From: WarmSpgs@aol.com
Message-ID: <50.133161ec.27ed8d6f@aol.com>
Date: Sat, 24 Mar 2001 00:41:03 EST
Subject: Re: LF: <Tech> BPSK and bandwidth
To: rsgb_lf_group@blacksheep.org
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In a message dated 3/23/01 12:11:23 PM Eastern Standard Time, 
mike.dennison@rsgb.org.uk writes:

<< We must not be trapped into thinking that bandwidths close to those used 
for 
 QRSS are essential. >>

An interesting thought.  Spectrum usage depends on more than just the 
bandwidth of a signal, after all.  It's also related to the amount of time 
required to complete a transfer of information, and sometimes also ergonomic 
issues.

A couple of years ago, I witnessed a curious thing on 160m.  A couple of 
stations using AM phone had a half-hour QSO on 1995kHz, reminiscing about the 
good old days of amplitude modulation, occupying a total of about 10kHz.  
During and after that conversation, in the course of checking the band, I 
encountered some SSB operators a little lower on the dial, discoursing 
mightily about what a terrible waste of spectrum AM is, and how it shouldn't 
be allowed on the air.  Through continual misuse of incremental tuning, their 
QSO was occupying about 4kHz, and it went on for two hours.  So, the AM QSO 
used 5kHz-hours while the SSB QSO used 8kHz-hours of spectrum.

Now, obviously, this isn't a comparison based on technical issues only.  But 
it does illustrate that occupied bandwidth is not the whole story of spectrum 
utilization.    If one technique uses sub-Hertz bandwidths but requires 
multiple nights to complete a rudimentary QSO, while another technique needs 
tens of Hertz but can complete the same QSO in half an hour, there is no 
necessary reason to exclude the broader method from a band plan.

73,
John