Mr Spaceman From Canada, joined Mar 2001, 2786 posts, RR: 9 Posted (11 years 9 months 2 weeks 1 day 5 hours ago) and read 1388 times:
What is the function of the silver square antenna on the red & white pole in the photos below? Is it part of the Localizer Antenna system? I suspect that the main LOC antennas are the several white boat shaped objects (over 12 of them) located across the width of the runway several feet above the grass.
I'm curious because I've never seen antennas which looks like these ones at the end of runways here in North America.
Also, are these antennas over in Europe newer/better technology then those used in Canada & the USA?
Mr Spaceman From Canada, joined Mar 2001, 2786 posts, RR: 9 Reply 2, posted (11 years 9 months 2 weeks 1 day 2 hours ago) and read 1299 times:
Well, hey I guess that's possible. It does kinda look like a giant fancy microphone. One things for sure...I've never seen an object like this up on a pole along the extended centerline at the end of a runway at any airports I've been to in North America. That's why I was wondering if it's European technology, and only used over there.
Ziggy From United States of America, joined Jun 2001, 178 posts, RR: 0 Reply 4, posted (11 years 9 months 2 weeks 22 hours ago) and read 1259 times:
For the U.S. at least I know this is what the Glideslope Antenna looks like. (could find a closer one) The antenna is the red an white stucture on the hill on the left side of the runway. But about the mystery antenna, I have no clue.
Zeke From Hong Kong, joined Dec 2006, 8271 posts, RR: 74 Reply 5, posted (11 years 9 months 2 weeks 20 hours ago) and read 1245 times:
Middle marker for the ILS, aircraft should pass about 200 ft above this, its about 0.6 nm (1000m) from the runway. Its normally at the same place/close to the decision height for a CAT 1 ILS. It transmits at 75 MHz, with a morse ident of dah-dit at 1300 Hz (high pitch).
You will only see these on ILS approaches, on ILS/DME approaches they have no marker.
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Mr Spaceman From Canada, joined Mar 2001, 2786 posts, RR: 9 Reply 6, posted (11 years 9 months 2 weeks 9 hours ago) and read 1193 times:
>Zeke, Thanks for that great info. Now that I know what it is, it makes me wonder...are the middle marker antennas at North American airports a different design/shape? I ask this because I've never seen one of these antennas in person or in any of the photos at A.Net.
>Ziggy, you're correct. That red & white antenna is the glideslope transmiter. As you can see, it's beside both the Precision Approach Path Indicator (PAPI) lights as well as the runway's large white Touchdown Zone markers. BTW, great photo!
Zeke From Hong Kong, joined Dec 2006, 8271 posts, RR: 74 Reply 7, posted (11 years 9 months 1 week 5 days 7 hours ago) and read 1141 times:
If the runway is served by an ILS/DME it does not need markers, an ILS requires markers. The markers provide check point to pilots as they do an ILS, if they have an ILS/DME they can use the DME distance for the checkpoint.
The antenna may be combined with other equipment such as approach lighting.
Without knowing the distance from the touch down zone, it could also be an inner marker.