Rear Mobile Antenna Location 
Rear Antenna Model 
Rear Antenna Azimuth Radiation pattern. Better for NVIS. Best radiation to front direction. |
Middle Mobile Antenna Location 
Middle Antenna Model 
Middle Antenna Azimuth Radiation pattern. Not good for short distance NVIS contacts. |
Front Mobile Antenna Location 
Front Antenna Model 
Front Antenna Azimuth Radiation pattern. Better for NVIS. Best radiation to rear direction. |
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As you can see if you want to optimize mobile antenna for short
or medium distance NVIS contacts eg on 80 meter, do not install it in the
middle of your car roof because you need high takeoff angle for NVIS. Middle
roof location provides very low gain in high takeoff angles (near 90 deg). Note also the slight directivity
when antenna is installed in the rear or front.
On the other hand if you are working on higher bands eg on 20 meters the middle location is fine for medium distance and for DX QSOs. Also on VHF and UHF middle antenna location is good because the signal is not reflecting from ionosphere and omnidirectional low angle radiation is then preferred. |
Update 2021-10-19 OH7SV
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