Yaesu FT-60R - Manual (Page 18)

R. G. Sparber KG7MQL February 22, 2015 Page 18 of 52
Let's think a minute about transmitting to a repeater. Say you use ½
watt of transmit power. You receive a report from your contact that
your signal is "scratchy". The repeater's receiver performs a function
called automatic gain control. If it receives a voice signal much larger
than the background noise, it can reduce gain which reduces both your
voice and the noise mixed in with it. If it receives a weak voice signal,
it will amplify the weak voice signal along with the noise mixed in
with it. This is why a strong signal sounds clear and a weak signal
sounds noisy.
Regardless of the quality
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of the signal into the repeater's receiver, the
extracted audio is passes to the repeater's transmitter. From there, the
audio is transmitted at full power to your contact. The contact might
receive a nice, strong signal but it might still be noisy if the audio out
of the receiver was noisy.
You raise your transmit power to 2 watts and the report comes back
that you sound fine. This means that the repeater's receiver got a signal
from you much larger than the background noise. This is often called
"full quieting". The clean signal is sent to the repeater's transmitter as
before but now the contact hears a clear signal.
What if you raise your transmit power to 5 watts? Well, 2 watts was
enough to get full quieting. Going higher in power simply wastes
power. Your battery won't last as long. If you live in a hot climate, like
I do here in Phoenix, Arizona, the radio can become too hot to hold
with a bare hand. Using more transmit power than necessary is also
counter to FCC guidelines.
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Your signal does have to be strong enough to be recognized by the repeater but that doesn't mean it sounds very
good.