[Elecraft] Cabinet resonance

[Jozef Hand-Boniakowski]

The K1 with the speaker does the same thing albeit at a higher 
frequency.  A couple of extra screws dead center on the top cover on 
either side might cure that?  What do people think?  I use headphones 
most of the time, but the lid resonance is not the best thing when 
showing the rig off.

Jozef WB2MIC
Wells VT

Ken Kopp wrote:
> The combination of the cabinet and speaker of my
> K2 (#5665) has a VERY pronounced resonance at about 450 Hz.  How 
> fortunate, as this is the frequency at which I like to copy CW. (:-)
>
> The resonance is so pronounced that it would present
> a problem if I wanted to use a higher frequency, say
> 600 Hz.  It initially caused me a bit of consternation as I was 
> setting up the filters ... until I realized what was going on.  Even 
> with the filter set up for 600 Hz I would still find myself tuned and 
> listening lower than the "Spot" tone ... sort of a human AFC circuit. 
> (:-)
>
> Has anyone else noted this?  I wonder if all the speakers supplied 
> with K2's are of the same design from the same supplier?
>
> Mine -does- have all options installed except the battery
> and I assume the resonant frequency of the box would be
> different ... or non-existant ... with different "fillers" inside
> the case.
>
> I have two of the "old" Skytech variable-resonance speakers stored 
> away that are fine examples of the application of housing / speaker 
> resonance as a CW aid.  They use a sliding tube to "tune" the  assembly.
>
> 73!  Ken Kopp - K0PP
> k0pp at arrl.net
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: Elecraft at mailman.qth.net
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft   
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>