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[Edward Pinniger]

When installing a 2.4ghz receiver in a model boat (not a sub) will there be any range/reception problems caused by locating the RX low down in the hull, below the waterline? 2.4ghz aerials are so short that there's no option to run the aerial up above the deck as you can with 27/40mhz radio.

People I've asked say there should be no problem, but I've also heard that 2.4ghz can't be used in subs as this frequency doesn't penetrate water. So does anyone know the definitive answer?

[karls]

This is a good Question i want to know the answer to this as well

[BlueWotsit]

The stock answer I was given to this when I was looking into it, is to mount the receiver and aerial as high in the boats hull as possible as this helps maximise distance.

There is always a possibility if a boat were leaning over, that the distance of transmission might be affected if the receiver / aerial were on the waterline or below as a result.

[Peterm]

In all of our boats fitted with 2.4 GHz radio systems, there is enough space for the Rx Ae to be above the waterline.   We have had no problems at all.   Pete M.   On reflection this does not answer your question, the answer is the aerial does.

[Netleyned]

No problems using it in a yacht with the antenna just above the waterline no loss of signal at 100yards at all angles of heel.
Unlike a submarine parts of the hull/deck are always above the water (hopefully  ) and unless its a metal hull radio waves will
penetrate into the hull but having said that keep the antenna as high as possible fo optimum results


Ned

[RaaArtyGunner]

No problems using it in a yacht with the antenna just above the waterline no loss of signal at 100yards at all angles of heel.
Unlike a submarine parts of the hull/deck are always above the water (hopefully  ) and unless its a metal hull radio waves will
penetrate into the hull but having said that keep the antenna as high as possible for optimum results


Ned

Not Having seen a 2.4 in the flesh, If I have understood what has been displayed on this forum the receiver has a chubby aerial as opposed to the conventional wire aerial for non 2.4 ghz sets. If so will this cause location difficulties in a model with slim silhouette above waterline ???

[Peterm]

In some systems the Rx aerial is about 3 inches long, in others about 1.5 inches.   Pete M

[barriew]

Not Having seen a 2.4 in the flesh, If I have understood what has been displayed on this forum the receiver has a chubby aerial as opposed to the conventional wire aerial for non 2.4 ghz sets. If so will this cause location difficulties in a model with slim silhouette above waterline ???

2.4Ghz receivers have short wire aerials - length varies and some brands have two. The Transmitters have short stubby aerials. I would certainly go for at least the tip of the aerial above the waterline, but as all mine are like this I can't say it wont work if you are below

Barrie

[Klunk]

I have a 2.4 in my victoria yacht. This is a 2 ariel system with one located horizontally above the water line on the side of the boat, and the other vertically on th eopposite side of the boat. I have had no problems sailing this, even in the wind at the Mayhem weekend!! We all now what happened there!!!

[snowwolflair]

Its only the last 2cm of the aerials that have to be as far above water as possible.  The Rx itself does not pick up signal.

[RaaArtyGunner]

Thank you one and all 

[Dueller]

Although this does not answer your question it does throw a spanner in the works.

I have a 2.4 helicoptor and was setting it up without the cockpit canopy and after a minor crash the only damage was to knock the antenna off of the reciever circuit board. I flew it at short distances for a while untill i could be bothered to re attach the antenna. Had no problems with signal loss, though i did keep it within 10 metres.

[AmbuTech]

Mine is lying almost horizontal and about 4cms below the waterline of my tug. I have no trouble what-so-ever upto and maybe exceeding 100 metres.

Rgds Ken

[ooyah/2]

Hi Edward,
I recently bought a PLanet T5   2.4 radio and was assured by the model shop that this would be O.K. as a radio for a model boat
As I have been involved with steam boats and engines most of my modeling career I decided that I would build a Touchwood D.Campbell K7 at 1/12 scale for some diversion and this was the radio for me.
On opening the box I was dubious about the receiver as it is encased in what could only be described as thin plasti-card with an arial of 1" long.
The K7 is powered by a brushless motor and Sub "C" 7 cell x 3700 amph battery.
I am pleased to say that there has never been any problem with the radio/receiver, the receiver is about 2.5" above the water line when it's flying at 35 mph and is under control at the far end of our pond which is about 500ft, so I would say don't be worried about it.
This was a cheapy radio at £40 and you can get an even cheaper one fro GIANTCOD.
This radio set up was installed in my Flash Steamer and again no problem ( see my club web  www.glasgowrichmondmbc.co.uk ) for pics of the steamer in action at 40 mph..
Hope this helps.
George.  )

[barriew]

I think the only problem is when they are surrounded with water - as in a submerged submarine. In a surface craft, even if below the waterline, they are not totally shielded by water.

Barrie

[Netleyned]

No problems using it in a yacht with the antenna just above the waterline no loss of signal at 100yards at all angles of heel.
Unlike a submarine parts of the hull/deck are always above the water (hopefully  ) and unless its a metal hull radio waves will
penetrate into the hull but having said that keep the antenna as high as possible fo optimum results


Ned

I agree with Barrie

Ned

[Edward Pinniger]

Thanks to all for the advice. I'm seriously thinking of changing all my radios over to 2.4ghz - there are so many advantages and you can get a basic 2.4ghz RX/TX now for barely more than a 27mz two-channel set. I already have one set (not yet tested on the water) and am planning to buy another plus a couple of extra receivers, which (using my removable RX/ESC setup) should be enough for all my models

The aerial setup was my only worry, I usually put the RX + ESC on the bottom of the hull (makes wiring setup much more straightforward) and run the aerial wire up into a cabin, funnel or similar above the deck level. I suspect it should be enough to put the 2.4ghz RX on its end with the aerial sticking up, in a model with a particularly deep hull the RX could be seated on a block of balsa for added height. I'll hopefully be trying it out tomorrow so will just have to see how it goes!

[Prophet]

heres a trick i use for testing distances .. put model in a bath tub turn it on get the wife to sit with the model, now i run 100 yards away outside the house and phone the wife's cell phone and talk to her about what the boats doing as i do this i run further away until the boat looses signal, memorise that point and get home and thank the wife for not drowning the model, to work out the distance i can get from the receiver i use goggle maps mark the boats location and my final and use the grid to check the distance, the advantage is that not only was the model in water, but it also have to get through walls as well the all the other junk signals traveling around homes and houses, every time i do this i find that the model will be out of site before i ever loose range so i never worry about such a thing as position of a receiver in the boat, i just make sure the Ariel is as far up as possible!

[malcolmfrary]

In the case of the indoor flyer, it was probably working on its safety margin at about the minimum signal it could tolerate, picking signal from its internal PCB.
The boat where it was just below water level - that I would put down, at 100 yd, to a combination of scatter from the waterline, reflection from the far side of the hull, and good luck, and much might depend on the height of the transmitter.  A big characteristic of digital systems is that they work perfectly right up to the point where they don't.  There is no soft fail.