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69

because there are a large number of operators who had to learn it to get their licence because there is a large (but slowly diminishing) number of operators who learned it while serving in the armed forces because the transmitters and receivers can be extremely simple and inexpensive, not needing much more than a key and headphones along with the rig, ...


34

The advantage? Efficiency! You get to put all of that power of your rig into a very small bandwidth, whereas voice modes need to spread the power out much more (for example, SSB uses roughly 2.8kHz of bandwidth). Quote from: http://home.windstream.net/johnshan/cw_ss.html : Going a little bit further, assuming a SSB signal takes up 2000 Hz., and ...


22

One of the reasons it's still in use is because of its inherent simplicity - no real signal processing is needed. Thus, CW transmitters and receivers are very simple and thus inexpensive.


20

One of the biggest advantages of CW is that users worldwide can contact each other without knowing English, or any specific language. Conversation is limited to the common Q codes, but these provide significant flexibility and ability to communicate making Morse Code a common language of sorts.


15

Nothing is preventing an SDR from transmitting the D-STAR protocol, other than the need to implement it as such. It is open, and currently I know that Digital Signal Decoder (DSD) can actually decode some data and textual frames. What prohibits transmission of D-STAR Digital Voice is the codec used to encode the voice - it's AMBE2000, which is patented and ...


12

Does mixed-mode operation qualify as a QSO? I'd say absolutely, yes. You're making contact with another amateur radio station on a frequency allocated to amateur radio; in my book, that qualifies as an amateur radio contact or QSO. What is the legal status of such a cross-mode QSO? Assuming that your license allows you to transmit on the frequency and ...


12

Your “B” is the stereo difference signal of broadcast FM stereo. It is placed at twice the pilot frequency so that it can be recovered by having the receiver lock onto the pilot signal and frequency-double it to obtain the subcarrier signal marking the position of the difference signal. The receiver uses this subcarrier to shift it in frequency down to the ...


11

Normally in amateur radio when specifying a frequency you specify the nominal carrier frequency. For SSB and other suppressed-carrier transmission modes, you specify the frequency to which the BFO needs to be tuned to re-insert the suppressed carrier. For this to work, you also need to specify which sideband you are transmitting on; lower, upper, or both. (...


10

Because it's fun to send and receive messages by Morse code! It's something that can be done without any specialized equipment for sending and receiving. It's a shared historic experience. It's a challenge, and a skill that is fun to learn. It puts you into a special "club," setting you apart from those non-CW capable hams. But mostly, it's just fun.


9

I am a new ham, and I decided to learn it, and use it, strictly for the purpose of efficiency. CW operation is low bandwidth, and therefore requires very little power to get a signal out over long distances. You will not get the same results from voice transmissions or other larger bandwidth data modes (although JT-65A and PSK31 are relatively efficient data ...


9

Morse code requires an extremely small bandwidth (and is usable in a channel that has a relatively low S/N) for a mode that requires no digital processing hardware or computer/digital logic chips (instead requiring just the skill of a couple of human brains) to communicate. Some people value accomplishing things using personally learned skills rather than ...


9

I love Morse code for these reasons: It's fun. There is something satisfying about pulling a really weak signal out from the noise just 10s of Hz away from another really strong semi-local signal, and making a decent contact with someone halfway around the planet with less than 100W. I can put headphones on and operate in the living room while the XYL is ...


9

I would echo the point mentioned by N8WRL: "Why do I operate CW? It is a blast!" I'm actually re-learning morse and realising I've been missing out on a lot of fun over the years. In terms of learning and training, it feels some way between learning a musical instrument and learning a new language. It is an excellent way to stimulate the brain - an ...


8

It depends on what you mean by propagation. If you mean, does the modulation scheme affect the physical means by which EM energy gets from point A to point B?, then the answer is no. Mostly, EM propagation is linear, so the differences in modulation have little effect on how the wave propagate. However, if you expand propagation to include the ...


8

I got my technician license in 1992 to play with packet and TCP/IP on VHF/UHF. I got bitten by the HF bug listening to the CW subbands. I decided to learn CW on my laptop on business trips. I struggled to pass 5 WPM for my Tech-plus but I did and I got on 80m CW. A few months later I had WAS and It wasn't long after that I passed 20 WPM for my Extra. Why do ...


8

In noisy conditions, CW is the most effective mode for "real time" communications. This is the primary reason that CW remains popular with DXers. Some digital modes can succeed under even worse conditions, but they do so by employing redundancy, which makes for very slow QSOs.


8

There are actually three different distinctions one could mean by referring to “narrowband” FM. Wideband FM in this context generally refers to the type of FM used for broadcast stations — those picked up by consumer FM receivers — as opposed to that used by two-way communications, including amateur transceivers. You are right that there is no fundamental ...


8

APRS is a data transmission protocol and is independent of the underlying connection details. So there is no required modulation for the protocol. That said, the common implementation of APRS is FM modulated 1200 baud AFSK in the 2m band. Several major vendors like Yaesu and Kenwood support the protocol with built in functionality for APRS. There have ...


7

In the UK, the terms of the licence start with: 1(1) The Licensee shall ensure that the Radio Equipment is only used: (a) for the purpose of self-training in radio communications, including conducting technical investigations; and (b) as a leisure activity and not for commercial purposes of any kind. CW/morse lends itself to the self-training aspect ...


7

It was all I could afford when I was a kid. AM and SSB gear was expensive and still is! Stuck with it because: Signals are stronger, More of a challenge, and a CQ gets answered faster. Great people on CW.


7

FCC Regulations, Title 97.307(f)(8) says yes, you can transmit with ATSC modulation in the US, BUT you can't use frequencies which match US ATSC channels. You would need to find a receiver (maybe PC controlled?) flexible enough to listen to amateur frequencies. As to DVB-T or DVD-S, well, they'll work with about 2MHz of bandwidth instead of the 6MHz ...


7

It's about transmission duty cycles. For example, FM has a very high duty cycle during transmission: the transmitter's output power is constantly at 100% regardless of the amount of modulation. AM varies between 50% (carrier only) and 100% (full modulation). SSB varies with modulation between 0% and 100%. CW is like FM, 100% power output during transmission,...


7

Back, before the Internet, the documents were published in magazines, conference papers and such – well after the protocols were designed and initial tests were done. In some cases CWID (transmitting callsign using CW every now and then) has been used to make sure the transmissions are well identified even if the actual data is a bit hard to decode. ...


7

Others do not gain access to the content of the message In the US amateur radio service, transmitting “messages encoded for the purpose of obscuring their meaning” is prohibited by §97.113 and specifically for spread-spectrum (SS) by §97.311. I would imagine other jurisdictions have similar rules which prohibit such transmissions and/or require that ...


7

One case where this might happen would be in the world of RF over fiber. In this technique, a radio-frequency signal is used to modulate an optical (usually infrared) signal for transmission over optical fiber. Light is, after all, just really high frequency electromagnetic waves. To the best of my knowledge, the modulation used here is always AM, so if such ...


6

In the US, disaster declarations need to be approved and that declaration with approval must be transmitted to a state EOC before state aid can be approved. Therefore, early in the game, packet has become popular to get that declaration to the state capital. Although HIPPA does not apply to amateur radio (as operators are not healthcare providers), there's ...


6

If you're used to dealing with protocols between chips, like UART, SPI and I2C, then APRS will feel quite strange. Whereas if you've been involved with CAN, Ethernet, USB at the low level, then APRS will seem quite familiar. It's not as simple as 1200Hz means 0, and 2200Hz means 1. There are two things which make it different, firstly bit-stuffing, and ...


6

There are a lot of things wrong here. Neither plot looks correct. There is no way that Qt plot is realistic for anything but a signal generator. Where's the noise? Where are the three missing constellation points in the Qt plot? APRS isn't QAM (it's AFSK over FM), so I'm not sure why you are expecting QAM. You don't have any filters, clock recovery, or ...


6

Fldigi is largely intended for HF operation. From the beginner's guide: Fldigi is a computer program intended for Amateur Radio Digital Modes operation using a PC (Personal Computer). Fldigi operates (as does most similar software) in conjunction with a conventional HF SSB radio transceiver, and uses the PC sound card as the main means of input from the ...


6

FM modulated radio is much more resistant to noise and can deliver better sound quality than AM radio. Under certain conditions, that is! Namely, additive noise, and a fading channel. or is this noise resistance also an inherent property of FM? Huh, that surprisingly can be a pretty philosophical question about what bandwidth actually is, but let's ...


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