Agree that vertical propagation is usually the way to go for transmit on
160m, although I live on a steeply sloping hillside and have had decent
luck with a low Inverted-Vee on 160m in the past.
Several years ago I worked a 3B9 DXpedition on 160m using a two element
wire yagi I had temporarily strung across a canyon near my house
specifically to work that DXpedition. The yagi was probably 150 feet
above the canyon floor and the terrain just happened to VERY steeply
slope toward 3B8 short path. I easily worked the DXpedition and on some
days I could hear them Q5 for almost an hour near my sunset. I was the
furthest west station to work them on 160m. I operated from my car with
a small solid state amp, and given the very long length of RG-8X (larger
coax would have been too heavy) I couldn't have been putting more than
200 watts to the antenna.
I was pretty proud of that at the time and posted the story on the
TopBand reflector. I soon received a reply from Bob Brown, NM7M (a SK
since 2007), one of the most accomplished propagation experts our hobby
has ever had. He told me that based upon the path from my QTH in
southern Arizona to 3B9 coupled with the electron gyrofrequency
phenomenon, horizontal polarization likely suffered an 11 dB penalty
compared to vertical polarization. Since the electron gyrofrequency
effect is a function of the interaction with the earth's magnetic field,
it is somewhat dependent upon the specific path involved. I still think
the brutal effort I expended repeatedly climbing those steep canyon
walls to put up the wire yagi was worth it given the results I had, but
probably less of a difference than I had thought. I suspect that the
steep slope provided some compensating benefit for the horizontal
polarization.
I'm no expert on the subject so if I got any of this wrong please
correct me.
Dave AB7E
On 1/13/2025 1:11 PM, john@kk9a.com wrote:
I have tried a low 160m dipole/ inverted V many times from the Caribbean
and they are incredibly bad. I had much better luck on 80m with a low
dipole. On top band you usually need something vertically polarized for TX.
John KK9A
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