HF propagation

[John Foss]

Since I discovered the RBN and POTA, I often look to see where a station is reaching before running upstairs to attempt a qso. Similarly, when I’m attempting an activation, I check to see how my signal is doing. I have noticed that most stations that report hearing me (and others in my general area), are north of an east west line - generally, nothing to the south. Anyone have an easy to understand explanation? I am in central North Carolina

Thanks,
John - WA4RXO

And thanks to those who make the RBN work - what a resource.

[Brian - K3ES]

Since I discovered the RBN and POTA, I often look to see where a station is reaching before running upstairs to attempt a qso. Similarly, when I’m attempting an activation, I check to see how my signal is doing. I have noticed that most stations that report hearing me (and others in my general area), are north of an east west line - generally, nothing to the south. Anyone have an easy to understand explanation? I am in central North Carolina

Thanks,
John - WA4RXO

And thanks to those who make the RBN work - what a resource.

Hi John,

I expect that there is no simple answer to this, and I am certainly no expert. Part of your observation may relate to the band or bands that you are using. Personally, I think of my signal (all other things being equal) as reaching a donut around my position. For 40m, I have most of my contacts between 200 and 500 miles distance. From NW PA this gets me NC, VA, MI, IN, NJ, NY, CT, etc. Less than 200 miles is normally in the skip zone. For 20m, I have most of my contacts between 1000 and 1500 miles distance. From NW PA this gets me FL, PR, AL, TX, CO, AZ, etc. If you are located in NC working 20m, this could put your "southern" contact zone in the Gulf of Mexico, the Carribbean, and Central America, where there may not be many RBN stations active. That could explaing less RBN data to your south.

There's a theory. Maybe somebody with a better understanding of propagation can set me straight.

73 de Brian - K3ES

[Andrew (grayhat)]

Since I discovered the RBN and POTA, I often look to see where a station is reaching before running upstairs to attempt a qso. Similarly, when I’m attempting an activation, I check to see how my signal is doing. I have noticed that most stations that report hearing me (and others in my general area), are north of an east west line - generally, nothing to the south. Anyone have an easy to understand explanation? I am in central North Carolina

Hi John, there are several way to check for propagation, a simple one (amongst others, by the way) is to use a web based SDR (be it a KiwiSDR or another one) to check if and how your signal arrives at a given spot; as for the fact that you're making contacts to N and to E-W and no contacts to S, it may also be due to the orography at your location/zone and due to the antenna you're using... now, which antenna are you using, what's its height from ground and which band(s) are you using ?

[John Foss]

Thanks for your response - well, I thought it was my antenna at first, or possibly the local topography, but these change when I’m portable. I use an end fed 40m dipole almost exclusively, installed vertically of some form of inverted vee, and my band of choice is generally 40. I’m basing my observation on RBN data only - maybe it’s a RBN issue rather than a propagation issue. I was hoping for an easy answer, but perhaps there isn’t one.