A new detection system was required and this would rely on detecting leakage signals from the local oscillator used in superheterodyne radio receiver circuits. Transmissions at this time were on the 405-line system and used the Band I (47 to 68 MHz), Band II (87.5 to 108.0, VHF / FM sound-only radio) and Band III (174 to 240 MHz) VHF bands. Because of the broadness of the TV transmission bands, and variations in the intermediate frequencies used, a detector receiver could have needed to be tunable between 29–240 MHz. By detecting either the fundamentals of Band III, or the harmonics of Bands I and II, the detector system managed to make do with 110–250 MHz.
Heathkit also brought out a pair of single band, low power, CW and AM phone VHF transceivers – the HW-10 and HW-20 for the 6 meter and 2 meter bands, respectively. Designed primarily for mobile use, they were much smaller than the tribes but bore a strong family resemblance down to their chrome knobs.
The Germans had not yet developed a magnetron suitable for use in such systems, so their equipment operated in the VHF region. At the NTRI, they followed the Germans and built a prototype VHF set operating at 4.2 m (71 MHz) and producing about 5 kW. This was completed on a crash basis, and in early September 1941, the set detected a bomber at a range of 97 km (61 mi). The system, Japan’s first full radar, was designated Mark 1 Model 1 and quickly went into production.
VHF Records is an American record label, known for their extensive work with several major experimental artists. The label is based in the Washington, DC suburb of Fairfax, Va., and it initially focused on indie and experimental bands from that region. The label has since branched out to release innovative and offbeat music from around the world, although Northern Virginia artists are still prominently featured in the catalog. The label was founded by Bill Kellum in 1991, originally to release a single each by his own band, Rake, and that of his friends, Wingtip Sloat. After a handful of releases by both bands, Kellum acquired the US rights to the first releases by UK psychedelic group Flying Saucer Attack including the CD edition of their debut album. Following this, Kellum released an album by Matthew Bower's Skullflower, which in turn led to the release of an LP by Bower and Richard Youngs. Since then, Youngs has released a dozen collaborative albums on the label, including 6 with Simon Wickham-Smith (who has also essayed two solo sets for the imprint), 3 with Alex Neilson, one from his progressive rock unit Ilk (with Andrew Paine) and one with Makoto Kawabata. Kawabata has also released 3 solo albums for the label. Other artists include Vibracathedral Orchestra, Roy Montgomery, Jack Rose, Pelt, and Stephen O'Malley's Æthenor. Matthew Bower released another 2 Skullflower albums on the label, one Total release and several more under his most recent solo alias, Sunroof!.
VHF radio can refer to several communications services in the very high frequency (VHF) range, including:
Sets can be fixed or portable. A fixed set generally has the advantages of a more reliable power source, higher transmit power, a larger and more effective aerial and a bigger display and buttons. A portable set (often essentially a waterproof, VHF walkie-talkie in design) can be carried on a kayak, or to a lifeboat in an emergency, has its own power source and is waterproof if GMDSS-approved. A few portable VHFs are even approved to be used as emergency radios in environments requiring intrinsically safe equipment (e.g. gas tankers, oil rigs, etc.).
Marine VHF radio refers to the radio frequency range between 156 and 174 MHz, inclusive. The "VHF" signifies the very high frequency of the range. In the official language of the International Telecommunication Union the band is called the VHF maritime mobile band. In some countries additional channels are used, such as the L and F channels for leisure and fishing vessels in the Nordic countries (at 155.5–155.825 MHz).
VOR signals provide considerably greater accuracy and reliability than NDBs due to a combination of factors. Most significant is that VOR provides a bearing from the station to the aircraft which does not vary with wind or orientation of the aircraft. VHF radio is less vulnerable to diffraction (course bending) around terrain features and coastlines. Phase encoding suffers less interference from thunderstorms.
The magazine focused on radio technology, products, and activities that exist on 6 meters, 2 meters, 440 MHz and above. CQ VHF covered a broad range of skill levels, from the new Technician to the Extra Class microwave experimenter, and included operating, technical and construction articles.
The VHF Data Link or VHF Digital Link (VDL) is a means of sending information between aircraft and ground stations (and in the case of VDL Mode 4, other aircraft). Aeronautical VHF data links use the band 117.975–137 MHz assigned by the International Telecommunication Union to Aeronautical mobile (R) service. There are ARINC standards for ACARS on VHF and other data links installed on approximately 14,000 aircraft and a range of ICAO standards defined by the Aeronautical Mobile Communications Panel (AMCP) in the 1990s. Mode 2 is the only VDL mode being implemented operationally to support Controller Pilot Data Link Communications (CPDLC).
The International Telecommunications Union (ITU) has established VHF channel 16 (156.8 MHz) as a distress, safety and calling channel, and it is monitored 24 hours a day by many coast guards around the world.
Police, fire, and military communications on the VHF bands are also DX'ed to some extent on multi-band radio scanners, though they are mainly listened to strictly on a local basis. One difficulty is in identifying the exact origins of communications of this nature, as opposed to commercial broadcasters which must identify themselves at the top of each hour, and can often be identified through mentions of sponsors, slogans, etc. throughout their programming.
The RP37 VHF Herald looked like a third-generation Herald, but the presence of a telescopic aerial indicated that this is an FM-capable receiver; indeed it was an FM-only radio. Like most Hacker sets from the 1960s and early 1970s, this set used two PP9 batteries. They were available in the same colour choices as the RP35 AM Herald, and there was a variant with a revised scale in royal blue that incorporated the Open University logo in place of the local stations. The terms of this arrangement are presently unclear.
Though sporadic in nature, signals on the FM broadcast and VHF television bands – especially those stations at the lower end of these bands – can "skip" for hundreds, even thousands of miles. North American FM stations have been received in Western Europe, and European TV signals have been received on the West Coast of the U.S.
Mirroring the changes in the RP25A Sovereign described below, the later RP37A VHF Herald had a revised FM tuner; recognisable because it has a clear plastic cover rather than an aluminium enclosure. At a similar time, the loudspeaker was changed from a grey painted unit made by Goodmans to a silver-framed Celestion or a unit supplied by Elac which was recognisable by the large ceramic magnet assembly. This latter loudspeaker was only ever fitted to the VHF Herald.
The use of aircraft for search and rescue in World War II brought line-of-sight VHF radios into use. The much shorter wavelengths of VHF allowed a simple dipole or whip antenna to be effective. Early devices included the British Walter, a compact single vacuum tube oscillator design operating at 177 MHz (1.7 meter wavelength), and the German Jäger (NS-4), a two-tube master oscillator power amplifier design at 58.5 and, later, 42 MHz. These were small enough to include in life rafts used on single-seat fighter aircraft.
VHF (very high frequency) telemetry typically requires a user to acquire VHF transmissions from a VHF transmitter (usually in a collar attached to the animal) using a hand-held antenna. VHF signals are either received by mobile or stationary receivers equipped with directional antennae. The location of the transmitter can then be determined by acquiring the transmissions from three (or more) different locations to triangulate the location of the device. VHF tracking is more commonly known as "radio-tracking."
CQ VHF was published by CQ Communications, publishers of CQ Amateur Radio magazine, WorldRadio magazine, and Popular Communications magazine.
Using the RTCM 12301.1 standard it is possible to send and receive text messages in a similar fashion to SMS between marine VHF transceivers which comply with this standard. However, as of 2019 very few transceivers support this feature. The recipient of the message needs to be tuned to the same channel as the transmitting station in order to receive it.
In the United Kingdom and Ireland and some other European countries Short Range Certificate is the minimum requirement to use a marine VHF radio. This is usually obtained after completing a course of around two days and passing an exam. This is intended for those operating on lakes and in coastal areas whereas a Long Range Certificate is usually recommended for those operating further out as it also covers HF and MF radios as well as INMARSAT systems.