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External ELT Antenna

I’m updating the ELT to meet 406 requirements and I’m going with the Kannad Integra AF (link to full kit)
In the process of buying one, I was informed that because it is a portable ELT, I do not need an external antenna for it.

>insert angry villagers with pitchforks here<

I’m having this verified with relevant authorities and will update with an official response.
Anyone else have experience with installing a portable ELT w/o an external antenna?

Last Edited by AF at 27 Jun 16:28

I feel that normaly it should be a poor performer if you ever come into a situation to depend on that. GPS signals are weak signals,easily blocked by metal frames.Moreover,distress signal at 406Mhz is best transmitted at “line of sight”.Actualy I have seen versions with fixed ext antenna AND another flexible one ,being fastened to the box,so that if you survive your emergency landing in Amazonia,you just remove the compound and get out to keep on transmitting position and distress.


Easy to start an argument with this subject as rules and regulations differ between countries. In the USA and Canada, an external antenna is required, but it only has to be external to the unit not necessarily the airframe.
“The INTEGRA ELT may also be installed on certain models of aircraft without having to fit an expensive external antenna (national authorities rules and regulations permitting) and an additional external GPS interface. This will reduce cost and complexity for the aircraft owner when choosing to install the all-important life saving device.”
I am not sure whether it transmits on 121.5, but an external antenna would be required for that feature.

MedFlyer wrote:

AND another flexible one

The Integra is just such an ELT, offering integrated, modular and externally mounted antennas.
Good point about the Al btw. Didn’t think Al completely blocked that frequency, but after digging a bit, it clearly does.
I’ll have to mess with it and see how much is blocked, or if the multipath through the cockpit is enough to reliably feed it…
Will run some tests. Thanks for pointing this out.

simon32 wrote:

I am not sure whether it transmits on 121.5, but an external antenna would be required for that feature.

It does, but that’s only mandatory in the US. As long as one doesn’t fly N or in the US, it isn’t really applicable. In any case, I’m betting a little more on the integrated GPS and Satellite link of the 406 anyway…

121.5 is fairly obsolete and there was a drawn-out discussion about getting rid of it altogether, but the US fleet is so large… there’s no chance (yet).

Last Edited by AF at 27 Jun 16:03

I don’t know the answer to the original Q but I do know that

  • Every PLB or ELT transmits on 121.50 because that is what S&R vehicles use for close-range DF (direction finding). Relatively few S&R assets have DF capability via any GPS coordinates transmitted on the 406MHz signal, or even the 406MHz signal itself, and anyway that signal is emitted only briefly, once a minute, AFAIK
  • The sentiments about 121.50 being obsolete are probably based on the fact that satellite monitoring of 121.50 ceased some years ago (and was never much good anyway, due to a vast number of false alarms) and AFAIK satellite monitoring of the mostly-military 243MHz ELT frequency has also stopped
  • There have been some “fixed” ELTs which could be fairly quickly removed and an external (BNC connector) antenna plugged in. My Kannad one can’t be officially used in that way but pretty obviously can be. The velcro strap holding it into the base is pretty obviously intended for that purpose.
  • I don’t think any “fixed” units will float in water
Shoreham EGKA, United Kingdom

Peter wrote:

transmits on 121.50 because that is what S&R vehicles use for close-range DF

Thanks for that detail. I’m learning quite a bit from EuroGA, thanks.

I’ve also updated my original post to include the product info for the Kannad Integra AF
It can be used as a portable ELT, but you’d need a rubber duck antenna to effectively use it that way (their products page lists the AP portable model).

I was hoping to get rid of an external Antenna and gain a few kts airspeed.
Sound like it would be a poor trade-off…

Based on this you would need more than just remove the ELT antenna

Shoreham EGKA, United Kingdom

I got this input from an avionics installer:

Shoreham EGKA, United Kingdom

Peter wrote:

The fixed unit DOES float, when you remove it from the aircraft.
Actually this is one of the required test to this unit after battery
check, it has to be submerced in a special fixture, to check for leaks,
and to see it will float when released. The unit will float with the
antenna upwards.

Thanks for all this info Peter. It is interesting that they require a float test for a fixed unit…
Just another special cost at annual… not very interesting for me.

The idea is a good one, to have all the components integrated to provide autonomous operation.
Clearly, that has not been effectively implemented. Bummer.

@Peter Just switched from the Integra to the Compact and saved 100 quid in the process, so thanks for that!
I got it here which was the cheapest price I could find.
They will do the programming for that rate as well.

Last Edited by AF at 29 Jun 08:53
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