The General Electric "Superradio" series has become somewhat of a legend in medium wave DX-ing circles.  People have claimed that it was one of the best AM/FM radios for those who wish to listen to distant radio stations or do some DX-ing.  With that in mind, I found a new Superradio III on sale at a local discount store, and decided to see just how good a radio it is.  After some testing here on the plains of Nebraska, I found the radio to be an adequate performer with very good audio, but somewhat of a disappointment for serious DX-ing use.
 
FEATURES: The radio is a rounded boxy black unit 13" long, 9" high, and 3.75" deep, weighing in at about 5 lbs without the batteries.  It covers from 530 kHz to 1700 kHz on AM broadcast, and 87-108 Mhz on FM broadcast (monaural), in continuous slide-rule type tuning along a 7 inch non-illuminated analog display across the top of the radio's front panel.  The frequency markings are somewhat small and grey in color, which can be difficult to read in less than bright room illumination.  The tuning knob is on the right side of the radio, and the tuning is smooth and easy.  Below the tuning knob is a 1/8" earphone jack, and the top of the radio contains the power button on its right end, as well as a carrying handle and the 35 inch telescoping whip for FM reception.  The front panel has the large speaker grille containing a 6 inch woofer and a 2 inch tweeter.  The right side of the front panel contains the AM/FM, AFC, and bandwidth switches, along with the volume, treble, and bass controls.  The back of the radio has screw terminals for 300 Ohm FM external antennas, as well as a terminal for an external AM wire antenna.  The battery compartment houses 6 "D" cells, as well as the AC power cord.  Unlike some radios, the SRIII has automatic switching between AC and the internal batteries, so the user isn't forced to remember to flick a hidden switch.  There is no input for an external 9V DC source, so you are limited to either AC or internal battery operation.  The radio is totally analog, so it should have very good battery life.

PERFORMANCE: The Superradio III is a fairly sensitive receiver with excellent audio, but its reputation as a DX machine is a bit overblown.  While the AM band is rich in activity with this radio, its performance for digging out real DX may be less than outstanding.  In the narrow bandwidth position, the radio exhibits a significant level of residual noise (most noticable in the daytime, or in areas where there are few strong stations), and there are one or two nasty broad birdies, with the strongest around 920 kHz.  Comparing it to my little Sony ICF-SW7600G, the SRIII was not as sensitive or selective, although it had better audio.  Using a signal generator to supply a weak signal for comparison, at 860 kHz, the Sony 7600G was over 3 db more sensitive than the SRIII.  I have an old Sound Design AM/FM boombox which did about as well, so the SRIII's sensitivity isn't exactly one of the best in the business.  Even Tandy's Superradio "clone", the Radio Shack Optimus 12-603A had a comparable sensitivity and a much lower nose floor than the SRIII.  The SRIII slightly outperformed the Optimus, especially in the "expanded" portion of the AM band beyond 1600 kHz, but the higher noise floor of the SRIII made listening to weaker daytime signals more difficult than with the Optimus.  The nulls in the Optimus loopstick were deeper and better than those of the SRIII, which made the SRIII a bit more plagued by multi-station interference in the graveyard sections of the band.  I placed it in my home-brew medium-wave loop, but the SRIII's performance did not improve as much as either my little Emerson hand-held 7-band radio or my Optimus did on the loop.  An external antenna would probably make the radio fairly suitable for some DX-ing, but the internal loopstick might not be quite enough if you are going for the really weak ones (like foreign MW stations).

     In selectivity, even in the narrow bandwidth setting, the SRIII couldn't quite manage a clean 10 kHz split between a weak station and my local 1kW KWBE on 1450 kHz, unless the end of the SRIII's loopstick antenna was pointed towards KWBE's tower.  20 kHz separations from strong local stations were done fairly well however.  By comparison, the Optimus 12-603A was less selective, often having trouble with 20-30 kHz spits with strong stations.  Away from strong stations, the SRIII did 10 kHz splits with little trouble, but narrower splits would probably not be easily done.  My little Sony 7600G routinely was able to get within 10 kHz of KWBE, and could do 5 kHz spits on weaker stations, so the SRIII's selectivity might not quite meet the needs of the serious AM DXer.

  With the bandwidth switch set to "wide", the audio on local or stronger stations was very good to excellent, rivaling some Hi-Fi receivers, but the selectivity in the wide position was extremely poor, and many of the really weak stations vanished.  For decent distant listening, the bandwidth switch had to be left on "narrow", as the "wide" position was nearly useless.  In addition, when running off of AC and in the narrow bandwidth mode, touching the receiver or draping the power cord near the radio caused a weak AC-hum modulation in the audio output on some stations.  Another problem with the radio was the lack of alignment and quality control.  Out of the box, the dial was over 200 khz off, and was not very linear.  I consulted my local GE service man, and found out that the main GE office wouldn't give out ANY servicing details, even to my local GE repair shop!  After some study of all the SRIII information on Werner Funkenhauser's website, I carefully opened the radio up to have a look inside (BE CAREFUL!, the Power switch is VERY fragile, and is easily broken unless carefully depressed).  I did some adjustments on the two trim pots R1 and R3 to both contract the AM band, and position the stations so that their frequencies would more closely match the markings on the dial.  I didn't have the SRIII alignment manual, so all I could do was try and peak the RF stages and test the IF alignment a bit.  I was able to reduce a strong birdie-like image next to KWBE with some tweaking of the capacitor C8, but otherwise, I was unable to improve the unit's AM performance significantly.

    On FM-broadcast, the Superradio was a fairly good performer.  The dial  was misaligned again by about 1.5 Mhz, but this wasn't surprising.  Using just its whip antenna, the SRIII received about 30 stations, compared with 22 on my Optimus Superradio clone.  The stations were often fairly loud, and the audio was excellent, but none was over 100 miles distant.  The sensitivity and selectivity of the SRIII were somewhat inferior to my Sony 7600G, which managed to pick up 49 stations in the FM band using just its whip (some over 100 miles away).  With an external antenna, the performance might allow some limited FM Dx-ing, but I still like using my Sony better during band openings.

     In summary, the G.E. SUPERRADIO III is a fairly good portable radio with good sensitivity and outstanding audio.  However, in my mind, it does not quite live up to the "myth", of the Superradios.  Those seeking somewhat better performance in a medium-wave DX-ing receiver might be advised to look elsewhere.

David Knisely

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