[TowerTalk] 2dB or not 2 be dB
Fri, 7 Sep 2001 12:14:08 EDT
In a message dated 9/7/01 7:38:14 AM Pacific Daylight Time, firstname.lastname@example.org
> On HF/MF skywave, is a 58% increase in power out (2db) noticable at the
My guess is that for moonbounce, 2db would make the difference between
being heard or not. However, in my double-blind test of 40m daytime
skywave with normal QSB,, no one could see the difference on their
R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
I would certainly agree with this in particular with a pulsating SSB signal
on S meter swing and AVC action. In AM days you could see 2 dB on the S
meter on an A/B test. It just occurred to me that 2 dB less gain of an
antenna system used for moon bounce would be a 4 dB loss as it's also used
for receive of transmitted signal from the same antenna.
I think that a -2 dB will be seen the most in a contest of a lower
intelligence and more repeats etc.
There is another way to measure relative and small differences in antenna
gain on a A/B test on SSB I've used since SSB came into use. Turn the RF
down and the audio gain up and do the A/B test. You will be able to HEAR
very small differences in audio level with a SSB signals as the audio level
your ear hears can be controlled and the AVC is disabled. Your ear has a
level affect also I'm told. Try it. You will be able to SEE very small
differences in comparative signal strength by connecting a scope to the
speaker output set for vertical deflection.
There is another affect on the ear from excessive volume. Guns can be fired
so fast that it sounds like one shot. Orvo Ajala could draw and double fire
a Colt SA 45 sweeping his thumb and little finger across the hammer spur so
fast "it sounded like one shot". He's the one who taught Jim Arness the fast
draw. On Gunsmoke he was the one in the opening action that had a shoot out
with Matt Dillion. At the Worlds Fair in 65 Orvo had a stand here. He would
let you hold a cocked 45 on him with blanks and he would draw and fire
you could just react and pull the trigger. I beat him one time. His draw
fire time was faster than many others reaction time. Rule of thumb--always
draw first if you ever expect to draw again.
At a fast draw contest in Vegas about then the winning time was .22 seconds
from a signal light to fire.
Your eyes don't cut off immediately when light shuts off either. That's why
moving pictures look like a continuous source of light. k7gco
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