Antenna Placement

[Ebenge]

I have two radio shack 20-176 antennas and I am wondering if I put them on the same mask, then how far apart I would have to place them.
If I would like to add another antenna of a different type how far would I place that.
All antennas are used for scanners only.
Thanks

 

[Taloniilm]

Twin "Sputniks"

I did mine like this. In the future I'll be moving my WX station to my other mast and mounting a Diamond D130J to the center positon on a short, (3-5 ft) extension. My separation is 6 ft.