However, when you use your SSB to transmit email with a Pactor TNC using
Pactor III mode, you will be running at almost 100% duty cycle and
drawing close to full transmit current while the email is going out.
Kelton
s/v Isle Escape

N1EE wrote:

One important point should be recognized.

FM radios draw full transmit current the moment
the micorphone is keyed up.

SSB radios only draw standby power until the
operator speaks--ie no extra power is drawn
until the voice signal is modulated. This
saves battery power.

So not only is more power put into the signal
with SSB, but your batteries are saved when
you are not speaking.

One disadvantage is that it can be difficult
to tell when the other party you are speaking
with has stopped talking.

It is easy to tell when the other party stops
transmitting on FM because the carrier will
drop. If your squelch is set correctly you
will hear nothing and if the squelch circuit
is open, you will hear static or background
signals which will be oticably different
from a full carrier signal.

So proper operating procedure with SSB is to
put the word "Over" or "Back to you" at the end
of each transmission. Some radios have what is
called a "Roger Beep" that is transmitted when
the microphone is unkeyed.

Bart Senior


"Bobsprit" wrote


VHF radio is FM which is the modulation of a sine wave carrier so that the
instantaneous frequency differs from the carrier frequency by an amount
proportionate to the instantaneous amplitude of the modulating wave.

Single sidebandband suppressed carrier modulation is a form of amplitude
modulation whereas the carrier frequency and one sideband of the modulated
carrier is suppressed.

For S/N the NBFM (VHF) performance is the same as DSB-AM in the presence of
white noise. The SSB performance is superior to both and to SSB-AM because
all the signal power is is placed into a narrower spectral band than the
former.

SSB detection requires the use of synchronous demodulation, preferably with
phase synchronization, otherwise a Donald Duck type voice appears.

Since you never venture far offshore, dixie cups with strings will provide
more than adequate performance.

RB

"Bobsprit" wrote

I'm not clear on marine SSB radios. Can someone explain how they differ

from

standard VHF? A friend is now offering me a pretty expensive Icom SSB. I

doubt

I have a need for it, but it's basically free. I may just tell him to sell

it

on ebay. I was thinking of adding a AM/SSB (CB) radio to the boat which

would

be better than the GMRS.
So can someone explain what the marine SSB is? Is it VHF with upper and

lowers?

Thanks in advance...

RB