K3/100 Assembly - Roofing Filter Loss Compensation (initial setup)

[Walter V. Gilles]

Greetings,

 

I'm performing initial configuration/filter loss compensation.  I have the following filters (slot #) - BW:

 

(1) 13.0 kHz (FM)

(2) 2.8kHz

(3) 1.8 kHz

(4) 0.40 kHz

(5) n/a

 

I noticed that in the Owner's Manual, for Configuration/Filter Loss Compensation, it suggests using 1-2 dB gain on the 0.40 kHz filter, doesn't mention the 1.8 kHz filter. (No compensation for the others I have is needed)

 

In the K3 Utility Help info, same subject, it suggests 2 db for the 1.8 kHz and 7 dB for the 0.40 kHz filter, which it says Elecraft uses for the factory assembled units.

 

I'm assuming that since there is a range of 0-8 dB gain defined for filter insertion loss, overcompensating the gain on setup would not be physically damaging to the K3, but perhaps it might not be operationally optimum.  And per some traffic on the reflector on this, it appears what is needed is just enough gain so as not to notice any degradation (nor unnecessary gain perhaps) when a narrower BW filter is switched in with its associated gain compensation.

 

I suppose I could start low and adjust upward if it seemed to need a bit more boost, but 1-2 dB vs. 7 dB is a bit of a difference between the Owner's Manual and the K3 Utility guidance.  As long as I can't damage the K3 by maximizing the settings (?), then trial-and-error might be the surest way, given individual K3 build deviations.  Any words of wisdom appreciated on these different suggested settings would be appreciated.  Thanks much.  73

 

Walter, N0DZJ

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[KK7P]

Hello Walter!

I'd use the latest guidance.  The Utility is being updated to match.  It
is possible to measure the loss directly suing a stable signal source,
but it isn't critical.

For 1.8 kHz filter, I suggest 0 dB.

73,

Lyle KK7P
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Walter,

The manual is updated periodically, but the information in the K3
Utility is usually more recent.
Even using the most recent data, remember that even that information is
only an average. Filters of the same width can vary in their actual
loss.  So use the most recent data as a good starting point and then if
you have a constant signal source, you can use the internal dBV meter in
the K3 to determine exactly the gain settings for your particular set of
filters.  Start from the widest and work toward the next most narrow
filter when doing the 'fine adjustment'.

73,
Don W3FPR

Walter V. Gilles wrote:

> Greetings,
>  
> I'm performing initial configuration/filter loss compensation.  I have
> the following filters (slot #) - BW:
>  
> (1) 13.0 kHz (FM)
> (2) 2.8kHz
> (3) 1.8 kHz
> (4) 0.40 kHz
> (5) n/a
>  
> I noticed that in the Owner's Manual, for Configuration/Filter Loss
> Compensation, it suggests using 1-2 dB gain on the 0.40 kHz filter,
> doesn't mention the 1.8 kHz filter. (No compensation for the others I
> have is needed)
>  
> In the K3 Utility Help info, same subject, it suggests 2 db for the
> 1.8 kHz and 7 dB for the 0.40 kHz filter, which it says Elecraft uses
> for the factory assembled units.
>  
> I'm assuming that since there is a range of 0-8 dB gain defined for
> filter insertion loss, overcompensating the gain on setup would not be
> physically damaging to the K3, but perhaps it might not be
> operationally optimum.  And per some traffic on the reflector on this,
> it appears what is needed is just enough gain so as not to notice any
> degradation (nor unnecessary gain perhaps) when a narrower BW filter
> is switched in with its associated gain compensation.
>  
> I suppose I could start low and adjust upward if it seemed to need a
> bit more boost, but 1-2 dB vs. 7 dB is a bit of a difference between
> the Owner's Manual and the K3 Utility guidance.  As long as I can't
> damage the K3 by maximizing the settings (?), then trial-and-error
> might be the surest way, given individual K3 build deviations.  Any
> words of wisdom appreciated on these different suggested settings
> would be appreciated.  Thanks much.  73
>  
> Walter, N0DZJ
>
>
> ------------------------------------------------------------------------
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.0.237 / Virus Database: 270.10.23/1953 - Release Date: 02/14/09 18:01:00
>
>  

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html