Topband: Demo of the value of one dB and the cost of sending too fast

[donovanf at starpower.net]

The weak signal CW recordings on AB7E's website are well worth 
a few minutes to listen to. His recordings clearly demonstrate 
-- much more convincingly than any other demo I've ever heard-- 
the significance of one dB of improved signal strength and the cost 
of sending too fast under weak signal conditions 


http://www.ab7e.com/weak_signal/mdd.html 




My takeaways from his recordings: 


- its well worth the effort to improve your signal by as little 
as one dB 


- when signals are very weak, sending faster (especially 
at speeds faster then than 30 WPM) costs the equivalent of 
many dB of reduced signal strength. 


If you haven't already clicked on AB7E's webpage, these are 
direct links to several of his recordings. 


A weak CW signal buried in noise with the signal strength 
decremented in one dB steps, 


http://www.ab7e.com/weak_signal/6_5_4_3_2_1_0_db.mp3 




Two weak CW signals buried in noise -- slightly offset in 
frequency -- with one signal one dB stronger than the other: 


http://www.ab7e.com/weak_signal/A_vs_B_1db_v1.mp3 
http://www.ab7e.com/weak_signal/A_vs_B_1db_v2.mp3 





Two weak CW signals buried in noise -- slightly offset in 
frequency -- with one signal two dB stronger than the other: 


http://www.ab7e.com/weak_signal/A_vs_B_2db_v1.mp3 
http://www.ab7e.com/weak_signal/A_vs_B_2db_v2.mp3 




CW signals sent at 20, 25, 30 and 35 WPM when buried in noise. 

http://www.ab7e.com/weak_signal/A_vs_B_2db_v2.mp3 



73 
Frank 
W3LPL