Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: shimsham on March 01, 2011, 01:53:37 pm
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Need some advice please, i use a Spk Dx 7 radio and i am fitting a mr3000 rx to a model slipway envoy it states in the instructions of the rx that the longest antenna has to be fitted up a tube which i would imagine would be on the deck which would then be a bit of a eye sore,is there any other way of fitting the longest antenna so it gets optimun signal from the radio.
Colin.
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Hi Colin,
I only use these receivers on my all my boats and I race IOM's at long range much further than the normal leisure boat skipper. I use a plastic pot for the radio gear with the longest aerial running length ways underneath the deck this way it's above the waterline the other I just leave in the pot at any angle I have never had any problems with range at all :-))
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I agree with SpamCanMan - just keep both aerials above the water line and preferably at right angles to each other. You can put one in a tube if you wish, I only do that to route it clear of hatches etc as they tend to be a bit springy and go where you don't want them {-)
Barrie
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spamcanman what do you mean you put it into a plastic pot dont just quite get that bit.
Cheers Colin :-))
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even the best boats take in a drop of water so mostly what we use in the racing boats is keep the winch a rudder servo clear off the bottom of the boat we also smear some vaseline around the base of the rudder servo where the screws are and the joint of the case just to keep out the water, the receiver and battery are located in a screw top plastic pot this makes the gear impossible to get wet. We sail our boats in 20 knot winds and high waves so we need to keep gear dry and reliable.
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Great stuff got it now,thanks very much.
Cheers
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spamcanman. what kind of battery do you use for the Rx and does it make any difference if you locate the Rx near the esc,i have been told on the other forum the noise from the esc can interfer with the Rx.
PS. I like the look of your boat in the photo could you tell me what it is.
Colin
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A little bit of confusion somewhere.
One aerial can be horizontal inside the hull. The other, can be either but longest is probably best, should be vertical. Only the last 'silver' bit actually receives the signal, the rest is just to get it as high as possible.
For scale boats like the Envoy tug, since the distance away from the Tx. you are likely to be sailing, is comparatively small, both aerials could be inside the hull as high as possible above the waterline.
The 3000 Rx. is a marine version and can withstand some dampness and the amount of water getting into a scale boat should be very small (barring accidents) so putting it in a waterproof container is probably overkill in this situation.
Yachts are another case altogether.
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I have two Spektrum 5 channel receivers and one MR3000 3 channel, two in steam boats and one in a yacht. All are mounted under the deck but above the waterline and none have any part of the aerial vertical, all sit horizontal. I have sailed the yacht as far away from me as my old eyesight will allow me to see it and have never had any problem comntrolling it. The steam boats do not get so far away but the aerials are still completely under the deck lying horizontal and they work fine. The two parts of the aerial are at 90 degrees to each other, just not vertical. Cheers, Ian
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If your at all worried about positioning it above the water line inside the hull, you could too to mount the Ariel inside the funnel of the tug which would give it not only hight but also keep it out of site..
Easiest way would be mount a small dia tube up the GPR casting so the wire is able to slide up, and yet allow you to pull out with 'little' fuss.
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Thanks chaps for your inputs they are all very interesting,so most of you have spektrum Txs can anyone clarify this for me "When binding the Rx to the Tx where do you position both of the sticks are they positioned in the neutral position or are they positioned in an aircraft failsafe position low throttle and neutral steeering.
Colin :-))
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Neutral positions for both steering and engine if you have reverse. If there is no reverse then the engine should be at stop. Better to let the boat drift than have it tearing off across the lake! %%
Any tube that encloses the majority of the aerial should be plastic not metal, but the end silver section should not be enclosed if you can help it.
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Thanks Brian.
Colin
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as mentioned it really doesn't matter if the whisker's are vertical or both horizontal as either one whisker is only a back up for the signal. As for battery's I use a 1600 NiMh battery in my boats but that is only because they fit into the pot and I need light weight battery's but even these last 4 hours without turning off the transmitter or receiver I just leave it all switched on for the duration of the day.
The yacht in the earlier picture is an Australian built TS2 it's not mine it's the only photo I could find showing a pot in the hull like we use, below is a picture of my boat it'd called an Arrival built here in the UK.
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Thanks spamcanman.
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Hi Chaps.Having trouble getting the motor to run it starts on its own,it hesitates when running,and dont have no control over it with the Tx on,its binding ok and can get the servo to move with the right stick,but cannot not get any control over the motor with the Tx ,could any of you chaps who have built the envoy tell me what ESC you use at the moment i have Actions P90.
Colin {:-{
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I'm sure that Mr ACTion will be along shortly, :-)) but in the mean time two suggestions
1. Have you tried swapping the ESC and Servo to check you don't have a faulty channel
2. I assume that you are following this sequence - Tx on, Rx on, leave sticks alone for 10-15 secs. The ESC needs to recognise the neutral signal, and may indeed twitch or run for a few seconds before this happens and it stops.
Barrie
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Hi Barrie. Carried both of those out.
Colin
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Hi Barrie. Had a multimeter on all connections tonight there is plenty of voltage going into to esc on the battery side,but going out the other side the voltage fluctuates,disconnected from the motor side of the esc and touched positive & negative on the motor and it went full throttle.
Colin
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Sorry chaps the ESC is a P80 not as above a P90.
Colin
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Hi Colin,
I only use these receivers on my all my boats and I race IOM's at long range much further than the normal leisure boat skipper. I use a plastic pot for the radio gear with the longest aerial running length ways underneath the deck this way it's above the waterline the other I just leave in the pot at any angle I have never had any problems with range at all :-))
Hi,
I've been using a variety of Spektrum radios (DX6, DX7) for five years in an IOM, generally with the AR6000 receiver. Not too many problems except at rather long ranges in rough water.
Because these are no longer available I recently tried the MR3000 with much disappointment. The range does not seem good at all and signal loss occurs regularly especially if someone or a group of boats gets in the way of the line of sight link, but sometimes when I'm the last boat left racing. The connection takes a long time to reestablish, sometimes requiring me to switch the transmitter off and on again, I understand that is due to the design of the surface radios with a faster response but more chance of the failsafe operating. To check this I repeated the range test with the AR6000 and found that I did have similar regular drop outs but I had not previously noticed because the link recovered so quickly. I have not tried the more expensive satellite receivers (AR6200 or AR7000) because I don't want to risk getting them wet.
The other recent change I have made is a change of NiMH batteries from the fat cells (1500 mA JP type) to AA size packs (1300 mA). Do they have less ability to keep up the voltage ? I use 5 cell packs.
Another problem when trying a DXi transmitter with the IOM was a loss of rudder with the winch still operating OK. It appeared there was no rudder signal from the stick, confirmed by looking at the stick monitor display, and by the impossibility of adjusting the rudder travel. The functionality eventually came back and I have not been able to get iti to fail again. Is that the same problem which resulted in a recall some time ago ?
Any help or ideas ?
Does anyone have a recommendation on which manufacturer or system offers the best range and the most solid link ?
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I have only used Spektrum, Corona and the relatively new Graupner HOTT system. The Graupner HOTT is the best by some distance on water with the best range also. You also get a signal quality reading beamed back to the tranmitter in real tome as a graphical display and also an alarm sounds before you are about to loose reception that gives you plenty of warning.
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Thanks Mankster, I'll look at the Graupner.
I've just tested my AR6000 receivers and although the range is no better than the MR3000 they all relink instantly after dropping out.
Anyone else with advice ?
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Hi,
I also sail IOM's, Marbleheads and 'A'class boats all fitted with MR3000 receivers the only problem I have ever had with range is when both whiskers have manged to be below the water line I have now cured that by fitting a hollow straw type near the top of the pot and running the longest whisker through it so it's always above the water line the second shorter whisker I leave inside the pot but make sure it's near the lid when I screw it on since then I have never had a glitch :-)
Spektrum is most probably the most common used TX's and RX's in boating there's absolutly nothing wrong with the product in fact they have the best after sales I know. :-))
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On a different tack!! Here's a few pictures of the Spektrum receivers available! :o
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Martin, you're just amazing!
I know Spektrum are always developing something new, but I had no idea how big the range is.
Now if only there was a shop which could stock all that and give the best advice I'd be there ASAP.
By the way my reported problems are not a criticism of the manufacturer, rather I'd like to know what I've been diong wrong. Some of the damage is self inflicted - such as running a leaky boat, sailing on wet days, and breaking my antenna. it would perhaps be fairer to say that all radios are vulnerable especially in a lakeside environment, rather than to say they are fragile.
For Spam can man, I've just developed an idea based on several IOM boats I've watched.
One observation is that water gets into the radio pot when you open it and through antenna and cable holes in the side. If the wires enter through the bottom wthout sealing, the water should be able to drain freely. For the antennae I will try taping the two wires at 90° to a disc of foam which should keep them as high as possible without piercing the side of the pot for a tube. This arrangement enables the pot to be pulled out between races, for airing, or for maintenance.
Research on many forums into possible reasons for poor reception seem to suggest :
- Installation and operation. Poor siting of boat antennae, or pointing the transmitter aeriel at the boat (should be bent through 90° - doesn't matter whether it's vertical or horizontal), passing behind people or trees, operating near metal structures or in rain. These situations don't seem to occur with aircraft except when flying by video where the aircraft might be behind the pilot.
- Early Spektrum DSM systems were nothing like the DSM2/DSMX systems for reception over or in water. That is now history.
- A drop in battery voltage (spikes) can cause the link to fail, the time to relink varying according to the receiver model and protocol. Poor batteries/wiring or heavy servo loads. Difficult to measure. Certainly not limited to Spektrum but it is suggested by the manufacturer that they need 4.5 volts rather than the 3.5 - 9 volts specified. Some other makes keep the link intact down to 3.5 volts or less, though the servos would generally stop working before then it is still better to keep the link intact.
- Faulty (or more likely damaged) transmitter aeriels.
There have been faulty transmitter stick potentiometers. A recall of some Spektrum transmitters manufactured during a brief period, but perhaps other instances for many makes due to rain penetrating or wear and tear (e.g. advice not to use an expensive transmitter for a flight simulator).
Thanks both for your help.
Jerry