Big Bottomed Hams Catch the Devil

Sociotechnical Aspects of Ham Audio

by Tom Morton.   Devil outfit modeled by Weezil.


How do you present yourself to the world?


 Initially SSB radios were setup to transmit the essence of the human voice with the narrowest bandwidth and frequency spectrum that yielded the highest transfer of voice intelligence.  This was a bandwidth of 2.4 to 3kc and a low frequency of about 350cps.  This put the maximum amount of the power in the most important part of the voice range, and made the signal the easiest to tune and maintain with the not-so-stable oscillators of the day.  The expanding Ham community also enjoyed the extra band space by replacing the 6kc AM signals with the more effective, narrower SSB signals.  In recent  years, Hams have been experimenting with the sound and quality of their transmitted audio, and more recently, radio manufactures have taken notice and improved the TX quality and range.  

Audio oriented Hams have adapted professional studio and broadcast microphones and processing equipment, giving a robust sound to the narrow bandwidth available.  Many Hams have been focusing on the low frequencies, the lower and stronger the better. This is seen as masculine, strong, and powerful.  This plays to the ego and self image, and the true objective is lost.  I have a cousin that is a photographer and he had a sign on his wall that read, "Portraits as you look...$5.00.  Portraits as you would like to look...$10.00.  Portraits as you think you look...$100.00".  This illustrates our propensity to be distracted by our ego.  Listening to our audio is like looking at a picture of ourselves.  Some Ham audiophiles seem to be trying to show the world a picture of them selves that has been severely retouched and the results are not good.  Your audio is the way the world sees you.  Would you go to the Mall wearing a red Devil suit with a "Look at Me" sign around your neck?  Of course not. You would dress appropriately.  

 In order for the station receiving you to understand your words, you must have modulation in the frequency range that represents the essence of the human voice.  This is from 350cps to 2,400cps.  Since a SSB signal is pure modulation, the power you transmit is distributed in your bandwidth and exists under your spectrum curve.  If the receiving station is listening with a narrower bandwidth, the power in your spectrum that does not pass through his filter is wasted.  Also if your low frequencies (below 350cps) are stronger than the rest of your spectrum, you are wasting power with modulation that can't be heard.  In poor band conditions or high noise, your only energy above the noise will be the lower frequencies which are unintelligible.  If the max peak power of your radio is 100Watts and your low frequencies are 10dB stronger than the rest of your spectrum (not uncommon), the power in the intelligible part is only 10Watts.  Also the AGC on the receiving station reacts to the low frequency peaks and knocks the level of the intelligible part even further down.  You then end up with a "10 over S-9, say again" situation.  If you cut off the frequencies below 350, your signal now is 1.6 S-units stronger. That's like adding a 1000Watt amp to the average station.  When the conditions are right and the receiving station has a wide band filter, then the low frequencies add to the received quality and listening pleasure, but it is important that the frequencies in the spectrum are all about the same level. Unfortunately, the lower the bottom frequency is, the more difficult it is for the other station to tune/clarify your signal.  If your low frequency is 50cps, a tuning error of 10cps is 20%. That's like a 70 cycle error on a signal with 350cps as the low frequency.  The tuning error induces a distortion often mistaken for FMing.  In essence you are QRMing your own signal.  It is annoying to try to listen to two Hams talking with lots of lows when they are not exactly on the same frequency.  

 Hams with boosted, heavy lows seem to be complimented and admired, like QRP stations.  In both cases the admired Ham should be poor guy that works them.  In other words, a boosted, low frequency bass causes big problems for the adverage Ham.  It is not necessary to have a low frequency below 120cps or a high frequency above 3kc to give your audio the robust "broadcast" sound.  If the power level on all the frequencies are the same (flat equalization), you will have your full 100Watts peaking on all of your spectrum.  If the receiving station has a narrower bandwidth or the Ham spent too many years backing up rivets in a boiler factory, what he hears will have your full power behind it.  If all the frequencies in your passband are at the same level, you will sound natural, like you were in the room with the receiving Ham.  You would think the goal of the Ham audiophiles would be to sound great in all situations and cause problems for no one.  But, unfortunately, there are many Hams that are more concerned with their opinion of themselves than consideration for the other Ham in the QSO.

 The best way to be truly sophisticated on the bands is to match your TX audio to the situation.  First, make sure that your audio spectrum has all frequencies at about the same level.  If you have a good strong signal, open your passband up and don't use any compression.  Listening to a  clean, balanced, uncompressed "broadcast" audio is very pleasent.  If the copy is difficult, narrow the passband and add as much compression as you can without over stressing your audio.  This will make copy much easier for the Ham on the other end.  In other words, dress your audio and your image for the occasion, and I apologize to you big bottomed Hams for giving you the Devil.