K3 Intermod with IF NB

[g0afh]

  Hello,

Primarily I use my K3 to drive transverters for the higher bands. I
transvert to 2m from 20m using the transverter interface on the k3.

Conditions on 2m have been enhanced in recent days so there a few big
signals on the band. Last night I needed to use the NB to deal with some
local power line noise. With the NB on there is far more intermod than I
would have expected.

Locally I have a beacon on 144.43 (s9+40). Station A on 144.32 (110KHz
from the beacon) could also be heard on 144.210. Station B on 144.270
(160KHz from the beacon) could be heard on 144.110. Both stations were
over s9. In both cases the spurious signals were around s4-5, distorted,
but easily identifiable.

Switching off the IF NB makes the spurious signals disappear.

Perhaps I shouldn't be surprised, using the NB is never a good idea with
strong signals around.

73
Ian.
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[wayne burdick]

Hi Ian,

The I.F. blanker should be run at the lowest effective level. It is  
intended for use on short-duration, high-energy pulse noise.

You might try using the DSP blanker first. Since it is post-crystal-
filter, it cannot cause mixing to occur between multiple signals  
outside the filter passband.

Typically a combination of the I.F. and DSP blankers and the NR will  
be the most effective.

73,
Wayne
N6KR


On Oct 13, 2010, at 8:06 AM, g0afh wrote:

>  Hello,
>
> Primarily I use my K3 to drive transverters for the higher bands. I
> transvert to 2m from 20m using the transverter interface on the k3.
>
> Conditions on 2m have been enhanced in recent days so there a few big
> signals on the band. Last night I needed to use the NB to deal with  
> some
> local power line noise.


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