Sony hand-held shortwave radios have rarely been much good at receiving much more than the more prominent international broadcast stations.
They usually cover only the major broadcast bands with inaccurate slide-rule style tuning, and in AM only. They often suffer from a lack of sensitivity, selectivity, stability, and good image rejection.
However, now there is a new small package receiver which may make a lot of people sit up and take notice: the Sony ICF-SW7600G. While not performing quite as well as amateur or high-end general coverage receivers, it does offer features and performance that make it really stand out in the under $300 market.
The radio is 7-1/4" by 4-1/4", and only about a inch thick. It covers from 150 khz to 30 Mhz continuously in standard AM, AM Synchronous detection, SSB, and standard FM broadcast from 76-108 Mhz (FM stereo is available using the headphone jack on the side of the radio).
The display is an easily readable LCD window which shows the status of certain of the radio's functions along with a digital frequency readout. It can be lighted for night operation for up to 15 seconds before it slowly fades away to save the batteries. The radio has both a numeric keypad for direct digital entry of frequency (to 1 kc below 30 Mhz), and dual-speed up/down buttons which support scanning.
The SSB fine tuning allows continuous adjustment +/- 3.5 khz from the displayed frequency, although the readout remains unchanged. There is keypad lock out button to keep you from accidentally changing the frequency, and a power lock to prevent the radio from being turned on when it is being stored.
The front panel also has buttons for control of the memory presets, the on-board 24 hour clock, and the three timers. A rather flat 3" speaker occupies the remaining portion of the left front panel, and is quite adequate for most listening, but it is not extremely loud (or clear) at full volume. The right side of the radio holds the SSB fine tuning, mode and tone select switches, and volume control.
The left side has the record output jack, the headphone jack, 6V DC input jack, and an external antenna jack (1/8" phono plug). Unfortunately the 6V DC jack is non-standard, forcing you to buy Sony's DC adapter if you want to operate the radio from a wall outlet. The receiver has a hefty 35" telescoping whip antenna for Shortwave and FM, and an internal loopstick antenna for Longwave and AM-BCB use, both of which are disconnected when an external antenna plug is in place.
The ICF-SW7600G's features include two event timers, each of which can be programmed to turn the unit on set to a frequency of your choice for an hour as an alarm, or for feeding a tape recorder while you are away. There is also a one hour sleep timer.
The radio has 20 memories (10 for AM/Shortwave, 10 for FM broadcast), which can be preset from the keypad. The memories are semi-non volatile, since they will remain set for only a few minutes while you change the four AA batteries. This radio also scans each of the major broadcast bands, holding on an occupied frequency for two seconds before resuming its scan.
The receiver's performance is quite good overall. On longwave, I was easily able to hear seven or eight Morse Code navigation beacons with the internal loopstick, although I did not hear any voice transmissions.
The AM broadcast band really comes alive at night with this radio, and I even managed to hear a few foreign broadcast stations between the US outlets.
Audio quality is fairly good, although tuning up or down 1 kc really helps the highs on AM. On shortwave broadcast, the receiver really shines, easily outperforming my old Yaesu FRG-7 in sensitivity, selectivity, and stability. The SW7600G's AGC performs very well, and doesn't seem to suffer from the "pumping" problem which many other receivers of this price range have.
With an external antenna plugged in, the radio becomes very competitive with some desk-top receivers, although it's dual conversion second IF does leave faint images of very strong broadcast stations 910 kc below where they actually are. The radio also has a few synthesizer birdies, but none are really very loud. There is a switchable attenuator for strong signals or noisy situations which does help reduce the effect of static on casual listening.
The synchronous detection system in this receiver seems to be more effective at maintaining the audio level during fading than in reducing distortion on broadcast signals. The system does cut distortion a little, but only functions well on moderate to strong stations. The sideband used for Synchronous detection is selectable, and I got slightly better high tone response when I chose USB. The sync mode is also useful for cutting the interference from an adjacent frequency by allowing the selection of the sideband farthest away from the interfering station.
There is no noise limiter or blanker, other than a "NEWS/MUSIC" tone switch, which helps only slightly. There is also no S-meter (only a tuning LED). When used in SSB mode, the ICF-SW7600G falls somewhat short of the modern amateur transceivers when it comes to selectivity, but this is not surprising, considering its 4 kc bandwidth. However, it is still very sensitive, rivaling my Yaesu FT-101E's performance, especially when an external antenna is used. I opened its shipping box around midnight, and with the radio sitting on the kitchen table, a Costa Rican amateur's station came booming in on 20 meters.
On 40 meters, I had little trouble hearing several VK's and ZL's, along with their stateside contacts. The next day during a sporadic E opening on 10 meters, I heard just as many stations as I did with my FT-101. I like to walk during the evenings, and I can now listen in on the round table discussions and nets on 75 meters while I get some exercise. If you used an external audio filter, the ICF-SW7600G might make a fair receiver for a portable QRP station. I have also used the radio for weather FAX reception using AEA-FAX, and it works much better than my FRG-7 does.
On FM-Broadcast, the ICF-SW7600G is also quite sensitive. With just the whip, I was routinely hearing stations over 100 miles away. Its stereo detection is automatic depending on signal strength, and the receiver does not have a balance control. Still, its audio into headphones was quite good, comparable to most WalkMan-style radios. In summary, the Sony ICF-SW7600G is a fine low-cost hand-held receiver for the shortwave listener, the broadcast DXer, and the Ham who just wants to keep tabs on HF activity.
David Knisely, KA0CZC
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