Major reduction in VORs
01-07-2012 | 05:48 PM
#11
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From: Curator at Static Display
Radiated Power?
USMC:
What is the rated power of OMs and LOMs? I think I read that OMs are about 5-10 watts, and LOMs about 15-20....but I can't remember where I saw that.
The reason I ask: the single Marker-Beacon Light in the T-38 (yes, that is non-standard---and it is Green instead of Blue, white, and orange!) only seems to work about half the time.
I have a theory it is due to low receiver sensitivity, and therefore, only the stronger Markers trigger it. I also think the receivers are not written-up unless they are perceived to be failed---and there is no BITS for the receiver.
In other words, I think a lot of them are in bad shape.
What is the rated power of OMs and LOMs? I think I read that OMs are about 5-10 watts, and LOMs about 15-20....but I can't remember where I saw that.
The reason I ask: the single Marker-Beacon Light in the T-38 (yes, that is non-standard---and it is Green instead of Blue, white, and orange!) only seems to work about half the time.
I have a theory it is due to low receiver sensitivity, and therefore, only the stronger Markers trigger it. I also think the receivers are not written-up unless they are perceived to be failed---and there is no BITS for the receiver.
In other words, I think a lot of them are in bad shape.
01-07-2012 | 06:10 PM
#12
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From: FAA 'Flight Check'
USMC:
What is the rated power of OMs and LOMs? I think I read that OMs are about 5-10 watts, and LOMs about 15-20....but I can't remember where I saw that.
The reason I ask: the single Marker-Beacon Light in the T-38 (yes, that is non-standard---and it is Green instead of Blue, white, and orange!) only seems to work about half the time.
I have a theory it is due to low receiver sensitivity, and therefore, only the stronger Markers trigger it. I also think the receivers are not written-up unless they are perceived to be failed---and there is no BITS for the receiver.
In other words, I think a lot of them are in bad shape.
What is the rated power of OMs and LOMs? I think I read that OMs are about 5-10 watts, and LOMs about 15-20....but I can't remember where I saw that.
The reason I ask: the single Marker-Beacon Light in the T-38 (yes, that is non-standard---and it is Green instead of Blue, white, and orange!) only seems to work about half the time.
I have a theory it is due to low receiver sensitivity, and therefore, only the stronger Markers trigger it. I also think the receivers are not written-up unless they are perceived to be failed---and there is no BITS for the receiver.
In other words, I think a lot of them are in bad shape.
We test each of the markers with the receivers set in a low sensitivity settings (I think lower than normal receivers). The threshold is 1700 microvolts to set off your receivers. I've seen a few so far that were either to small or too large or had what we call 'holes' in them (a gap in the splay larger than 300'), but for the most part I've found them to be working as advertised.
I'll see what I can dig up for you UAL.
USMCFLYR
01-08-2012 | 02:25 PM
#14
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From: Sr. VP of button pushing
May that's why they don't work that good, 2000 is optimum and yet they're supposed to range from optimum + 400 to optimum + 2200. Oh well, good enough for government work. (Talking about the standards, not you USMCFLYR.)
01-08-2012 | 04:28 PM
#15
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From: FAA 'Flight Check'
Marker beacons transmit an elliptical pattern with dimensions of approximately 2,400 ft in width and 4,200 ft in length at 1,000 ft above the antenna. The optimum width is 2,000'
As I said - in the ones that I have been part of the checks over nearly the last year, I have only seen problems with two. A quick adjustment of the power fixed each quickly. If you have good reason to believe that a marker is not performing to standards I encourage you to make a user complaint. The standards are black and white. If the marker doesn't meet the standard, it is either fix (if maintenance is on site) or taken off the air.
USMCFLYR
01-08-2012 | 08:58 PM
#16
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From: North by Midwest
Ok guys you both have me convinced there is a problem with attack vulnerabilities on both systems, but realistically how much of problem is it? Let assume the fool doing it does not get caught rapidly, is the cost involved in keeping VORs a big enough investment considering the risk of GPS interference? I mean when I was born you still had steam gauges in your 707s now it's rare to see an airliner that is not glass and people had their trepidation about that, so really is eliminating VORs and forcing GPS that big of risk? From the cost and risk standpoint mind you.
01-08-2012 | 10:01 PM
#17
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I say set up a bunch of NDB's. They are cheap to operate and nice to have in the event of a catastrophic GPS failure.
(Nuke outside atmo, solar flare, etc)
ADF equipment shouldn't be expensive, hell, it's 1920's tech, there should be an app for it by now...
(Nuke outside atmo, solar flare, etc)
ADF equipment shouldn't be expensive, hell, it's 1920's tech, there should be an app for it by now...
01-11-2012 | 06:11 AM
#18
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From: FAA 'Flight Check'
this is the only thing I could find with a quick search and questioning the techs.
It is out of an FAA pub though I didn't write down the reference doc.
It contains the other items that I quoted earlier from our publications, but the power part was not listed in our own pubs.
1. ILS marker beacons have a rated power output of 3 watts or less and an antenna array designed to produce an elliptical pattern with dimensions, at 1,000 feet above the antenna, of approximately 2,400 feet in width and 4,200 feet in length. Airborne marker beacon receivers with a selective sensitivity feature should always be operated in the “low” sensitivity position for proper reception of ILS marker beacons.
USMCFLYR
01-14-2012 | 06:32 AM
#19
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From: FAA 'Flight Check'
UAL -
this is the only thing I could find with a quick search and questioning the techs.
It is out of an FAA pub though I didn't write down the reference doc.
It contains the other items that I quoted earlier from our publications, but the power part was not listed in our own pubs.
USMCFLYR
this is the only thing I could find with a quick search and questioning the techs.
It is out of an FAA pub though I didn't write down the reference doc.
It contains the other items that I quoted earlier from our publications, but the power part was not listed in our own pubs.
USMCFLYR
With further research (called studying on a weekend), I also found in our pubs that Compass Locators, in this case ones associated with a marker - LOM or LMM - have power outputs of less than 25 watts.
I think this answer is more in line with your original question since you specifically stated LOMs.
USMCFLYR
01-15-2012 | 05:42 AM
#20
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From: Curator at Static Display
Thanks!
USMC:
Thanks---this is ballpark what I thought I remembered. OMs are very low powered---3 watts is about an old-fashioned Christmas-tree bulb, and 25w for LOMs is a refrigerator light!
I think it confirms my suspicion that the Marker Beacon receiver in the T-38 is often out of limits, but since it is a "fly to fail," and no one knows it has failed----it doesn't get fixed.
I'm going to talk to our MX on Tuesday and ask what kind of inspection cycle is done on them.
Thanks again for the leg-work.
Thanks---this is ballpark what I thought I remembered. OMs are very low powered---3 watts is about an old-fashioned Christmas-tree bulb, and 25w for LOMs is a refrigerator light!
I think it confirms my suspicion that the Marker Beacon receiver in the T-38 is often out of limits, but since it is a "fly to fail," and no one knows it has failed----it doesn't get fixed.
I'm going to talk to our MX on Tuesday and ask what kind of inspection cycle is done on them.
Thanks again for the leg-work.
