42nd YEAR ANNIVERSARY - JANUARY 2022

Isotron 80

 

Get ready for the fall/winter season.

The bands have opened well.

 

www.isotronantennas.com

 

The Best Way To Operate HF

 

Easy installation

Excellent performance

Durable construction

CC&R Friendly (XYL also) 

Please forward this article to those you feel would be interested.

Audio Quality on SSB 

Single Side Band voice communication has been a benefit to the HF spectrum. It uses less band width than AM. Therefore more stations can use the band. At least that is what it should do.

The Single Sideband transmitters are designed with a relatively narrow band width. The pass band filters on the radios are anywhere from 3 KHz to 1.8 KHz.  Where as the AM modulation is around 6 KHz.

This means that the  SSB filter only allows a portion of what we can hear. In an auditorium the speech quality is restricted to about 300 to 3,000 Hz. With a Digital Signal Processor they notch out the frequencies that tend to cause feed back. This allows for more audio power to be delivered. When  music is played the DSP is normally bypassed.

SSB utilizes audio best between 300 and 3,000 Hz. However, due to other noises on the band some choose to set the low end at 500 Hz. This allows the human voice to penetrate better. Once you are set up for your voice characteristics you will be understood better even at a low a signal strength.

A second important factor is keeping the audio distortion out.  Most transceivers are designed to maintain this. However, if you use an amplified microphone or a miss-matched one, you can have a distorted audio out of the transceiver.

Where distortion becomes a more common problem is when an amplifier is used. Over driving the amp will not only cause excessive bandwidth and interference, but the audio can experience distortion. Possibly not a lot, but not the quality that it should be.

Much of the digital audio communications are very distorted. Many are used to hearing this poor audio. However, it is to no ones advantage to have this poor audio on the HF bands.

Scrutinize your audio by having several others listen to it and check the band width. Get your audio clean and clear. You will enjoy the hobby much better.

73,

Ralph WD0EJA

Dec 2021