[Orion] RE: SSB Bandwidth, readability, power, etc.

Eric Scace K3NA eric at k3na.org
Wed Nov 5 12:33:07 EST 2003


   Outside of the question of intelligibility, if one makes ones signal narrower (e.g., 1800 Hz vs 2500 Hz), does one invite
adjacent stations to encroach on ones transmit frequency?  Would encroachment increase difficulties when trying to copy other weak
stations?

-- Eric K3NA

-----Original Message-----
From: tentec-bounces at contesting.com
[mailto:tentec-bounces at contesting.com]On Behalf Of Bill Tippett
Sent: 2003 November 5 Wednesday 07:14
To: tentec at contesting.com
Subject: [TenTec] SSB Bandwidth, readability, power, etc.


	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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