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>> Home > Tags > rf noise

rf noise
rf noise
rf noise
Internal wiring & bottom skins by robbob Fleet Admiral!   Posted: 2 months ago
Hi Alan. Thanks for the cautionary comments. Placing the battery up front is the only practical location and I'm using 12 SWG wire so current handling won't be a problem but inductance could be a factor. I could fit a ferrite ring but that would only help to suppress any RF noise so there's not much more I can really do other than put the ESC up front too but that would mean re-plumbing the water cooling and the motor wires too. I'm gonna have to trust my luck on that score 🤞. Best Wishes. Rob.

BRAVE BORDERER by jbkiwi Commander   Posted: 5 months ago
Good to hear you are making progress with the noise. My ESCs are not programmable as far as I know (There may be a card somewhere). They were cheap Chinese waterproof car/Buggy ESCs with Fwd and Rev which I wanted for independent drives but for the price and how well they work, you can't beat them (about NZ $20 each) They have a very soft start (you can count the revs) programmed in as std, and the only problem I have found is that they sometimes won't go straight into reverse without quickly nudging forward and back, (just need to drive in a scale manner and it's fine.) I'll put a pic of the unit and motor in (also a brushed one I am using in the MTB (x2) which work perfectly only NZ $9.00) They have braking, FWD, FWD+REV and batt type adjustable by jumpers. Throttle set-up is simple with full FWD and partial Rev set by the sticks. Both types are 30A and never even get warm. I purchased some fans for them but have never used them. The brushless units have a fan plug on them. The squealing I have may just require a switching frequency change on the ESC (8kHz/16kHz -more RF noise on 16kHz but more efficient) but I don't think I have that option (do you have that option to try on your set-up ? might be worth a crack). The sound units muffle it a bit anyhow. Boat runs at 10mph (GPS) flat out (looks way off scale) but only needs about 1/4 - 3/4 throttle for normal cruising. Will try to put up an external vid soon. Transmitter is easily modded to twin throttles,- excellent cheap set for boats ( later model has internal aerial)

Martin's Taycol Conversion Boards by Westquay Fleet Admiral!   Posted: 7 months ago
As to knowing the bigger motors, I have never run the Double Special and the Supermarine was normally on a single 6volt Lantern battery. Only occasionally on 2 lantern batteries to appease my Dad's need for speed, but an oyster bed was not really big enough for 12 volts and REP single channel bang bang RC! Beyond that and the wonderful noise it made, I know nothing, I'm afraid. Martin

Hull Pt2: Motorisation - Come What May!! by RNinMunich Fleet Admiral!   Posted: 7 months ago
As promised (or threatened?😁) stage two of the hull work and thoughts on motorisation. The hull was sprayed with two coats of grey primer/filler. Pic1. As usual this showed up the remaining imperfections (pics 2 & 3), but I'm not going to worry about them until I've got prop shaft tube and rudder stock sorted out and permanently fitted 😉 After my attempts to make and thread a 3mm prop shaft went awry Martin (Westway the Mechanicals Master👍) stepped in and made me a decent one complete with a bushed stuffing tube 👍 Vielen Dank Meister😊 I did however manage to make a 4mm to 3mm reducer so that I could fit a Rabeosch 35mm prop as seen in pics 2 & 3. The tube and shaft from Martin, arrived Saturday an' he only made it on Monday😊, have been dry fitted so that I can start setting up the gears, necessary to bring the drive down to the prop shaft fitted very low down in the hull, and motor mount. Pic 4. Motorisation: (Remember folks - this kit was designed and built as a static model!) I want to use the old 1950s Taycol Target motor which my Dad originally fitted in the Sea Scout which I have renovated and upgraded to brushless. See Build blog 'Sea Scout - Jessica' Many of you will know that the Taycol motors were field coil motors, meaning that they have no permanent magnet around the rotor coil, and thus reversing the battery connections to the brushes had no effect on the direction of rotation, as this simply reversed the magnetic fields of both stator and rotor coils🤔 To counteract this so that the motor could be used in both forward and reverse with a conventional brushed ESC I modified the motor slightly (separated the two coils) and built a simple converter board to connect it to the ESC. Again see the Sea Scout blog for the details of the conversion. Basically; once the field coil and brush-gear (rotor coil) have been separated a simple diode bridge can be used to apply the output of the ESC to the motor. This enables the reversal of EITHER field OR rotor coil polarity, depending on how you connect the converter to the motor. Thus reversing the direction of rotation of the motor. Beneficial side effect is that the diodes also suppress the commutator sparking😊 In my case, with the Taycol Target, I also cleaned, flattened and polished the commutator. Thus significantly reducing the potential for spark generation in the first place! A peculiarity of the Taycol motors is that they all use metal brushes, pressed phosphor bronze strip, so they need oiling! DO NOT oil conventional brushed motors with carbon brushes unless the brushes are exchangeable or you want to have to buy a new motor!!!!! Pics 5 & 6 show the proposed position of the Taycol in Gina 2 and pic 7 the prototype converter board I knocked up to test the motor, together with a Graupner Navy V30R Marine Brushed ESC. Details and results in the Sea Scout blog, including video of the sparks and oscilloscope pics of the drive waveforms before and after conversion! The latter showing the spark suppression effect of the converter😊 Some samples attached - last 3 pics. Pic 8 pic shows a more compact version of the converter, one of a few types I'm doing for Martin's various Taycols as a trade for the prop shaft he made for me and some useful material he sent. Thanks mate👍 Next steps will be 1) mounting the gears correctly on the shafts, requiring the manufacture of a 3/32" to 4mm adaptor and a 1/8" to 4mm adaptor, and keying them to the shafts - Hooray for mini milling machines 😉 2) manufacturing bushed end plates to hold the gears in place, 3) fitting the motor mounting platform. I'll probably borrow from my experiences of real shipbuilding and do this as a suspended 'false floor', i.e. mounted on stiff springs to enable adjustments to optimise the gearing mesh! On real naval ships this is done to improve shock resistance and to minimise engine noise / vibration conduction to the hull, thus significantly reducing the acoustic signature of the ship. Not that I'm tooo worried about being torpedoed 😁 Worth a try😉 Pic 9 shows the cleaned up and renovated Taycol Target motor. Pic 10 shows the drive waveform complete with sparks before modification.🤔 Pic 11 the cleaned 'forward' waveform with the converter board. Pic 12 the cleaned 'reverse' waveform, no suppression capacitors needed 😉 More soon folks, Cheers, Doug 😎 PS Along the way a new keel was fitted as can be seen in pics 1 to 3. The original builder had 'buried' the keel in the hull planking! 😲

Couplings by Westquay Fleet Admiral!   Posted: 2 years ago
They tend to work OK on angularity, but not actual misalignment. I'm happy with slot and pin! Or those wonderful Taycol ones with two sections that have a rough square shape bashed into the ends, then a square stick in between. They help the Taycol famous noise which I love. Who wants silence anyway? Martin

Using old motors by Westquay Fleet Admiral!   Posted: 2 years ago
Doug, that looks lovely. I can't guarantee the performance would be anything but sedate with the Target, but that kind of boat in the real world would rarely be seen exceeding about 10 knots if that. It's essentially a river boat. I would be inclined to keep with the scheme it has as it's nicely period with the off white. Maybe line the deck with a Rotring a la period too and veneer the coach house sides. I certainly wouldn't strip it as there'll be joints and filler and boring old plywood underneath. No, paint is the Aerokits look for sure Delamination needs only epoxy, either the repair and build stuff or the liquid a la West, SP, etc.. slide a knife in the delamination and convince some epoxy in, then lightly clamp it twixt layers of greaseproof paper (when the GF's out) or plastic bag or similar. I use Plastikard, but I was given a box of lasered off cuts by Ivan at the Vintage Boat Company. He's now sold out to SLEC who are even nearer where I live! Anyway I have plasticard in three thicknesses to waste. If you stroke the surface with a scriber, it will make a weird hollow noise if delaminated. If it is, make a cut, persuade the edges up and insinuate some epoxy into the crack you've made. Ain't nuttn. you can't repair. You should have seen the window frames in my house when I sold it. A festival of epoxy, firewood and P38 car filler. Surveyor passed it with barely a look. Reallygood paint saved the day. Stupid waster! 400 quid Mr. Client, chching! As for the extra gizmos, I'd ditch them to save weight and complexity. You might find a 3 blade prop works better, but I'm no expert there. Finally instead of "this belongs to", I'd simply name her Jessica, in a nice script. I hope that helps. Cheers, Martin

Soldering suppressors to motor by Dave M Fleet Admiral!   Posted: 2 years ago
Regarding brushless motors, you must not add any capacitors across any of the three connectors. The interference is caused by sparking between the commutator and brushes on a brushed motor, and brushless have neither. I would tend to agree with AlanP regarding lack of interference from un-filtered brushed motors when using 2.4Ghz. However if you are into fast electric then suppression is important as their motors can generate lots of RF noise and losing control of a fast craft is not to be recommended. Whatever RC system is being used all signal wires must be routed well away from any motor high current wires. It's good to see that we have members who have and share their knowledge and experiences. Dave

RFI problem by Haverlock Fleet Admiral!   Posted: 3 years ago
How worn are the brushes on your motors? The older the brushes as a rule the more they spark and sparks == RF noise. Black coils ? RF chokes? Have you checked the suppression of these motors? When you say "feedback" what do you mean? Some ESCs have problems with the switching speeds of some 2.4MHz systems. Unfortunately fault finding at a distance is never easy so all we can do is guess.

interference suppressors on electric motoers by Dave M Fleet Admiral!   Posted: 3 years ago
HI Chris Welcome to the site. I use 0.1mfd caps across the terminals and from each terminal to the metal case. I have used 0.022mfd across the terminals but the 0.1mfd work OK. Some motors have internal caps fitted, you can usually spot these through the case slots by the brushes. Adding more will increase the value and may make matters worse. The main culprits are the heavy current fast brushed motors but all brushed motors generate interference. Brushless motors do not and must not have capacitors added to their leads. Keep all dirty (high current) wiring well away from the aerial, rx and servos and try and route servo leads as far away as possible from the power (battery) wires. I usually route the different wires on opposite sides of the boat. 2.4Ghz is relatively interference free but high current dirty motors should be suppressed to prevent interference. The Rx might be 2.4Ghz but the electronics in the ESC are still susceptible to high levels of electronic noise so keep the wires well apart and fit caps. Our All Things RC section has some suggestions. dave

Pulsing ESC by Dave M Fleet Admiral!   Posted: 3 years ago
HI Eric Seems a neat installation. However the rx and aerial appear to be right next to the ESC and motor with the aerial actually running alongside the motor. Speed 600 motors are fairly good at generating electricaol noise, especially at speed, and it is possible that it is this interference that is causing your receiver to lose signal in the middle of the lake. Ideally your high current power wires need to run as far away from any receiver wires and the aerial. With 2.4 Ghz the aerial must at all times be above the waterline as the signal cannot penetrate water, unlike say a 40Mhz system. I usually try and run he power wires on one side of a boat with the receiver wires on the other. Running power and rx low current wires in close proximity can result in noise being induced ( bit like a transformer). I had a problem with a model Trent lifeboat where I had placed the rx with the aerial pointing down into the boat as it seemed sensible, but it was below the waterline and about 10yds out it started stopping and starting. Looking at your videos the signal is being lost causing the ESC to reset. As you apply power the signal is again lost and the process repeats. Initially try just moving the Rx so the aerial is pointing away from the motor and ESC. Ideally you need to move it away from the ESC as that is also a high source of interference. Hopefully your rx will then not lose signal. If this is a new TX/rx its possible you have a faulty set. Can you run the tx in reduced mode to check output? Sorry I do not have a FlySky set so am not familiar with its settings. I also notice that you appear to have a separate voltage dropper. The Viper has a built in BEC so you can't use both at the same time. You can cut the red wire in the lead from the ESC to the receiver. I usually just remove the red connection from the plug and tape it to the lead so I can replace on another boat. Please let me know how you progress. There are other steps that can help reduce the motor noise, but its not normally necessary with 2.4Ghz sets. Cheers Dave 😀

wanted 40ghz receiver futaba by andy_mart Chief Petty Officer   Posted: 4 years ago
I did see a post somewhere re the 40Mhz/35Mhz from someone who worked at Futaba. I have tried it and never had any bother to be honest range wise. Another reason for going to 2.4Ghz is less interference from other users or electrical noise from the motor or speed controller. You can pick up Planet RC systems from Ebay or Howes Models sometimes a little lower than Cornwall model Boats. That said though the customer service at Cornwall MB is excellent. Personally I would go with a more known manufacturer such as Futaba, Spektrum, JR, Graupner etc if you feel you will get the bug and continue with modelling

black tornado & surfury by groovydad Seaman   Posted: 4 years ago
I used to live in West Bromwich and regularly made the trip to Walsall to SH Graingers to lust over the 36" Black Cigarette they had in the window. I remember the Surfury being available to scratch build on MAP plans and I was put off as it was a planked hull so never made one. Nice models, especially like the Irvine powered boat, nothing like the smell and noise of a 10cc glowplug engine at full tilt.

maybe not by dbninja Captain   Posted: 8 years ago
sorry Westquay but with the lack of venues for "proper" nitro/diesel powered boats.. there Is just no point trying to keep one running on 1960's lo-tech electric motors. they were pretty poor In their day... and they are down right abysmal by todays standards. modern "brushless/Lipo" set-ups are now totally out performing their I.C. counterparts of yesteryear! lots of these old 60's hulls are still very very good designs and modern technology makes the most of them with no noise or polution... I still remember the bleeding hands from trying to coax a well worn diesel Into life (frog 349) 😀 db

Gannet 15cc engine by Lyle Sub-Lieutenant   Posted: 9 years ago
Hello from the colony. Well sparkie engines were my delight 1. The sparkie donks , need good cooling and very much so as they are hotter fueled petrol, but you need to have good large water pipes to enable a high rate of 'heat transfer ' In the water rate flow from the head or a large sized water cooling pipe diameter (say 1/4 Inch to 3/8 Inch pipe dia) from the pick up and through the model to exit . The principle Is actually not to cool off the combustion running temperature of the cylinder but rather to allow for the departure of 'excess heat' from the combustion temperature. So many 'over cool' the engines rather than allow for normal operating temperature ' to continue. Hence engines are fiddled with In the Winter cold having so called poor performance when If allowed to operate at normal temperature they are then so reliable. Similar when In warmer water they need the excess above operating temperature heat to be dispelled. As best Illustrated In air cooled motor mower engines which rely upon the effective excess heat dissipation above that of normal combustion operation. 2. A good quality motor oil Is essential and we used basic 'standard '/ 'neat' petrol In those days , probably low octane car unleaded Is the equivalent today, however do not go for the ethanol additive fuel sold these days for motor cars as I think It Is not suitable as It Is a cocktail blend when the old motor pump fuels were more straight petrols without the chemical additives of todays engined fuels.3.Using nicads or nickel hydrides (?) not sure on actual chemical name for Ignition Is great these days as they have more kick and do use a auxillairy pair of batteries for booster when starting as to not drain onboard battery supply to the coil. 4. Keep spark plug very clean and try to have a small paper type pad to Insert between the points to 'dry" away excess oil to help spark jump across points. As It Is the spark which Is the only excuse for not too ready starts. 5.Sparkies should be easy to start these days with transistorised Ignition circuits and better current/ oomphah batteries and are easy on fuel gulping as very economical.6. But sometimes they can be a bit noisy but generally a good big 2''/3" daimeter muffler box/pipe say 3 to 4 Inches long helps with noise dissipation. The exhaust energy Is best dissipated with large rates of expansion In a large chamber then the following contraction Into the exhaust pipe say 1/2 Inch outlet to air and noise energy Is thus lessened, good for all stable running boats but not too much approved by the high speed types who want Mach 1 performance horses and tuned exhausts etc. 7. Also the large capacity Sparkies ( not sure about the smaller capacity sparkies) can throw a heavy flywheel as low down power / grunt on less revs , hence can take a very large daI prop with a big pitch as steam boat props tend to do. 8. Remember It Is not a high revving glo at 14,000 to 23,000 and more revs, but a nice high power for Its day of latter day design and machining tollerances and mettalurgy. See ya from the colony. Lyle.

fireboat cof g by nasraf Commander   Posted: 9 years ago
A bit of a reply to all Dave M I will post a few more pictures of motor mount. I t ended up like this as I wanted to use old IC engine mounting and the material was something I had. I Initially I thought It was a bit heavy so drilled some of material away, but now think It Is a good solid mounting and to some extent Is a heat sink for motor,also makes It easy to get motor In and out. As to radio I have 40 Mhz unit so may not be troubled by Interference, I have Increased slot size In coupling so may Increase level of RF generated If It Is proportional to audio noise level. thelegos I am not sure what your mixture Is, probably a sort of grease with the vaseline being like the soap. A few days ago I was an advocate of grease but Peter has proved correct In his advocacy of oil, see my test results. pm devlin I am joining your club with ball race at motor end, I am going for closed bearing pre packed with lubricant and some oil down the shaft with a plastic bearing at prop end. Mine Is made of TUFSET polyurethane because I had some, I will find out If It Is OK later and It easy to make others. I am going to try silicone oil squirted up the prop shaft tube, It Is very slippery stuff as I found out when I got some on a tiled floor. Now to the results from tests these are shown In attached photos. The speed v. voltage graph shows that with no prop load the speed does not vary much for various prop shaft arrangements, this may be due the motor characteristics and back emf, I will have to look at a bit of dc motor theory. The same tests plotted on Current v volts show a considerable current Increase when grease Is used as a lubricant, this Is confirmed In the fact that the prop shaft tube gets quite warm during the tests. In the third graph I have plotted the power losses for various motor volts and this shows the bad news for grease especially at high speed. So no more grease, Peter was correct from the start. I think the tests were worth doing as It has Increased my understanding of the subject and I hope of others who are members of this admirable and Interesting web site.