ELT Antenna Installation

[taildraggerpilot]

This is a picture of how the ELT antenna has been installed in my airplane. Per the Ameri King instructions, it is permissible to install the antenna internal on fabric aircraft. There have been inquiries in the past as to how.

[Gilbert Pierce]

I keep my airplane on a grass strip, 01TN. Went to the airport one day and a truck was waiting at the locked gate to get in. The driver said he was with the CAP and there was an ELT going off that the satellite had place close to the airport. He needed to get in to find it. I had a sinking feeling as he said this as the day before I had removed my instrument panel and had forgotton about the remote elt control panel.
Sure enough, my elt was going of.

My ELT antenna is mounted like Ben's in the picture above. I was an Aviation Electronics Technician in the Navy in my previous life. I have had enough antenna theory to know that the steel tubing in the airplane should theoretically distrup the radiation pattern of the antenna.
It did not keep the CAP from finding my airplane. The kicker is the hangar is steel frame and with steel siding. Defies logic.

[Zac Weidner]

Where did you install you ELT? We were going to mount the AK451-2 on the tubes behind the baggage compartment with the angled bracket in the installation instructions, but that antenna mount helps tremendously. You wouldn't happen to have any more pictures of it, would you?

Do you have the 406/121.5 model or the strictly 121.5 model? Will this method work for 406?

I feel like I have been bothering you lately with questions Ben, but I hope not.

Thanks

[taildraggerpilot]

Where did you install you ELT? We were going to mount the AK451-2 on the tubes behind the baggage compartment with the angled bracket in the installation instructions, but that antenna mount helps tremendously. You wouldn't happen to have any more pictures of it, would you?

Do you have the 406/121.5 model or the strictly 121.5 model? Will this method work for 406?

I feel like I have been bothering you lately with questions Ben, but I hope not.

Thanks

Not a problem at all. The free exchange of ideas is what this forum is all about and how we are able to keep these airplanes flying.

I installed my ELT in the baggage compartment and mounted it to the floor panel. I mounted it in the baggage compartment for three reasons: 1) it's easy to access since I have a tailwheel airplane, 2) that's where it was mounted before, and 3) I couldn't find a better place due to all the cables and static system plumbing aft of the baggage compartment.
Before I permanently installed the floor panel, I located the ELT bracket, back drilling the mount holes to match the included ELT bracket (I also have an Ameri King ELT, but currently have the AK450), and then installed rivnuts in the floor panel to later install the bracket to the floor.

Attached is a picture of where I mounted my ELT and a couple other notes. If you require other pics let me know and I can snap a few this weekend when I go to the hangar.

Looking at your proposed mounting location, I have concerns the ELT may not be properly orientated per the installation manual. The arrow on the ELT indicates the direction the ELT must point when installed and I believe it may also be labeled which side is to be UP. I think your proposal may work if you used the EBC brand ELT, as they still have a direction for the G switch, but since it sounds like you already have an AK451 an alternate location is likely necessary.

I've been debating on whether to install the 406 MHz ELT or keep what I have and buy a Personal Locator Beacon that I can have next to me. It appears on the surface the 406 MHz ELTs have the same packaging as the old 121.5's and I'm sure the mechanisms are the same. From what I've read and experienced, ELT's don't always go off as expected and it would be nice to have something in reach. Sure the AK450 has a panel mount remote switch, but wires can get severed, antennas can be broken; if I'm hurt and can't move, the PLB may be a better option?

[Zac Weidner]

It seems that the baggage compartment would be too easy to have the activation switch bumped with baggage. We were planning on using the bracket that allows it to be mounted in a situation such as this. With only brief reading about the EBC model, it seems to require the same conditions as the Ameri-King model.

We do not have any ELT yet, but we are looking at what the best model is. We want to go with the 406 model, as it does not make much sense in our situation to install the older type nowadays, since we would like to travel to Alaska eventually.

Can the antenna be mounted inside the fuselage? I only read that the antenna can be mounted on the exterior of the airplane, so I'm not sure if it is acceptable. However, I see no place to mount an exterior antenna in the aft portion of the airplane.
Our fuselage is already covered, so all of this must be done in a manner that can accommodate these limitations.

I can't tell for sure from your picture, but does your antenna bracket utilize the steel clamp welded to the lower left longeron for mounting? We were planning on doing something very similar, but we were thinking of making it stick out the bottom of the fuselage until we read the instructions, and now we don't know what to do for sure.

I have no knowledge of how the system actually works, but I thought maybe that the ELT would go off if wires were severed?

The drawing that I made on MS Paint was mostly to show the DER that we are working with how we plan to use cushion clamps for installation, but we plan to mount it in this area. We are, however, still discussing the specifics of the installation. It can certainly be varied to the best method.

Thank you again,

Zac Weidner

[JoeB]

The ELT in my Pacer is mounted behind the rear seat and is NOT pointing forward, not saying that it is properly installed by any means, but the 'forward' arrow is pointing to the right...

Seemed a bit odd to me when I found it mounted this way, but it isn't my biggest concern right now!

[taildraggerpilot]

...Can the antenna be mounted inside the fuselage? I only read that the antenna can be mounted on the exterior of the airplane, so I'm not sure if it is acceptable. However, I see no place to mount an exterior antenna in the aft portion of the airplane...

...I can't tell for sure from your picture, but does your antenna bracket utilize the steel clamp welded to the lower left longeron for mounting? We were planning on doing something very similar, but we were thinking of making it stick out the bottom of the fuselage until we read the instructions, and now we don't know what to do for sure...

Thank you again,

Zac Weidner

I have mounted the antenna inside the fuselage and have known of other who have done something similar. I think the Ameri-King website addresses this in their FAQ seciton.

As for the antenna bracket, yes I utilized the steel clamp on the lower longeron for the third mount location. The insl manual says the antenna should be mounted within 20 degrees of vertical, so this location works well for that.

Another side note, Ameri-King has their instl manual for the AK450 here: http://www.ameri-king.com/pdf/02%20IM%2 ... Manual.pdf (http://www.ameri-king.com/pdf/02%20IM%20450%20Rev%20A%20Installation%20Manual.pd f)
Note: On pages 13 and 21, their are figures indicating the proper direction the unit should be installed.

[Zac Weidner]

Thank you for pointing that out for me. That looks like it will work well for the antenna mount. We think we have figured out the mount in the location I illustrated, I will illustrate if you are curious.

The final question I have is what material did you use for that antenna bracket?

I did find the instructions on their website, which is where I was getting most of my information.

[avcan]

Hi,
I have recently fitted over 40 406 MHz ELT's as the New Zealand CAA have recently mandated these in all aircraft.
No matter what brand it is, it must be pointed forward (i.e. in the direction of flight) or the g switch will not work in the event of a sudden deceleration. Most can also be angled down slightly (normally up to around 30 degrees).
The biggest problem with the 406 MHz models in fabric aircraft, is getting a big enough ground plane for the unit to pass the self test. By this I mean, the antenna must be mounted onto a metallic plate of a minimum size to transmit enough energy. I have found this usually needs to be at least 1ft x 1ft. In my pacer, I have the antenna mounted on the top of the wing root fairing, using a doubler to stiffen it. In other fabric aircraft (eg Pawnee's), I have made a ground plane using Aluminium tape in a "star" shape, with the antenna mounted in the centre.
The plain 121.5 MHz ELT's don't seem as sensitive to all this, as they normally don't have an automatic self test function.

Not sure if this helps?

Cheers
Craig

[Steve Pierce]

Good to know Craig. People are starting to ask about installing the 406 MHZ ELTs.

Ben, If you carry a PLB or a Spot put it on your person. There was a guy in Idaho last year who went off the end of a strip and the Spot that was on the glare shield, flew through the windshield and it took him an hour to find it to activate. Luckily he was physically able to look. :shock:

[Frank Green]

I have my elt mounted on the hat shelf behind the rear seat technically within reach so I don't need the remote switch. One less thing to go wrong. I have the antenna on the root strip, a short routing and cable away in trail behind the com antenna. I have no plans for now to buy a 406. Will probably buy a spot. One saved a friend of mines life when he crashed in SD on a sandbar a couple of years ago when they first came out. Bought it at Oshkosh the week before and was headed for Alaska.

[Steve Pierce]

Frank, I met him at New Holstein during Oshkosh. His accident really woke a lot of us up.

[taildraggerpilot]

Good to know Craig. People are starting to ask about installing the 406 MHZ ELTs.

Ben, If you carry a PLB or a Spot put it on your person. There was a guy in Idaho last year who went off the end of a strip and the Spot that was on the glare shield, flew through the windshield and it took him an hour to find it to activate. Luckily he was physically able to look. :shock:

This is a little off subject, but it's good discussion nonetheless. Also anyone can chime in here as well, but Steve, if you had the choice, would you rather carry a PLB or a Spot? The spot is significantly cheaper, but I don't know enough about it vs. the PLB's on the market to know what's better/more reliable. What are your thoughts?

Thanks,

[smcnutt]

I didn't do the installation of my ELT as it was done before we bought the plane. However, since I happen to have a real clear picture I thought I would post it here and see if it might help. It's an old 121.5 mounted directly behind the baggage compartment along with the power supply for the strobes.

[attachment=0:1yxqb4e7]PA190244.JPG[/attachment:1yxqb4e7]

[imported_shortwing]

I have a Spot messenger and I really like it. I know guys that carry both the Spot and the PLB, but I don't feel that need right now.

My wife really likes the tracking mode on the spot so she can keep tabs on me. The surgery to have it implanted in my skull was only marginally painful.. :lol:

It is also very inexpensive for the service - even with tracking.

Just my 2 cents!

sj