Koden radars?

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" <fast DeleteThis @btpost.net> wrote in message
news:fast-948D57.09502405012008@netnews.worldnet.att.net...
> In article <flo595$4kn$01$1@news.t-online.com>,
> "Steve Lusardi" <stevenospam DeleteThis @lusardi.de> wrote:
>
>> Bruce,
>> The 20 degree fan does prevent the helmsman on my boat from being in the
>> path of heavy radiation and the sidelobe power outside that 20 degree fan
>> is -28 DB and that is important to me. The specs for Furuno radiator
>> XN20AF/6.5 Beamwidth (H) 1.23 degrees, Beamwidth (V) 20 degrees. On the
>> other hand their S band antennas are 25 degrees like the SN30AF. In point
>> of
>> fact all the Furuno X band radars are 20 degrees, not just the 6 footer,
>> which is in line with your statement that all Slot-Line anennas have the
>> same vertical fan, but the number is 20 for X Band not 25, but I do
>> recall
>> that antennas by other manufacturers are 30 degrees.
>>
>> By the way, I did listen to your advice last year and scrapped the 6 KW
>> Decca and acquired an FR2125BB.
>> Steve
>>
>> "Bruce in alaska" <fast DeleteThis @btpost.net> wrote in message
>> news:fast-02DC90.12492804012008@netnews.worldnet.att.net...
>> > In article <flji7g$rsi$00$1@news.t-online.com>,
>> > "Steve Lusardi" <stevenospam DeleteThis @lusardi.de> 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

In article <flopc2$DKr$01$1@news.t-online.com>,
"Steve Lizard" <stevenospam.DeleteThis@lusardi.de> wrote:

> 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

Yep, you got that right Steve, You don't "Know"...... The Average Power
is not the Peak Pulse Power, but it IS, your Peak Pulse Power. * the
Pulse Length, * the Pulse Repetition Rate. Typically in a Marine Xband
10Kw Radar the Maximum Average Power is about 20 Watts, now if your 4
Foot slot-Line antenna has a Horizontal 3 db Beam-width of say 3°, then
divide that into 360°, and you are being sweeped less than 1% of the
time, so figure, now it is 2 Watts Average Power. Now figure that
Power is at the Magnetron and not the Antenna Face, so you lose, oh
say 1.5 db in the Waveguide, Rotary Joint, etc, so now your down to say
1.5 Watts, spread over the Face Antenna, which is 4Ft X 4" or 192 Sq
Inches, and 1.5 Watts spread over 192 Sq Inches, would be in the
neighborhood of 8 Milliwatts per Square Inch, as the Output Power
Density for the Typical 10Kw Marine Xband Radar, at the Antenna Face.
Now if one figures the Inverse Square Law into Distance from the Antenna
Face, the Power Density is even LESS significant..... Like I said do the
MATH, and it becomes a Non-Issue.... You get more Non-Ionizing radiation
from the Sun, on a Cloudless day, by FAR......

--
Bruce in alaska
add <path> after <fast> to reply