[TowerTalk] 1dB more RF Power?

[Jim Thomson]

<Your recommendations are fine for YOUR ESSB ragchewing operation at 
<higher power than US stations are permitted, but it's lousy advice for 
<speech intelligibility under weak signal conditions, for the reasons 
<noted. My advice is for the latter.

<IMO, if you need a parametric as opposed to octave-band EQ, there's 
<something seriously wrong in your system. Maybe a poor choice of 
<microphone, or a noisy shack.

<73, Jim K9YC

## Hundreds  of  tests  have  been  run,  with ssb  signals  right  at the  noise  level,
or  slightly  above  the  noise  level.  And  in  every  case,  increasing the  top  end
improves  speech intelligibility  by  a HUGE  amount. 

##  all  as  we  have  done..is  re-invented  the  wheel.  This  is  all  old  news.
Get  yourself a  copy  of... Single  Sideband  Systems  and  Circuits,  2nd  edition.
Its  also  in  any university  library.  652  pages +  a  disc. 
Its  the  definitive gold  standard text  for commercial  SSB.  
Go  to  chapter  TWO,.... System  Design  Considerations.   Read  pages  12-22.
They  depict  no  less  than  seven  graphs,  for  articulation index, intelligibility  etc.

##  In  each  graph,  bottom  end   is  cut off  at  200  hz.  Top  end is  incremented,
starting  at 2000 hz,  then 2500 hz,  then 3000 hz,  then 4000  hz, 5000 hz,  6000  hz.

##  Run  the  tests  yourself  if  you  dont  believe  me..or the rockwell  collins  engineers
who  wrote the  book. 

##  NU9N  has  loads  of various  MP3  recordings,  done  by  dozens  of  hams,  with
different  TX  BW segments.  IE:   <3  khz.  3000-3900 hz.  4000-4900 hz.   5000-6000 hz. 
http://www.nu9n.com/mp3.html

##  My   deq2496  digital  eq  has a unique  graphic  eq....  its Q  /  BW  can  be  adjusted  wider
than  normal.   The  parametric  eq is  for  fine  tuning  in  a couple  of  places.  I  have a 
2nd  and  3rd digital  parametric  eq,  which  will  go  from  +12db....  down  to  -48db.  I  use
that  one  to  limit  top  end  tx  BW.  I  can  stagger,  or  overlap  the bands...to  slice  off
the  top  end.  Its  the  only  way  I  can  limit  top end   TX  BW  externally,  since the  filters
in the  xcvr  are  both 6  khz. 

##  shack  is  sound proof.  Microphone is a RE-27.

Jim   VE7RF