Topband: Spotlights can be very small
vk6vz at arach.net.au
Sun Jan 24 00:05:06 EST 2016
It has been interesting to read about the spotlight propagation being experienced by USA operators chasing VP8STI. In my experience the size of a spotlight can be very small – 50km or less perhaps.
Back in November 1998, just prior to the CQ WW Contest, Mike VK6HD and I were trying to work Kenny 6Y5/K2KW at our local sunset. This is a very difficult path, due east and with only a few minutes overlap in VK6 sunset and 6Y5 sunrise.
In those days, Mike and I lived apart 25 km apart – me in Glen Forrest and Mike due south of here in Bedfordale. On 22 November, Mike and I were on for our sunset (only a few tens of seconds apart) and Mike heard and rapidly worked Kenny at solid RST 559 on 160m. To my dismay, I heard absolutely nothing of Kenny’s signal.
The following night, I came on for sunset and was amazed to hear Kenny coming through at a solid 559 and we worked relatively easily, thanks to USA stations giving me a clear shot. On phoning Mike ten minutes later, he said he could not hear a trace of Kenny’s signal that night – mirroring my experience of the previous night.
The Forrest Gump analogy of the box of chocolates (‘you don’t know what you’re gonna get’) is exactly right for 160m. Herb’s analogy of sunlight leaking into a closet, how much depending on how far the door is open, also seems a pretty good way of explaining how the spotlight prop on 160m can work.
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