mooney

didn't say I painted water....you said that. I said I painted Lake Erie...you can in the winter time...in the great lakes....ok maybe i should have been more specific. Wanting to divert around the shoreline of lake erie, and/or the ice mass that is what we call lake erie in the winter. happy now? sorry i forgot you are a detail freak

Airsupport

lol, center we need to do a 180, there is a solid line ahead, with no openings!!! lol

Dash8Pilot

Memphis is a scary place. As a rule, I divert around it to avoid the plane being damaged by small arms fire.

IBPilot

I recall somewhere that the power output of the -200 radar is 2 watts is that correct?

GravellyPointer

From the Canadair RJ FCTM (Flight Crew Training Manual): The CRJ's radar beam width is 7.3 degrees (effectively 7 degrees). It's a 14 in. antenna plate, and power is 25 watts, not 2. The manual states that the solid state design provides better performance than a high powered old radar of 5000 watts.

The rule of 1 degree/1 nm = 100 ft of altitude change applies to all radars, it is a basic dimension rule.

You use it along with considering the width of the beam and the angle, and your altitude above ground to guess at what range you should see ground returns. Conversely, you can determine the tops of the storm you're painting by knowing the angle of the beam, the width of the beam, your altitude, and the range at which you're painting the storm.

With the CRJ radar tilted at +1.0 the bottom of the beam is at -2.5 degrees. To paint ground at 80 nm range you would need to be at 20,000 AGL (2.5 * 100'/nm/degree * 80nm).

At 8,000 AGL with +1.0 tilt at what range would you see ground returns in the CRJ?

Ok, one more. You're at FL300 in the CRJ, and you're painting a storm at 40 nm range. Raising the tilt up to +6.0 degrees makes the cell disappear. What altitude is the T-storm tops?

Gain IS useful. Flying in FL or in areas that are full of moisture (extensive rain showers vs. SCT TS's) will show lots of yellow and red returns. Turn the gain down one or two levels to show the differences between higher and lower precip areas. When it's cloudy with some moisture, but little TS and cumulus develpment, and actual precipitation, you can still find the bumpy areas by turning UP the gain one or two levels. The areas that paint, which didn't before, are areas with higher turbulence levels. Ask for ATC deviations around these areas to best serve the peeps in back.

GCS 'reduces the intensity of ground returns so that many of them disappear from the display, which makes the preip returns easier to identify.' . . .'GCS should only be used to identify ground clutter. GCS can make some precip retuns show reduced in intensity or eliminated from the display'.

Hope this helps.

JetPipeOverht

When approaching outstation small airports, one CA was explaining how on the BraKilla you could paint the road and at night watch all the brake lights come on due to them thinking it's a cop lighting them up with an X band radar

TonyWilliams

6 degrees up, minus (7.3)/2 equals 2.35 degrees up at the bottom of the beam.

2.35 times 40 miles equals 94 times the formula 100 feet equals 9400 feet above your present altitude of FL300, so the tops are FL394.

DublinFlyer

Great post by the way!!!

Wow, that's way too much math for me. I hate math. I look at the radar like this. If I have the range at 20 miles, and I move the tilt up or down 1 degree I'm moving the beam 2,000 feet up or down. At the 40NM range, moving the beam up or down 1 degree is 4,000 feet difference. Moving it up to 6.0 would be 24,000 feet leaving the tops at 54,000ft. I may be completely balls ass wrong, but I don't think so.

How did I do GravellyPointer?

cospilot

This is what I know about the CRJ200 radar made by Collins.

There are only three things I use regularly on the CRJ200 radar:

- TILT
- GAIN
- GCS

When the radar is selected ON, the TILT can be adjusted from a range of -15 degrees (Nose Down) to +15 degrees (Nose Up). When I fly enroute, I use the tilt so that the radar beam is pointing to the middle and lower parts of the storm cell to find the most reflective part of the cell. This is an ongoing process with me. I'm always scanning up and down and moving the range in and out because you are always changing position and you need to be aware of what's developing.

GAIN can intensity or reduce the radar return and helps better define the storm cell. Don't increase the gain though and freak yourself out. You have to take in the whole picture. I've had first officer's scare themselves witless by turning the gain up so high that it made it look like a hurricane was ahead of us.

Always return the gain control to NORM when done with the radar. Collin's recommends this.

Ground Clutter Surpression (GCS) is great because it basically eliminates false returns that the ground can give off. Some pilots point the TILT so low that they pick up cities and think they are cells. Press the GCS button. If the green disappears, you had the radar point too low. Once you bring the tilt up, press the GCS again. If it does't go away, bring of the GAIN. Now you might have something to worry about if something is still there.

A few things I don't use or use rarely.

I don't use the AUTO TILT function because en route, since my altitude isn't changing it's doesn't help me. Even when I'm descending or climbing, I am continuously moving the range in and out and the tilt up and down. I want the big picture.

The STAB button keeps the scan horizontal but again I rarely use it. I'm never in turn that long that it is of any worth.

The SEC button reduces the total scan from 120 degrees (60 degrees to the left and 60 degrees to the right) to a total of 60 degrees. (30 degrees each side). The SEC can be useful but again I think the width of the beam is really too small to be of any real use.

So to me TILT and GAIN and GCS are my favorite tools when dissection a storm. If all else fails, talk to ATC and follow the person in front.

You can read more about the CRJ200 at my blog, Almost the Speed of Sound

P.S. These are my techniques and they work for me. You may have your own and I respect that. Fly safe.