Tuesday, February 25, 2014

ARRL DX CW 2014

The first ARRL CW contest when I did not need to spend the entire weekend with antenna building a week before the event! So relaxing.. I used the time for preparations though. I checked the past 30 days SSN numbers to run propagation predicitons at K6TU's site. The software uses by default the predicted SSN figures which seemed to be a bit conservative this time based on the last 30 days historical data. I decided to run a prediction for SSN 130 to see a best case scenario. The reality ended up with even higher numbers than I expected, which did not change much on the outcome, but was helping me to define a worst case sleeping strategy.

Relative to the previous year's contests when the night openings were quite rare and limited to a few hours on one of the two nights only I expected higher activity this time. The predictions have supported the theory plus the high SFI numbers have already indicated that 15/10m bands will be open to attract people working there for the shorter daylight openings. Therefore the QSO rates during the local daytime openings on 20m were even slower than normal. But the nights.. sometimes S7-9 signals with very low noise levels and decent rates.

I made a post contest "prediction" to compare propagation conditions of mine with the two high scoring competitors in Europe (OH8L & 9A2NA). I set the same station configuration (antenna heights/number of elements/output power) for all three predictions to see purely the propagation diversities provided by the station location latitudes.

The prediction files contain 3 x 24 pages for every single hour during the day. I did not want to insert all of them in here; the daytime conditions are quite close among the three, so I picked the timeframe of 22-23UTC to show the real difference.. this is really unfair guys !!!(hi)
Again; in this simulation there is nothing to do with antenna gain and output power and tower heights, terrain (plains and hills).. it is purely propagation diversity of the same continent!

OH8L @ 22:00 UTC



9A2NA @ 22:00UTC
 

HA7GN @ 22:00UTC


 
A weekend after the contest I spent a few hours to run a "spot analysis" with the related support program of the Reverse Beacon Network. I found it an extremely useful tool for:
 
- Confirming the signal strength prediction accuracy of the K6TU program thru the actual spots of real CW skimmers.
- One can compare signal strenght of his station to other competitors
- Visual feedback on antenna stack performance per target area (applicable if subject skimmer detection is providing adequate readings with minimum standard deviation)
- Comparing the operating/sleeping strategy with other competitors (assuming the skimmer was able to detect all subject stations in the period of examination)..was it a good idea or not to switch off for a nap at 9:00UTC as such..

The post contest analysis included checking all the North American skimmers being active during the contest weekend. As I did not see the claimed scores of UA5C on the listing at 3830, but quite few spots reported with strong signals; I thought would be wise to involve him in the comparison besides OH8L and 9A2NA. Here below is a few of the lot can be viewed at the RBN site. All of them clearly (sadly) showing that at around 21:30 UTC my signals are declining remarkably relative to 9A2NA and OH8L; just like in the prediction. (The numbers besides the vertical axis represent the signal-to-noise ratio in dB) The program is Beta experimental version; they may fix it later that the legend can be moved out from the graph area.. I did not check how far the database is searchable back in the past, but I was able to run queries for the 2012 ARRL CW just now..
 
N6TV skimmer spots at Reverse Beacon Network - 15FE2014
 
 
VE6AO skimmer spots at Reverse Beacon Network - 15FE2014


 
 
N8MSA skimmer spots at Reverse Beacon Network - 15FE2014



I have run a comparison analysis to see the differences among Hungarian contest stations for benchmarking my signal levels relative to the big boys. HG5D, HG1S and HG7T were entering in all band competition, thus if no spot appears in the timeframe where mine are displayed it could mean they were on a different band. Without extensive analysis it looks that it is not that bad.. (my setup was: KT36XA + 4L longboom monobander + OM2500A)

N7TR skimmer spots at Reverse Beacon Network - 15FE2014
 

AC0C skimmer spots at Reverse Beacon Network - 15FE2014
 
 
VE6AO skimmer spots at Reverse Beacon Network - 15FE2014




NN3RP skimmer spots at Reverse Beacon Network - 15FE2014
 


All in all it was a great contest with rarely experienced good conditions. It gave me the best QSO count ever, even if it was not enough to beat the guys at the top spots. I congratulate to them and will try to catch up to their scores in the coming years. My claimed scores are 234,030 ( 1,345 QSO / 58 multipliers).
CU in the SSB part this weekend.

73/DX
Gabor - HA7GN