All of these impairments are additive.
If you listen to a signal transmitted by a radio with lots of phase noise,
and your receive introduces more phase noise, the
problem is compounded. So cleaning up part of the picture definitely helps.
And we can expect contesters to migrate to radios which let them hear
better, so gradually the transmitted junk level with
improve (but very slowly).
-- Eric K3NA
-----Original Message-----
From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com]On Behalf Of John Rippey
Sent: 2003 December 5 Friday 13:42
To: tentec@contesting.com
Subject: [TenTec] Orion and phase noise
The ARRL lab has found the Orion's transmitted phase noise to be the lowest
of any rig ever tested there. It's -140 db/Hz from the get-go. If I read
the ARRL Handbook correctly (2004 edition), transmitted phase noise is a
critter that is much harder to tame than receiver phase noise because you
can use crystal filters in the receiver signal chain to limit the bandwidth
getting to the IF, etc. So going by this reasoning, the engineers at
Ten-Tec have set a new very high bar on transmitted signal junk while the
RECEIVER phase noise of the Orion must be below the ability of any lab to
measure . . . (?)
But what does this get you when the airwaves are full of solar and man-made
junk? Looking at past ARRL Lab reports, all but the ICOM PROs show quite a
lot of transmitted phase noise. So in a contest, such as the upcoming 160
meter deal, there are lots of signals transmitting a lot of junk. Nirvana
would be if all the contestants were using Orions, or ICOM Pros, but
they're not. So the wonderful low phase noise of the Orion's receiver sits
there underneath all the signal traffic that is being received and processed.
Isn't the end result that a receiver with much less attractive phase noise
numbers can probably perform just as well as the Orion in the current noisy
signal environment? Is this truer for phone than CW?
Am I missing something?
73,
John, W3ULS
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