K2 - Filters adjustement

[F5UL]

I found all the literature on differents site very interesting, particularly the one using Spectrogramm to see what we are doing and have a good result.

I used it after modification to inprove the filter rejection (positive) and it helped a lot. But I was not very glad with the results !
As I am using MixW as interface with digital modes, I remade the filters (CW, Low and Upper sideband, RTTY) adjustement and by visualising the waterfall and switching between waterfall and line display, I finaly arived to a very good filter implementation,

CW   1.0 -  0.7 - 0.4 - 0.2
LSB  2.4 -  2.0 - 1.8 - 1.6
USB  2.4 - 2.0 - 1.8 -  1.6
RTTY 1.8 - 1.5 - 1.0 -  0.6

I will test all these passband and may be readjust them but I think it give me a good start !

Any way the Spectrogramm is a good tool and MixW is a very complementary tool !

73 to all the list

F5UL/Bob

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[Steven Pituch]

Bob said:
> I used it after modification to inprove the filter rejection (positive)
and it helped a lot.
> But I was not very glad with the results !
> CW   1.0 -  0.7 - 0.4 - 0.2
> LSB  2.4 -  2.0 - 1.8 - 1.6
> USB  2.4 - 2.0 - 1.8 -  1.6
> RTTY 1.8 - 1.5 - 1.0 -  0.6

Hi Bob,
I use MixW too.  I was using it with my TS850 with its nice 8.8 mHz 270 Hz
filter for PSK31.  With the MixW waterfall I could see that the Kenwood
filter was pretty much about 300 Hz wide.  It was a pretty nice setup for
PSK31.

I have an old K2 (s/n 402) that has not yet been upgraded with all the
filter mods.  I put the K2 in line with MixW and put in the 100 Hz wide CW
filter.  Note that I have not aligned this rig in 5 years.  The 100 Hz K2
filter outperformed the 270 Hz filter in the TS850.  I would say that the K2
filter at the nominal 100 Hz setting was about 175 Hz wide as judged by
looking at the MixW waterfall and spectrum views.  I'm sure using
Spectromgram would give a better esult.

I sold the TS850 to help pay for some K2 upgrades.

So the K2 filtering stands up to and surpasses one of the better analog
radios ever made.  True - the filtering will not be IF Digital brick wall,
but with the addition of the AF DSP unit, and the good BDR and IMD numbers
that the K2 has, it should be tough to beat.

Regards,
Steve


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