Thursday, June 4, 2020

Video about the VK9XG expedition to Christmas Island in 2018

In October of 2018, six radio amateurs from the UK activated Christmas Island which is to the south of Indonesia in the Indian Ocean. A presentation on the expedition was given at the RSGB convention in 2019 and the RSGB have now just put it up on YouTube.



I have to admit that I have pretty much no interest in these type of expeditions but I found a few points of interest in the video.


As you can see from the map below, Christmas Island is located to the south of Indonesia.


This meant that while it was easy to work areas like Japan, it was more difficult to work Europe and North America.

As you can see from the image below, they were located next to the Indian Ocean, an ideal spot for radio.

Back in October of 2018, the Solar Flux would have been very low as we were well on the way to the bottom of the sunspot cycle. This essentially meant that the higher HF bands like 10m & 12m were very poor and most of the contacts were on 21 MHz and below.


A breakdown of the modes is... SSB 11.5%, CW 68% and FT8 20.5%. This suggests that for the SSB only operator then it was going to be hard to make a contact with them.

It also reflects the explosion of interest in what was then the new FT8 digital mode and the decline in modes like RTTY.

The use of FT allowed allowed an analysis of received signal strengths.


Those with a signal to noise ratio of 0dB and above would have supported a SSB contact.
Contacts on CW would have been possible at -12dB and above.
Those contacts below -12dB were only possible on FT8.

This reflects the poor conditions and shows again that it was tough going for the SSB only operator to catch them.

It also reflects why weak signal modes like FT8 have had such an impact as it allows those with modest stations to compete with the rest.

160 Metres... It was interesting to see how they were able to work stations in the USA and how the pattern followed the areas just before sunrise.

On a more disturbing note, there were also stations on the east coast of the USA renting out time on a remote station on the west coast to make a contact on top band.

Technically it's within the rules of the ARRL DXCC programme. Morally, it's just cheating.


Links...
1) Info on ClubLog

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