What was the wire for?

[Atlantic75]

Just curious

On older Aircraft like the 1-11 there was sometimes a wire running from the top of the tail to the centre of the main body. Was this for comms, navigation or something else? Why are they not seen anymore and did they ever come off in flight?

Thanks

A75

[FlapsOne]

Most probably the HF aerial and, yes, they did occaisionally come adrift.

[azzamang]

i was flying a Baron resently, when we entered icing conditions. After a while of flying and a build up of ice on the HF wire it snaped off
Resulting in a lovely "Just Married" type of affair when we landed

[Global Pilot]

Indeed the HF aerial and nowadays they are kinda hidden in the fuselage of the aircraft. Yes they do snap sometimes. Did a recent ocean crossing in a light aircraft (not quite a one eleven) were we deployed the HF out the side window. Getting poor reception talking to Gander so we just reeled it in, noticed it was about 20feet shorter than when it went out, replaced it with a spare and Gander were back loud and clear (well as best you can get on HF anyway).

[Herc Jerk]

Eg, on the 737NG the HF aerial is located in the LE of the tail fin

[ETOPS]

If you are very old (like me) you will remember the original ADF receivers that had a two position switch labelled "sense" and "loop". The aircraft was fitted with a wire aerial, usually strung from atop the fuselage to the fin and a seperate directional aerial that was circular. This was sometimes faired over with a "bullet" shaped housing. When "sense" was selected the receiver could be sensitively tuned to the beacon using the "wire" and then the direction ascertained by selecting "loop". The interference generated by the loop motor usually blocked out the signal from the beacon which is why the two stage procedure was needed.

These days you kids just dial up the GPS and away you go.......

[currawong]

There is a wire like this on many agricultural aircraft.

It is not an aerial, it is for fending off powerlines.

Yes, they do work.(within reason)

[Dan Winterland]

HF aerials that are 'buried in the fin' are probably an ATU, an Aerial Tuning Unit. The whole airframe is used as the aerial, the ATU adjusts the current flowing into the airframe to match the frequency.

[965Bedstead]

A question that I never asked in service so here it is now.......

How come when we were doing HF functionals on SeaKings we had to be out at 1 spot (or somewhere equally 'miles away') but during a transmission whilst flying it was perfectly safe to sit 2 feet away on the other side of a perspex window??

Thanx

965
(We did have fun at 27Megs transmitting and crocking the yokels CB radios :-)