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CQ Worldwide SSB Contest – Comparing Receivers

cq worldwide ssb contest

By comparing receiver performance during the CQ Worldwide SSB Contest, I confirmed that Flex 6300 is both elite-class and competition grade compared to a legacy radio. 

CQ magazine has been around since 1945. It’s probably the second most popular ham radio journal, next to QST. CQ Amateur Radio has more than 60,000 subscribers. I’m not one, but occasionally read it at the Calgary Public Library. Every year, this magazine sponsors the very popular CQ Worldwide DX Contests – one for SSB and the other for CW. These are held on the last weekends of October and November, respectively.

This past weekend featured the CQ Worldwide SSB contest. Propagation conditions were favorable but not great. Nevertheless, there was lots of activity on the bands. Usually, I enter this contest for fun and to work a few new countries. But, this year, I just used the masses of strong signals to compare receiver performance.

In particular, I wanted to compare my new Flex Radio 6300 against the legendary Yaesu FT-1000D. For many years, the FT-1000D has been a benchmark for contest performance. Yaesu introduced this radio in 1989, calling it “elite-class” and “competition grade”. So, 30 years ago, the FT-1000D was about as good as you could get. The ARRL lab test at the time referred to this radio as the best it had ever tested in terms of both sensitivity and dynamic range. In particular, it has cascaded eight-pole crystal filters to handle really strong nearby signals of the type that flood the receiver during contests. Hard to believe that I have kept this rig as my secondary “classic analog” radio, instead of the main radio.

CQ Worldwide SSB Contest – Flex versus Yaesu Receivers

While my comparison was entirely subjective, it contained some logic. What I did was find weak signals that were adjacent to or slightly covered by much stronger signals. My objective was to see if either receiver was better at “digging out” the weak signals in the face of strong interference. Generally, the weaker signals were S2-S3 and the strong signals were S9+10dB or greater. In layman’s terms, this means that the received voltage ratio between the strong versus weak signals was at least 1,000 to 1.

So, what did I find? No real difference. The direct sampling Flex 6300 performed pretty much the same as the once-elite class FT-1000D. The DSP filters in the Flex did as good a job sorting out signals in the CQ Worldwide SSB contest as did the cascaded crystal filters in the Yaesu.

It was easy to find the adjacent pairs of weak and strong signals using the Flex computer display. Once tuned in, I just switched antennas back and forth between the two radios, listened, and tweaked. I suspect the Flex might out-perform the Yaesu in the CW contest next month. We will see.

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