Hot answers tagged

40

The usage of "73" for such a purpose comes from the Phillips Code, originally devised in the era of telegraphs to speed up transmission of common messages by mapping them to numbers. "73" mapped to "best regards" or "my compliments" and was intended as a general valediction for transmitted messages. It is still used for that purpose today in morse code ...


34

A link budget is a summary of a communications link that tries to take into account all factors which have an impact on the received signal strength. It is often used to determine the minimum amount of output power required at the transmitter for a given signal strength at the receiver, and takes into consideration power output, antenna gains, propagation ...


31

"Getting a nickel" is a reference to how metered pay phones work (worked?). You'd put in some coins, make your call, and when the time you'd payed for expired, the phone operator would demand another nickel to buy more time and keep the call going. Repeaters on automatic control typically have a "time-out" function that acts as a ...


18

The Etymology of Ham Radio Wikipedia article states that the term was originally used in a derogatory way by professional radiotelegraph operators about amateurs similar to the way an incompetent actor would be called a ham. The term was embraced by amateur radio operators and turned into a term to describe themselves. I found some other interesting ...


17

73 is, as Amber said, Phillips code for best regards or my compliments. I just wanted to add that it's redundant to say 73s, which amounts to Best Regardses or My Complimentses. This puts one in mind of Smeagol, talking to Hobbitses.


17

"QRM" is one of many Q-codes used as abbreviations in radio communication. "QRM" in particular refers to human-generated interference (as opposed to "QRN" which is used to refer to atmospheric noise). "QSB" refers to fading (variation in signal strength over time). The codes originated from the desire to keep CW (morse code) transmissions as brief as ...


17

If you don't know what a frequency is, you need to read up on waves-in-general and radio waves. But the other two terms can be defined in terms of frequency; frequencies are the “natural” thing and everything else are things people invented on top of that. A frequency band, or band, is a range of frequencies with a specific least frequency and greatest ...


15

The emission type specifier is made up of several fields, which are defined as follows. First comes an (optional) specifier of the necessary radio bandwidth. This is four characters, mixed letters and numbers, with one of H (Hz), K (kHz), M (MHz) or G (GHz) where the decimal point would be. For example, 400H specifies a bandwidth of 400 Hz, 2K40 specifies 2....


14

That's a pretty good answer but I can add some more details. The exact formula for path loss is $$ 20 \times \log_{10}\left( 4 \times \pi \times \frac{d}{\lambda{}} \right) $$ $ 20 \times \log_{10}\left(4\times\pi{}\right) \approx 21.98$, and that's where the '22' comes from. If your receiver specs give a minimum signal strength, then the analysis above is ...


14

The ITU bands are actually delineated along plain powers of ten! They're just hiding a bit. From the description above a table of all the bands on Wikipedia: As a matter of convention, the ITU divides the radio spectrum into 12 bands, each beginning at a wavelength which is a power of ten ($10^n$) metres… So the HF band is from 100–10m, or the UHF band ...


13

The Jamboree-on-the-Air, or JOTA, is an annual Scouting event that uses amateur radio to link Scouts around the world. Held on the third full weekend of October each year since 1958, this worldwide jamboree requires no travel, other than to a nearby radio amateur’s ham shack. Over 500,000 Scouts participate in JOTA, making it the largest single Scouting ...


13

What is dBm? dBm stands for decibels relative to one milliwatt. Decibels represent multiplicative factors, or ratios; by establishing a specific reference level they can instead be used as absolute values: 0 dBm is 1 milliwatt, 3 dBm is approximately 2 milliwatts, etc. How do I convert it to watts? Convert the decibel value to a scale factor and ...


12

Homebrew is (as the name suggests) when you make your equipment yourself, as opposed to buying it. An amateur setup consists of many components - the largest and most complicated of which are a radio transceiver (or separate receiver and transmitter), and the antenna. A power supply is also needed, but these are relatively inexpensive compared to the cost ...


11

This became clear to me after a bit of time to think, but it wasn't at all clear on initially jumping in. It helps to know the formal definitions of the codes used: CQ is “Calling any station”. The station is asking for (new) contacts from anyone. QRZ? is “Who is calling me”. The station is asking for a calling station to repeat their callsign. Only a ...


10

It's intended for contest logging. Most contests require that you "exchange" some information. Sometimes it's as simple as an RST signal report and you'd just enter whatever signal report you gave an received, other contests require a serial number (you send "1" to your first contact and increment that by one each time, so that each contact gets a unique ...


9

I keep these "Q" signals in line with this : QRN is "N"atural band noise ( lightning ) QRM is "M"an-made band noise ( crowded signals ) QSB is "B"utterfly effect from Ionosphere in-stability.


9

Originally, the term "ham" was used to describe an operator with poor skills. However, it gained usage pretty early on not only in a neutral but even positive way. The usage of the term seems to have solidified in the second half of the 1910s, as a neutral-to-positive word to describe an amateur (as in unpaid) operator. Wikipedia lists several false ...


9

Marcel Wallace founded Panoramic Radio Corp. and details his "Panoramic radio receiving system" in patent US2279151A (1938). Page 2, column 1, line 19 of the patent gives us a clue as to how the physical "panoramic" concept made its way into what we now consider to be a purely electrical phenomenon: ...provide a panoramic radio compass system having ...


8

A scanner is a specialized receiver with features for effectively monitoring many frequencies, classically by tuning to each in rapid succession (scanning) and stopping when a signal is found, then continuing when the signal ends. The scan function can of course be disabled to use it as a receiver for a single channel. Scanners as commonly discussed are ...


8

As has been mentioned, many radio amateurs tend to be in the types of fields where various forms of rules are the name of the game. Electricity always behaves the same. So does a computer (assuming it is working correctly, it simply executes one instruction after another; it doesn't deviate or take initiatives of its own). And so on. However, there is ...


8

A calling frequency is a common channel known to all - this is the channel that anyone can jump onto and say Hi! Or a specific person you know may be monitoring this channel, you can call out to them. Should you wish to hold a longer conversation, you would use this channel to agree upon which channel you will be switching to.


8

It is ham radio laughter. HIHI, sometimes HI, other other times HIHI. It's origins are in CW (aka Morse Code), not voice. In fact, I believe old-timers might think it is silly to say HiHi or something on SSB or other voice comms when you can merely laugh if something is funny. But, with Morse Code, laughter is not in the alphabet so HIHI gets the job. ...


8

My personal opinion is that QRP means using significantly less power than is customary for a given mode of operation. In that sense, a 5W HT would not be QRP because pretty much everybody else with an HT is also operating at (or near) 5W. 0.5W might be considered QRP in this case.


8

My understanding of "QRP" is simply the use of as little power as possible to make contacts over interesting distances. There isn't a specific power level that equates to "QRP" - it is more a function of what's less than expected. 1W on 2m/UHF for 10 mile simplex (or local/regional repeater communications) isn't QRP. 0.1W on 2m/UHF for 250 mile simplex ...


7

Deepness of QSB refers to the magnitude of fading. A very deep fade-out can make the received signal so weak that it becomes unreadable. A shallow fade-out would be one where the signal level drops only slightly, not affecting readability. Radio propagation conditions often change quite quickly over time. For example, QSB might start in the middle of a ...


7

I think there are two parts to this; why are they so "anal" /strict / uptight about the rules? why are they so hostile / aggressive / generally unpleasant? The first part I think is due to something that most people don't appreciate. The Ether (if you'll excuse the name) is a shared resource. The rules are there to try to let us all use it as ...


7

It is known as an SF style SMA connector. It is also commonly known as a Motorola SMA connector since they seem to be one of the few large scale users of this style connector You can find some adapters for this style of connector such as this RFB-1142-4 BNC adapter: http://www.hitechwireless.com/rf-industries-rfb-1142-4-bnc-f-sma-f-adapter/


6

As said by other answerers, it's typically the station announcing 'I'm ready for more contacts at this time.' It doesn't necessarily have to be a DX station, but any station that is attracting a lot of traffic during contests. It is kind of informal usage, as Kevid Reid mentioned, the official QRZ definition is 'who is calling me?', and CQ means 'calling all ...


6

During contests, a popular station (say DX) has a pileup with lots of stations trying to make contact. A station will often merely say QRZ for picking up someone from the pileup. Thus, in this I am agreeing with the previous answer but with the following comment. I believe that this method of saying QRZ is now so popular in this pileup situation (that is, ...


6

Are there specific problems or equations that are easier to deal with in dBm vs watts? Decibel units, dBm being an example of such, provide a more intuitive measure of some property that responds logarithmically, like power frequently does. Consider, if you are transmitting now with 1W, and you add 1W more, you have doubled your transmit power. That's a ...


Only top voted, non community-wiki answers of a minimum length are eligible