Previous: Modifications

Page Contents

  1. The competition
  2. Image sources
  3. Related and unrelated links
  4. Glossary

The competition

Of course, Sony's offerings were never without any counterparts from other manufacturers. To mention a few:


[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] - 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 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


Amplitude Modulation, also: mediumwave band (see MW), or (Sony) the whole LW/MW/SW range.
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.
Broadcast Band, see MW.
A harmless acronym: by the way.
Dual conversion
See IF.
Originally meaning "distance unknown", this acronym is generally understood as reception of distant, hard to hear stations, or chasing for them.
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).
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.
Infml.: radio amateur.
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.
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.)
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.
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.
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).
Longwave; the respective broadcast band (mainly used in Europe) ranges from 150 kHz to 281 kHz, with a 9 kHz channel spacing.
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.
Printed Circuit Board - the basis for all those ICs, capacitors, resistors and stuff.
Single SideBand; see the ICF-SW7600G additional information section.
Slow Scan Television; narrow bandwidth picture transmission used by hams, various analog modes in both monochrome and color plus digital transmission.
Shortwave; generally the frequency range 3...30 MHz, contains various broadcast and other bands.

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Created 1999-06-01 (yyyy-mm-dd)
Last revision 2009-01-16