Fighting for Annobon, 3C0W


3C0W is working CW, split operation, on March13th, 2018. After showing up on 10.119 kHz, a pile up starts.

Ham radio operators under a rare call sign mostly work “split frequency” to efficiently serve as many stations as possible. The screenshot on the top shows this in practice: 3C0W from Annobon starts calling “up” on 10.119 kHz on the bottom of this spectrogram. Within minutes, a pile-up builds up, getting stronger in the number of stations as well as in width (“spread”). On the top of the picture, 3C0W requests a break (QRX), and most calling ceases.

The picture at the bottom shows just a 20 seconds’ clipping of this session. It is an excellent illustration of a sentence by the late L.A. Moxon, G6XN (author of e.g. “HF Antenna for all Locations”, RSGB Potters Bar, 1982, p. 216): “Communication in the amateur bands is usually restricted by interference rather than noise so one might argue that little would be lost and much gaines from a power limit of 30W, universally applied”. And even back in 1924, S. Kruse, the then-Technical Editor of ARRL’s “QST” wrote (May issue, page 36): “Practically none of us paid the slightest attention to making the signal redable or steady; no, the main idea was to make a noise.”

As you see, many problems still remain after nearly a century: people are calling when the DX station is transmitting and definitely cannot listen, and some station overdrive their transmitter in a way that they nearly bury the DX signal.


Annotated detail of this pile-up: It shows overdriven signals calling even when 3C0W transmits and cannot listen …


  • Hi Nils, you touched on something I’ve long thought about. What if people invested in high quality preamps instead of final amps? If people could run 100w and be heard wherever there was propagation, there’d be far less noise and interference than exists today. Reducing the local noise floor, increasing rx gain, and perhaps a steerable array… would reach rx nirvana. I’d love to see mfj or someone roll out a new phasing unit that could take two antenna feeds and phase them, kinda along the lines of a product improved mfj 1026 or whatever their phasing unit was called. It would of course satisfy hobbyist hfdf urges as well.



  • Hi, Chris – your thoughts are very much welcomed, thanks. From the point of propagation, 100W (SSB) is really enough, if: universally accepted, with some knowledge of propagation and some practice of DX work. Digital modes further reduce this to 10W or even lower with having FT8 in mind. I worked P5/North Korea with 5 W/QRP in RTTY – so it works. Local QRM/QRN is a problem nowadays, but clever techniques like the passing you mentioned can be a tool to efficiently combat it. The future of amateur radio will be smart amateur radio. And we will be part of it! 73 Nils, DK8OK

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