There is something I dont understand about radars. I have a JRC 1500 radar
(16 miles), in according to the manual, the antenna is supposed to send out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be able to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt. It
is the same effect of an electical owen.

Aron Tvedt wrote:
There is something I dont understand about radars. I have a JRC 1500
radar (16 miles), in according to the manual, the antenna is supposed
to send out a radarbeam of 2000 watt. My engines (yanmar 4lha htp)
generator produses 12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be
able to produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of
2000watt. It is the same effect of an electical owen.

Surely it depends on the voltage at which the 2KW beam is generated?
Remove "nospam" from return address.

Also consider that the radar sends a pulse of a couple of microseconds so
it's not continuous power drain.

Regards
Al

"Aron Tvedt" wrote in message
...
There is something I dont understand about radars. I have a JRC 1500 radar
(16 miles), in according to the manual, the antenna is supposed to send
out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be able
to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt.
It
is the same effect of an electical owen.

aha, Amp=W/V?

"Dennis Pogson" skrev i melding
news:EAi0c.974$vY.636@newsfe1-win...
Aron Tvedt wrote:
There is something I dont understand about radars. I have a JRC 1500
radar (16 miles), in according to the manual, the antenna is supposed
to send out a radarbeam of 2000 watt. My engines (yanmar 4lha htp)
generator produses 12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be
able to produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of
2000watt. It is the same effect of an electical owen.

Surely it depends on the voltage at which the 2KW beam is generated?
Remove "nospam" from return address.

Your radar is only transmitting 2000 watts for a very short time, maybe a
microsecond. It also is only transmitting for less than maybe 1% of the
time, so the average power at 1% would only be 12 watts.


"Aron Tvedt" wrote in message
...
There is something I dont understand about radars. I have a JRC 1500 radar
(16 miles), in according to the manual, the antenna is supposed to send
out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be able
to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt.
It
is the same effect of an electical owen.

doh....20 watts

"phil" wrote in message
news:drm0c.439369$na.1050869@attbi_s04...
Your radar is only transmitting 2000 watts for a very short time, maybe a
microsecond. It also is only transmitting for less than maybe 1% of the
time, so the average power at 1% would only be 12 watts.


"Aron Tvedt" wrote in message
...
There is something I dont understand about radars. I have a JRC 1500
radar
(16 miles), in according to the manual, the antenna is supposed to send
out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator
produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be
able
to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt.
It
is the same effect of an electical owen.

On Sun, 29 Feb 2004 10:44:53 +0100, "Aron Tvedt"
wrote:

There is something I dont understand about radars. I have a JRC 1500 radar
(16 miles), in according to the manual, the antenna is supposed to send out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be able to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt. It
is the same effect of an electical owen.


Radar uses a pulsed transmission, and the advertised power is the peak
power during a pulse. Since a radar actually transmits for much less
than 1% of the time, the average power consumption is much less than
1% of the advertised power - for one 2KW radar I had, I calculated
that the average power used by the transmitter was only 1 watt! The
fuse in the power feed to that set was only 2.1 amps, and I could run
the radar for hours on a sailboat (while sailing) with no concern
about running out of power.

Most radars will use more power for the display, and to turn the
antenna, that for the transmitter.


--
Peter Bennett, VE7CEI
peterbb (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

THe JRC 1500 has three pulse widths. The fastest is .08uS (.00000008
second) at 2,250 Hz (.000444 second). That means the pulse is about
1/5550 of the cycle. The slowest is .8 uS at 600 Hz or about 1/2000 of
a cycle. Most of the rest of the time a capacitor/inductor circuit
stores up power at a low rate and then blast it out all at one time.

Aron Tvedt wrote:

There is something I dont understand about radars. I have a JRC 1500 radar
(16 miles), in according to the manual, the antenna is supposed to send out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be able to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt. It
is the same effect of an electical owen.



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

I work on weather radars that have up to 250kiloWatts out.
this is a peak value.
with the pulse widths we use it's actually only an average of 120Watts or so
out.

Now, don't think that since you have 200W speakers and are safe standing in
front of them, that you are safe sitting in front of your 20W (average)
radar. Just a note for safety...exposure times and all.....


"Aron Tvedt" wrote in message
...
There is something I dont understand about radars. I have a JRC 1500 radar
(16 miles), in according to the manual, the antenna is supposed to send
out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be able
to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt.
It
is the same effect of an electical owen.

The 2KW is PEAK power, only during the very short radar pulse. The
average power is very low because the time in between pulses is very
long, in comparison to the pulse. If you measure the DC power applied
to the radar, you'll only get a few amps of DC power because of this.
Power is stored in what is called a "pulse forming network" so the
magnetron has a charged source of power to pull the big pulse of
current from. This is why there are no big DC cables going up the
mast to power it. The electronics fires the stored power through the
magnetron, very quickly, producing a very narrow pulse time, which is
why you can see that bouy so close to the boat.

You'll have no problem powering even the 8KW radar from any
alternator......


On Sun, 29 Feb 2004 10:44:53 +0100, "Aron Tvedt"
wrote:

There is something I dont understand about radars. I have a JRC 1500 radar
(16 miles), in according to the manual, the antenna is supposed to send out
a radarbeam of 2000 watt. My engines (yanmar 4lha htp) generator produses
12v 80A (1120watt).

I dont use the radar all the time, but if I did, would the engine be able to
produse enough power to my batteries?

Some experienced sailors say my radar cannot have an effect of 2000watt. It
is the same effect of an electical owen.




Larry W4CSC

No, no, Scotty! I said, "Beam me a wrench.", not a WENCH!
Kirk Out.....