Saturday 22 August 2020

Time to tidy up our SSB transmissions

I have been astounded at the quality of SSB transmissions that are revealed by today's SDR receivers which show both a waterfall and a band spectrum. These are as seen on Hack Green SDR WEB receiver.

When I focused in on different transmissions I find

1. GOOD MODULATION

Beautiful, clear, full audio bandwidth, excellent audio processing.

2.  VERY BAD SPLATTER, PROBABLY DUE TO OVER MODULATION

Very poor and over modulated transmissions two on both sides and one on one side only. These transmissions often received reports of "good audio" which just shows that the quality of SSB transmission cannot be judged by just listening.

And it can't get worse than this

Just as he said "thanks for the report on good audio". Report "no audio artifacts", needs to use an SDR.

3. BOGGLED TRANSMISSIONS


This is about the worst in terms of quality. Patchy audio EQ, severely bass heavy and muffled and an outstanding transmission of a faulty transmitter or a wrongly used audio processor, giving a transmission of more than 9kHz wide!! This gentleman received a report of "clear, good audio"!!!

Then check this out. Two guys talking about "I like to focus on audio..." Here's the same guy again at 9kHz wide and severley distorted at the top end.


SDR BW is 3kHz, so top one is 4-5kHz wide and the bottom one more than 9kHz!!!

AND ACROSS 80M 


Very mixed quality of signals. Lot of audio processing and poor/good microphones?

NEW CODES NEEDED

The regular reports of 5 and 9 are not good enough. We need a better reporting system - a bit like SSTV which reports 5 & 9 plus video quality.

1 comment:

Bob G3PJT said...

I couldnt agree more- 80m LSB on a typical day has plenty of poor SSB transmissions, wide and distorted.
And its so easy to have great audio if you take a bit of care in setting things up. And use Hack Green or similar to listen to yourself.

73 Bob G3PJT