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13
votes
6answers
3k views

Why are vacuum tubes still used in amateur radios?

I wonder, even in this modern generation why the outdated vacuum tubes are used. In other electronic circuits they have been replaced by more efficient (and small) transistors years ago. Why they are ...
10
votes
3answers
870 views

What does the spark-gap do in a spark-gap transmitter?

I read the Wikipedia article about spark-gap transmitters and I have to admit that I’m even more confused as to what the spark-gap actually did. The article references this simplified circuit ...
9
votes
5answers
463 views

How did hams manage to tune their antennas before VSWR meters?

In the early 20th century --back when the hobby was still new-- before VSWR meters and antenna analyzers were invented, how did radio operators know whether they were tuned for maximum power out? ...
9
votes
4answers
956 views

What did it mean to “align” a radio?

I've heard older hams talk about "aligning" their equipment. E.g. "I sent it to a guy for alignment" or "that rig probably needs to be completely aligned before you use it". As a kid, sometimes I ...
8
votes
2answers
294 views

How were 1920s hams able to measure megahertz frequency?

I was reading 200 Meters and Down but one thing that was unclear to me was that hams in the 1920s were operating on the 200 meter frequency, which is around 1.5 Mhz .... or 1500 kilocycles to use the ...
6
votes
4answers
837 views

Why do some straight keys have a slider that shorts the contacts continuously?

I ended up with an old straight key that has a curious feature: below the main arm that you would tap on, there's an extra metal flange that can sort of loosely pinch an extra sliding lever underneath,...
6
votes
1answer
113 views

USA/callsigns: Why is California region 6? And the midwest in regions 7-9?

I don't quite understand the regional callsign system for the USA. At first it seems to make sense with CT, MA, ME, NH, RI, and VT being region 1 and then going west NJ and NY are region 2, and then ...
5
votes
2answers
316 views

How did the terms like QRZ, QTH, and other forms of ham shorthand evolve?

I've wondered if many of the abbreviations are empty, or if they are similar to the recursive acronym like PHP and GNU. For instance, I learned that CQ mimics the two syllables of a French word for ...
5
votes
2answers
120 views

What additional information do I get from an RF ammeter, as compared to a regular SWR/wattmeter?

I've grown up using SWR/power meters. They're "simple" devices: They show forward and reverse power, and show the standing wave ratio. They, however, do not show antenna efficiency. New hams are ...
5
votes
1answer
109 views

Is there a practical way for hams to participate in cellular-related technology advances?

My understanding is that there used to be more timely overlap between commercial and amateur radio technology — e.g. helping study ionospheric propagation, relatively early adoption of SSB technology, ...
3
votes
2answers
277 views

Using approximate signal strength at a distance to estimate reception strength of a radio station

I have some historical data on radio stations, but unfortunately, the dataset only has these variables: the power of the transmitter, in watts the coordinates of the radio tower Unfortunately, I don'...
3
votes
1answer
890 views

What is a panadapter?

To what does the term "panadapter" refer? (Physical hardware or software?) How did the term "panadapter" originate as related to radios or electronics? How is the term "panadapter" different from ...
3
votes
2answers
220 views

When was the first radio transceiver (transmitter/receiver) built, and by whom?

I'm really passionate about signals and communications ever since I was a child where we "built satellites" - little did I know that it would become part of my future. So here is my first question: ...
3
votes
1answer
223 views

Where exactly is the Morse code character “;” defined?

I've seen that quite often in Morse code tables (for example here), under punctuation, a semicolon ";"character is listed. However, the ITU-R M.1677-1 doesn't specify that character as a part of ...
2
votes
2answers
177 views

Lightbulb as an SWR detector?

Back in ye olden days before SWR meters and auto-tuners, how was a ordinary household lightbulb used to help tune an antenna system? What did the circuit and tuning procedure look like?
2
votes
1answer
95 views

What were the reasons why ATIS identification was introduced?

I am just about to make my inland waterways’ marine VHF radio license in Germany. In Germany, all inland marine VHF radios must be equipped with an ATIS transmitter, which basically sends the stations’...
1
vote
2answers
98 views

Is the Relay in ARRL still relevant?

The second R in ARRL stands for Relay, but is that still as relevant in the 21st century? Has it been relevant since broad damped-wave spark transmitters were supplanted with tube-generated CW, which ...
1
vote
1answer
339 views

Are there famous radio frequencies? [closed]

I am going to mention a radio frequency of an emergency broadcast radio station in a post apocalyptic video game (I'm part of the dev team), and I would like to make a reference to real world radio. ...