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First DX Contest with Flex 6500

Charles - K5UA
Charles - K5UA Member ✭✭
edited June 2020 in SmartSDR for Windows
Worked 20 hours of the 48 hour ARRL DX CW Contest, single Op, single transmitter. Had 1255 contacts, score was about 1.4 million points. The 6500 did a good job in spite of a lot of dirty CW signals. Had one unexplained freeze of SSDR when resizing a panadapter, restarting cured everything. Discovered a minor persistance problem of the speaker gain in the slice flag not remembering where it was set as I moved band to band (is that the way it is supposed to act?). Got an object lesson in CW bandwidth as a function of keying speed and key clicks. Although received CW waveforms are reasonably narrow for the first 30 or 40 db of signal strength, the very strong signals literally explode in bandwidth near the noise floor of the panadapter, sometimes being as wide as 800 - 1000 hz. If you are trying to copy a weak signal near one of these stations, it doesn't matter how good your filter shape factor is if that adjacent station is putting energy inside your filter bandwidth. You are going to have a hard time hearing the weaker signal. BUT..... if the adjacent signal is clean and does not have key clicks, the selectivity of these steep skirted DSP filters is remarkable. I wish I had a screen capture to illustrate what some of the strong, dirty CW signals look like on the panadapter. In summary, there are some conditions where the best DSP narrow filters will be nullified by an adjacent dirty, key-clicking CW signal. Unfortunately, the NR system made no difference on 80 meter noise. NR would have been very helpful. Overall, a good first test of the 6500 under adverse conditions. (Could have really used those dotted XIT lines proposed by Al, NN4ZZ--- also more panadapter zoom levels and a good NR system). I know it will get better.


  • Jim Bryce W5HFS
    Jim Bryce W5HFS Member ✭✭
    edited November 2018
    Try the Pixel magnetic receivining loop antenna to reduce noise on 80 meters.
  • Charles - K5UA
    Charles - K5UA Member ✭✭
    edited July 2018
    That's on my personal roadmap. Heard lots of good things about that antenna.
  • Ken - NM9P
    Ken - NM9P Member ✭✭
    edited June 2020


    I worked about 18 hours off and on and was able to get 361 contacts in 82 countries and just under 200,000 points with dipole and vertical and 100 watts, which was my best ever contest result.  How do you get four times as many contacts in roughly the same time frame?  WOW!  What antenna and are you running an amp?  Congratulations.

    BTW, I found the 50 Hz filter and APF to be very helpful in combination.  But yes, usefulness limited by phase noise and keying products of other stations.

    The NB helped somewhat, but would periodically "forget" what it was doing and I had to cycle it off and on a couple of times to get it working again.

    For the first time I was able to make good use of the XIT control to shift my signal just enough to be heard distinctly from other stations in a pileup.  (Thanks to the Flex Control Knob.)  The Proposed XIT/RIT lines would have made this much more easy to visually "tag" the frequency of the last station working the DX.

    The New TX/RX panels were helpful.  Thanks FRS.  FRS Should think about buying the code for Bob's S-Meter and incorporating it into the panel!  That would be really nice. (or something like it.)

    DAX was also very helpful so I could use CWGet to assist confirming some calls.  My CW is rapidly improving, but some stations are still much too fast for me!  Nothing beats the ears, but it is nice to have a little help.

    I haven't had so much fun in a contest in years and the 6500 helped make it so.  I am sure my XYL got tired of hearing me cry "Yes!" when I scored a new multiplier in the contest.  But not having worked that much DX, especially on 40 Meters, this was a thrill.

    I am looking forward to giving it a workout on the 160 SSB contest.

  • DonS
    DonS Member ✭✭
    edited January 2020
    I also enjoyed the cw contest over the weekend, however, I just worked 10m and on occasion 20m.  10 was wide open and when it got dark outside I would switch to 20m.  One of the issues I encountered was when I had the cw filter at 100hz or even 50hz and the signal was zero beat at 600 hz, unless the signal was relatively strong I ended up using the APF which really brought the signal out of the noise.  It just seemed like the weaker signal went down in the mud when I was zero beat.  I guess it could have been the result of have very strong signals close by but outside the filter range.  I even had an opportunity to use the RIT, however, when I hit 9991 the SSDR shut down, but I believe that is a known issue. 
  • Ernest - W4EG
    Ernest - W4EG Member ✭✭
    edited January 2020

    The contesting ability were confirmed in July 2013 when we did a side by side radio challenge at the (SDDXC) San Diego DX Club operating site.  This was just several weeks after the released of SmartSDR and my Signature 6700 radio. I had never seeing the radio or the software (in other word, I barely knew how to turn the radio on.) The results are on this forum, check out the competitions and the results.  Only thing I could say you will never know ... unless you try it!
  • Dave-N9CHM
    Dave-N9CHM Member ✭✭
    edited December 2016
    The Pixel RX loop is very good for noise reduction, especially on the low bands. The results are amazing.  See my QRZ site for pics on noise reduction.  I have 2 Pixels, one N/S and one E/W, I instantly switch between them to reduce/eliminate man made noises as well....no waiting to rotate :)
  • Charles - K5UA
    Charles - K5UA Member ✭✭
    edited March 2015
    Here are the numbers Ernest: BAND QSOS PTS DX 80m 76 228 44 40m 202 606 75 20m 285 855 83 15m 336 1008 93 10m 356 1068. 87 ----------------------------------------- 1255. 3765 382 Total score: 1,438,230 My personal best Single Op ARRL CW DX contest ever.
  • Charles - K5UA
    Charles - K5UA Member ✭✭
    edited March 2015
    Dont know why my nicely laid-out numbers were reformatted by the upload. Too bad.
  • Barry N1EU
    Barry N1EU Member ✭✭
    edited February 2017
    No doubt the Flex 6K is an extremely competent contesting radio right now.  But what I really look forward to is GUI and human interfacer innovation down the road.  I don't like reaching for a mouse and looking at the computer screen so much.  Fingers on knobs and buttons baby  ;-)

    Maybe a touch screen or virtual hardware front panel?
  • Ron
    Ron Member
    edited December 2014
    What Software were you using for the contest?
  • DonS
    DonS Member ✭✭
    edited July 2014
    fldigi. makes me wonder if fldigi switched sidebands when the radio changed to digl.

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