Home |
Search |
Today's Posts |
|
#1
![]() |
|||
|
|||
![]() "Jimmie D" wrote in message ... This afternoon while cleaning a closet I pulled out an old US map that had been marked with contacts I made back when I worked 10M a lot. After the local stations there is a big empty area on the map then I started making contacts again at about 300 miles. Antenna used was a 1/4 lambda groundplane with the radials drooping so to match 50 ohms. A chart I found indicates that this means I have a vertical angle of radiation of 50 to 60 degrees. Is this correct??. I didnt think the angle would be so great for this antenna. The gap between the farthest of the ground wave contacts and the nearest of the skip contacts is termed the Skip Zone and the 50 to 60 degree number you cited sounds accurate. It represents the highest takeoff angle that is successfully refracted back to earth. Please note there is no one takeoff angle. It's a range of angles and your transmissions at many angles are returned simultaneously. A quoted takeoff angle is merely the angle for the strongest signal. For a given paths a particular takeoff angle may be optimum, but others will still work. |
#2
![]() |
|||
|
|||
![]() "Sal M. Onella" wrote in message ... "Jimmie D" wrote in message ... This afternoon while cleaning a closet I pulled out an old US map that had been marked with contacts I made back when I worked 10M a lot. After the local stations there is a big empty area on the map then I started making contacts again at about 300 miles. Antenna used was a 1/4 lambda groundplane with the radials drooping so to match 50 ohms. A chart I found indicates that this means I have a vertical angle of radiation of 50 to 60 degrees. Is this correct??. I didnt think the angle would be so great for this antenna. The gap between the farthest of the ground wave contacts and the nearest of the skip contacts is termed the Skip Zone and the 50 to 60 degree number you cited sounds accurate. It represents the highest takeoff angle that is successfully refracted back to earth. Please note there is no one takeoff angle. It's a range of angles and your transmissions at many angles are returned simultaneously. A quoted takeoff angle is merely the angle for the strongest signal. For a given paths a particular takeoff angle may be optimum, but others will still work. Makes sense, since as I get further away, 600 miles the density of contacts actually increases. Seems to be a really strong concentration of contacts in gulf area from louisianna on toward texas from here in north carolina. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Electromagnetic Radiation | General | |||
Electromagnetic Radiation | Policy | |||
Angle of Radiation | Antenna | |||
Radiation angle vs turns count in a coil | Antenna | |||
Electromagnetic radiation | Shortwave |