Topic: Amateur radio
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🔗 Olivia MFSK
Olivia MFSK is an amateur radioteletype protocol, using multiple frequency-shift keying (MFSK) and designed to work in difficult (low signal-to-noise ratio plus multipath propagation) conditions on shortwave bands. The signal can be accurately received even if the surrounding noise is 10 dB stronger. It is commonly used by amateur radio operators to reliably transmit ASCII characters over noisy channels using the high frequency (3–30 MHz) spectrum. The effective data rate of the Olivia MFSK protocol is 150 characters/minute.
Olivia modes are commonly referred to as Olivia X / Y (or, alternatively, Olivia Y / X ), where X refers to the number of different audio tones transmitted and Y refers to the bandwidth in hertz over which these signals are spread. Examples of common Olivia modes are 16/500, 32/1000 and 8/250.
Discussed on
- "Olivia MFSK" | 2019-06-11 | 162 Upvotes 27 Comments
🔗 QSL Card
A QSL card is a written confirmation of either a two-way radiocommunication between two amateur radio or citizens band stations; a one-way reception of a signal from an AM radio, FM radio, television or shortwave broadcasting station; or the reception of a two-way radiocommunication by a third party listener. A typical QSL card is the same size and made from the same material as a typical postcard, and most are sent through the mail as such.
QSL card derived its name from the Q code "QSL". A Q code message can stand for a statement or a question (when the code is followed by a question mark). In this case, 'QSL?' (note the question mark) means "Do you confirm receipt of my transmission?" while 'QSL' (without a question mark) means "I confirm receipt of your transmission."
Discussed on
- "QSL Card" | 2023-04-08 | 99 Upvotes 46 Comments
🔗 Slow-Scan Television
Slow-scan television (SSTV) is a picture transmission method, used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or color.
A literal term for SSTV is narrowband television. Analog broadcast television requires at least 6Â MHz wide channels, because it transmits 25 or 30 picture frames per second (see ITU analog broadcast standards), but SSTV usually only takes up to a maximum of 3Â kHz of bandwidth. It is a much slower method of still picture transmission, usually taking from about eight seconds to a couple of minutes, depending on the mode used, to transmit one image frame.
Since SSTV systems operate on voice frequencies, amateurs use it on shortwave (also known as HF by amateur radio operators), VHF and UHF radio.
Discussed on
- "Slow-Scan Television" | 2023-11-13 | 117 Upvotes 24 Comments
🔗 Balloon Experiments with Amateur Radio
Balloon Experiments with Amateur Radio (BEAR) is a series of Canadian-based amateur radio high-altitude balloon experiments by a group of amateur radio operators and experimenters from Sherwood Park and Edmonton, Alberta. The experiments started in the year 2000 and continued with BEAR-9 in 2012 reaching 36,010 metres (118,140Â ft).
The balloons are made of latex filled with either helium or hydrogen. All of the BEAR payloads carry a tracking system comprising a GPS receiver, an APRS encoder, and a radio transmitter module. Other experimental payload modules include an Amateur Radio crossband repeater, and a digital camera all of which is contained within an insulated foam box suspended below the balloon. A parachute recovery system is automatically deployed when the balloon bursts at altitude.
Discussed on
- "Balloon Experiments with Amateur Radio" | 2020-01-27 | 65 Upvotes 25 Comments
🔗 International Reply Coupon
An international reply coupon (IRC) is a coupon that can be exchanged for one or more postage stamps representing the minimum postage for an unregistered priority airmail letter of up to twenty grams sent to another Universal Postal Union (UPU) member country. IRCs are accepted by all UPU member countries.
UPU member postal services are obliged to exchange an IRC for postage, but are not obliged to sell them.
The purpose of the IRC is to allow a person to send someone in another country a letter, along with the cost of postage for a reply. If the addressee is within the same country, there is no need for an IRC because a self-addressed stamped envelope (SASE) or return postcard will suffice; but if the addressee is in another country an IRC removes the necessity of acquiring foreign postage or sending appropriate currency.
Discussed on
- "International Reply Coupon" | 2024-07-07 | 57 Upvotes 13 Comments
🔗 Heathkit
Heathkit is the brand name of kits and other electronic products produced and marketed by the Heath Company. The products over the decades have included electronic test equipment, high fidelity home audio equipment, television receivers, amateur radio equipment, robots, electronic ignition conversion modules for early model cars with point style ignitions, and the influential Heath H-8, H-89, and H-11 hobbyist computers, which were sold in kit form for assembly by the purchaser.
Heathkit manufactured electronic kits from 1947 until 1992. After closing that business, the Heath Company continued with its products for education, and motion-sensor lighting controls. The lighting control business was sold around 2000. The company announced in 2011 that they were reentering the kit business after a 20-year hiatus but then filed for bankruptcy in 2012, and under new ownership began restructuring in 2013. As of 2019, the company has a live website with newly-designed products, services, vintage kits, and replacement parts for sale.
Discussed on
- "Heathkit" | 2014-10-07 | 38 Upvotes 17 Comments
🔗 AMPRNet: Amateur Packet Radio Network
The AMPRNet (AMateur Packet Radio Network) or Network 44 is used in amateur radio for packet radio and digital communications between computer networks managed by amateur radio operators. Like other amateur radio frequency allocations, an IP range was provided in 1981 for Amateur Radio Digital Communications (a generic term) and self-administered by radio amateurs. In 2001, undocumented and dual-use of 44.0.0.0/8 as an internet telescope began, recording the spread of the Code Red II worm in July 2001.
Discussed on
- "AMPRNet: Amateur Packet Radio Network" | 2015-11-18 | 25 Upvotes 14 Comments
🔗 British Amateur Television Club
The British Amateur Television Club (BATC) is the world's largest television technology club; it has members in the UK and all around the world and is a non-profit making club run by an elected committee of volunteers for the benefit of its members. Membership is open to all who are interested in television, amateur or professional, indeed the club has many members who work for major broadcasting companies.