Re: What Kit's would be nice for 2021
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An NDB is used by aviators and mariners for long-range navigation and are typically located on mountaintops and promontories overlooking coastlines. They simply transmit one, two, or three Morse characters at 5 wpm over and over, on 190 KHz to 1,750 KHz, although normally NDBs in North America operate between 190 KHz and 535 KHz (some AM radios can pick up those on 530 - 535 KHz) modulated by either 400 or 1,020 Hz. They're depicted on navigation charts (there's no such thing as an aeronautical or maritime map) by this symbol:
Therefore, their position is precisely fixed and known, and they're broadcast-only - you can't communicate with them. However, their power levels can be as low as 25 watts, and some range up to 2 KWs. They're favorites of DXers because, under the right conditions, they can be received much further than their intended range (but you can't receive a QSL card from them!).
The U.S. system is being decommissioned by attrition at the least-used sites, as well as a plan to eliminate about 50 per year through 2025. Aviators and mariners are strongly opposed to this plan, because GPS can be fragile for a variety of reasons, including lack of good coverage at higher latitudes, and others which can't be discussed at the unclassified level.
Jim KJ7JHE, FAA certificated pilot, and U.S. Navy shipboard navigator