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Author Topic: Will this work?  (Read 4150 times)

Patrick Henry

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Will this work?
« on: May 17, 2010, 11:18:56 am »

On my LCM space is at a premium, so if I glue a small length of 1/16th brass tube into the rear of the deck section and run the antennae wire up through the tube, will that work? It will only be the section of the antennae that is covered by the outer tube, the exposed section of the antennae will out in the fresh air.



Radio is a GiantCod 2.4ghz, by the way.
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Peterm

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Re: Will this work?
« Reply #1 on: May 17, 2010, 11:21:27 am »

Should be OK.   Pete
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Patrick Henry

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Re: Will this work?
« Reply #2 on: May 17, 2010, 11:23:19 am »

Thanks Pete...that'll do for me. Range won't be vast anyway, it's only a small boat.


Rich
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malcolmfrary

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Re: Will this work?
« Reply #3 on: May 17, 2010, 11:58:30 am »

Why not plastic tube?  Sort of, painted bit of drinking straw or similar.  Probably lighter than the brass tube and no chance of any unwanted shielding going on.  Using a metal tube with a wire up the middle is re-inventing the co-axial cable, as used for TV aerial leads.  Very good at avoiding interfering pick-up.
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PMK

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Re: Will this work?
« Reply #4 on: May 17, 2010, 12:07:43 pm »

Rich, as Malcolm says, I don't wish to put the mockers on your otherwise neat idea, but the brass tube could likely attenuate the signal at the antenna.
The alternative would be to use a non-metalic tube (perhaps a straw or somesuch).
Don't take this as gospel, for you may well indeed find that brass tube idea will work fine - especially as long range is not an issue. But bear in mind that RF signals and metalic objects are usually otherwise a no-no.

As always, good luck.
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DickyD

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Re: Will this work?
« Reply #5 on: May 17, 2010, 01:41:19 pm »

Rich your local model shop will sell plastic tube made for this purpose  :-))
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Patrick Henry

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Re: Will this work?
« Reply #6 on: May 17, 2010, 01:47:49 pm »

Thanks for the advice gents...as always, much appreciated.
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andyn

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Re: Will this work?
« Reply #7 on: May 17, 2010, 01:54:37 pm »

The plastic aerial tube in model shops can't be painted, what you want Rich is some evergreen plastic tube, same material as plasticard.
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Netleyned

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Re: Will this work?
« Reply #8 on: May 17, 2010, 02:27:52 pm »

The range should be quite adequate with the antenna run around under the deck as long as it is above the waterline
no need to come up through the deck at all unless the tube is simulating some fitting and you might as well make use of it.

Yours Aye

Ned
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FullLeatherJacket

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Re: Will this work?
« Reply #9 on: May 17, 2010, 03:09:05 pm »

Are we not all confusing VHF megglehurts with microwave gigglehurts here? I know SFA2 about microwaves but I somehow doubt that shielding that little bit of "insulation" will affect the range like it would with a 27 or 40 meg set. Does anyone out there know any better?

FLJ (retires to workshop to build P101s.............)
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Netleyned

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Re: Will this work?
« Reply #10 on: May 17, 2010, 03:46:36 pm »

The aerial feeder is like a micro coax unbalanced feeder with the end stripped back 1 wavelength
to act as the antenna
as long as this short length is not shielded by metal all will be fine


Ned
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PMK

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Re: Will this work?
« Reply #11 on: May 17, 2010, 04:18:28 pm »

Does anyone out there know any better?

I don't know about better, other than in order to satisfy my own curiosity I just 'sleeved' both of the Futaba 2.4G antennae with a 4-inch length of alu. tubing, then walked to the end of the garden path with the Tx and didn't notice any discernible difference at all. No unwanted servo jitter or suchlike - it just works the same as when both antennae are dangling in free air.

Now that *is* weird because I was expecting at least some attention of the signal - even at 2.4GHz frequencies.
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FullLeatherJacket

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Re: Will this work?
« Reply #12 on: May 17, 2010, 04:31:20 pm »

Now that *is* weird because I was expecting at least some attention of the signal - even at 2.4GHz frequencies.
Was the Tx aerial lying down or standing at attenuation?  8)
FLJ
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Patrick Henry

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Re: Will this work?
« Reply #13 on: May 17, 2010, 04:49:11 pm »

Take a look at the attached image..



This is how I set the antennae wire in the LCM...I've just tried it out (had to borrow my neighbour for this technical test) by leaving the boat in the lounge and me going walkies down the stairs, out of the front door, over the road and down the footpath under the trees a good 150 yards away, with the building, a kiddies play park and half a forest between me and the boat.

We were in contact via mobile phones, and neighbour reported no loss of movement and no unwanted twitches on the motors at all. I stopped them, started them, one ahead and one astern...no problem. I told him what I was doing  and what should be happening, he told me what was happening....all was well. What happened in here corresponded to what stick inputs I was making out there.

So gentlemen...now we know.

Thank you all kindly,


Rich
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PMK

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Re: Will this work?
« Reply #14 on: May 17, 2010, 05:10:36 pm »

Quote
Was the Tx aerial lying down or standing at attenuation?

Oh very witty!

I always get confused with this one, I'm not sure if they call it the prostrate or the prostate position. All I can tell you is that both ant's were horizontal... as too was the Tx ant. I even jabbed the low power range-test button in order to jack down the juice,  and yet all seven channels/servos still kept working merrily. I didn't walk quite as far as U33 because I'd ran out of of garden path by then.
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FullLeatherJacket

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Re: Will this work?
« Reply #15 on: May 17, 2010, 05:25:25 pm »

I'm not sure if they call it the prostrate or the prostate position.
Touché. I'll get back to me amplificators, then............
FLJ
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