Does anybody uae this radar 'trick'

[JammedStab]

"A major concern going into BOG was the developing TRW in the evening. Much later on the 767, flying with XXXXXXX Airlines crews who lived in South America flying, I learned about the radar ‘trick’ they used. This was to put the radar on max gain, set the range to 40 miles, and tilt to 8-10 degrees down. By doing this, you picked up the “shadow” of a dry TRW in development. Earlier, I found out the hard way, during a descent through a haze layer, that there was a developing TRW ahead of us."

[msbbarratt]

Reminds me of how the Chain Home operators became so good at interpreting their A scope displays they were able to out perform anyone's wildest expectations.

Operators have always found innovative ways of using their kit in a manner not expected by the designers. As an equipment designer I have been pleasantly surprised many times by just what my operators could achieve. Experience gained through real world usage cannot be beaten.

[Sciolistes]

TRW? Anyway, for the Honeywell systems at least, it is a manufacturer recommended technique.

[Good Business Sense]

Hi,

As I'm sure everyone is aware but just to clarify

you can't pick up "dry" - that's why you aim the tilt for the temperature band approx -10C and above. Anything colder does not reflect, particularly with the modern day radars of approx 120 watts (think of the energy per square foot/mile or whatever out at 40/80/100 miles over the tilt angle)

Now the 60 kw radars from the old days that was a little bit different - I sometimes felt you could pick up individual raindrops with them - just so much more return energy.

Cheers

[Centaurus]

The use of MAX Gain at high altitude is good operating procedure with some radars. This technique used with appropriate tilt control will sometimes reveal a tiny echo inside 40 miles that is the top of large CB particularly over the Pacific where we used it on the 737-200. Works over Vietnam where there are huge CB at times. In the normal AUTO position, chances are there will be no returns from CB tops. On MAX gain chances are an echo is visible.

The Pilots Guide for Collins WXR 700X Weather Radar (October 1994 edition) Page 44 states in part:
"The ability to adjust the Gain Control during weather detection modes provides some advantages in weather detection at the shorter ranges...specifically aircraft operating at high altitudes run a greater risk of encountering low reflectivity targets such as ice crystals. Adjusting the Gain to provide maximum detection capability will aid in locating areas of low reflectivity targets.
Remember that by increasing the system Gain, the target will appear to be more reflective than normal weather detection conditions would indicate."

In other words very tall CB tops.

[MarkerInbound]

but I CAN say that this thread is the first time I've seen thunderstorms referred to as TRWs.

TRW is used on US radar summary charts. Which is odd because the NWS definition of a thunderstorm is when either thunder or lighting are observed. Radar does not detect either.

[JammedStab]

Any American ATP will be familiar with the term TRW for thunderstorms and rainshowers. I just quoted the article but immediately knew what a TRW was. For simmers and some foreigners, now you know.

[Denti]

If i unterstand the manual of my rockwell collins WXR 2100 correctly, it uses that "trick" in auto mode. And can differentiate the required gain between ocean and landmass under the weather in question.