For gascan and I, we spent one year running on NiCd receiver packs, and one year running on the high-current BEC built into our ESC's. Either way made no difference, we were still getting random, inexplicable loss of signal. Our receivers were mounted to the subdeck, with primary and auxiliary receivers on either side of the CO2 bottle. Despite extensive tests, we were unable to duplicate the signal loss symptoms with any sort of consistency. I do not know how many other skippers who had issues had taken measures to prevent voltage spikes causing loss of bind, but everyone was aware of the possibility. Who knows what sorts of local background radio emissions may be interfering in different areas? I know a lot of people use wireless networks near where we usually battle. The local utilities company also installed wireless meter readers a while ago, that reportedly have been causing interference with all sorts of electronics. Maybe it's magnetic storms on the sun. Maybe specifically adding a capacitor would solve the issue. Whatever it is, I do not have the equipment, time, or money to figure out why 2.4ghz radios have so many problems in my local club.
I like the splitter idea. The 2.4 is a popular thing for LOTS of devices. even so, it seems to be better than the older tech for me personally.
Oh yeah, one more thing I completely forgot about. I have fiberglass hulls for I-403 and I-404 in my garage, waiting for me to figure out how to make them dive, and 2.4ghz just doesn't work with submarines. Last year I watched another club member try putting a Spektrum 2.4 in the I-401, and he kept on wondering why it wouldn't dive well during swimming pool tests. It was pretty funny to watch
That is funny. Yeah 2.4 doesn't do everything but I figure if it's underwater....I'm going in anyway. subs make sense though. What does the sub clubs use? they have radios
My brief experience with these radios glitching out stemmed from the fact that these 2.4 ghz radios lose signal contact when the power supply voltage drops below 5 volts on the receivor battery. I found too that I had to use a larger than stock tx battery to keep a lot of power available for a long run. I had no issues as long as I kept the receivor powered at 5v and above. Once below that's when I noticed a loss in signal. I used giant size packs at IRCWCC NATS 2010 and had no issues with the radio. The only issue I had was I forgot to plug the pack into the receivor and through my frustration I pulled the boat out and thought it was an electronic glitch so I didin't go back in the sortie. ..DOH!!
Hey all, I have been using a Spektrum for a couple of years now and had no problems at all with it (knock on wood). It has never come uncoupled from the radio and I have never lost signal. The antenna wires are in my water tight box, a "Lock n Lock". I don't keep batteries in it and even over the winter, it is still plug and play. As far as 2.4s and subs, the 2.4 doesn't have the power to properly penetrate the water to any depth, not without increasing the output power of the TX. Alot of the sub guys have water proof radio setups and dive with their boats. Makes it easier to see what the model is doing I guess. J
A little thread necromancy, but sub clubs use lower frequency radios. the 27 mhz radios should work the best for subs as they are in the HF band. As the frequency increases, the ability to penetrade water decreases; this is why real military subs use VLF-ELF for communications. The antennas have to be massive, but the RF will penetrate to a greater depth. Our old radios not counting the 27 mhz HF radios (50, 72 and 75 mhz) are all VHF. They penetrate water to a certain extent, but not to a great depth. As you probably don't want your subs going too deep, these are a good option and probably what most sub guys use because they aren't hard to come by. 2.4ghz is S-band microwave. That's why they have such short antennas; they don't need a huge antenna because the wavelength is significantly shorter. The signal doesn't penetrate water though. The recon aircraft I flew in the Army carried an X-band RADAR which we sometimes used for RADAR imagery. Water came back as a huge black hole. Same deal with the Ku-band radar that we used from time to time. Microwave energy just skips off the water and dissipates. It's been a long time since my radio and radar theory classes, so I might have some of the exact details wrong, but when dealing with water penetration, the essentially bottom line is, the lower frequency, the better it will work. EDIT: To be more on topic, there are some 2.4ghz modules you can get to hack onto your old 72 mhz radio and make them work at 2.4 ghz. I haven't tried one yet, so I can't speak for whether they are any good or not. Here are some links: http://www.hobbyking.com/hobbyking/store/__9770__Corona_2_4Ghz_DIY_Module_RX_DSSS_.html http://www.hobbyking.com/hobbyking/store/__8354__X8D_2_4GHz_trainer_port_X8_hack_module_PPM_Only_.html Here's a link to a thread where someone details adding the Assan module to his old futaba skysport 6: http://www.rcgroups.com/forums/showthread.php?t=970828
FYI - A captain used those very modules at the Brouhaha last year and his radio went NUTS! It would only work if he stood as far from other radios as possible. If anyone with a 2.4ghz walked near him he lost control of the boat. I am not sure if he had to rebind or it started working again. Based on that experience I woudlnt recommend them. In teh end he fixed the problem with a new Spektrum radio. Myself.. I am leaning more towards 75mhz again.. the range is so much better than my experience with 2.4ghz. Granted I have the Spektrum park version so maybe the others can reach much further.
That's good to know. I have an ancient 72 mhz radio I was thinking about getting the module for and trying to convert so it would be useful to me. I may still pick one up because....well the radio is useless to me either way. It's nice to know I should manage my expectations though. Do you happen to know which brand of hack module that captain was using? I believe the technology is similar to what's used in a Spektrum where the radio locks onto a channel. It's one reason I prefer the Futaba FASST system, it's a true freq hopper, and you're not going to interfere with it, period. Range with the 2.4 FASST has been excellent; I have /never/ sailed it out of range.
I'll definitely be googling and doing more research on reviews before I pick one up. As much as I hate having a wasted radio, I'd hate even more spending the money then having it continue to be worthless.
Yes, you can convert them, but the cost is usually about as much as a brand new radio. My thought was, if I can get a module for 50.00 and have the radio meet my needs, why spend more for a conversion or a new radio?
Another option is to convert using the newest spread spectrum module on the market called Anylink. www3.towerhobbies.com/cgi-bin/wti0001p It will convert almost any 72/75/2.4 transmitter into a 2.4 signal. The downside is it will only connect to a propriatory Anylink receiver. www3.towerhobbies.com/cgi-bin/wti0001p The upside is the system seems reliable by all reports. Also, it is relatively low cost at $55 total for module and reciever, with additional recievers priced at $30 each.
That sounds like a pretty decent deal, I might have to give that a try. I like the fact that it plugs into the trainer port rather then having to solder it in. Edit: I ordered an adapter and the reciever. We'll see how it works.
crzyhawk, did you get a chance to test the 2.4GHZ adapter and the reciever? Would like to know how that turned out. I have a old 72 6 channel collecting dust would be nice to put it to good use. Mike
Yes, I did, I posted a review in the reviews section. The short version is, the anylink adapter worked flawlessly for me. The biggest drawback is that it doesn't seem to work with Airtronics. Since I dont use any airtronics stuff, it's not a problem for me. http://www.rcnavalcombat.com/Forum/tabid/58/aff/567/aft/442520/afv/topic/Default.aspx
There are lots of options for converting 72mHz to the LEGAL 2.4 gHz. Tower Hobbies has the Tactics brand add-on module (the Anylink mentioned above) that plugs into the trainer port. Aloft Hobbies has the FRSky modules that do the same or a DIY module that you replace the internal RX module of your radio with (and it allows telemetry!) for under $30, I believe. HK also carries them. Pretty simple, you only have a V+, a Ground, and an RF pulse signal wire (3 wires total) to attach. The about $50 telemetry module attaches to your radio and wires in with the same 3 wires, but has no telemetry wires coming out to a display. If you do not want telemetry, FRSky, Corona, and others have DIY modules available. Some of the DIY kits (non module) do require you to drill a couple of holes (one for the bind switch, one for the LED). Far better than crashing someon's airplane a mile away or incurring a hefty FCC fine for operating on 72mHz. Cheers,
As someone stated above, rx power voltage is the most important thing with 2.4ghz. The second most important thing is that you choose a true frequency hopping system to begin with. Let's take these one at a time. Do not use a 4.8v ex battery, period! Use either a 2cell Lipo, or best choice is a dedicated 2200+ mah life 2 cell. The ones from places like mile high rc in Denver are good quality as they use true A123 systems brand cells. These are the best choice possible in a lifepo4 cell. They invented them. Basically what happens is that any large current drain on the rx, like say a guy is using a radio without end points, or just don't take the time to use end points, will have a servo that will stall, or lock hard against something, like a pop it valve, before the servo reaches its travel limit. You will pull a major amp draw and the result is a voltage drop that will cause what we in the aircraft community call, a brown out, and yes that's a double entendre. Usually causes one or more people on the flight line to brown out their underwear hehe. An A123 or liFe as they are known, can more easily handle this amp draw than a nicad or nmih pack can. They also have an extremely flat discharge curve. The others do not and will compound that voltage drop issue as the pack comes off full charge and starts to stabilize at its rated voltage, then gets worse than that as it gets below half charge. So in summary, 1, use a good 2 cell liFe pack for the rx and don't power anything else off that pack. Charge between sorties, it takes less than 15 min to charge a dead one. If you charge between sorties, it should take about 5 min or less. 2, Set up all servos so they cannot bind. 3 stay away from the single channel, non hopping systems if you plan to run with more than just a few guys, you will run out of band quite quickly with spread spektrum as each one uses 2 channels in tandem in an attempt to gain a more robust link. Go with the new hopping spectrum sets. The x protocol, name escapes me at the moment. 4 ensure the antenna is not below the waterline or shielded by metal or other signal blockers for a full 360°. I have been flying since the old wideband days and have over 20 yrs experience in messing with radios. In aircraft reliability is an absolute necessity for obvious reasons. Hope this helps.
