W8JI led a crusade against clicks on CW. He has largely won but there are still a few operators who have almost 2 KHz clicks and do nothing against because the clicks clear frequencies around.
In recent CQ 160 SSB, a midwestern strong station was taking almost 8 KHz. The main signal was about 2.5 KHz wide. However his sidebands were as long and only 20-25 db below; -25db during the first second and -20 later. There was no way to hear 100W stations within 4 KHz of his signal. Unless one had a receive antenna back to him. He made an excellent score, partly due to excellent antennas and partly due to having clear frequency for listening. He has no incentive to improve his TX signal.
There are two ways for narrower SSB signals. First, amps with low IMD and using 50W drive so that 100W rigs generate less IMD. For example K3/Alpha combination. Second, radios with adjustable bandwidth. Many stations use 1.8 KHz on receive, meaning the frequency response around 300-2100. Yet nearly all rigs generate 2.4k-2.7 K signals. Should we petition the manufacturers to produce radios with sharp frequency cutoffs, like in receive?
Or, with adjustable IMD
.
Ignacy, NO9E
