[Elecraft] K1 Filter Board Questions

[Tom Hammond]

Hi Daniel:

Well, he MIGHT be able to come up with a filter to cover 80/60, but I'm not 
certain about the signal inversion on that band... might not permit USB 
reception... can't believe the FCC mandated USB in a (larger) band segment 
which typically ALWAYS defaults to LSB, due to mixing 'standards'.

73,

Tom

At 08:14 AM 9/3/04, Daniel Reynolds wrote:
>But - if you consider that he also wants to receive on 60m (although I don't
>know enough about tuning bandwidth considerations for the K1, and whether or
>not the SSB would be normal or inverted), maybe the filter could be 
>constructed
>so that he has 80/60 and 40/30?
>
>- Daniel / AA0NI
>
>--- Tom Hammond <n0ss at earthlink.net> wrote:
>
> > Hi Ron:
> >
> > At 10:34 PM 9/2/04, you wrote:
> > >I have obtained a K1 and have a couple of questions regarding the KFL1-4
> > >board. Is there any reason it can't be constructed with 80 - 40 - 30 - 20
> > >meters? If you purchase a new one it comes with 40 - 30 - 20 - 17/15 
> meters.
> > >
> > >Considering the state of the solar cycle I'd prefer a board with lower
> > >frequency capability. So is it possible to build a board with 80 - 40 
> - 30
> > >- 20?
> > >
> > >Second question has to do with 60 Meters. Is it technically feasible to
> > >have 60 meter receive cavility on a K1, assuming the toroids and other
> > >components aer appropriate to the frequency?
> > >
> > >The K1 is a super little rig and I'ce already become very fond of it. It
> > >would be perfect if I could get my preferred band selection on one filter
> > >board.
> >
> > The K1 4-band board CAN be constructed for 80M, BUT then you'll have to
> > give up 40M!!! Here's why...
> >
> > The two 2-band filters in the KFL1-4 are designed so that the upper
> > frequency cutoff of each filter is above the higher of the two 
> frequencies,
> > BUT LOWER THAN the 2nd harmonic of the lower frequency.
> >
> > In other words, the 40M/30M filter cuts off above 10MHz, and BELOW 14MHz.
> > If you were to build the first filter for 80/40 meters, then the filter
> > would have to be able to pass both 3.5 and 7.0 MHz energy, thus allowing
> > any potential 80M 2nd harmonic energy through to the antenna... this comes
> > under the heading of "Bad things will happen". So, in order for the KFL1-4
> > to be built to accommodate 80M, it's have to cut off at a frequency lower
> > than 40M, which means that you'd have 80M, but not 40M.
> >
> > Sorry pal.  Good try though...
> >
> > 73,
> >
> > Tom Hammond    N0SS
> >
> >
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