B747 & B707 Pointy things.

[ChristiaanJ]

Originally Posted by Graybeard

Notch/slot antennas on commercial aircraft are single, fed by two transceivers and two tuners/couplers wired in parallel to that single antenna.

On Concorde I think the "belt and braces" principle went as far as to having two separate slot antennas as well.
I'd have to look up the relevant parts of the maintenance and wiring manuals.

CJ

[Graybeard]

Sorry, CJ, I should have written "later commercial aircraft."

[Nepotisim]

Hey ChristiaanJ,

Where was that picture of the Concorde taken? It appears that it is attached to a Qantas start cart. I presume somewhere is Australia.

N

[NSEU]

They are much more efficient, as they excite the entire airplane into an antenna, vs. just a probe.

I was told that the 747 probe antennae also excited the fuselage.

Either location makes the tuners a pain in the *ss to change. Personally, I prefer the old 747 location (high work platform versus one, sometimes two cherry pickers). Definitely not engineer-friendly

[ChristiaanJ]

Originally Posted by Nepotisim

Where was that picture of the Concorde taken? It appears that it is attached to a Qantas start cart. I presume somewhere is Australia.

Vey well seen, N !
Cropped and reduced to illustrate the aerials, but the original legend said "Melbourne - 1972".

CJ

[Graybeard]

Properly designed HF antenna systems have the tuners in the overhead of the aft cabin, and the antenna in the slot below the #2 engine, as in DC-10/11 or in the dorsal, e.g. Fo-100. Some AB have the tuners in the cabin, too, I believe.

GB