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[BrianB6]

Can anyone advise me how to stiffen a 2.4Gig aerial on a Spectrum receiver please?
Will the signal be affected if I coat it with superglue or araldite?

[inertia]

I used 1.5mm dia heat-shrink tube on mine. Don't cover the "bared" bit at the end.
DM

[BrianB6]

It is the bare bit that needs stiffening. 
That could have been expressed better. Hope I am not moderated.
The Rx is in a tug and just above the waterline and I cannot get the aerial any higher.
There is a permanent bend in the wire which I cannot get to reman straight upright.

[inertia]

It doesn't matter that much as long as the whole thing is above water-line. I would definitely not use any adhesive on the aerial myself.
DM

[malcolmfrary]

You can also poke it up the inside of a drinking straw to get rid of the bend ( to the mods).  Heatshrink should be OK as well, as far as I know, it is transparent to microwaves, and an extra layer of insulation should have no effect on the signal.  The end inch is a different colour because usually the layer of shielding has been removed (its a lot like your TV aerial lead, only smaller) along with the outer layer of insulation, so only the end inch does anything.  And like Dave says, keep glue off the end inch.

[Robert Davies]

In my experience of experimenting with 2.4ghz systems over water for our type of usage, I would say that it does not matter - to quite some range - if the antenna on the boat is below the waterline.

How so? The boat is at water level, but on a typical pond, even if seated, you will be transmitting from at least two feet above water level, so the TX antenna will be 'looking' into the boat, below it's waterline, for quite some distance (150yds+ is not unusual in my experiments).

How can you prove the effect? Take the boat out a fair distance with the RX antenna below the waterline whilst TXing from a standing position. Lower the TX until the boat's control is lost (you DID set the failsafe didn't you?).

Stepping aside from that momentarily, I find that the best orientation for Spektrum antennas is a 45 degree angle upwards/downwards and northwest/southeast or northeast/southwest across the boat - It gives the best balance of reception when travelling abeam and fore/aft.

Answering the OP somewhat, as long as some part of the antenna is above the waterline of the boat, and you are not operating from the prone position, you'll be fine to around 100yds and probably more, in my experience.

-Rob

[Netleyned]

A lot of people try to point the Tx aerial at the model.
The  propagation from the aerial is from the sides.
Not a lot comes out of the end.

Ned

[BrianB6]

Thanks all of you.
I don't usually sleep whilst running the boat so lying down is not a problem.
Ned, I usually remember to have the Tx aerial vertical but sometimes I forget.  One of the problems of old age.

[Peter Fitness]

Back in my RC aircraft flying days one of the first things I learned was NEVER point the Tx aerial at the aircraft because, as Ned rightly points out, not much signal comes from the end of the antenna.


Sometimes I run the receiver aerial inside a plastic tube, often the outer sheath of an aircraft push rod "snake". I don't own a Spektrum, but I assume most 2.4 Ghz radios are similar. In the case of "normal" radios, I always do this, as high as possible inside the hull. I have found that my radios will work to the limits of visual range on water, in other words, if I can see it I can control it, and this applies to AM, FM, and 2.4 Ghz.


Peter.

[BrianB6]

Thanks Peter.
I will try putting it in some rigid plastic tube.
It is only the tug that is a possible problem, all my other boats have sufficiently high freeboards that I  can mount the aerials higher up off the waterline.
I am not sure if 2.4 gig Rx and Tx aerials need to be aligned in the same plane for maximum range. i.e. either both vertical or horizontal, or is it only TV etc. due to polarization.  I always try to do this but I suppose the fly boys have them in all directions. Maybe some boffin can explain.
Back in the early days of 1/2 wave 27 meg. they were always in the same alignment but then a 6 foot Tx. aerial would be a bit dangerous if waved around, not to mention tiring on the arms.

[Netleyned]

A half wave 27MHz antenna would be more like 5Metres long 
With most 2.4GHz stick transmitters having a foldable antenna I use it folded'
This means when looking toward your model you are presenting the side of the antenna to the model.
I have had no problems with either yachts or powered scale models. With the Orange rx's there is only
just over an inch of antenna outside the case so I have never felt the need to orientate it. In a yacht it
would be moving around quite rapidly at times. Ihave never had range problems apart from the MkI eyeball

Ned

[Steve J]

Can anyone advise me how to stiffen a 2.4Gig aerial on a Spectrum receiver please?

Depending on location, use either glow engine fuel tube or a rigid plastic tube. See the attached photo for an example of the latter. The other antenna on the MR200 in that model is mounted horizontally at the front.

Steve



PS Is there a way to have this photo as an expandable thumbnail ?

[Peter Fitness]

The photo below, of my Nordkap under construction, shows how I route the receiver antenna through a tube. It's just below deck level completely within the hull, and I've never had reception problems with the antenna in that location. The Futaba 36 Mhz FM radio has since been replaced by a Hobby King 2.4 Ghz unit, but the aerials (this particular model has 2 receiver aerials) are in a similar position. Again, reception has been faultless.


Peter.

[radiojoe]

I use a Saturn 6 Rx that has two quite short antennas about 5" long, I have the Rx on the centre line with each antenna fixed to the opposite hull sides as high as possible at about 45 degrees to centre line, this has given faultless performance in all my boats. Joe