Newsgroups: rec.radio.shortwave
Subject: Are major broadcasters using SSB?
Date: Fri, 09 Oct 1992 12:43:21 -0500

 MZ> : Well, in the USA, the FCC plans for us to go to SSB sometime after the 
 MZ> : turn of the century. The idea is to reduce congestion on the
 MZ> international 
 MZ> : bands because SSB takes only half the bandwidth. 

In preparations for the 1992 WARC, some non-broadcast, USG, HF users favored a
move to SSB by broadcasters by 2007 in lieu of giving up spectrum.  

This is a short sighted view by those who do not understand the need for more
spectrum for broadcasting and the lunacy of going to SSB any time soon if you
want to reach people who can barely afford existing receivers or find someone to
share their old, non-SSB capable radio.  There has been plenty of research by
the EBU showing the need for more spectrum is on the order of 4 to 16 times as
many frequencies as are now available!  These studies are based not only on
unrealistic schedules submitted to the ITU for 'testing' of a proposed spectrum
planning system, but with real data of what's on the air today.  These is no
definitive indication that HF broadcasting is decreasing in the face of
increased use of other media -- satellites, etc.

Studies that indicate a significant savings in spectrum by going to SSB are
based on a 10kHz channel spacing for HF.  We all know that the actual channel
spacing for HF broadcasting is 5kHz.  I submit that a conversion to SSB would
result in very little, if any, savings in spectrum while forcing listeners to
purchase receivers that are capable of receiving SSB AND forcing broadcasters to
convert all their transmitters to SSB.  

Even a relatively big, wealthy broadcaster like VOA only has a few SSB-capable
HF trasmitters in our inventory of over 115 hi-power facilities.  To convert all
of those transmitters to SSB or to buy more modern units would be prohibitively
expensive.

Broadcasters, including the VOA, are using out-of-band spectrum for HF
broadcasting under Resolution 342 of the Radio Regulations on a non-interference
basis.  This has proved the ultimate resolution to congested shortwave bands. 
Additional spectrum offerred in 1979 and 1992 WARCs merely 'legalizes' what's
happening already.  It's also interesting to note that the great majority of the
FCC-managed, private US HF broadcasters use out-of-band frequencies!  It's not
illegal; it's an accepted, effective method of getting relatively weak signals
to their intended audiences.

 MZ> Are they talking about Supressed Carrier SSB (J3E) or one with
 MZ> a regular carrier (H3E or R3E).  According to Monitoring Times, some 
 MZ> US Medium Wave broadcasters are using a AM compatible SSB with some 
 MZ> system that Kahn sells. (Powerside?)

VOA has begun use of -3dB carrier reduction on two transmitters at our
Greenville, NC facility and on all 4 transmitters at our Botswana relay station.
 We have found no significant reduction in audio quality or coverage as a
result, but have begun to realize increased reliability on these transmitters
and reduced power consumption!

Bill Whitacre
Frequency Management & Monitoring Division
Voice of America

Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU