Born again model boater

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13 July 2013 at 22:07 #42160
DEREK SPEDDING 1
Participant
@derekspedding1
Hi All.

I have a Futaba M series that I bought in 1975. It has been in the loft for quite some time and despite resoldering and replacing the nicads it refuses to work.

Soo. Time to move on and in the last 20 years things seam to have changed, so I am in need of some up to date advice.

I intend building a big J class yacht or similar. prob abot 6-7ft long to sail at my full size sailing club. Therefore as I have a big model I can therefore see it and operate it from quite a long distance.

Question is? Am I better buying a 2.4g system or reverting back to 27meg ( with which I never had a range problem. I am thinking of pob 200-300 mtrs range over water. Any ideas welcome

Regards Derek
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13 July 2013 at 22:07 #5241
DEREK SPEDDING 1
Participant
@derekspedding1
Adv on radio gear
13 July 2013 at 22:19 #42161
Colin Bishop
Moderator
@colinbishop34627
2.4 ghz will be fine and a cheap solution to your requirements. Maybe best to get one of the mid range outfits.

Colin
13 July 2013 at 22:46 #42162
neil hp
Participant
@neilhp
I would disagree with Colin on this one, sorry, Colin…………….I have had 27 and 40 meg since taking up R/c boating in 1978 ………….and never had any problems with those, especially sailing on salt water………and it didn't matter one little bit where I placed my receivers in the boat……….they always worked on Fleetwood and any other lake, and over some considerablwe range, if you know Fleetwood, it's a long lake.I fitted 2.4 ghz radios ( all brand new sets) to my three lifeboats last year, and get absolutely no range at all from my boats…….the receivers have always been set as low as poss in the boats and the areal wires run around the combings…………………sadly with 2.4 gig, I have been told that because I sail on salt water the radio receivers HAVE TO BE placed above water line and the areal stuck through the deck……………….hard to do on a classic lifeboat….. …… so sadly I will be reverting back to 40 meg……….would I buy 2.4 ghz again………..absolutely not.
13 July 2013 at 22:54 #42163
Colin Bishop
Moderator
@colinbishop34627
I have three models with cheap 2.4ghz sets and have no problems with them. Yes, the aerials ideally need to be placed above the waterline but that's not usually a problem.

Most people these days seem to use 2.4ghz without undue difficulty but ovbiously there is no harm in using 27 or 40mhz as long as you check that there is nobody else on the same frequency.

Colin
14 July 2013 at 06:59 #42164
DEREK SPEDDING 1
Participant
@derekspedding1
Thanks for the replies chaps.

I remember well some folks using the cheaper 27 meg sets loosing contact with their boats probably due to low tx batteries, holding the transmitter high over their heads to regain control and bring the boat back into range, Would this work with the 2.4g system?

Neil, you mention mounting your receivers below the waterline, do you actualy mean below deck level? or down in the bowls of the boat?

Derek
14 July 2013 at 07:46 #42166
Peter Fitness
Participant
@peterfitness34857
Derek, below the waterline means just that, below the level of the water. I would venture to suggest that just about all receivers in model boats are below deck.

I also sail on salt water, using a cheap Hobby King 2.4Ghz set, and have had absolutely no problems at all. As long as I can see my boat, it responds to all inputs. The aerials in some cases are actually below the waterline, too. About half of our club members are also using the 2.4Ghz sets, from a couple of different manufacturers, and have all found them to be more reliable than the older UHF sets. We have a "Bermuda Triangle" area in our lake which, for some unknown reason, can cause interference with the 27, 29, 36 and 40Mhz sets, but the 2.4Ghz units are completely unaffected. However, I have been told by those who know that 2.4Ghz is unsuitable for submarines in salt water.

I suppose we can only speak from personal experience. Obviously Neil has problems with the 2.4Ghz sets, in which case I don't blame him for sticking to what works best for him. The last thing he wants is for one of his master built models to go sailing off into the distance, never to be seen again.

Peter.

Edited By Peter Fitness on 14/07/2013 07:47:36
14 July 2013 at 15:34 #42173
neil hp
Participant
@neilhp
well………..after listening to you, Peter, and Colin…………………..all I can say then is that it must be the type of set that I have………………..as when I went back to the shop I bought them from, that is what the shop owner told me……………I certainly won't buy 2.4 again though.
14 July 2013 at 19:24 #42175
ashley needham
Participant
@ashleyneedham69188
I would have thought that, if only two channels are required, a 27m set will be more that adequate,.

You dont seem to be able to but a three of 4 channel 27 or 40 set nowadays so a 2.4G set then would have to do.

2.4G will NOT work underwater fresh or salt as the wave is too short.

Ashley (only needs 2x chann and has only 27m sets) (likes Jurassic park)
14 July 2013 at 23:24 #42180
Malcolm Frary
Participant
@malcolmfrary95515
On a large model of a J class, there will be no problem whatever planting the TX and its aerial below deck and above the waterline.

While a yacht only needs 2 channels, having options for later on rarely does any harm, and since a fairly basic 2.4GHz outfit costs about the same as a 2 channel 27MHz set, no contest.

Add to that, it will be sailed in a "not model boat" environment where someone else might have a cheapo RC toy, but no knowledge of RC. A 27MHz hobby grade transmitter will spoil their fun, running a 2.4GHz outfit, no such problems. Yours won't interfere with theirs, theirs won't interfere with yours, you never have crystal problems.
18 July 2013 at 08:55 #42240
DEREK SPEDDING 1
Participant
@derekspedding1
Thanks for all your input chaps.

On balance I think I will send for a Spektrum 5ch with a full range receiver. Only prob with this is that I will have to buy new servos as I am told the resolution of my existing ones will cause hunting or some other sort of instability on a modern system. ( my existing servos are 40 years old though).

As i may be sailing at dusk after a full size race the extra channels will give me the extra flexibility of controlling Nav lights , deck flood lights and maybe a sound controller shouting "Water at the mark there, I say water at the mark" etc.

I will test it in my existing small yacht and report back.

Regards

Derek
18 July 2013 at 13:18 #42248
Gareth Jones
Participant
@garethjones79649
Hi Derek,

Before you rush off and buy some new servos, try your old ones first. We have two Spektrum DX5E transmitters and have used them with a wide range of servos, in conjunction with MR500 receivers, without any problems at all.

However I have had some odd effects with the new Spektrum 2 channel marine receiver when used with a Hitec HS815BB sail winch. I think it might be a side effect of the fail safe system but as yet I am not certain and still investigating.

Gareth
1 August 2013 at 14:43 #42556
Tony Bell 2
Participant
@tonybell2
One of the major problems buying new Tx/Rx and servos is that nothing is compatible.

I would not consider anything other than 2.4Ghz as you will have to keep changing crystals. Have you worked out the cost of them for a box full. (they come in pairs)

Buy a transmitter with End Point Adjustment and you will be able to adjust your sheet travel and rudder angle as you want for any make of servo. If not you will have to buy two separate Servo Expanders ( £15 x 2). Factor that into your calculations

It is a good idea to put the antenna above the waterline horizontally or vertically. My research shows good Tx/Rx will work at 100m with the receiver antenna below the waterline. I stopped trying below 40mm. Salt water may cause problems.

For the size of your boat you will have to buy large serovs. Hitec 785 and other like it will not be powerful enough. Don't be tempted to buy from China unless you know what you are doing. I know to my cost. I have restarted building my 1/10 scale Jolie Brise, the hull is 1.7m

Tony

Edited By Tony Bell 2 on 01/08/2013 14:44:43
2 August 2013 at 07:38 #42584
DEREK SPEDDING 1
Participant
@derekspedding1
Thanks for the info chaps.

As it happens, minutes before i received Garaths post I had ordered a Tamco 2.4g 7 chan system with a couple of servos after advice from John at Howes Models. (John had said that it had a long range receiver)

I tried it out yesterday an on old yacht that had been in the loft for many years and was happy with the range. I had it out on our 90 acre sailing club lake and had full control at 230mtrs , this was with me standing on our slipway about 2 mtrs above the water level. I was reluctant to sail it further away as the wind was gusting some at 20 knots. I can be sure of this distance as it is where our number 9 buoy is placed .

I had mounted the receiver on the underside of the deck with the antenna horizontal. After Gareths advice I soldered new connectors on to the existing 40 year old Futaba servos and one worked fine and the other did not respond.

Derek.
2 August 2013 at 08:37 #42590
Dave Milbourn
Participant
@davemilbourn48782
Derek
The old Futaba 3-wire servos required a signal of 1.3mS for neutral while practically every current radio uses 1.5mS. For the price of a couple of new servos I'd consign the old ones to the display cabinet if I were you.

Dave M
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