My home made RC Submarine

[Bob Gato]

This guy explains it the best so here's a link: https://forum.rc-sub.com/forum/gener...r-c-submarines Also note that its the second post in "Tips and Tricks" on this forum...you might want to check the rest of them out.

[MakeHobbyRC]

Any kind of metal type or shape for a efficient antenna?

[MakeHobbyRC]

Great ! Thanks for all these precious informations! I might go for the 35MHz! But FIRST if I just have to make a few adjustments I will continu trying the float! So about your advice: the 3 pin plug is not in the water it is in the dry sub. In the water passes the coax cable fully waterproof. I will dismantle the float (bottle) to add an solid antenna to the central cable! (How should I do this properly?) should I remove insulation from the coax cable? (Should i uncover both the antenna wire and the parasite wire!?) or just the antenna wire? Then can I solder it to a solid metal antenna? ( and finally the length of that antenna: you say the same as the existing receiver antenna: it is itself a coax with 2 lengths: one long length with both antenna and parasite coax, and the end of it is just the antenna without the surrounding coax! Which length should I measure!?). Thanks a lot that is all great info to me! Very best!

[Bob Gato]

Lets see if I have this right-you have a 5 meter coax cable soldered to your receiver where the old antenna was. Then it terminates in a floating water bottle. Then you asked about a straight stick of metal for an antenna. So you just have the coax with nothing on it? the shielding of the coax blocks all the signal and keeps it traveling to the end where there should be , yes, an antenna-EXACTLY the same size as the antenna that came off of the receiver.Also 5 meters might be too long to allow this to work. I also think the RCA plug will let water short out the signal from the center pin-IT MUST be watertight.There are more details that might cause failure but those are the big ones.

[trout]

35MHz will travel through water and into your WTC.

[MakeHobbyRC]

Oh and what about a 35MHz radio control???? I have one... any chance under water? well you know what I mean I am not suggesting to use it underwater.. 35MHz would go through water?

[MakeHobbyRC]

Hi again! And just to update you and also to ask for advise maybe... I have been fitting the "antenna on a float". I have bought a coaxial cable, 5 meters long, and "connected" one end to the sub (via a 3 pin RC type plug, using the middle red cable for antenna cable, and the other two exterior cables for the "parasite coaxial cable". (hope the terms a understandable.)... And it ..... DOESN"T WORK!!! If we consider the soldering was done properly (very delicate) can it be the exterior antenna part, in the water bottle floating on the water that is not picking up the signal? Any need to solder the inner part of the coaxial cable (hence the antenna wire) to a straight stick of metal (To simulate an antenna)? Any suggestions.... ? Best to all and thanks in advance... advancing slowly but surely... ;)

[MakeHobbyRC]

Yes correct, France! Well spotted. And thank you, I am still waiting for the delivery of my coaxial cable, hope it will do the trick and be souple enough. We shall see...I will keep you posted ! Best,
William

[cheapsub]

Sorry batter late then never.
all in Japanese but you get the idea.

I see you are using meter and a "," not '.' , so some where in Europe, switch to a used 40 MHz system, just to make things easier.

[MakeHobbyRC]

You need to insulate any antenna extension by using coaxial cable. Standard cable will not work.

Can you tell me if " this https://www.aliexpress.com/item/3282...chweb201603_53 " coaxial would do the trick please? Need any-further information? Thanks a lot!

[He Who Shall Not Be Named]

ah thanks, this is precisely the point I was wondering about. What would you suggest I buy as coaxial antenna? Any diameter required ( for about 2 to 3 meters long antenna), any other technical specification I must be aware of before buying coaxial cable (type, diameter... ?), I know nothing about it. Thank in advance, very helpful information, Best

Buy this: https://www.ebay.com/itm/RF-Coaxial-...0AAOSwcSxaUteJ

[He Who Shall Not Be Named]

ah thanks, this is precisely the point I was wondering about. What would you suggest I buy as coaxial antenna? Any diameter required ( for about 2 to 3 meters long antenna), any other technical specification I must be aware of before buying coaxial cable (type, diameter... ?), I know nothing about it. Thank in advance, very helpful information, Best

David

[He Who Shall Not Be Named]

You need to insulate any antenna extension by using coaxial cable. Standard cable will not work.

Hey, Boss: I can't find it at the forum, maybe you can. Send this guy the link to my manual on how to shield the antenna wire between receiver and antenna proper. Some photos to wet this guys apatite.:





















David

[MakeHobbyRC]

ah thanks, this is precisely the point I was wondering about. What would you suggest I buy as coaxial antenna? Any diameter required ( for about 2 to 3 meters long antenna), any other technical specification I must be aware of before buying coaxial cable (type, diameter... ?), I know nothing about it. Thank in advance, very helpful information, Best

[RCSubGuy]

You need to insulate any antenna extension by using coaxial cable. Standard cable will not work.