![]() Shortwave receiver designs had traditionally employed vacuum tubes, but solid state circuit designs began to emerge in the 1950s. įollowing development of several prototypes between 19, Zenith introduced the Model 7G605 Trans-Oceanic 'Clipper' in 1942, an early portable shortwave receiver marketed to consumers. By 1936 it was estimated that 100 percent of console models and 65 percent of table model radios were able to receive shortwave broadcasts. Superheterodyne receiver circuits soon essentially replaced all previous receiver designs, and radio manufacturers such as RCA, Zenith, Philco, Emerson, and Stromberg-Carlson offered consumers table or console model "all wave" sets that could receive both mediumwave and shortwave bands. In 1936, Hammarlund introduced their " Super-Pro" superheterodyne shortwave receiver. Hallicrafters introduced the "Super Skyrider" in 1935, a superheterodyne shortwave receiver available in several different models that covered the broadcast band up to 30 MHz. ![]() Scott Radio Laboratories offered its superheterodyne "World's Record" shortwave receiver kit in the late 1920s, and In 1931 Hammarlund introduced the "Comet Pro", the first fully assembled commercial shortwave superheterodyne receiver. Other notable early shortwave receivers included Pilot Radio's "Super Wasp" line of regenerative receivers. National Radio Company introduced the SW-2 "Thrill box" shortwave regenerative receiver in 1927, and later offered improved models, such as the highly regarded SW-3. Such converters were generally found unsatisfactory in performance, and so dedicated shortwave receiving sets soon appeared on the market. Buy it quick, though, as I suspect that it uses chips that are no longer available.While home built shortwave receivers had been used by amateur radio operators and radio experimenters prior to World War I, the first time shortwave radio reception was available to the general public was through the use of shortwave frequency converters sold as accessories to broadcast-band radio sets during the mid 1920s. It uses a pot to apply CV to a varactor for tuning. Ramsey Electronics still makes their FR-1C kit. ![]() If you must have CV control over tuning, you are in luck. (if you're going to gut a cheap FM radio, you could just hook up a Vactrol or other optocoupler to the Scan button so you can operate it with a pulse.) With any luck, you might be able to find an old portable radio or clock radio that uses a TDA7000-type chip, and figure out how to inject a CV into the varactor to forcibly tune it. If you can find a TDA7000 family chip, they can be set up for use with a varactor diode. The SL ones are more self-contained and don't need much outboard componentry. Silicon Labs makes similar devices, intended for microprocessor control, which seems to be the way they're all headed. They usually need external IF transformers and an RF tank circuit too, so they're not easy for a DIYer to use. (Look it up.) Those parts are obsolete and difficult to find.īut most of the modern ones use digital frequency synthesis. Rod Serling Fan Club wrote:I think the main point of having a radio module, aside from just using a commercially available radio, is if it had CV to scan the stations.Īnalog FM-radio receiver chips used to have CV inputs for tuning control, as they simply used a varactor diode. Perhaps now I can go back to lurking and wait for someone to design the module I'm looking for. I've explained why I'm only interested in SW and I've apologised for mixing up up the terms. ![]() This has nothing to do with a radio module. It'll remain as weird and interesting post-switchover as always has. I don't care about that - I just want to know what the spectrum will sound like when it goes digital, and nobody's talking about that. It's hard to find any real technical details amoungst all the search hits for the switchover politics. I've not read or heard any details about how digital comms use radio, so I don't know what size those gaps would be. Maybe there'll be some gaps in the spectrum that we can use for noise sources. The UK radio switchover is set to begin in 2015. I was trying to be consistant with terms already being used, so.oh well. However, I do apologise for mixing up the terms. SW is, as the name suggests, an extreme end. I was mostly talking about frequency bands.
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