[TenTec] SSB Bandwidth, readability, power, etc.

ac5e at comcast.net ac5e at comcast.net
Wed Nov 5 13:19:36 EST 2003


Narrowing TX bandwidth depends on the operators voice. One of the hams across town is a good judge of voices and very familiar with my "coffee shop conversation." Experimenting back and forth we find 2200 Hz with the SP on 3 is about optimum for cross town ragchews with MY voice - but dropping the TX bandwidth to <1800 Hz and setting the SP on 4 or 5 is about optimum for contest use. No loss of intelligibility, big increase in copyability! 

And by the way, kudos to Ten Tec for the speech processor, which provides very natural audio even at the higher compression numbers. Turning it on makes a BIG difference in the number of LED's that stay lit on the amps and, I am told, a big difference in intelligibility with no loss of audio quality at the other end of the QSO.

73  Pete Allen  AC5E
> 	Was away since last Thursday and read all the
> comments about 2.8 kHz SSB bandwidth.  This reminded
> me of a question I had about Orion.  You can adjust the TX
> SSB bandwidth from 900 Hz to 3900 Hz (I assume the 900
> Hz is for using digital modes with soundcards).
> 
> 	In the recent CQ WW SSB contest, I felt I could
> adjust received BW all the way down to 1600 Hz with
> decent readability by setting PBT to +150 and RX EQ to
> -10 dB.  This would probably be dangerous to try for my
> TX signal, but here's why I might try setting my TX audio
> as low as possible for good readability.
> 
> 	Output power is limited to 1500 watts measured
> with a peak-responding meter.  For sake of argument,
> assume my TX bandwidth is set to 1800 Hz.  If I am
> transmitting my 1500 watts into an 1800 Hz BW, does this
> mean I would be 3 dB stronger than someone transmitting
> his 1500 watts into a 3600 Hz BW?
> 
> 	It seems to me like this should be true if the meter
> were measuring the integrated peak power within the chosen
> BW, but I think this falls apart since peak meters only respond
> to peaks anywhere within the BW (i.e. not integrated).  Intuitively
> it makes sense to only use the minimum part of the voice
> spectrum that maximizes readability, but I wonder if this power
> argument makes any sense?
> 
> 				73,  Bill  W4ZV
> 
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