[Elecraft] K3: SSB - WPX - Filters - Controls

[Björn Mohr]

Lee,

The WPX contest was an interesting experience with the K3. I was working 670
contacts in single op all band non assisted high pwr mode. I am not a very
experienced contester, but I have been working a number of SSB contests with
my MP over the past 2-3 years.

My impression of the K3 is similar to what you and Mark Roz describe. First
I thought it was the headphones but soon I realized that the radio sounds a
little different that I am used to. Some high pitched audio appeared very
sharp, and less filtered than I am used to and splatter was hard to fight.

I was normally starting with a 2.4 kc bandwidth, working my way down below 2
kc when there was a lot of splatter. I also noticed that I had to center the
passband very low in most cases to dig out the signal. That seemed a little
different depending on the spectrum energy in the received signal, but most
often my passband was tuned very low for best receive. After the WPX
experience I am now willing to try a sharper SSB filer, I think it is
needed. 

I also tried noise reduction as higher bands sometimes where very noisy and
signals weak. For me, DSP NR never really worked well. The NR in the K3
seems to do a pretty nice job, but still my brain is far better.

I have also noticed the fluctuation in output, not being sure if it was my
low band antennas rocking in the wind or something else. I read Sunday about
some SSB issues in the current firmware release, so they might be dealt with
soon. Unfortunately I updated my firmware right before the contest.

On the positive note I have to say that the K3 is well thought trough. I
feel comfortable with the physical layout and the radio is very easy to
operate. Most of the time I used the filters in shift/width mode, not LO/HI
and sometimes I was running with AGC off using RF-gain instead.

Would be interesting to hear others experience. With 600 radios out there,
there should be quite a few that's been exercised this weekend.

73 de Björn /SM0MDG & 7S0X




On 080331 15:31 , "Lee Buller" <k0wa at swbell.net> wrote:

> 
> I would like to make a few comments and ask some questions.  This is by no
> means a put-down of the the K3, because I am not sure I am operating the rig
> correctly.  After all it is a SDR and it is new.
> 
> During my first foray into SSB Contesting with the K3 during WPX, I found that
> I need either:
> 
> 1.  Understand more about the DSP and the controls for BW, Hcut and Lcut
> 
> 2.  Obtain a narrower roofing filter for SSB - like a 1.8 Khz filter
> 
> 3.  Or both.
> 
> I spent some time trying to find the sweet spot in the radio for SSB using the
> 2.8 Khz filter.  I don't think I found it.  At least, I am not satisfied.
> 
> I tried narrowing up the filter bandwidth to 2.4 or 2.2....some times 1.8.
> I tried shifting it up and down the bandpass.
> I tried to use High Cut and Low Cut depending on where the offending signal
> was coming from. 
> AGC was on Slow with the standard settings.
> Used the RIT a lot
> 
> It seemed I was always fighting some sort of side band splatter or stations
> close in on the frequency.  Maybe it was just a crowded 20 meter band, but the
> same things happened on 40 meters.
> 
> Do I need to go to a 1.8 Khz filter to give the DSP a break?
> Do I need to understand and play with the RX more to make sure I am doing it
> right.
> 
> I would like to some feedback and comments on how other people set up their
> K3s for SSB contesting.
> 
> I want to learn more about this radio.
> 
> Lee - K0WA