![]() ![]() If your interest is more recreational, you'll do much better if you get a set with SSB (ie LSB and USB settings) as Nevertheless AM remains suitable for groups desiring cheap car-to-car communications amongst themselves. Major retailers have stopped selling 27 MHz radios, so you will need to find one of the few specialised communications shops, haunt the pawn shops or peruse the localĬlassifieds to find equipment for sale. These days, you'll have no problem finding a vacant channel even in major cities it is common to flick through them all and hear nothing. Year during times of high sunspot activity.Ģ7 MHz AM activity has declined enormously in the last 20 years. ![]() Long-distance propagation is most common in December/January each year and throughout the Well-equipped home stations will do better than a mobile station.On SSB, distances of between 15 and 30 kilometres are common, with 3000 km sometimes possible under favourableĬonditions.Good conditions are often called 'skip', so-called because the signal bounces ('skips') off the ionosphere on its way to the other station. Locally, expect communication distances of between 5 and 15 kilometres on AM.Actual range achieved will depend on antenna efficiency, terrain and interference levels. What 27 MHz can do depends on the transmission mode (AM or SSB), with SSB providing better results when signals However the latter cannot be relied upon. In the 1980s, and declined since the 1990s as most users moved to UHF CB, amateur radio, mobile phones, IRC internet chat or simply gave it away.Ģ7 MHz is capable of both local and interstate communication. 27 MHz activity peaked in the 1970s, remained fairly popular Though usage of 27 MHz CB has fallen, it remains the cheapest method of basic local communications, especially in hilly areas. However operators must still use their equipment in accordance with theĬB class licence, a copy of which is available on the Australian Communications and Media Authority website. This was recognised in 1994, when the government abolished CB licence fees. The cost of policing was probably higher than revenue foregone. Provided you did not cause interference, used illegal amplifiers or make a nuisance of yourself, the chance of being caught by Department ofĬommunications inspectors was slim. Most CB operators did not bother with licensing. You hear an inexperienced person talk about 'CB' the chances are that they are referring to 27 MHz. A basic 40 channel 27 MHz AM only set is pictured below. However it proved so popular that the band was extended to its current 40 channels in 1982. In Australia 27 MHz CB was planned as a temporary allocation, with users to move to UHF in five years. However unlike amateur radio, no technical examination was required. Operators had to obtain a government call sign, pay an annual licence fee and use type-approvedĮquipment. The government initially allocated 18 channels for CB. Wanted cheap, local communications for personal or business purposes. Australia legalised CB in the late 1970s, following a vigorous campaign by truck drivers and others who Information is also provided on deciding between the two and the limitations of CB communication.Ģ7 MHz CB started in the United States in the 1950s and spread worldwide in the 1970s. The differences between 27 MHz and UHF are explained below. Signals on different frequencies behave differently, and thus affect the performance of equipment. 27 MHz is between the 530 - 1602 kHz AM and 88 - 108 MHz FM broadcast bands.Ĥ77 MHz is between the VHF and UHF TV channels. The 'megahertz' (MHz) refers to the radio frequency on which the equipment operates. There are two types of CB equipment: HF 27 MHz and UHF 477 MHz. Equipment is inexpensive and there are no Check your country'sĬommunications agency website for details though Wikipedia also has a good summary.ĬB radio is intended to provide short-range radio communication for almost any purpose, business or personal. Europe has PMR on 446 MHz and the USA Family Radio Service on 462/467 MHz. Australia and New Zealand have 477 MHz UHF CB. 27 MHz AM/SSB allocations are similar across countries though some places also allow FM. NOTE: The following relates to CB radio in Australia. Enjoyed this website? Please support it by starting your online shopping here: Amazon eBay (no extra cost). ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |