Topband: Inverted L & radials
cris blak
cyo3fff at yahoo.com
Mon Mar 19 10:50:49 EST 2007
Hello,
Last weekend I build an inverted L antenna as follow:
a total of 38m wire (PVC isolated 2.5mm copper wire) , 13m vertical and 26m horizontal toward about 260 degree azimuth.
it is feed by RG213U coax cable. the shield of the coaxial is connected to the ground through a 1.5m length 30mm copper pipe. from this point is going 4 radials of 15m and 2 of 22m. The radials is laing on the ground.
Comments:
I don't use any tuner, just the coaxial to the TS450. VSWR were about 1.1 to 1.3 between 1800 to 1860KHz.
I've notice that when I run the radials along the horizontal part of the antenna (below this part) the VSWR increase so, I run all of theme perpendicular and in the opposite direction of this segment.
During the weekend Russian's contest I've notice that the eastern station (especially UA9) is coming very well on this antenna comparing to INV.V. I've testing several times UA9 station calling first with INV. V, getting nothing in return (even in a clear frequency) than calling with this antenna when they came back right away. Amazing! On the reception side were the same situation.
On the NW-W direction the signals were better on INV. V than on this one. The INV. V is for 160m and its wire is oriented on NW-SE direction. These test were made in the evening till the mid night (local time).
Next day around 7:30 local time (5:30UTC) I've listening to the EU and couple of USA station (K3NA, NY4A,etc. - the best were WJ9B). This time, the best signal were on INV. V...(on the reception side because I couldn't complete with none of the USA station...
Questions:
1. Is there some of you that experience the same effect with such antenna (an decreasing performance toward the horizontal segment comparing with the opposite direction)?
2. The radials are made from PVC isolated 2.5mm copper wire and is running on the ground. Should it be un-isolated and buried under the ground?
Please feel free to share your impression regarding this antenna. I build it for TXing having in mind the vertical low angle (about 30 degree) comparing with INV. V.
Many thanks.
73 de YO3FFF
Cristi
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