[CQ-Contest] CQWW Worldwide SDR Recording

Steve Sacco NN4X nn4x at embarqmail.com
Thu Mar 7 20:25:39 EST 2013

For those concerned about cheating in the CQWW, I think this is great news:



The new generation of Software Defined Radios (SDR) has the ability to 
cover wide frequency ranges and record all of the activity within that 
range. This digital data can be spooled to disk for storage and 
transport. Other software allows the user to go back and “tune” through 
the recording by frequency and time. It is just like listening to a 
replay of the contest as it happened over the air!

The CQ WW Contest Committee has used SDR recordings in the past to 
assist with the log checking. It is incredibly valuable for us to be 
able to go back and listen “live” to what happened at the time and 
frequency shown in the logs.

Lead by Steve Bolia, N8BJQ, the committee made a much greater effort to 
collect and use SDR data for checking the 2012 contests. SDR recordings 
of the complete SSB and CW contests for 2012 were made at 9 sites in 
Europe, North America, and Oceania. The following stations volunteered 
their SDR setups to make recordings:

HA1AG with HG6N guys
S50XX and S52X

Having so many locations provided very good coverage of all of the 
contest bands and most of the world. There are a few gaps which we are 
looking to fill in for the 2013 contest season.

Before the contest SKYPE messenger was used by the recording stations to 
work out the technical details of collecting the data using CW Skimmer 
software (for CW), a QS1R receiver, and OL5Q’s CWSL software. This 
required lots of tweaking of settings, some software changes, and test 
recordings, but all was finalized the week before the contest. All of 
the SDR clocks were synced to a time standard.

During the contest each site collected approximately 1.3TB of data on 
USB portable hard drives. The US stations and ZL2HAM mailed their drives 
to N8BJQ who copied the data and returned the drives for use in the next 
contest. Each drive took about 17 – 18 hours to copy! All drives made 
the two-way trip with no problems. The European SDR sites transferred 
data using FTP to one or two sites. That took a couple of days for each 

Once the recording data was on hand, S50XX, CT1BOH and N8BJQ supported 
the log checking team by providing recordings of log segments or QSOs as 
requested. The recordings were used to help check for things such as 
band change violations for Multi-Op stations, not In log checks, single 
op stations using more than one operator, stations having two signals on 
the air at the same time, stations working outside of their band, and 
some signal strength comparisons.

Two examples will illustrate how valuable the SDR data can be. The 
multi-single and multi-two categories have very specific rules about how 
many transmitted signals can be used and when band changes may occur. 
The SDR gives the committee the ability to know exactly what time a QSO 
was made and on what band. We are also able to listen to multiple 
frequencies at the same time. This lets us check if a station is 
transmitting more than one signal on a band. We were very impressed at 
how well some of the top multi-op teams stay within the rules!

Thanks to N8BJQ, S50XX, CT1BOH, and the SDR team for their help to make 
the CQ WW DX Contest results as accurate as possible. If you would like 
to join the recording team, please contact Steve, N8BJQ at 
n8bjq at cqww.com for more information.

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