i am messing around with the new weather radar and I see there are a few knobs. I see a gain that goes from -15 to +15. What's the difference here? Thanks.

i am messing around with the new weather radar and I see there are a few knobs. I see a gain that goes from -15 to +15. What's the difference here? Thanks.

 

AUTO...kinda. The question is somewhat like asking "what's the best autopilot mode?" The answer would be "VNAV/LNAV...kinda."

 

Speaking from a non-academic level (if you want academia, go look at the manuals):

First, you have the display modes (that are simulated, anyway): WX and WX+T. One displays turbulence in precipitation, and one doesn't. It's just personal preference here, unless an SOP mandates it.

 

Second, you have tilt: +15 to -15. This allows you to tilt the radar beam between +15 and -15 to see weather above or below your current path. Doing this would allow you to see weather you may be climbing or descending through. Additionally, liquid is the most reflective substance (in terms of potential precipitation) shown on the radar. This means that, if you're trying to paint a storm, you should paint it below the freezing level. The best technique to do this, when you're expecting stormy weather, is to aim the radar such that you pick up ground clutter on the edge of the display (ground clutter isn't simulated, but that's just the technique).

 

Third, you have gain: +15 to -15. This allows you to adjust the sensitivity of how the system interprets the data received. It's similar to how a scanner has an adjustable squelch. Basically, when a scanner or weather radar scans something, it's differentiating between a base level of an "undisturbed" versus one that is disturbed. In the case of a weather radar, "undisturbed" would be clear air. Water in the air causes the frequency to shift slightly as it passes through. The gain adjustment allows you to set the system to be more or less sensitive to those shifts. Counter-intuitively, a reduction in the gain will help you to determine the strongest parts of the storm to avoid (as the strong points remain red, and the borderline red areas drop to yellow).

 

Most of the time, though, it's best left in AUTO. Other options are to be used tactically.

Thank you for the fantastic answer!!!

Its an art you got to master

 

Here is the collins WXR 2100 manual

 

http://www.smartcockpit.com/download.php?path=docs/&file=Collins_WXR-2100_Operators_Guide.pdf

Kyle, so ground clutter isn't simulated then? If it was it would show as green is that correct?

Correct, ground clutter hasn't been simulated (yet?).  It would provide the strongest returns, so yellow and red would be possible (unless you reduce the gain).

 

 

It would provide the strongest returns, so yellow and red would be possible (unless you reduce the gain).

 

Brings to mind a story I heard many years ago about a young chap in the right hand seat of an airliner who wound the tilt right down, un-noticed.

 

The result was that immediate avoiding action was taken on the island of Jersey  .

I keep it on auto until cruise and for that I set my display to -5 and full gain, and the other nd set to -2 and full gain. WX+T

 

This way back out each nd to 40 and 80 miles and it makes hunting for storms and finding holes much easier.

Brings to mind a story I heard many years ago about a young chap in the right hand seat of an airliner who wound the tilt right down, un-noticed.

 

The result was that immediate avoiding action was taken on the island of Jersey  .