Page Contents
The competition
Of course, Sony's offerings were never without any counterparts from other manufacturers. To mention a few:
- Panasonic RF-B50(L), Toshiba RP-F11 (a.k.a. Kenwood R-11) and Sharp FV-610 were mid-80's ICF-7600A competitors which had similar concepts but typically included 22m band coverage and provided extra features. The RF-B50L had a selectable AM IF bandwidth (with wide and narrow qualifying as just that, the '7600A was in between) and antenna inputs (not in Germany model) and, while not the very hottest set ever on the shortwave bands, was noted to have excellent MW and LW reception. (The RF-B50 covered a 120m ... 50 m "tropical band" segment instead of longwave, much like the later ICF-7601.) The RP-F11 featured electronic band switching and an analog S-meter and was found to be an even better performer than its Sony counterpart on the AM ranges (especially MW and LW), only the tuning knob mechanics weren't as direct as they could have been. The FV-610 had a digital frequency readout and probably is the rarest of them all, which is not to say that the others would be common.
- Panasonic RF-B65(D/DA): A fine portable from the late 80s (ca. 1989...1993) with 1 kHz steps and SSB. Very rugged due to its metal case, and very good reception, too (though the filters could apparently have been a bit narrower; these were two SFE10.7MAs for FM and an SFR450I or SFR459I plus a tuned IFT for AM, BTW - sound familar?). Was a bit more expensive than a comparable "7600", but also quite a bit more comfortable. Too bad these haven't been made since 1993 or so. (Looking at the schematic, the receiver is quite a bit more complex with more discrete parts than later comparable models and probably got too expensive to manufacture in the end.) The older model RF-B60 (1986...1989) had no SSB and was a little noisier, but in the international version it apparently featured air band reception, just like the ICF-2001D/2010.
- Panasonic RF-B45: Presumably targeted at the ICF-SW7600 and with similar features (5 kHz steps on shortwave, SSB, 9+9 memories), but not as a good a performer (selectivity in particular). Unlike most receivers of this class it tuned down to below 150 kHz, namely 144 kHz. The older model RF-B40 had no SSB, but more memories.
- Grundig's (later) Yacht Boys, from the single-conversion
sets of the early 80s (most just average performers) to the Yacht Boy
400 of the 90s, which offered a better feature set than the ICF-SW7600
and partly even the ICF-SW7600G (more memories, switchable AM filters, but no
synch), but had worse SSB reception than the ICF-SW7600G (no sideband
selection, and distortion due to a non-ideal AGC time constant; on the other
hand, it was much better on FM). The latter one, which interestingly also
covers longwave down to 144 kHz, is still available as the Grundig/Eton
YB-400PE in the US, which differs from the original version by its silver
colored case (the paint of which seems subject to wear like on cheap notebook
computers, eek...).
The Yacht Boy 80 (YB80), commonly found over here (attractively priced at that) but not in the US, appears to be a good overall performer on all bands, only SSB is subpar. A high 1st IF (like 55.845 MHz) is being used for the AM bands. It actually is a rebadged Sangean PT80. - Sangean's first set that could be seen as competition to - then - the ICF-SW7600 was the ATS-808, later updated to the ATS-808A, without SSB but with dual bandwidths and 45 or 54 memories, respectively. Currently, they offer the ATS-505 (targeted a bit below the ICF-SW7600G/GR; IFs of 21.44 MHz and 450 kHz, selectivity a bit weak with a 4-element filter) and the well-known ATS-909 (targeted above it). The closest thing to a direct competitor nowadays is the more recent PT80, see Grundig.
- In recent years, interesting shortwave portables have come from a number of
aspiring Chinese manufacturers / brands, like Degen,
Tecsun, Redsun and Kchibo.
Degen's first dual conversion set was the DE1101 which basically used a slightly beefed-up ICF-SW30 concept (IFs 10.7 MHz / 450 kHz on shortwave, 450 kHz on MW, with an IF filter choice between a two-element and a 4-element filter and much better FM filtering thrown in). The later DE1102 (now dual conversion on all AM bands) added SSB reception and 1 kHz steps and remains a popular choice for a small, inexpensive and generally well-performing set. The first set to use a high 1st IF of 55.845 MHz was the DE1103, which has an LCD-based analog dial simulation and tuning knob much like the ICF-7600DA and thus a little weird ergonomics; yet, IF filters now are 4-element and 6-element types, AM coverage is 100 kHz .. 30 MHz continuous, the FM frontend is improved, and high overall performance at very interesting pricing have made this another popular model. Other models have been a little less interesting (e.g. the "dual conversion light" DE1107 or the smallish upright PLL synthesized dual conversion DE1105, which is a little antenna limited). Watch out for rebrands (US: Kaito, EU: Scott RXP80 = DE1102).
Tecsun's small PLL portables had exclusively been single conversion sets without SSB (even if e.g. the PL350 was far from a bad performer) until the PL600, which has not made it out of China yet. The R-9700DX mentioned in the ICF-7601 section is a "dual conversion light" analog with FM stereo.
Redsun, the newest player of them all, is best known for larger portables, e.g. RP2000/2100. They do offer an analog dual conversion set with frequency counter, the RD1220, which unusually has an RF gain control and allows turning off the AFC for FM.
The company behind the Kchibo brand is known for making all kinds of low-grade radios with questionable build quality, but they can do better. Their first dual conversion set with synchronous detection was the KK-9510HF, which caught some attention but never really made it beyond the Chinese borders. More recently, their second effort KK-S500 became available, a set that features 1000 memories (among which 600 are for FM - huh?) and "borrows" part of the Sangean PT80 design but is smaller and runs with 3 AA cells; this can now be bought worldwide. The most promising model is the conspicuously named KK-S7600L which has been in development for a long time and seems to be just about finished; this will have all the bells and whistles, including a remote, and apparently is intended to surpass even Sony's 7600s; battery wise, it will run off two lithium cells, which strikes me as highly odd. [Ed. note: Apparently it has ultimately been scratched.] - Etón / Lextronix, owner of the Grundig brand in the US, has been selling slightly modified Tecsun radios; they also bought the rights for the receiver that was going to be the Degen DE1106 and have it made exclusively for them as the E5 (or Grundig G5). The E5 uses the receiver PCB (and tuning knob) of the DE1103 but combines it with a different, more conventional and most importantly, much more friendly user interface featuring a normal keypad and 700 memories with alpha tags. Unsurprisingly it has proven to be a popular choice. (Ironic footnote: While in the US the E5 is quite a bit more expensive than a rebranded DE1103, here in Germany an officially imported DE1103 used to cost 10€ more than the E5 for quite a while.)
Sources
[1] Radio Nederland's RealRadio
[2] R. Lichte, "Modifikationen am Sony ICF-7600D", weltweit hören
3/84 (copy)
[3] Dave's Radio Receiver Page
[4] Weltempfänger Testbuch Nr. 8 (7?), Siebel
Verlag, pp. 125-128 (copy)
[5] DXing.com - Modern
Shortwave Receiver Survey
[6] A photo of a SONY ICF-7600DS I got from R. Lichte
[7] Sent to me by nice people (1,
2, 3)
[8] Sony Germany website
[9] Shortwave Radio Reviews by rec.radio.shortwave listeners, revised version
[10] Murata's product catalog
[11] Universal Radio catalog
[12] The 7600GR specs on the website of Grove Enterprises. (defunct as as Sep 06, 2003)
Related links
- Web site of a radio guy in Japan who got bitten by the radio bug as a kid (remember, back in the '70s shortwave was very popular among Japanese youngsters, and the ICF-5800 was one of the radios that fueled this radio boom) and has pages on the ICF-5900W (including realignment), ICF-5500M, ICF-5800 (the latter in Japanese only)
- On the infamous ICF-SW100 ribbon cable and how to fix it
- Yet more Yahoo! Groups: SONYICFSW77 (ICF-SW77
discussion), icf2010
(ICF-2010/ICF-2001D discussion), sw55 (ICF-SW55 discussion),
SW07 (ICF-SW07 discussion);
R9700DX (Tecsun R-9700DX), Grundig-Yacht-Boy-Radios, KAITO-DEGEN1102, kaito-de1103, EtonE5, panaport (Panasonic portables), and there are even more of them out there... - A thread on Google Groups about the ICF-SW55 TAPE I/O "easter egg" that allows saving and restoring the memories via the line out.
- If you like rather inexpensive, compact shortwave radios, you may want to head over to radiointel.com.
- If you need a service manual in or near Germany, Schaltungsdienst Lange probably has it. (Even stuff like a CRF-150 service manual.) Rather reasonable pricing, too.
- A page about modifying a Sony pocket radio for better sound
- Steve Waldee's old SWLing pages
Glossary
- AM
- Amplitude Modulation, also: mediumwave band (see MW), or (Sony) the whole LW/MW/SW range.
- AGC
- Automatic Gain Control (older term that basically means the same: AVC = Automatic Volume Control); a measure to ensure that stations are virtually always equally loud regardless of signal strength. Better receivers allow changing AGC time constants and even turning it off which may be helpful in certain DX situations.
- BCB
- Broadcast Band, see MW.
- BTW
- A harmless acronym: by the way.
- Dual conversion
- See IF.
- DX
- Originally meaning "distance unknown", this acronym is generally understood as reception of distant, hard to hear stations, or chasing for them.
- FET
- Field Effect Transistor. Commonly used in receiver front ends for RF amplification and mixing. On shortwave and lower, one typically uses n-channel junction FETs, while on the FM band and higher dual-gate MOSFETs are also popular (they can have very good noise figures up there, but are not so great at low frequencies due to high levels of 1/f noise).
- FM
- Frequency Modulation. This is employed by broadcast stations on the FM band (wideband FM, 150 kHz bandwidth) and the Citizen Band (CB) (narrow-band FM, ~10 kHz). On shortwave FM is basically only used above some 25 MHz (like CB on 27 MHz or part of the 10 m ham band), while it's a widespread standard modulation type on higher frequencies.
- Ham
- Infml.: radio amateur.
- IC
- Integrated Circuit; a compact part that offers the functionality of conventional circuits with separate capacitors, coils, resistors and all. A receiver like the ICF-SW7600G(R) uses ICs for demodulation (AM, Sync, SSB, and FM in conjunction with an external filter), for frequency synthesis (PLL), as audio amplifiers, and of course the microprocessor controlling the whole thing can also be seen as an IC.
- IF
- Intermediate Frequency (of a superheterodyne receiver). Superheterodyne receivers or superhets mix the incoming signal to a constant IF (after some RF pre-amplification, usually) which simplifies filtering enormously when compared to older concepts (superhets were invented in 1917 or so). Since the mixing process generates two signals twice the IF apart (see Image rejection), general coverage shortwave receivers use a rather high (1st) IF, however the higher the IF the more difficult / expensive it is to find good filters. Therefore they're usually dual conversion designs with a high 1st IF (which used to be just a few MHz in the days of tube receivers and lots of separate bands with bandpass filters, and is usually 45...70 MHz today with exceptions like the models with the "cost-effective" typical FM broadcast IF of 10.7 MHz allowing the use of FM IF filters there) which typically uses one or two crystal filters (typically 30, 15 or 8 kHz @-6 dB) and a lower 2nd IF with good filter choice (typically 455 kHz, or 450 kHz on older designs). This usually keeps image frquencies away pretty well, but very compact receivers tend to exhibit leakage issues around the 1st IF filter. Dual conversion receivers also have better dynamic range than single conversion designs built with the same efforts. (See IM.)
- IFT
- IF-level transformer. When tuned by means of parallel capacitance, acts like an additional LC filter circuit. Tuned IFTs on IF level are typically used to improve ultimate rejection and reject spurious filter responses.
- IM or IMD
- Intermodulation (distortion); a by-product of strong signals generated by amplifiers, mixers and the like when signals no longer fall into the linear working range. Attenuation of signals can help to eliminate the resulting "ghost stations" (and parts / circuits with better dynamic range, of course). On shortwave the most common types of IM products are 2nd order (usually found far away from the signals generating them, like at the sum of the frequencies of two strong stations) and 3rd order (found within or next to crowded bands). 2nd order IM products can be defeated rather easily with high-/low-/bandpass filters, so 3rd order IM products are seen as being more critical. Less expensive shortwave receivers tend to have wideband frontends, thus they can generate both types.
- Image rejection
- The ability of a superheterodyne receiver to suppress stations that are twice the IF (or one of the IFs) away.
- Intercept point
- This is a calculated value given in dBm that can be used to describe how good a receiver is in rejecting intermodulation products of a certain kind (mostly: 2nd order --> IP2, 3rd order --> IP3). The larger, the better. You'll mostly find the input IP3 published, which for many portables is below 0dBm and can reach +30dBm and more on very good receivers. Note that in practice with a high number of signals it's not always the mixer with the highest IP3 that performs best. In addition, you need to know where the input noise floor is (i.e. how sensitive it is when looking at a complete receiver) to judge dynamic range properly - a mixer intended for VHF use is likely to have a low intercept point, but it'll have a low noise figure, too.
- LO
- Local oscillator; oscillator that is used to generate one input signal fed to a mixer in superheterodyne receivers. It be noted that high LO levels tend to improve strong signal handling, but depending on the mixer may lead to overly high LO radiation (which for FM receivers is straight in the VHF air band).
- LW
- Longwave; the respective broadcast band (mainly used in Europe) ranges from 150 kHz to 281 kHz, with a 9 kHz channel spacing.
- MW
- Mediumwave; the respective broadcast band ranges from 531 kHz to 1611 (1700) kHz, with channel spacing being either 9 or 10 kHz depending on region.
- PCB
- Printed Circuit Board - the basis for all those ICs, capacitors, resistors and stuff.
- RX
- Receiver.
- SSB
- Single SideBand; see the ICF-SW7600G additional information section.
- SSTV
- Slow Scan Television; narrow bandwidth picture transmission used by hams, various analog modes in both monochrome and color plus digital transmission.
- SW
- Shortwave; generally the frequency range 3...30 MHz, contains various broadcast and other bands.
