[TowerTalk] Low 160m Dipole - how bad?

[David Gilbert]

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 at 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
>
>