio operators use the following bands: 160 meters = 1,800 - 2,000 kHz 80 meters = 3,500 - 4,000 kHz 40 meters = 7,000 - 7,300 kHz 20 meters = 14,000 - 14,350 kHz 15 meters = 21,000 - 21,450 kHz 10 meters = 28,000 - 29,700 kHz International broadcasting stations have several bands set aside for them: 49 meters = 5,800 - 6,200 kHz 41 meters = 7,100 - 7,500 kHz 31 meters = 9,500 - 9,900 kHz 25 meters = 11,650 - 12.050 kHz 19 meters = 15,100 - 15,600 kHz 16 meters = 17,550 - 17,900 kHz 13 meters = 21,450 - 21,850 kHz 11 meters = 25,600 - 26,100 kHz Note that the broadcast and hams share 7,100 -7,300 kHz, and interference is heavy in that range. Broadcast in tropical regions have special bands set aside for them. In such areas shortwave is the only way to reach isolated locations: 120 meters = 2,300 - 2,500 kHz 90 meters = 3,200 - 3,400 kHz 75 meters = 3,900 - 4,000 kHz 60 meters = 4,750 - 5,060 kHz The rest of the shortwave range is filled with marine,aeronautical and military stations. Such stations usually use either SSB or CW, and can be found outside the amateur and broadcast bands. (/all-11/28/95)