Re: Proper adjustment of audio levels for transmit


Mike Miller <mike.kc9doa@...>
 

I think it is rig dependent and I have seen information posted
that claimed better IMD by controlling output with the rig power
control rather than audio drive.

With my FT-857D, a lower the power setting caused a greater ALC
indication. This is less noticeable on my TS-2000. It may even
happen. I've gotten into the habit of setting rig power to 100%
and adjusting audio drive for the desired output. It might not
yield the optimum IMD, but it seem that it should be at least
acceptable.

Hopefully at least some of the rig manufacturers know the best
way to run their equipment and if there are specific
instructions for data modes maybe they should be followed.

73
Mike kc9doa

On 25 May 2012 at 7:27, W4ATK wrote:

Elecraft in their instructions for the K3 using DATA A mode
(default is USB) suggests about 4 "ticks" of ALC and then
adjusting power output with the POWER control. So it would seem
ALC is not your enemy, it is driving the amplifier out of its
linear region. I think due to differences in rig design and
application there may be more than one solution. With that in
mind, I would be hesitant to be too dogmatic in postulating a
single rule of operation where where this is concerned.

FWIW this is where I run my K3 and I find I can vary the power
level from a normal 35 to 50 watts up to a maxed out 110W and
still get acceptable IMD reports. The K3 has a 100% duty cycle
rating for up to 5 minutes, but I chose to not push that and
will very rarely exceed 85 watts.

73s and Gud DXing, Jim, W4ATK

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