Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: Tom_DK on June 11, 2008, 07:07:15 pm

Title: Poor transmitting range in salt water
Post by: Tom_DK on June 11, 2008, 07:07:15 pm

Anyone has some suggestion how to improve the transmitting range of my U-47 in salt water?

All my transmitter are running 40 MHz. Tried Futaba FF9, Futaba T14MZ and some other old transmitters, but in salt water the max dept is less than 1m (3 feet). My boat has a fail safe function, so it just makes a dive to surface when loosing the signal from the transmitter, but still the range under water is poor.
Is 2.4 GHz better?
Or any other suggestions?

(http://www.rcgalleri.dk/uploads_large_wm/167710.jpg) (http://www.rcgalleri.dk/uploads_large_wm/167711.jpg)
(http://www.rcgalleri.dk/uploads_large_wm/167707.jpg) (http://www.rcgalleri.dk/uploads_large_wm/11951.jpg)
Regards,
Tom

Title: Re: Poor transmitting range in salt water
Post by: dougal99 on June 11, 2008, 07:14:59 pm

2.4GHz does not work underwater (the wavelength is so short it bounces off).

Doug

Title: Re: Poor transmitting range in salt water
Post by: andyn on June 11, 2008, 07:18:49 pm

Don't know whether they do them in 40Mhz, but the Schulze recievers are superb, they are just about the only recievers that can recieve signals when next to Glassfibre or Carbonfibre, they would be good to try

Title: Re: Poor transmitting range in salt water
Post by: Mankster on June 11, 2008, 08:14:15 pm

Schulze Rx are indeed available in 40 mhz, but it wont be any good if the signal doesn't get there  :)  Unfortunatley salt water has a dramatic affect on radio range, the only viable option is to bring your rx antennae wire to the surface.

Title: Re: Poor transmitting range in salt water
Post by: Subculture on June 12, 2008, 11:16:12 am

I ran my Seehund at a pond in Southend once. Unbeknown to me, this pond is fed from the sea, as soon as my sub went beneath the surface the failsafe kicked in, and up she came.

You need to make a long aerial out of brass rod. I would recommend at least a foot high- this will give you aabotu a foot of diving depth, adequate for most people.

Cover it in heatshrink tubing or paint it well- brass corrodes heavily in salt water.

Andy

Title: Re: Poor transmitting range in salt water
Post by: das boot on June 12, 2008, 08:40:19 pm

The Patrick Henry would touch bottom in any swimming pool I ever used it in and still be in full control...I took it to Princes Park in Eastbourne once, could'nt get any more than six inches down due to the salt water content.

I did take U-117 out to sea on several occasions and had no problems with her at all...perhaps it was due to the all wood contruction?

Cheers,

Rich