Radar Gain

[EatSleepFly]

Can anyone correctly explain the Gain setting on weather radar for me?

I've watched the Archie Trammel tape a few times (*snore*), but I can't remember him ever mentioning the Gain. Perhaps I was zoning. Whenever I mess with it in flight, it doesn't seem to do much, so I was just curious. Only one of the airplanes even has a gain setting. The rest don't. Any info. would be appreciated. Thanks!

~ESF

 

[TIS]

Well, I don't know which Archie tape you watched but he does go into the gain thing quite heavily.

Most of the time you should leave the gain set to the preset position. Asdsuming you have a color scope, what this will do is preset the contours as follows:

Green - 10-19 dbz
Yellow - 20-29 dbz
Red - 30 or more dbz

These return levels are correlated by Trammel in terms of the danger they represent. Basically, he says stay out of the red because that has some legitimate potential to be a thunderstorm.

He points out that according to his research, all the accidents that have been partially attributed to thunderstorms and/or windshear have resulted from storms that were returning 50 dbz or more. This brings up the reason for the gain adjustment to be taken out of the pre-set position. The manufacturer should be abel to provide you with an index of how many dbz each hashmark represents when you hand-tune the gain. By using this you can shift the dbz thresholds for each color contour by redefining the gain values.

So here's how this works. Let's say you have a big return on your scope. It's got some yellow and of course some green around its fringes but red is the attention getter. All you know about the red is that it's 30 dbz or more. By adjusting the gain according to the calibration schedule you can shift the red return so that it appears at 40 dbz and then perhaps 50 dbz. What it will allow you to do is see where the storm is most intense. It will also let you see if the red threshold is just a 30 dbz return and nothing more than that.

Now, the big word of caution - if you take the gain control out of pre-set keep your mind on what you're doing. If you forget and leave it out of the pre-set mode you will have made the radar less sensitive making its indications misleading as to rainfall intensity and thus storm danger. The best rule to follow is whenyou're done playing with the gain put it back to pre-set.

Does that help?

TIS

 

[labbats]

Well said. Helped me out too.

 

[EatSleepFly]

Well, I don't know which Archie tape you watched but he does go into the gain thing quite heavily.

Well, apparently not the right one.

That helps a ton, THANK YOU!

 

[integrale]

If the weather is nice I will crank it up and I can usually pick up traffic before TCAS

 

[Lead Sled]

Well, I don't know which Archie tape you watched but he does go into the gain thing quite heavily.

Most of the time you should leave the gain set to the preset position. Asdsuming you have a color scope, what this will do is preset the contours as follows:

Green - 10-19 dbz
Yellow - 20-29 dbz
Red - 30 or more dbz

These return levels are correlated by Trammel in terms of the danger they represent. Basically, he says stay out of the red because that has some legitimate potential to be a thunderstorm.

He points out that according to his research, all the accidents that have been partially attributed to thunderstorms and/or windshear have resulted from storms that were returning 50 dbz or more. This brings up the reason for the gain adjustment to be taken out of the pre-set position. The manufacturer should be abel to provide you with an index of how many dbz each hashmark represents when you hand-tune the gain. By using this you can shift the dbz thresholds for each color contour by redefining the gain values.

So here's how this works. Let's say you have a big return on your scope. It's got some yellow and of course some green around its fringes but red is the attention getter. All you know about the red is that it's 30 dbz or more. By adjusting the gain according to the calibration schedule you can shift the red return so that it appears at 40 dbz and then perhaps 50 dbz. What it will allow you to do is see where the storm is most intense. It will also let you see if the red threshold is just a 30 dbz return and nothing more than that.

Now, the big word of caution - if you take the gain control out of pre-set keep your mind on what you're doing. If you forget and leave it out of the pre-set mode you will have made the radar less sensitive making its indications misleading as to rainfall intensity and thus storm danger. The best rule to follow is whenyou're done playing with the gain put it back to pre-set.

Does that help?

Well said TIS. I've had the opportunity to attend 4 or 5 of Archie Trammel's seminars (The company sent us every couple of years as part of our recurrent training program.) as well as Dave Guinn's (Honeywell's) course and a couple of others. Archie's was pretty good, but I highly recommend Dave Guinns course - it's far and away the best. I would highly recommend that you guys who have never attended a formal weather radar couse to make arrangements to attend one. At one time the Honeywell course was free - you just had to reserve a slot in the various cities around the country where it is given.

'Sled

 

[FN FAL]

We don't have those "airline style" scopes you guys got...in order for us to adjust our "simple" radar scope's gain, we have to put the radar in the ground mapping mode. Otherwise, twiddling with the gain knob don't do squat.

 

[ArcticFlier]

Aw...we used to use it to spot ships in the shipping lane between SAN and LAX with the radar. Painted a few 757's off of SNA with the gain way up.


Gotta do something to stay awake.....................



AF

 

[TIS]

I will second the comments about Dave Gwinn's presentation. Archie Trammel is fine as far as he goes but Gwinn's seminar is far and away the most useful day almost any pilot could spend learning about a component they stare at every day they fly.

Radar is a funny thing. Everyone pretty much knows what it does - or thinks they do. Taking ANY sort of well thought out course is a must because it turns on every light in the room. It's then that you realize you're standing in the largest warehouse (metaphorically speaking) you've ever been in.

Once again, Trammel a good workshop. Gwinn and outstanding presentaiton - and funny too.

TIS

 

[Rook]

I will second the comments about Dave Gwinn's presentation. Archie Trammel is fine as far as he goes but Gwinn's seminar is far and away the most useful day almost any pilot could spend learning about a component they stare at every day they fly.

Radar is a funny thing. Everyone pretty much knows what it does - or thinks they do. Taking ANY sort of well thought out course is a must because it turns on every light in the room. It's then that you realize you're standing in the largest warehouse (metaphorically speaking) you've ever been in.

Once again, Trammel a good workshop. Gwinn and outstanding presentaiton - and funny too.

TIS

Hey TIS thanks for the extra info. Is there anywhere that sells a Dave Guinn radar seminar on video?

Rook