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Q on Setting K3 Filter Offsets

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Grant Youngman

Q on Setting K3 Filter Offsets

I have all 8-pole filters in my K3. I've always noticed a slight
audio response difference between LSB and USB positions. Read some
list history on the topic. I do have a wideband noise generator and
spectral analysis software, but have been too lazy to get everything
set up. So I did a quick and dirty, just equalizing the receive
response aurally on all of the installed filters.

Ended up with -0.12 on the 2.8, +0.06 on the 1.8 and -0.05 on the 400.

I'm curious wether the experts around here think that's close enough
for government work, or if it's really worth going the spectrum
analyzer route. Could these results just be due to unequal skirts,
and maybe I should just "don't worry, be happy" and leave the 8-pole
offsets set to zero?

Thanks ... Grant/NQ5T

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Don Wilhelm-4

Re: Q on Setting K3 Filter Offsets

Grant,

The answer depends on how much you can trust your ears to discern pitch
- mine are terrible at that task, so I use the spectral analysis
software as my 'crutch', but if you have good pitch recognition, your
settings may be as good as it gets.

73,
Don W3FPR

Grant Youngman wrote:

> I have all 8-pole filters in my K3. I've always noticed a slight
> audio response difference between LSB and USB positions. Read some
> list history on the topic. I do have a wideband noise generator and
> spectral analysis software, but have been too lazy to get everything
> set up. So I did a quick and dirty, just equalizing the receive
> response aurally on all of the installed filters.
>
> Ended up with -0.12 on the 2.8, +0.06 on the 1.8 and -0.05 on the 400.
>
> I'm curious wether the experts around here think that's close enough
> for government work, or if it's really worth going the spectrum
> analyzer route. Could these results just be due to unequal skirts,
> and maybe I should just "don't worry, be happy" and leave the 8-pole
> offsets set to zero?
>
> Thanks ... Grant/NQ5T
>
>

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Grant Youngman

Re: Q on Setting K3 Filter Offsets

i guess I'll end up breaking down and do a real SA measurement over
the weekend to double check my ears :-)

Grant/NQ5T

On Feb 13, 2009, at 9:09 AM, Don Wilhelm wrote:

> Grant,
>
> The answer depends on how much you can trust your ears to discern
> pitch - mine are terrible at that task, so I use the spectral
> analysis software as my 'crutch', but if you have good pitch
> recognition, your settings may be as good as it gets.
>
> 73,
> Don W3FPR
>
> Grant Youngman wrote:
>> I have all 8-pole filters in my K3. I've always noticed a slight
>> audio response difference between LSB and USB positions. Read
>> some list history on the topic. I do have a wideband noise
>> generator and spectral analysis software, but have been too lazy
>> to get everything set up. So I did a quick and dirty, just
>> equalizing the receive response aurally on all of the installed
>> filters.
>>
>> Ended up with -0.12 on the 2.8, +0.06 on the 1.8 and -0.05 on the
>> 400.
>>
>> I'm curious wether the experts around here think that's close
>> enough for government work, or if it's really worth going the
>> spectrum analyzer route. Could these results just be due to
>> unequal skirts, and maybe I should just "don't worry, be happy"
>> and leave the 8-pole offsets set to zero?
>>
>> Thanks ... Grant/NQ5T
>>