[ADXA] The Gray Line

[Joel Harrison]

Radio propagation varies depending on the frequency and time of day,
meaning whether you're in sun light or darkness. We all know that (or
should!) The small zone between daylight and darkness is called the
terminator. Please don't confuse this with an Arnie Schwarzenegger flick
as one is BS and the other is real! You make that call and then decide if
you really need to renew your ham ticket!

The terminator is also known as the gray line. Several hams talk about it
but very, very few understand it. You'll have an opportunity to talk
one-on-one with one of the few experts, Carl K9LA, at our convention in a
few weeks.

Last night provided a perfect example of the propagation impact of the
gray line. I was sitting in the shack re-reading and reviewing some
material on an antenna project I'm currently working and had the radio on
160 CW for entertainment (I don't watch TV). 9U4M was on 1.826 although
their signal was no where to be heard in Arkansas. They were listening up
and I had Skimmer running as I like to "see" who is calling them so I know
who has propagation (or who is cheating by using a distant remote
station!). For the entire evening only the extreme northeast in Maine and
upper east coast near the ocean were hearing them and calling.

Around 0320z, about 10 to 15 mins before their sunrise (SR), I began
hearing a faint sig on their freq. That caught my attention so I grabbed
the cans and put them on the see who it was. Over the next two minutes
9U4M's sig started building and about 5 mins before their SR they were
peaking 10 dB above my noise floor....a very nice Q5 copy. Their signal
remained strong until about 10 mins past their SR and around 0345z their
signal had been eaten by the rising sun in Burundi.

They were also spotted on 75 meter SSB on 3.790. I listened to their sig
come out of the noise there and build to a very respectable Q5 copy during
that same time.

This is but one example and there are many, many examples that can be
told. The lesson for everyone from this is do NOT bail from the op
position just because you do not hear a DX station you need at one
particular moment in time. Study and understand propagation and know when
the good times are to listen. My example here is for the low bands,
although another recent example I have shared with you at a meeting
earlier this year was VK0EK Heard Island in March 2016. I was listening on
10 meter CW where they were spotted one morning by the east coast....if we
are lucky propagation should be coming this way, right??? That's the way
the sun moves! I started hearing a faint sig on their frequency and for 15
seconds they popped out of the noise just long enough for me to make a Q.

Don't miss K9LA's two presentations on December 2 at our convention.

73 Joel W5ZN