Model Boat Mayhem - Forum

Dry Dock / Shipyard: Builds & Questions => Sports boats, Race, Power and Leisure Boats: => Topic started by: mbm999 on December 10, 2018, 08:31:27 PM

Title: Receiver wire routing and length
Post by: mbm999 on December 10, 2018, 08:31:27 PM
Hi,

I've recently returned to model boats after a (rather large) gap and i think i'm in need of a bit of guidance (quite a lot actually). Hope someone can help.

I bought a second hand, complete, Lisa M, just to help me get started (and I like the boat!).

So, first question is about the radio gear it came with:-
It's an Acoms ap202 transmitter/receiver on 27Mhz (it all seems to work) when close to the boat.
Does anyone know how long this aerial should be and how it should be routed in the boat (it has been connected to a removable metal antenna on the top of the superstructure).
The wire out of the receiver is about 19" long and then the metal antenna is 11" long.

Hope that's clear(ish), any clarification, please ask.

Thanks,
Mark
Title: Re: Receiver wire routing and length
Post by: martno1fan on December 12, 2018, 11:43:59 AM
Sounds good to me have you tried it at distance yet :-)) ,length sounds right to me so it should work fine.
Title: Re: Receiver wire routing and length
Post by: mbm999 on December 15, 2018, 11:16:23 PM
Hi,Cheers for the reply.I guess i was more asking about what the length of the receiver wire should be (ie. has it been shortened from its original length to accommodate the metal antenna?). I'm thinking of re-routing the aerial away from the motor to reduce any potential interference.
If i do this. how much of the aerial should be external to the boat (if any)?
Thanks,Mark

Title: Re: Receiver wire routing and length
Post by: rnli12 on December 16, 2018, 08:27:36 AM
Generally its to provide a greater volumetric area for signals to be picked up, for example running the length of the boat or up masts, the shorter the length the less 'capture' you get. Ive extended some of mine and coiled up so its personal choice.

Rich
Title: Re: Receiver wire routing and length
Post by: Andyn on December 16, 2018, 09:03:54 AM
Most factory antennas tended to be about 3 feet. This has been covered at length over the years and info is easily found on this forum and Google.


What's also covered at length is how much better 2.4ghz is, and how most (non dark age) modellers have now rid themselves of 27mhz  %)
Title: Re: Receiver wire routing and length
Post by: chas on December 16, 2018, 09:23:14 AM
The ideal length is 39 inches, that's a quarter wave antenna if my old memory is still working, but in most boats this isn't critical as range is seldom an issue. What's more important is to have as much as is practical above the decks, inside the hull is a bad idea.
  To reduce interference, make sure you suppress the motor, and route the aerial away from the motor and power lines.
  Of course, the best answer is to get a 2.4 gig set, as has been said they are much better
 Chas
Title: Re: Receiver wire routing and length
Post by: Netleyned on December 16, 2018, 10:00:43 AM
The wavelength at 27MHz is 11metres,
A quarter wave would be about 2.75 metres
or 8ft in old money.
39 ins seems to be the norm though.
Ned
Title: Re: Receiver wire routing and length
Post by: martno1fan on December 25, 2018, 09:48:29 AM
If you go with 2.4 then you dont even need an external antenna i run all my antenna wires inside even on my gas boats, never had an issue .
Title: Re: Receiver wire routing and length
Post by: Andyn on December 25, 2018, 11:35:25 AM
Wot he said...


Aerials can be seen top center and bottom right, inside a carbon Kevlar boat. No issues :-))


(https://www.modelboatmayhemimages.co.uk/images/2018/12/25/IMG_20181225_113258.jpg)
Title: Re: Receiver wire routing and length
Post by: JimG on December 25, 2018, 01:36:38 PM
Don't try and run 2.4GHz aerials inside a fully carbon moulded hull, being conductive microwave radio will not pass through it. Carbon sailplane fuselages have shown this, as long as you have the ends of the aerial outside the hull this will work.
Jim
Title: Re: Receiver wire routing and length
Post by: Andyn on December 25, 2018, 04:23:20 PM
It's been working consistently inside a carbon Kevlar hull, under a 6mm plexiglass lid, with a steel pipe over it, next to six servos (digital) for nearly a year, having been on the water with other boats, and at speeds around 50mph  %)
Title: Re: Receiver wire routing and length
Post by: JimG on December 25, 2018, 08:26:24 PM
Sounds like it is carbon reinforced not completely carbon, also the plexiglas lid is transparent to the radio, replace this with a carbon sheet and expect  a different result.
Jim
Title: Re: Receiver wire routing and length
Post by: Arrow5 on December 25, 2018, 10:11:35 PM
Is kevlar alone transparent to radio ?
Title: Re: Receiver wire routing and length
Post by: Andyn on December 25, 2018, 11:24:25 PM
Is kevlar alone transparent to radio ?



Reasonably yes, carbon isn't. The hull in question is a layer of carbon with a carbon Kevlar inner, with epoxy filler mix in the corners.
Title: Re: Receiver wire routing and length
Post by: Arrow5 on December 26, 2018, 11:00:56 AM
Thanks, and bullet-proof in some applications I believe.
Title: Re: Receiver wire routing and length
Post by: martno1fan on December 28, 2018, 03:36:59 PM
Depends on the bullet trust me Kevlar isnt stopping any military grade round which is why the British army still use steel breast plates . My son is in the Royal Engineers Commandos  :} lol .
Title: Re: Receiver wire routing and length
Post by: Netleyned on December 28, 2018, 03:49:41 PM
My eldest did that in the RE.
Everywhere in the middle east
by chopper, airstair was a long rope :-))
Ned
Title: Re: Receiver wire routing and length
Post by: martno1fan on January 09, 2019, 08:05:37 AM
My eldest did that in the RE.
Everywhere in the middle east
by chopper, airstair was a long rope :-))
Ned
Nice one you must be very proud  :-)) .My son has just landed Stateside with his squad and the Royal marines they re doing a few manoeuvres with the American Marines its Brits versus Americans  , should be a doddle he reckons lol   ok2 .
Title: Re: Receiver wire routing and length
Post by: Onetenor on January 09, 2019, 11:45:50 PM
Grandson was RM corporal in Afghanistan and Iraq Now runs The Masons bar in Liverpool
Title: Re: Receiver wire routing and length
Post by: roycv on January 10, 2019, 06:48:57 AM
Hi I have found over the years that as long as there is some vertical above deck part of the aerial then all works OK. You can also put a connector on the aerial and plug it into a metal mast etc, which I do on some boats.  Total aerial length does not seem to matter much.

regards

Roy
Title: Re: Receiver wire routing and length
Post by: martno1fan on January 14, 2019, 08:13:49 AM
Grandson was RM corporal in Afghanistan and Iraq Now runs The Masons bar in Liverpool
:-)) :-)) :-))