As a practical matter "My K3 increases power by
10% when in Space as opposed to Mark": is this
really something to be concerned about?
Phil W7OX
On 11/10/14 10:51 PM, Brian wrote:
And what if this was done this with the standard
2.7 KHz filter? Filter passband ripple has the
the stock answer to what people are observing.
Also what about dynamic vs static differences.
Is it possible in the dynamic situation the
differences would be greater?
It does sound like there is some confusion
precision with accuracy. A measuring device
might offer high precision and resolution but
lower absolute accuracy. People often make
accurate difference measurements with with a
device which less accurate than the delta one
observes. If the difference are small, they can
be quite accurate.
73 de Brian/K3KO
On 11/11/2014 02:13, Joe Subich, W4TV wrote:
> My K3 increases power by 10% when in Space
as opposed to Mark.
Two things here ... 10% is abut 0.4 dB. How
did you measure the power
difference and did you do so with an instrument
with enough resolution
to accurately measure that difference at the
power level you were using?
For example a Bird Wattmeter can't possibly
measure with that level of
accuracy nor is one likely to be able to read
an analog meter that
closely.
I have measured my K3 on RTTY with a wattmeter
traceable to NIST and
specified for 3% accuracy and have done so at
four specific power
levels (25, 55, 80 and 105 Watts) to eliminate
any ALC non-linearity
or PA compression from consideration. The
specific Mark/Space power
levels were measured by placing the rig into
transmit in FSK_D mode
with the FSK input closed (Mark), measuring the
power output for a
given power setting, then opening the FSK input
and noting the PO
(and change).
In all cases, the difference between MARK and
SPACE was less than 2%
(less than the meter's specified accuracy) and
at two power levels (55
and 80 W) the measured difference was less than
0.2W (<0.2 dB at 55W).
These measurements were made with standard
"High tones" (2125/2295 Hz)
and the K3 was equipped with the optional 2.8
KHz, 8 pole IF filter.
73,
... Joe, W4TV
On 2014-11-10 8:42 PM, Bill Lewis wrote:
I am looking for information on how to
eliminate incidental AM when using
FSK-D.
My K3 increases power by 10% when in Space as
opposed to Mark.
Thanks much, Bill, W8NN
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