tbaysal2000

Can you share photo of your radio box so I can see how you place the antenna please? I loose connection with transmitter when the boat is running towards me; probably because of the engine in between?

I have Sanwa (Airtronics) MX-3X and RX-451. There is a very small bend at 1/3 of the cable where it comes out of the plastic tube. I tested it on the field when not running and range was quite ok but in the sea, I'm losing it at about 150 - 200 ft.

Ron Olson

My Feedback: (1)

I mount my RX's on the radio box lids as close as possible to the antenna tube. I'm one of those old-schoolers where I like my antennas as high up as I can get them although some people leave theirs laying inside the box..
You mentioned a bend in the antenna wire which could be a problem. I tried looking at the Airtronics RX's on their site but they were no help. On my Futaba 2.4 Gig antennas, they are what's called top-load antennas as there is a coil of wire at the top. Futaba advises not to bend the wire up there as it can damage it.
My RX is attached with a double-sided silicone tape (Parma) but you can use regular double-sided tape or Velcro if you wish.
Do not use the antenna tube cap to hold the wire in place! If it wants to slide down, use radio box tape or a spot of silicone like Shoe-Goo to hold it.

qdemon

Hi firstly you did not say how your antenna system is set when operating at SHF (Super High Frequency) such as 2.4hz you should have your antenna system matched both vertical or horizontal.
If you try to cross polarize a signal at these frequenices it results in a drastic loss of recived signal at the RX end, you have to bere one thing in mind your transmitter is putting out a VERY low power signal i,m not exactly sure of the permitted amount on 2.4Ghz, perhaps 10 milliwatts but I could be wrong !

i'm sure I will get a few people saying my antenna is curled up in the radio box and it works GUD Luck.
Also some brands on radios work better fror marine use than others on this band, Futaba seem to have a better reputation than others.

PS. ( fully licenced radio ham that operates in the 2.4ghz band ).

tbaysal2000

qdemon: my tx has one antenna so how can I set it vertical and horizantal? Making an L shape in the box?

Ron: please see the photo. I believe mine is also like coil on top?

qdemon

Just about all tx's have the ability to swivel the antenna vertical to horizontal, looking at the 2nd picture that looks like the antenna has sustained damage.

Bob.

Paul M

I agree. The antenna has been damaged. They are not expensive. Replace it and I am betting your reception woes will be resolved.

tbaysal2000

Thanks. Is there any site which I can find a replacement antenna for airtonics/sanwa? It is hooked inside the rx with a special connector.

Could shortening the wire be an option? I remember it has to be an exact measurement. Where I play is free of other tx so I want to try the range with a mode first.

Paul M

I only run Futaba so can;t help you there.

Very bad idea to try and alter the antenna or repair it.

A guy I used to run with tried to lengthen a 2.4 rx antenna. He lost control of the boat. Fortunately no one was hurt.

qdemon

Hi Ty ( sorry I dont know your name )
the mini connector I think is a standard one although i have never seen the inside of a sanwa RX you can buy longer antennas for the futaba recivers that should work on the sanwa but you would have to hunt for them there was a chap selling them on the jims rc forum.
do not under any curcumstances shorten the antenna of the RX they are a fixed lengh mini coax cable if you get another antenna you will need some very small tools to fit it the connector can be a pain to snap back on to the curcuit board ( dont use excesive force.

Bob.

tbaysal2000

Sorry, my name is Tufan and last name is Baysal. I'm from Turkey, Izmir.


I'm adding the interior of the RX so maybe you can tell it's interchangeable. It looks solid there.

I googled a bit and another solution is cutting off the damaged part and leave exactly 31.25 unshielded wire. I know someone who can do precision work on extremely high resolution optics etc so probably I'll try this route first until I can find out if replacement is possible and where I can find it.

The Ghost

Ty,
You can remove the antenna that is shown, it is a micro conector(see photo) I get antennas at http://www.hobbyking.com/hobbyking/s...nna_60_cm.html

Cheers

tbaysal2000

So I've got this antenna but it cam with a black part at the end. The person who sold this to me flies airplanes and he received it as is from HobbyKing. Any idea if I would damage the cable if I remove the black part as I want to insert this in the antenna tube as high as possible.

The Ghost

You can remove the black part(small piece of tube), but then you will have to remove the outer covering of the coax to get the antenna end out
Cheers

tbaysal2000

I contacted again the seller and he told me to keep that part which is supposed to add more range. I will have to find another way to install it in a tube. I also have a 15cm shorter one so first I'll try that one keeping it in the box and if it gives me enough range, I'll stop there until I complete all my work with the boat.

When kept in the box, is it better to align it horizantal or vertical or no difference?

The Ghost

I buy the 60cm ones from HK and cut the tubing off the ends and I can run the boats out of sight and not loose range, It would be used in aircraft as they are a lot further away. I fly 73" wingspan 30cc models and I usually fly between 500 to 1000 feet in height, most boats are only around 200feet away.

Cheers

tbaysal2000

Do you mean you cut the excess part after the length you need and you don't take peal off the shield as well? If so, why are these sold with the end part with no isolation abt 3 cms (must be an exact number anyway).

Also I noticed 2 antennas in your purple boat, why?

The Ghost

Just need to do as in the photos, the purple one has a MR3000 RX and has twin antennas
Sorry for the delay had a hard drive fail this morning and lost a lot of infh, had to reload everything.

Cheers

The Ghost

Length of exposed antenna is 32mm if you need to know

Cheers

tbaysal2000

Hi Ghost. No problem with your reply speed. I actually appreciate all of you to care to do so. I just noticed you are from Australia. What a great site, I get support from USA, Canada, Germany, Australia being in Turkey

So there are 3 photos showing step by step the progress. So that you are leaving 3.2 mm, antenna at the 3rd photo is still not cut to the exact length, right?

And if the black thing helps for better range, why not finding a way to keep it?

The Ghost

The length left is 32mm(1.5inch) NOT 3.2mm, the black thing is just a piece of alloy tubing crimped to the antenna, if you want to keep it just measure the total length of the antenna end and the black tubing and then cut the shielding to that length. I have almost run the boats out of sight and have no problem with range wiht only the 32mm length of the antenna

Cheers

tbaysal2000

Great, thanks