The DB-23 was
A: an audio amplifier
B: a dual boom headset
C: an RF preselector
D: a computer data cable connector
Answer is C…Boosts the gain and signal-to-noise ratio of Amateur receivers.
The Electro-Voice RME DB23 (RME stands for Radio Mfg. Engineers)is a low noise, radio-frequency preselector amplifier which can substantially improve receiver performance in the following amateur bands: 3.5-4, 7-7.3, 14-14.5, 21-21.5 and 26-30 MHz. It utilizes three tubes (3 x 6J6). It operates from 117 VAC 50-60 Hz.
This is a receive-only device.
|Click on the Spec sheet below for a full view
What thing found in nature was the object of research by the Army Signal Corps for use as a viable radio antenna?
D: Copper Mines
Answer is B…. For the whole story about Major General George O. Squier’s idea of “floraphone” please click here to go to Atlas Obscura
Of the 6000 active amateurs at the start of World War I, what percentage served in the military during that war?
Below is an artical from QST magazine 1995 written by W8LUX Dan Davis
For a printable and downloadable version ClickHere
Radio show host Arthur William Bell III was an Amature Radio Operator, American broadcaster, author and conspiracy theorist. What was his US callsign?
Answer is D… He was the founder and the original host of the paranormal-themed radio program Coast to Coast AM, which is syndicated on hundreds of radio stations in the United States and Canada.
More about Arthur William Bell III at… Wikipedia, NPR including show recordings
Which HamFest has a seminar called The Contest University
- Fort Worth
Answer 2… Dayton; Contest University is separate from the Dayton HamFest, Contest University is a full day seminar on the ins outs and tricks of contesting and much more. This is a separate charge and location from Dayton Ham Nation..
To get around HOA restrictions for VHF communications which would be the most creative
- A Flagpole
- Spray on Antenna
- Satellite TV Dish
Answer 4… Turn a satellite dish tv dish into a slot antenna. This is a narrow rectangular opening in a large conductive surface, such as a TV satellite dish. Slot antennas are familiar in the commercial radio world, but not to hams. They’re common in TV broadcasting, the skin of aircraft and in radar, microwave and cell phone applications. This disguised TV dish slot is equal to a J-pole.
Below is a PDF by “W6NBC John Portune”
What direction does the Evaporation Duct refract RF signals
- Horizontal following the curvature of the earth
- Horizontal up and down following the curvature of the earth
- Horizontal parallel to the earth’s curvature
Answer is “3”… The drop in the refractive index of the atmosphere within the first few meters above the surface of the sea causes incident radio waves to be refracted towards the earth more than normal so that their radius of curvature becomes less than or equal to that of the earth’s surface. The sudden change in the atmosphere’s refractivity at the top of the duct causes the radio waves to refract back into the duct, and when it comes in contact with the surface of the sea, it gets reflected upwards again.
For more view the documents below….
Related to atmospheric ducting are atmospheric optics; What is the atmospheric optic Fata Morgana
- Complex mirage
- Polar mirage
- Meteorological optical phenomena
- Naturally occurring phenomena
Answer is 1… Complex mirage. It is a complex form of a superior mirage. It is an Italian term named after the Arthurian sorceress Morgan le Fay. The Flying Dutchman, according to folklore, is a ghost ship that can never go home, and is doomed to sail the oceans forever. The Flying Dutchman is usually spotted from afar, sometimes seen to be glowing with ghostly light. One of the possible explanations of the origin of the Flying Dutchman legend is a Fata Morgana mirage seen at sea.
More at Wikipedia on Complex Mirage, Polar Mirage, Meteorological optical phenomena and Naturally occurring phenomena
ARDF (Amature Radio Direction Finding) began as a sport in what country
Answer B… The sport originated in Northern Europe and Eastern Europe in the late 1950s. Amateur radio was widely promoted in the schools of Northern and Eastern Europe as a modern scientific and technical activity. Most medium to large cities hosted one or more amateur radio clubs at which members could congregate and learn about the technology and operation of radio equipment. One of the activities that schools and radio clubs promoted was radio direction finding, an activity that had important civil defense applications during the Cold War. As few individuals in Europe had personal automobiles at the time, most of this radio direction finding activity took place on foot, in parks, natural areas, or school campuses. The sport of orienteering, popular in its native Scandinavia, had begun to spread to more and more countries throughout Europe, including the nations of the Eastern Bloc. As orienteering became more popular and orienteering maps became more widely available, it was only natural to combine the two activities and hold radio direction finding events on orienteering maps.
For More, Wikipedia and Amature Radio Wiki
What is Vestigial sideband (VSB)
A. A form of DSB (Double Sideband)
B. An old form of SSB
C. New form of Commercial radio
D. A type of amplitude modulation technique that encodes data by varying the amplitude of a single carrier frequency
Answer D… VSB modulation lies between SSB and DSB modulation, whose purpose is to save the bandwidth, to reduce the transmitted power and to avoid the distortion.
Limitation of single-sideband modulation being used for voice signals and not available for video/TV signals leads to the usage of vestigial sideband. A vestigial sideband (in radio communication) is a sideband that has been only partly cut off or suppressed. Television broadcasts (in analog video formats) use this method if the video is transmitted in AM, due to the large bandwidth used. It may also be used in digital transmission, such as the ATSC standardized 8VSB.
The broadcast or transport channel for TV in countries that use NTSC or ATSC has a bandwidth of 6 MHz. To conserve bandwidth, SSB would be desirable, but the video signal has significant low-frequency content (average brightness) and has rectangular synchronising pulses. The engineering compromise is vestigial-sideband transmission. In vestigial sideband, the full upper sideband of bandwidth W2 = 4.75 MHz is transmitted, but only W1 = 1.25 MHz of the lower sideband is transmitted, along with a carrier. This effectively makes the system AM at low modulation frequencies and SSB at high modulation frequencies. The absence of the lower sideband components at high frequencies must be compensated for, and this is done in the IF amplifier.