I See Your Lips Moving, But…

By Don Keith, N4KC

Let's open up that can of worms known as single sideband audio.

Let's don't, though, take off on a diatribe against so-called ESSB—enhanced SSB. I actually enjoy listening to those guys sometimes, even if some of them are occupying a bit more bandwidth than some would like for them to. As long as they are not plopping down on top of somebody else, where's the harm? The bands are wide enough for all of us. And I see nothing wrong with trying to get the best sounding audio one can have, even if it may not be the most efficient way to communicate.

And let's don't jump on stations who deliberately EQ their audio—completely within legal limits but not necessarily achieving a sound you or I find pleasing—all in order to better stand out in the pack. Beauty is in the ear of the beholder. Or something like that.

The point of this article: adjusting our SSB audio so it is the most efficient it can be to communicate the way we want to communicate without interfering with the other guy's right to communicate the way he wants to. That is sort of the Golden Rule of On-air SSB Audio.

Like a lot of things in life, many of today's amateur radio transmitters come equipped with far more capability than many of us can handle. Or, if we have head room on our credit cards, there are all sorts of flashy audio devices we can purchase and hook up. It is like buying a car with the capability of 150 miles per hour on the speedometer when most of us don't have the experience, reflexes, or highways to safely operate a vehicle at anything close to those speeds. That does not stop some of us from trying it if we get the urge. Now, add a rocket booster to that car or some outboard audio processing gear to that radio and let the fun begin!

Allow me to make a statement here and see if you agree. SSB audio should be adjusted so it is the best it can be for whatever task you are attempting to accomplish—with the caveat that it must be legal and that it follows good operating practice, and preferably both. Note that I did not say it should necessarily sound like recording studio quality, or even that adjusted-to-fit-the-job audio should be pleasant to the average ear.

See, if I am attempting to get the dxpedition in East Nowhere to pick my puny little signal out of the pileup, I don't need flat-from-50-to-5000-hertz response and beautiful, harmonious EQ. I need a little thing called “talk power.” And that, my friend, requires some careful adjustment of my modern ham radio rig.

I can crank the audio gain and compression up to “10,” boost the midrange voice frequencies to the top of the pot scale, and scream into the microphone like a lunatic, but that does not necessarily give me maximum talk power. It probably gives me distortion, splatter, lots of snide comments from others in the pile-up, and—maybe most importantly if I really want to land that new country—LESS signal.

Let's talk about a couple of terms (for the newcomers because I know every seasoned ham knows what these things mean, right?).

First, why single sideband? When SSB first began to appear on the amateur bands in the late 1950s-early 1960s, the war between early adopters and the majority AM operators made the “no code” arguments look like a tea party! Oh, it was vicious! However, it did not take long for hams to see the advantages of not wasting power transmitting a big, old whining carrier or utilizing both audio sidebands, each of which carried basically the same information. (Let me hasten to add that there is nothing wrong with using AM today. It's fun, especially if you are reviving some old boat anchor rig. I enjoy listening to AMers, too, and especially those with good sounding audio. I even jump in sometimes with my 25-watt rice box.)

By suppressing the carrier and filtering out one sideband, a station needed only a fraction of the output power to reliably communicate over the same distance with the same signal strength. The reasons for this are beyond the scope of this article as well as my ability to explain it, but the point to grasp here is that, because of the way SSB works, there is more emphasis on how you adjust your audio if you want to fully take advantage of the mode. The peak power you put out is directly determined by your voice, your audio.

Now, how about that “Audio Gain” knob or menu setting on your shiny radio? Based on what I just said in the last paragraph, crank that gain to max and you'll be loud, right? Loud equals more power, true? Not necessarily. What you will probably be doing is overdriving a stage or two in the modulation circuit. That not only makes your voice distorted and difficult to understand, but it also causes bad things to happen to the signal you are modulating. You will splatter, causing interference up and down the band. But it may be more distressing to you to realize that you are wasting precious “talk power” transmitting all that splatter and distortion. You are actually being robbed of watts that are tied up trying to transmit all that ugly, unnecessary modulation information you are casting out into the ether.

Again, the reasons for this are beyond this little article and my writing ability, but Google “ssb modulation” or similar, or take a few minutes to read about the subject in the ARRL's Communications Handbook. You need every watt of signal you can get. Don't waste any of it by trying to be too loud!

There's another control there, one called “Compression.” Most radios today offer you the ability to compress the audio that feeds into your radio from your microphone. This is not to be confused with data compression, in which computer files are squeezed into a smaller package. Audio compression as it is typically implemented in ham equipment, works to boost quieter sounds up, bringing them closer to the same level as louder sounds. It actually works to overcome an otherwise pretty nice thing called “dynamic range,” another good term to Google. This compression stuff has a valid purpose. It is designed to make the level of your voice more consistent, making what you are saying more understandable to the operator on the receiving end. Properly set up, the compressor takes advantage of the RF you are emitting and fills it with just the right amount of audio information. Enough to make it more readable. Not so much that you waste power on all that ugliness.

Like the swiftness of your car or a cold beer after work, such an otherwise good thing can be abused. I remember in commercial broadcasting when the battle to be the loudest station on the band made everybody sound like a cement mixer full of anvils. The modulation monitor needle did not rise and fall. It sat there at 100% and merely quivered! I worked on the air at one station with the compressor set so I could hear in my headphones traffic on the street outside the studio, people talking in the lobby, and the receptionist typing on her old manual typewriter, all in addition to the highly entertaining disc jockey patter I was spitting out. I did not dare pause or the listener might have heard some most unpleasant exchanges down the hall in the corporate offices.

This happens on the ham bands, too. In an effort to be loud and communicate, you actually sound abysmally grungy and muddy, and the DX station, for some reason, can't make out your call sign, no matter how clever your phonetics. Plus your nice compressor circuit is sucking up every other background sound it can, just doing its job, making every noise close to the same level as your voice. You've heard stations with the background noise of the amplifier fan boosted until it was almost as loud as what the op was preaching. Either that or he really was operating from a bi-plane crop duster. He drops his pen, it reverberates like a tree falling. Or you can hear the TV from the other side of the house well enough to tell who just got voted off the island.

Now clearly such practices as running too much audio gain or too much compression defeat the stated purpose of enhancing your ability to communicate. If you merely want to be loud, don't care how many other stations you interfere with, are not afraid of having your parenthood questioned by fellow hams, or don't mind getting mail from Official Observers or the FCC, go right ahead and—as one of the members of the legendary rock band Spinal Tap recommended—turn it up to “11.” But just because you can does not mean you should.

If you do want to efficiently work that DX station, pass traffic without endless repeats and fills, or have guys in your roundtable spontaneously gush about how good your audio sounds, then I have the following recommendations:

So that's my bit. Let's all work for a less polluted spectrum and for more efficient communication.

Adjustable gain and compression are nice to have under the hood, but don't run the thing into a tree!