Aerial placement

[Old School]

A basic question, but very few boats these days have an external aerial, so how is the aerial lead mounted in the hull, please?

[rol243]

you can buy an antenna kit with comes with the alloy mount / tube and push on top cap. the antenna goes inside this short tube and you just bend the last 1/2 inch and push on the cap to make it waterproof. [ rc boat bitz ]

[Old School]

Thankyou, that is for an external aerial mount, however, many boats do not seem to have external antennae. I will have a look on the site.

[rol243]

sorry it all depends on what type of receiver your using , i use Futaba with a single antenna wire i prefere to have this in line of transmitter sight for better range. also if you have a carbon fibre hull you don,t want to run the antenna inside the hull as you will lose range.

[Prodrvr]

You don’t bend 2.4g antennas.

[Old School]

I also prefer line of sight so was surprised that so many run their antenna inside the hull.

[rol243]

yes you can bend the last 1/2 inch where there is no insulation. the bend is what holds the antenna from slipping back down the tube when the cap is pushed on.

[Mxkid261]

You can use something like this. https://www.offshoreelectrics.com/pr...prod=aero-6028

Sometimes I just used a piece of aluminum tubing, silicone it into the hull, and put a plastic tube in it held in by some tygon fuel line. Simple and free if you have stuff laying around.

22141145_10159406185800716_3089018734855408953_n.jpg

[Fluid]

yes you can bend the last 1/2 inch where there is no insulation. the bend is what holds the antenna from slipping back down the tube when the cap is pushed on.

Sure you can - if you want to damage your antenna. Futaba specifically warns not to repeatedly bend the antenna to avoid compromising the antenna internals. That last 1” of the antenna is the only part which receives a signal from the transmitter, damage it and no reception. Too, folding it over reduces it’s effective length so lowered reception again. This is likely one reason folks report poor range on a radio which used to work fine.

You “can” do it, just as you can text while driving or smoke cigarettes - but it is ill-advised and not necessary.



.

[NativePaul]

yes you can bend the last 1/2 inch where there is no insulation. the bend is what holds the antenna from slipping back down the tube when the cap is pushed on.

The uninsulated part at the end of the antenna is the only part that is actually working as an aerial, the rest is shielded, and is only there as an extension so you can get the aerial out or a carbon hull/fuselage/chassis or up past your motor/battery/ESC etc that can block the signal. You can do what you want with the insulated part as long as you dont damage it, but for best reception the uninsulated part should be kept straight and oriented in the same plane as the TX aerial.

Nearly all the aerials I have seen on 2.4ghz RC sets (all with good performance) are tuned to a quarter wavelength which is 31.25mm for a direct mounted (internal) antenna like on a Tactic RX, or as the dieletric effect of the 50ohm coaxial slows down the radio waves a little it is 28.8mm on extended antennas.

If you bend it, it will no longer be a tuned length and reception will suffer dramatically, best case scenario is that you bend it exactly in half and make it 1/8 wave length (not nearly as good as straight, but much better than a random length). There is no need to bend it over the top, the low mass of the wire and its stiffness means that you can just poke it up any reasonably sized tube, and it wont fall back down.

If you only have 1/2" uninsulated at the end of your antenna I suspect that it has been broken off at some point, and I would advise you to check out the length of a brand new one at your LHS. If it is indeed shorter than stock, open up the RX, many have the antennas easily user replacable with a U.fl plug/socket, and replacements are made by Futaba, Spektrum, Frsky that I know of and likely many more that I don't, any will do as they all use the same U.fl connector, 50 ohm Coax, and 28.8mmm aerial length. If it is soldered to the board as some low end sets are, you could very carefully strip the coax back leaving 28.8mm of the inner aerial that looks uninsulated (it is actually insulated to stop it shorting on the coax sheath, but with very thin transparent insulation) poking out , buy a new RX, or if you run solo on a private lake, feel free to carry on with what you have and hope for the best.

[MadProps]

I had no external antenna mount and found anywhere near the limits of the range the signal would get lost in hard turns as the antenna would be below the water line. I installed an external antenna and all is well with extended range

[Old School]

Thankyou all for your replies

[rol243]

i have fitted my 2.4 gig antennas like this since i first started using 2.4 gig radio and have had not one single issue atall with range , its not that i would bend and re bend this end every time as just about all of my receivers stay in the boat and are not transfered to other boats as there only about $50 a pop to buy.
maybe i should just leave the antenna inside the hull and hope for better range. lol

[CraigP]

The uninsulated part at the end of the antenna is the only part that is actually working as an aerial, the rest is shielded, and is only there as an extension so you can get the aerial out or a carbon hull/fuselage/chassis or up past your motor/battery/ESC etc that can block the signal. You can do what you want with the insulated part as long as you dont damage it, but for best reception the uninsulated part should be kept straight and oriented in the same plane as the TX aerial.

Nearly all the aerials I have seen on 2.4ghz RC sets (all with good performance) are tuned to a quarter wavelength which is 31.25mm for a direct mounted (internal) antenna like on a Tactic RX, or as the dieletric effect of the 50ohm coaxial slows down the radio waves a little it is 28.8mm on extended antennas.

If you bend it, it will no longer be a tuned length and reception will suffer dramatically, best case scenario is that you bend it exactly in half and make it 1/8 wave length (not nearly as good as straight, but much better than a random length). There is no need to bend it over the top, the low mass of the wire and its stiffness means that you can just poke it up any reasonably sized tube, and it wont fall back down.

If you only have 1/2" uninsulated at the end of your antenna I suspect that it has been broken off at some point, and I would advise you to check out the length of a brand new one at your LHS. If it is indeed shorter than stock, open up the RX, many have the antennas easily user replacable with a U.fl plug/socket, and replacements are made by Futaba, Spektrum, Frsky that I know of and likely many more that I don't, any will do as they all use the same U.fl connector, 50 ohm Coax, and 28.8mmm aerial length. If it is soldered to the board as some low end sets are, you could very carefully strip the coax back leaving 28.8mm of the inner aerial that looks uninsulated (it is actually insulated to stop it shorting on the coax sheath, but with very thin transparent insulation) poking out , buy a new RX, or if you run solo on a private lake, feel free to carry on with what you have and hope for the best.

Paul, are you saying that the plastic insulation on the antenna is a magnetic shield? You do realize that an antenna works on principles of electromagnetic radiation, right? The plastic only comes into effect if the frequency is super high, then it gets a bit lossy. But gigahertz antennas are very short. The orientation of the antenna is, is you any many pointed out, very important.

[NativePaul]

Rol243, you are doing well in getting the aerial up above the hull, I am glad you have not had any issues and I hope you never do, I just wouldn't feel right in not pointing out that the bend is far from optimal, and that you may have broken part of the tip off making it less optimal still.

CraigP, No, of course I don't think the plastic insulation on the antenna is a magnetic shield, the grounded woven metal sheath of the coaxial cable is the shield. Do you not know how coaxial cable works?