Dipole antenna with no ground plane

[Birdseyeview]

Has anyone installed the ACS dipole antenna in their kitfox? The ACS ad says that it is best mounted internal to the skin and requires no ground plane. It also is claimed to outperform all externally mounted coms antennas. Pretty lofty claims but is it true? The Spruce ad shows a flexible strip of something (assume metal) 43" long and about an inch wide with the BNG connector in the middle of the strip. It is attached to a piece of wood that is attached diagonally to opposite corner side frame stringers behind the cockpit. So it is positioned at a 45 degree angle in the plane of the propeller. Reasonable price tag too. Some real world experience would be very interesting to hear about if there's any out there.

[HighWing]

I am curious about comments as well. In the real olden days, I was a Ham Radio operator and the dipole antennas were favored when long distance directional communication was desired. I guess this explaines somewhat the diagonal orientation of the antenna mounting. The best communication will be in the directions perpendicular to the antenna with significant reduction in transmit and receive power in the directions of the long axis.

[rainbird]

I mounted one of those vertically in the rudder about 4 inches FWD of the aft edge of the rudder. I notched the ribs to make the ante a flush with the rib surface and glued it in place. Of course do this before covering the rudder. I ran one piece of coaxed from the radio to the antenna. A 4” round access is necessary to connect the coax to the antenna.
My plane only has 10 hours on it but it works good both in the air and on the ground. On the ground I can clearly hear another airport 50 miles away with mountains in between.

[HighWing]

Sounds like a winner. Mounted vertically it would provide the strong signal in the directions most desired.

[Birdseyeview]

Rainbird - thanks for the response. This does sound like a winner on a number of fronts. I noticed that there are two types of connector orientations. Did you have a preference or would either one work in a similar install as yours?

[rainbird]

I used the one with the connection coming out the side, with it pointing forward. I drilled a hole in the elevator cover with a grommet then a small loop to allow rudder movement then thru a small reinforcement hole and back to the antenna

[896tr]

I did the same as Rainbird and from inside my hanger I could hear LAS ground from 55 miles away on the other side of Mount Potisi. Transmit was increased dramatically also.

[Birdseyeview]

Your experiences are showing excellent results and confirming the ACS claims. Did you mount yours vertically in the rudder or in the vertical stabilizer or somewhere else?

[Mesteve]

Why the rudder and not just the vertical stabilizer? Would eliminate the need to have moving wires and a failure point.

[n85ae]

I built my own dipole's out of copper tubing and replaced the Archer wingtip
antennas I had previously been using for my VOR, and GS antennas, and my
range is significantly better.

The ground side of the dipole is between the spars, and the other end stretches
out into the tip.

I had wondered myself for a long time how they would work, and tried it one
day and was quite surprised how much better they work.

Jeff

[Delta Whisky]

I mounted an ACS di-pole in the VS yesterday and hooked up a handheld to make sure it had a chance of working. (Although others have said the surrounding metal framework won't bother it . . . . . well, you might say seeing is believing.) It picked up Dulles/Potomac approach control!! The airport is 34 miles away and approach is located about 15 miles away. I'm in the hills and there are lots of them between me and approach - not to mention the aluminum garage door. Bottom line - I'm pleased and impressed. The only downside with putting it in the VS - the bottom end will have to be moved (i.e., bent a bit) to get the HS in. I moved it thru what I think will be the required range and it was no big deal - no permanent deformation at all.

[efwd]

Hi Darrel
Don't want you to get into a corner, I put my ELT in a very similar location but slightly further toward the rear. I have room to get the connectors in and out but Im still a bit cramped. Your ELT is closer to the header tank. Are you going to be able to make your connections?

[Delta Whisky]

Opps - you might be right and before I forget, thanks for speaking up. I forgot that I had removed the header tank and was looking at clearance to seat only. I'll bet that target fixation got to me - - - - again. Guess what I'll be checking on first thing tomorrow?

[Delta Whisky]

Eddie - morning UPDATE: good catch!! Hopefully we'll meet up in person someday and the first and second beers are on me. It looks like it should fit fine on the pilots side - unless there is something that I haven't seen that goes there as well. Cheers, Darrel

[efwd]

Eh, that's how the forum works. Glad to be able to help. :)

[Voyager]

A dipole is one of the best omnidirectional antennas available. Mounting it as close to vertical as possible is best, but even at an angle, the toroidal radiation pattern should work well for airplane use. Radiation is weakest off the ends of the antenna so you might have trouble receiving a station directly below you or an airplane directly above, but this likely will not be an issue as those transmitters are also closest to you so that mitigates the relative weakness of the pattern in those directions.

Definitely will outperform almost any monopole unless you have a fantastic ground plane.

[Birdseyeview]

Delta Whiskey, Great pictures on your builders log. Thanks for posting the link to your log - pictures are usually worth a thousand words. When you cover the HS will you leave a hole through it for the bottom of the dipole to go through? Or are you planning to not cover the middle section of the HS, which I assume will be completely hidden by the side covers? Or are you planning to bend it forward or aft over the top of the covered HS?

[Delta Whisky]

Larry - it is too early for the really final decision. As of now I'm planning on re-mounting the HT and setting the control limits very soon - before covering in any event - and will make an interim decision at that time. (Note, I've learned to use program manager terms like interim decision(s) as that gives me a chance to label my mistakes in assembly or decision making as "interim steps".) At this time, the very rough measurements I've taken lead me to believe I'll put a reinforced hole between the two center ribs in the HS for the antenna. The antenna is a flat ribbon that bends easily left and right and I think I'll be able to bend it to right as the HS is inserted from the left side and then pull it into position. We'll see and I'll try to get some pictures.

[Birdseyeview]

Delta Whiskey, I'll be very interested in your findings as you progress since I have recently purchased the same dipole and I'm also planning to mount it somewhere in the VS. Your tentative plan seems sound so far as long as you don't over bend the dipole during the install of the HS. The flexibility of the dipole is a big plus in allowing various install options but it does have bending limitations. I think the only potential issue that I see may stem from the dipole manufacturer's statement that they recommend a minimum bend radius so as not to over stress the fiberglass matrix of the antenna. As along as we don't violate that recommendation it should be a very good install. It may turn out to be a non-issue or there may be some tricks you come up with to help reduce the bending radius during the assembly. I'll follow your progress with great interest. Good luck.

[jeffbock]

Just purchased the Uavionix EchoUAT ADS-B and have decided to place the antenna in wingtip. The antenna included is the stick and ball type like the typical transponder antenna. I need to know if there is a dipole type antenna that doesn't require a ground plane. Or, if staying with the provided antenna how do I install a ground plane? North Idaho

[Delta Whisky]

Jeff - check with these folks and see if their L2 antenna with work as an ADS-B antenna. http://www.advancedaircraft.com/#ourproducts


And, yes the Ted type antenna will need a ground plane - most folks are recommending a square of 120mm per side. Some say 100mm works great. I researched this a few nights ago and should have saved the addresses of the best sites but made my notes and pressed on. Anyhow, I made mine 120mm square. I do remember that a round ground plane is a textbook perfect answer but a square accommodates several issues if the location isn't perfect for reasons only an antenna engineer will understand. Anyhow, it is easy to find lots of writings on the subject via our knowledgeable google/bing etc friends. One thing to point out - for best results the antenna should be mounted vertically with the ball end down. That might/could be an issue if you are planning on mounting it in the wing tip. Maybe others have done it this way and can tell us how well it worked. Take pictures and let us know what you do and how well it works as more and more folks will have inquiring minds as we get closer to 2020.


You can see my very recent installations at the site below.

[Delta Whisky]

Larry - I'm calling the experiment complete as I was able to install the elevator and HT without apparent damage to the antenna.

First I "bent" the antenna up and out of the way, inserted the elevator and hung it out of the way:

https://i151.photobucket.com/albums/s145/dewatson_2007/Step%201%20antenna%20positioning_zpsdcfgxxf0.jpg (https://s151.photobucket.com/user/dewatson_2007/media/Step%201%20antenna%20positioning_zpsdcfgxxf0.jpg.h tml)

Then - insert the HT:

https://i151.photobucket.com/albums/s145/dewatson_2007/step%202%20insert%20HT_zpsmjwp5oir.jpg (https://s151.photobucket.com/user/dewatson_2007/media/step%202%20insert%20HT_zpsmjwp5oir.jpg.html)

Then with a slight twist forward the antenna goes into place easily.

https://i151.photobucket.com/albums/s145/dewatson_2007/Step%203%20lower%20antenna_zpsnrwymzjb.jpg (https://s151.photobucket.com/user/dewatson_2007/media/Step%203%20lower%20antenna_zpsnrwymzjb.jpg.html)

And, not to change subjects, but . . . . .

Oops, I then discovered a forgotten promise - that I would fabricate the slide pucks before putting the tail pieces in. So I had an opportunity to prove it is possible to remove the HT without damaging the antenna during that process as well.

I have no idea how one would or could fit the stops and drill the 4130 receivers and match drill the stops in place IAW the manual. I chose to carefully make measurements and do all on the workbench.

Then, back in the fuse it went. No damage to the antenna. I'm calling the experiment complete.


Now I'm looking for recommendations to answer your (someone's ??) earlier question - how to handle the fabric goes where question.



Hope this is useful information. Cheers, Darrel

[Birdseyeview]

Thanks for the follow through and the great pictures. This is very helpful.

[Birdseyeview]

For those wondering about the dipole antenna pictured below it is found on the Aircraft Spruce website under the title "Advanced Aircraft Electronics High Gain VHF Antenna". The one pictured is the model 5T.