N2EY wrote:
In article . net,
robert casey
writes:
A big reason for SSB is that, in a pile up, the
receiving station can make out people's voices
without carrier heterodyne whistles.
Not just in a pileup, either.
Also no
wasted power transmitting carriers. Take a
listen to a crouded CB channel sometime and hear
all those heterodyne whistles.
I'll take your word for it ;-)
The biggest reasons for SSB displacing AM on the ham bands, IMHO,
a
1) Allows more simultaneous QSOs in a given amount of spectrum
2) Greater "talk power" from a given rig (all the power is in the
sidebands on
SSB vs. ~2/3 of it in the carrier on AM)
3) High power SSB can be less expensive to build and operate than
high power
AM.
RTTY: 1.5%
FM/NBFM: 0.3%
NBFM might have been better than SSB except it's
wider bandwidth...
No, NBFM was even worse than AM in terms of "talk power". At the
narrow
deviations allowed for hams below 29 MHz, an NBFM transmitter was
roughly
equivalent to an AM transmitter running one-fourth the power. OTOH
heterodynes
were much reduced - capture effect meant you heard the strongest
signal and
little else.
Other modes: 0.6%
VHF/UHF (all modes): 12.1%
Even back then, half the hams perferred voice
(phone) modes (AM, SSB, FM). Compared to a bit
over 1/3 perferring CW.
Yep - despite the fact that in those days the spectrum available for
US hams to
use HF 'phone was much less than today. And the rig-cost differential
was much
greater. No WARC bands back then, and 160 wasn't included in the
survey.
It should be remembered that in 1961:
- only ~8 years had passed since Generals and Conditionals got access
to HF
'phone on the ham bands between 2 and 25 MHz
- only ~7 years had passed since 'phone was allowed on 40 meters, and
15 meters
was opened to hams
- there were less than a quarter million US hams
- VHF/UHF repeaters were almost unknown on the ham bands. RTTY meant
an
electromechanical teleprinter in the shack, whose cost new exceeded
the cost of
many hams' entire stations.
It would be interesting to see how the mode and band use would break
down
today.
73 de Jim, N2EY
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