I don't know Bruce, but I guess the average power of this is something just
less than 5 KW on long range and the distance between the radiator and
helmsman is around 10 ft and when rotating at 24 rpm the helmsman is in the
zone 14% of the time, so the average power exposure is still 700 watts at
the Slot Line and 300 Watts at 10 ft. Still, that can't be healthy over
time. Perhaps I did not do the math correctly, but that's what I came up
with.
Steve

"Bruce in alaska" wrote in message
...
In article ,
"Steve Lusardi" wrote:

Bruce,
The 20 degree fan does prevent the helmsman on my boat from being in the
path of heavy radiation and the sidelobe power outside that 20 degree fan
is -28 DB and that is important to me. The specs for Furuno radiator
XN20AF/6.5 Beamwidth (H) 1.23 degrees, Beamwidth (V) 20 degrees. On the
other hand their S band antennas are 25 degrees like the SN30AF. In point
of
fact all the Furuno X band radars are 20 degrees, not just the 6 footer,
which is in line with your statement that all Slot-Line anennas have the
same vertical fan, but the number is 20 for X Band not 25, but I do
recall
that antennas by other manufacturers are 30 degrees.

By the way, I did listen to your advice last year and scrapped the 6 KW
Decca and acquired an FR2125BB.
Steve

"Bruce in alaska" wrote in message
...
In article ,
"Steve Lusardi" wrote:


Ok Steve, Please tell us all about why this would be important.
Actually, the Vertical Beam-width of a ANY Slot-line Radar Antenna, is
NOT related to the length of the Antenna, at all, but IS related to the
design of the Slot-line shielding, and slot-line position inside the
shielding. If you look at the Furuno Antenna Spec's you will notice
that ALL the Slot-Line Antennas, have a 25° Vertical Beam-width, and
have had since Furuno first Started importing their products to the
USA, back in the KRA-121 days.

--
Bruce in alaska
add path after fast to reply

So your inference is that "IF" a RADAR Antennas Main radiation Lobe
intersects with where a human stands, that this is somehow "Bad",
or dangerous? Hmmm, have you ever done the math, to calculate the
Power Density of the RF Energy at the face of the antenna, at a
distance of twice the Slot-Line Antenna Length, or even at 20 Ft
from the Antenna? Then consider that it is Rotating, and the human
is only in the Radiation Field less than 5% of the time. Add to that,
the fact that for non-ionizing Radiation, it is Average Power, and not
Peak Power, that creates harm to biologics. What is the Average RF Power
Output from this Xband Marine Radar? As in all RF Radiation, Marine
Xband Radar Energy follows the Inverse Square Law.

Your concerns, however irrational, are yours, to deal with, but the Math
doesn't compute in your favor, here.

Bruce in alaska

--
Bruce in alaska
add path after fast to reply