Skip to main content
13 votes
Accepted

Single Side Band AM vs FM

First of all, you're not 100% right that SSB will reduce transmit power. I often keep talking on SE about power spectral density. So let me start with that again and first assume that we have a ...
AndrejaKo's user avatar
  • 2,893
12 votes
Accepted

How does signal strength relate to bandwidth?

It depends on what you mean by "stronger". Ignoring actual limitations of your hardware and just considering the theory of communications, if you have 25 W of transmit power, then you can spread that ...
Kevin Reid AG6YO's user avatar
  • 24.6k
11 votes
Accepted

Is it legal to transmit scrambled or encrypted voice via SSB on ham bands?

In the US, the FCC prohibits this type of operation if the purpose is to obscure the meaning of your transmission. 97.113 Prohibited Transmissions (4) ... messages encoded for the purpose of ...
Glenn W9IQ's user avatar
  • 18.6k
10 votes

Single Side Band AM vs FM

Firstly, FM is a constant-envelope modulation, meaning the amplitude is constant. SSB, being a kind of amplitude modulation, obviously does not have a constant amplitude. Consequently, FM can employ a ...
Phil Frost - W8II's user avatar
8 votes
Accepted

SSB Generation. 4th method?

I could imagine a class D pwm system doing the Envelope and the phase modulated carrier getting clipped and fed into a class E amplifier and then you could run 100Watts with no heatsinks allowing ...
Brian K1LI's user avatar
  • 7,868
8 votes

Can an SSB transmitter be used to transmit PSK?

The short answer is "absolutely!". :-) I started out using Digipan on Windows, but other software such as Fldigi has been released since then. Audio from the sound card to the mic input --and from ...
Mike Waters's user avatar
  • 8,023
7 votes

What exactly is a "balanced modulator"?

To put it simply, a balanced modulator is a mixer which has two inputs and two outputs. The outputs are (input1 + input2) and (input1 - input2). So, if the inputs are 100kHz and 1kHz, the outputs are ...
Scott Earle's user avatar
  • 4,599
7 votes

Does the output of a BFO for a short wave receiver have to be exactly a sine wave?

So, the job of a BFO is essentially "faking" the carrier oscillation of the AM transmission that was suppressed, together with the other sideband, so that the rest of the receiver can ...
Marcus Müller's user avatar
6 votes
Accepted

What are the practical differences between the different voice modes (and why aren't there any SSB Handheld Transceivers (HT's))?

SSB phone requires good frequency stability to be intelligible. Anything over 10Hz of frequency difference between transmitter and receiver and the signal starts to sound funny; beyond 50-70 Hz of ...
hobbs - KC2G's user avatar
  • 12.5k
6 votes

How can I check if my CB radio is AM or AM/SSB?

As mentioned in another answer, it sounds like it’s not SSB. The next question is whether it’s AM or FM. “CB” can mean different things in different countries, and you don’t say which country you are ...
Scott Earle's user avatar
  • 4,599
5 votes

What exactly is a "balanced modulator"?

Partial answer, because I don't know the actual electronics theory, but I hope which will help make progress towards a complete answer: A balanced modulator is a mixer with a particular feature. ...
Kevin Reid AG6YO's user avatar
  • 24.6k
5 votes

How does selecting the opposite sideband when receiving CW on HF reduce interference?

If you are using (or building) a vintage radio that does not have a narrow CW audio filter, the audio bandwidth above and below a listenable CW audio side-tone frequency can be quite unsymmetric. By ...
hotpaw2's user avatar
  • 13.4k
5 votes

SSB filtering in the frequency domain?

For DSP with complex samples, whether you are working in the time domain or the frequency domain, you don't need an AM demodulator, or complex conjugation, or a Hilbert filter. You say you have ...
Kevin Reid AG6YO's user avatar
  • 24.6k
5 votes
Accepted

Is there a way to get FreeDV output level to follow the input audio amplitude?

It seems that FreeDV encodes the input audio signal in both the frequency and time domains, which means that the output signal amplitude doesn't follow the input signal amplitude, but rather the ...
Marcus Müller's user avatar
5 votes
Accepted

Does the output of a BFO for a short wave receiver have to be exactly a sine wave?

The BFO is one input to the mixer, the other being the RF signal you're wanting to receive. An ideal mixer simply multiplies its inputs: if at one instant one input is 2V, and the other input is 3V, ...
Phil Frost - W8II's user avatar
5 votes

What does ALC do on a transceiver?

ALC, in general, stands as an abbreviation for Automatic Level Control, which is a class of circuits designed to back-feed information about the output signal to an amplifier. The goal is to change ...
jstarek's user avatar
  • 222
5 votes

What's the realistic SSB reception range for 25W on 20m and 40m?

All things are possible (if a bit harder). The CQ WW SSB contest has a QRP category (maximum of 5 watts of power), and the top scorers in that category in 2020 worked more than 100 countries in 48 ...
hobbs - KC2G's user avatar
  • 12.5k
5 votes

What's the realistic SSB reception range for 25W on 20m and 40m?

Depends on ionospheric propagation conditions (sun spots, solar flux index, time-of-day, direction, and etc.). People have completed QSOs at well over a thousand miles with a few milliwatts in CW. A ...
hotpaw2's user avatar
  • 13.4k
5 votes
Accepted

HF SSB etiquette when someone is working quick but not contesting and you're not sure they got you?

Re "When I gave my call he read back something that sounded a lot like my call, but some noise got it so I couldn't make out if it really was mine or just a similar call. " When that happens,...
AA6YQ's user avatar
  • 726
5 votes
Accepted

What is the etiquette for answering real world, non-contest HF SSB calls?

Welcome to amateur radio! While it is true that communications are supposed to follow a standard, folks can become lazy. You will find some frequencies where some folks have set up shop, apparently ...
David Hoelzer's user avatar
  • 1,053
4 votes
Accepted

SSB Modulation and Differential Signaling

My current understanding from reading and looking at spectrum plots from SDR software is that the sound is modulated with the carrier, but only half the carrier wave. That's — not really accurate. A ...
Kevin Reid AG6YO's user avatar
  • 24.6k
4 votes

How does this circuit work? Why is the antenna connected to the output of the amplification stage?

EDIT to be more specific about the input circuit per Phil's comment: The antenna (aerial) is connected to the the oscillator of the first transistor stage formed by VC, L and the self capacitance of ...
Glenn W9IQ's user avatar
  • 18.6k
4 votes

SSB filtering in the frequency domain?

If you want to do SSB in the frequency domain: 1) Compute the complex FFT. 2) Pick the frequency band of interest. 3) Perform a backwards FFT on the bins that contain the signal of interest. ...
sm5bsz's user avatar
  • 1,009
4 votes
Accepted

Required SSB sideband and carrier suppression?

There is no such specific legal requirement, because AM and double-sideband suppressed carrier (DSBSC) are allowed. Different emission types occupy different bandwidths, as the FCC clearly ...
Mike Waters's user avatar
  • 8,023
4 votes

LSB modulation and demodulation

USB is basically AM with the carrier suppressed and the lower sideband filtered out. LSB is basically AM with the carrier suppressed and the upper side and filtered out. To demodulate either, you ...
Scott Earle's user avatar
  • 4,599
4 votes

Where can I find a table listing the maximum PEP per band?

The ARRL's band chart (PDF) includes the maximum allowed power for stations in the United States and its territories. Sometimes the power limit depends on the license class of the operator and/or the ...
rclocher3's user avatar
  • 9,242
4 votes

How can I check if my CB radio is AM or AM/SSB?

Australia has two CB bands, the old 27MHz band, where radios were either AM or SSB, & the UHF one, which uses FM.(which is apparently, the one you have.) Other countries have variations in either ...
Bryan Wheeler's user avatar
4 votes

Receiving range of ham radio on SSB with a portable radio receiver

The range of ham radio communications ranges from zero to unlimited. At the longer range of the scale, some hams direct their signal at the moon, where it's reflected back and received back on Earth. ...
Phil Frost - W8II's user avatar
3 votes

What exactly is a "balanced modulator"?

A balanced modulator is a kind of mixer. Specifically, it's one that works in all four "quadrants", that is combinations of each of the two input voltages being positive or negative. Along with that ...
Phil Frost - W8II's user avatar

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