[easygoingMBA]

Greetings all,

I am new to the board but old to the hobby… not sure if that came out right but, on with my story.

I build Ships, and I have 2 sisters (9ft long) ready to go in to the water excepting one troublesome issue. You can see them here (http://seanlougheed.ca/models.htm )

I went over to 2.4gh as I could not round up another ancient mariner as I call them (Nautical commander). I got a Turnigy 9X as it has enough channels to run everything, reconfigured it and all is cool. The range out of the ship with the original antenna is great- over 1 km.

The ships hold all their electrical equipment including the RX in a water tight compartment in the top of the hull (The "bunker" as it is called is made from aluminum), since the superstructures lift off it is just the best location for it. Except… the antenna is too short to get out of the bunker, besides all the superstructure is aluminum too and would block signal from most angles. The best place to put the antenna is up high, on top of the funnel. not so easy...

Here is what I have done and so far and has not worked:
• Removed the antenna from the RX and terminated it into an SMA Coax connector. (no change to antenna)
• Soldered an SMA coax into the RX. (good continuity)
• Patched the whole works together with a 4 foot coax extension that places the antenna on top of the funnel.
Net result has been about a 100m range.
• Next try was to put a 2 watt 2.4gh wifi booster between the RX antenna and the RX (assuming that the coax was the loss in signal gain). Net result. Zero. Same 100m range. To explain this logic, 2.4 is 2.4 it shouldn't care what is being said by the signal. Normally a booster is used on the TX, but assuming the signal loss was at the RX end, placing the booster to boost the signal coming through the coax should have given the RX much more signal to see.
So, The theory is sound to extend the antenna but something is going awry. Same factory antenna, with properly shielded coax in between. Total of about 4 feet 3 inches with 2 connections.
So the question is, how can I get sufficient signal?
Changing to long equipment will not necessarily help as the radios range is fine, moving the antenna seems to be the problem.
I have heard that SMA is "lossy" so it has resistance but this seems a bit much.

Any suggestions or questions please bring them on.
Thanks all

[davidmc36]

One thing is the booster may actually make things worse as it will boost noise as well as desired signal.

If the coax/connector is the wrong impedance for what the Rx wants to see no matter how great you shield and how great the quality of coax it may attenuate the signal immensely.

Was the antenna soldered on to the Rx in the first place?

There are fairly long 2.4 antennae available as replacement units that have the right coax and the ones I got have a very tiny push on connector on the end. That connector could be removed and the coax just soldered onto the Rx, takes a fine hand but if you already got an SMA to attach you must be OK with that part.

Sample connector that is common to 2.4:

http://www.digikey.com/product-detai...554-ND/1657749

The proper type coax, soldered to the Rx, with the right amount of shielding stripped (30-31mm) from the top end may make a great antenna, eliminate all the connectors etc.

[easygoingMBA]

using a straight coax would locate the bottle neck in signal and that would help a lot. thanks.

What you say about the booster seems to prove true, as it only makes up for itself some how... I am not a wiz on radio stuff.

I think the connectors are 50 ohms each and there are 2 of them. I will try a straight coax but that would be really hard to deal with on the ship as it would be wound through the superstructure. The idea of connecting it... in at least one place was to easily service everything in the hull. (disconnecting the superstructure portion)

Thanks very much

Sean

[easygoingMBA]

Oh, and yes the original antenna in the RX was soldered. It is a little piece of coax itself then stripped back. (originally wrapped in heat shrink)

[Dennis Pedersen]

Could you place the receiver up high in the super structure and put like a couple multiplex (Hitec) wing connectors in the leads to just unplug the servos ect. This way the receiver could be up high and you would just have to unplug a couple plugs to disconnect everything from the receiver ? This would allow the antennas to stay hidden up high and out in the open . I also have 2.4 antennas here that are approx 9.5" long if that would help . They are Airtronics replacement 2.4 antennas for there receivers . Good luck and your ships are incredible works of art !!

[dashpuppy]

Queen of Nanaimo hey :P

[davidmc36]

I got some of these for my Graupner Rx's because they have the correct HiRose connector. The end could be cut off and soldered to your Rx. You may be able to find longer too. Also, the big piece on the end under the black heatshrink which is a piece of brass tube can be removed. It is soldered to the shield to form a Di-Pole at the end and I did not see any noticeable negative effect from removing them.

http://www.ebay.ca/itm/600mm-Long-2-...item20e5491d7c

If you used something like the outer tube from Sullivan Goldenrods to house the antenna it should slide in and out of it pretty easy when you want to lift the superstructure. Could you install the red outer tube (even with some curves in it) into the supersturcture? Even if it had some pretty good curves the coax would be stiff enough that it would slide right up the length of it when you dropped the superstructure back on.

[easygoingMBA]

Thanks Dennis, for the complement on the girls.

Your idea of a multiplex is quite brilliant. I have tried to stay away from mounting the RX up high because it would have to live in the funnel which is really inconvenient to work in... or I could rework access into the funnel uptake area on the upper deck which would be a good place. If the antenna things don't work out this gives a great back up plan.

Mostly the hurdle was a mental one of unhooking and hooking up 8 channels. The idea of using the multiplex is a good because once wired up I wouldn't have to get into the funnel or unhook a gaggle of servos.

I have to admit that all the lights, radar and camera (yes it has a micro cam on the bridge) all feed into the superstructure with a 6 pin multiplex. Overlook the obvious... that is pretty normal .*)

[easygoingMBA]

Thanks David,
The idea of a tube to carry the antenna up is right on, I actually built a 3/8 inch tube into the New Westminster (the bigger one) It will pass a coax with a connector with ease, but Nan (as I call her) was too far along, and I get squeamish thinking of drilling through 3 decks as there are wires glued along the roof connecting all the lights. But the refit sleeve could be pretty small. No connector = small hole and the small sleeve would keep the coax straight. That would be nice and easy to deal with when lifting the superstructure.
Thanks

[easygoingMBA]

Your towns namesake. Don't ask why I built her in particular but I liked that she still had her 1960's charm by not being lifted and modernized. Supposed to be retired in 2016, but the way BC ferries ticket counts were this summer you will probably see her for another decade, heck she is only 51 years old now....