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Model Forum / Radio Controlled / Water Models / September 2005Frequency?
I'm new to RC and would like to know what two channel radio system/frequency gives the best distance/control, AM or FM ? I'm planning on using them on a small lake that is maybe a city block across and two city blocks long. I'm thinking electric but don't rule out combustion type power. RM ~ depends which country you are in??? at a Guess your in the states?? > I'm new to RC and would like to know what two channel radio > system/frequency gives the best distance/control, AM or FM ? I'm planning > on using them on a small lake that is maybe a city block across and two > city blocks long. I'm thinking electric but don't rule out combustion type > power. RM ~ >>>> depends which country you are in??? at a Guess your in the states??<<<< Yes, I'm in the states. RM ~ over here in the UK AM or FM seems to make little difference both have a greater range than a my eyesight >>>>> depends which country you are in??? at a Guess your in the >>>>> states??<<<< > > Yes, I'm in the states. RM ~ >>> both have a greater range than a my eyesight <<< Thanks, I wonder if the frequency makes any difference in range or reliability? I think we have the option of 27 or 75 MHz here. RM ~ PS, Does this newsgroup have a companion binary group? >I'm new to RC and would like to know what two channel radio system/frequency >gives the best distance/control, AM or FM ? I'm planning on using them on a >small lake that is maybe a city block across and two city blocks long. I'm >thinking electric but don't rule out combustion type power. RM ~ Either AM or FM can operate on the same frequency. Both are generally equivalent in terms of distance. However, FM is more able to reject interference. AM (Amplitude Modulation) receivers can be overwhelmed by a stronger transmission source than your transmitter. This can be something like a commercial radio, police, fire, etc. FM (Frequency Modulation) is not as susceptible. AM radios are generally cheaper & have limited features. JM >>>AM (Amplitude Modulation) receivers can be overwhelmed by a stronger >>>transmission source than your transmitter. This can be something like a >>>commercial radio, police, fire, etc. <<< Okay, I'm probably better off getting a 75 Mhz FM then. I hadn't thought about that but I'm within a half mile of an Interstate highway that has truckers gabbing 24/7 on their CB's. Thanks, RM ~ >>>>AM (Amplitude Modulation) receivers can be overwhelmed by a stronger >>>>transmission source than your transmitter. This can be something like a [quoted text clipped - 4 lines] > truckers gabbing 24/7 on their CB's. > Thanks, RM ~ 75MHz is surface frequency, for car and boat. This frequency range offer many choices of frequencies, so less likely to have one in a nearby distance use the same frequency. 2 guys using the same frequency will cause lost of control. I don't remember it exactly, there are likely 30 frequencies you can choose. In 27MHz, there are only 12 frequencies you can choose. In the old days 27MHz have only 6 frequencies. 72MHz is for air. FM receivers for US has double superhyterodyne, very reliable but more expansive too. Combustion type model can have longer running time. I saw electric boat modeler bought 10 batteries, can have total of 80 mins running time, 10 battries likely cost 500 US dollar. I mix glow fuel by myself, each liter cost about 3 US dollar. Can power a .21 engine for a few hours. See these boats, one use electric power(AC motor). http://www.btorcboat.com/html/picturesByAll.html >>>> Combustion type model can have longer running time. I saw electric >>>> boat modeler bought 10 batteries, can have total of 80 mins running >>>> time, 10 battries likely cost 500 US dollar.<<<< That's interesting, if I had been betting I would have put my money on the electric. >>> I mix glow fuel by myself, each liter cost about 3 US dollar. Can power >>> a .21 engine for a few hours.<<<< Would you mind telling me how this is mixed? >>> See these boats, one use electric power(AC motor).<<< These boats are sort of what I have in mind, the detail is great. I would also like to try an air boat. I saw a fellow several years ago who had a 3 wheel air car and I was quite fascinated with it. Thanks for your input, Rob Mills >>>>>Combustion type model can have longer running time. I saw electric >>>>>boat modeler bought 10 batteries, can have total of 80 mins running >>>>>time, 10 battries likely cost 500 US dollar.<<<< > > That's interesting, if I had been betting I would have put my money on the > electric. Because of battery cost, I think electric power is expansive. And too short running time. >>>>I mix glow fuel by myself, each liter cost about 3 US dollar. Can power >>>>a .21 engine for a few hours.<<<< > > Would you mind telling me how this is mixed? I use 84% methanol, 15% castor oil and 1% acetone. Use kitchen measuring cup to do. Adding niromethane can increase the power, but will increase fuel consumption too. Small engine tend to require more castor oil. Consider the rate of change of cylinder surface to rate of change of volume. >>>>See these boats, one use electric power(AC motor).<<< > [quoted text clipped - 3 lines] > > Thanks for your input, Rob Mills >>>> I use 84% methanol, 15% castor oil and 1% acetone. Use kitchen measuring cup to do.<<<< Thanks, I'll file this info and maybe give it a try >>> Adding niromethane can increase the power, but will increase fuel consumption too.<<<< I used to drag race back in the 50's when drag racing was just catching on. None of the locals knew anything about nitro when one of them figured it out and started mixing a dab of nitro in his "B gas class" Cad powered 54 Oldsmobile, he started smoking the tires the full quarter mile with times/speeds not far behind the dragsters which at that time were still struggling to get a time under 10 seconds. We all stood around with our eyes bugged open wondering what that funny smell was. If I remember right he was running about 116-17 mph at a tad over 12 seconds. Thanks again, RM ~ Don't write off the electrics so fast. New batteries and motors are allowing this form of propulsion to rival that of internal combustion. Depending on the application, electric can actually be the better choice. Years ago I had a Fletcher class destroyer. It went well over scale speed on a pair of cheap Radio Shack electric motors. I used a 4.8 volt 1000 ma Kraft Radio Receiver Battery to drive the motors. It lasted a good hour before recharge. Imagine what I could do with some of today's newer batteries? >>>>> I use 84% methanol, 15% castor oil and 1% acetone. Use kitchen > measuring cup to do.<<<< [quoted text clipped - 18 lines] > > Thanks again, RM ~ >Don't write off the electrics so fast. I don't know if it is an issue in the US but in the UK an increasing numberof model boat lakes won't allow IC engines due to noise / pollution / insurance risk isssues. Fast and slow electrics and steam engines (provided a valid boiler certificate is available) are OK. As to frequency, we suffer from cheap Chinese imports of ready to go boats (often from ebay) using 35MHz band which is not legal for surface craft in UK. We also find similarly sourced aircraft on 40Hz band, again illegal. >>Don't write off the electrics so fast. > [quoted text clipped - 7 lines] > surface craft in UK. We also find similarly sourced aircraft on 40Hz > band, again illegal. Obviously the UK frequency spectrum is controlled as well as it is here in the US. As for the motors? Usually one can find a pond or such that allows IC engines. But you can find a whole lot more that allow electric and sail. Sign of the times I imagine. We have a 12 foot battleship in the club once held the record for longest run on a single battery. It ran for over 24 hours on a car battery. I also know someone with a 12 model that runs for 4 hours on a single pack of four cells. Depends on motor and current drain! James Moir > Don't write off the electrics so fast. New batteries and motors are > allowing this form of propulsion to rival that of internal combustion. [quoted text clipped - 28 lines] > > > > Thanks again, RM ~ >>>>>I use 84% methanol, 15% castor oil and 1% acetone. Use kitchen > > measuring cup to do.<<<< > > Thanks, I'll file this info and maybe give it a try Be careful, this oil content is low. The risk is increased damage if you run it lean. | > Okay, I'm probably better off getting a 75 Mhz FM then. I hadn't thought | > about that but I'm within a half mile of an Interstate highway that has [quoted text clipped - 7 lines] | frequencies you can choose. In the old days 27MHz have only 6 | frequencies. 72MHz is for air. I don't know what countries you're talking about, but your IP address suggests Hong Kong? Here in the US, there's (still) only 6 27 mHz R/C channels, not 12. They're probably pretty safe from CB radios a half mile away, unless somebody is using an illegal amplifier. But yes, here 72 mHz = air only and 75 mHz = ground only. | Combustion type model can have longer running time. I saw electric boat | modeler bought 10 batteries, can have total of 80 mins running time, 10 | battries likely cost 500 US dollar. That seems a bit silly. All he really needs is perhaps four packs and a few chargers. It certainly works for the R/C plane guys. And the packs don't have to cost that much. You can get low end 6 cell 1500 mAh NiCd subC packs for around $10 US, which probably work just fine in a boat unless you're racing or doing something where you need better performance (mostly longer runs.) (Weight isn't quite the issue in a boat that it is in a plane. Though of course it is still a concern.) | See these boats, one use electric power(AC motor). | http://www.btorcboat.com/html/picturesByAll.html To be more precise, it's a brushless motor. The power going into the ESC is still DC.  SignatureDoug McLaren, dougmc@frenzy.com The only time you have too much fuel is when you're on fire. |
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