There are no limitations on installation height as we state on each case ' Mount the higher the better' due to the curvature of the earth. Mast shadow applies to all reflectors as the mast prohibits the interrogating radar from seeing the complete reflector. Below is a chart of mast shadow.
As there are variables if you take 22/24 degrees as a mast shadow on a typical 30ft yacht with fitted with an EM230 them you will not be far out.
|Mast size length x width||Centre tocentre spacing||Azimuth Shadow angle||Remarks|
|130mm x 93mm||215mm||24.40 20' - 25'||Yacht|
|155mm x 104mm||228mm||25.70 25' - 30'||Yacht|
|177mm x 124mm||239mm||29.10 30' - 35'||Yacht|
|206mm x 139mm||253mm||30.70 35' - 40'||Yacht|
|237mm x 162mm||269mm||33.50 40' - 45'||Yacht|
|130mm x 93mm||265mm||19.90 20' - 25'||Yacht|
|155mm x 104mm||278mm||21.20 25' - 30'||Yacht|
|177mm x 124mm||289mm||24.20 30' - 35'||Yacht|
|206mm x 139mm||303mm||25.80 35' - 40'||Yacht|
|237mm x 162mm||319mm||28.50 40' - 45'||Yacht|
John Firth the inventor of the Echomax symmetrical array was adamant that no radar reflector should be fitted to a mast but suspended from the cross trees or halyard which virtually eliminates mast shadow and enables compensation at heel retaining virtually full response up to 20 degrees.