Re: [RCSE] Antenna Info
On Fri, Aug 13, 2004 at 11:49:42AM -0700, Bill Swingle wrote: | But, in my experience. Most any antenna designed to be shorter than the | factory monopole will Decrease signal. The R/C site agrees with this and | claims a minimum range reduction. No surprise here. Right-o. Probably the best receiving antenna for a plane would be a dipole with an electrical length of 1/2 wavelength (1/4 wavelength per side.) But this would only be marginally better than the half dipole that most receivers come with, and would require that you open up the receiver and figure out where the second wire should be connected. Probably not worth messing with in most cases. Now, there is some room for improvement by making sure that the antenna's electrical length is exactly 1/4 wavelength, as most antennas seem to be sort of close but not right on, but even doing this assumes that you know that they don't tune the antenna internally somehow. The same goes for transmitter antennas -- the manufacturers seem to be sloppy about the length, but it could just be that they tune for whatever antenna length they can get cheaply, and so adjusting the antenna length would be a bad thing. It all depends. You can get antennas with high gain, but for general R/C use high gain is bad. A high gain transmitting antenna sends most of it's signal in one direction -- which is great, as long as the antenna is pointed in the right direction. If not, things are *worse*. Receiving antennas work the same way -- if they have high gain, that means they receive best in only one direction. (Even a dipole has some gain, but it's low.) But ultimately, none of this matters because most of the time we have more range than we need. With standard equipment you can get 1.5 miles of range but probably can't see your plane at much over 0.5 miles away, so it doesn't matter. Unless you're trying to break altitude records, you don't really need to muck with your antennas, and you can even get away with installing less efficient but smaller antennas, or by not stretching the antenna straight out, stuff like that. If the plane has a foam wing, and you aren't covering it with carbon fiber or foil or some other conductor, just use an exact-o knife to cut a shallow trench (just one cut, just deep enough to bury the antenna) out on the wing, and spread it apart and stuff the antenna into it, then cover. You probably won't even know it's there. If you have to, you can double the antenna over itself, or turn at a 90 degree angle, but do be aware that things like this will reduce your range a little, so do it as little as possible. Don't ever cut the wire, unless you plan on fixing it later -- changing the length away from the 1/4 wave length will really affect your range. If you ever remove the receiver, cut the antenna off and leave it in the plane, but make a note of how long the part that was cut off was so you can make a replacement antenna, and so the new receiver knows how much antenna to cut off in order to use it. For your replacement antenna, all that really matters is that the length is the same. It's also smart to use stranded wire, because as was already mentioned, it's much more resistant to breaking. But beyond that, thickness, material, etc. don't matter much. Solder it on to make sure there's a good connection. -- Doug McLaren, [EMAIL PROTECTED], AD5RH For adult education nothing beats children. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
Hi Bryan, Tuning (I'll assume you mean adjusting length) is not required. All RX's offered have similar lengths of lead material @ 1/4lambda. One OEM to another may be slightly different depending on their particular RF front end. This implies those frequencies near the middle of the range will be closer (hint hint) to maximum gain (sensitivity), offering the most headroom. A proper (read rigorous) range test regime will determine whether indeed you have adequate headroom for that particular installation. Quoting Bryan Becker [EMAIL PROTECTED]: Simon, Is there an easy way to tune your antenna length, once you have installed your RX in your model? --Bryan -Original Message- From: Simon Van Leeuwen [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 1:34 PM To: Jared Cc: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info Just to be clear here, longer is not better. Take 72MHZ, a frequency that is resonant at ~4 meters. This equals lambda, therefore 1/4lambda is ~1 meter. In order for an antenna to be resonant, it must be close to these values in length. changes in length either way (longer or shroter) produce the same losses. Quoting Jared [EMAIL PROTECTED]: Thanks for everyone's replies! I think I'm going to do a little more digging about building antennas before I start on this. Bill - the only way that I could see to make a longer antenna less effective than a shorter one is to have it tuned out of the wavelength...or to have a unidirectional antenna pointed the wrong way ;) But I do agree that in general longer = better. Again thanks to everyone for their replies! Jared -Original Message- From: Bill Swingle [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 1:50 PM To: Albert E. Wedworth; Jared; [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: [RCSE] Antenna Info I have always had great sucess with R/C Direct products.. Please understand; I was not commenting on R/C Direct products specifically. But, in my experience. Most any antenna designed to be shorter than the factory monopole will Decrease signal. The R/C site agrees with this and claims a minimum range reduction. No surprise here. I was merely trying to headoff the folks who have in the past touted a few antennas that are better than stock. It was just sales baloney and I'd hate for folks to be misled again. Smaller equals worser; doesn't have to be that way. But, that's just how it tends to be. I'd love to find an exception. Bill Swingle RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
Because of a lack of shielding in most RC transmitters you don't really know how long the antenna really is. The real length includes the base that goes into the transmitter, sometimes all the way to the bottom, and also the wire from the RF deck to the antenna. The only way to tune the antenna length is to use a SWR (standing wave reflection) meter, which requires rewiring of the transmitter. Since all current transmitters have more than enough transmitted power to control the plane within sight there really isn't a reason to go to all this effort. Anker -Original Message- From: Bryan Becker [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 3:42 PM To: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info Simon, Is there an easy way to tune your antenna length, once you have installed your RX in your model? --Bryan -Original Message- From: Simon Van Leeuwen [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 1:34 PM To: Jared Cc: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info Just to be clear here, longer is not better. Take 72MHZ, a frequency that is resonant at ~4 meters. This equals lambda, therefore 1/4lambda is ~1 meter. In order for an antenna to be resonant, it must be close to these values in length. changes in length either way (longer or shroter) produce the same losses. Quoting Jared [EMAIL PROTECTED]: Thanks for everyone's replies! I think I'm going to do a little more digging about building antennas before I start on this. Bill - the only way that I could see to make a longer antenna less effective than a shorter one is to have it tuned out of the wavelength...or to have a unidirectional antenna pointed the wrong way ;) But I do agree that in general longer = better. Again thanks to everyone for their replies! Jared -Original Message- From: Bill Swingle [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 1:50 PM To: Albert E. Wedworth; Jared; [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: [RCSE] Antenna Info I have always had great sucess with R/C Direct products.. Please understand; I was not commenting on R/C Direct products specifically. But, in my experience. Most any antenna designed to be shorter than the factory monopole will Decrease signal. The R/C site agrees with this and claims a minimum range reduction. No surprise here. I was merely trying to headoff the folks who have in the past touted a few antennas that are better than stock. It was just sales baloney and I'd hate for folks to be misled again. Smaller equals worser; doesn't have to be that way. But, that's just how it tends to be. I'd love to find an exception. Bill Swingle RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
Hi Anker, As you are refering to the transmitter antenna, you can include your body and the surrounding ground making up the GNDplane. As a result, the premise that the worst point of radiation os off the end of (directly in line) the antenna element is not true. These extra factors have the null point somewhere above the plane of the antenna element... Quoting Anker Berg-Sonne [EMAIL PROTECTED]: Because of a lack of shielding in most RC transmitters you don't really know how long the antenna really is. The real length includes the base that goes into the transmitter, sometimes all the way to the bottom, and also the wire from the RF deck to the antenna. The only way to tune the antenna length is to use a SWR (standing wave reflection) meter, which requires rewiring of the transmitter. Since all current transmitters have more than enough transmitted power to control the plane within sight there really isn't a reason to go to all this effort. Anker -Original Message- From: Bryan Becker [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 3:42 PM To: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info Simon, Is there an easy way to tune your antenna length, once you have installed your RX in your model? --Bryan -Original Message- From: Simon Van Leeuwen [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 1:34 PM To: Jared Cc: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info Just to be clear here, longer is not better. Take 72MHZ, a frequency that is resonant at ~4 meters. This equals lambda, therefore 1/4lambda is ~1 meter. In order for an antenna to be resonant, it must be close to these values in length. changes in length either way (longer or shroter) produce the same losses. Quoting Jared [EMAIL PROTECTED]: Thanks for everyone's replies! I think I'm going to do a little more digging about building antennas before I start on this. Bill - the only way that I could see to make a longer antenna less effective than a shorter one is to have it tuned out of the wavelength...or to have a unidirectional antenna pointed the wrong way ;) But I do agree that in general longer = better. Again thanks to everyone for their replies! Jared -Original Message- From: Bill Swingle [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 1:50 PM To: Albert E. Wedworth; Jared; [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: [RCSE] Antenna Info I have always had great sucess with R/C Direct products.. Please understand; I was not commenting on R/C Direct products specifically. But, in my experience. Most any antenna designed to be shorter than the factory monopole will Decrease signal. The R/C site agrees with this and claims a minimum range reduction. No surprise here. I was merely trying to headoff the folks who have in the past touted a few antennas that are better than stock. It was just sales baloney and I'd hate for folks to be misled again. Smaller equals worser; doesn't have to be that way. But, that's just how it tends to be. I'd love to find an exception. Bill Swingle RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
On Fri, 13 Aug 2004, Simon Van Leeuwen wrote: Hi Anker, As you are refering to the transmitter antenna, you can include your body and the surrounding ground making up the GNDplane. As a result, the premise that the worst point of radiation os off the end of (directly in line) the antenna element is not true. These extra factors have the null point somewhere above the plane of the antenna element... Can you please clarify it. Are you saying that the worst position for the TX antenna is when it is sighting below the model? And best position is when it is pointed straight up? Arne RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
Hello Arne, Close. Generally it is accepted that pointing the transmitter antenna at the aircraft will create the worst signal reception as seen from the aircraft's receiver. Due to the human, and the near earth ground plane, the actual area of worst reception (null point - or area of minimum radiation fromn antenna element) is when the antenna is pointed below the aircraft. Where exactly can change based on the height of the transmitter from the ground and the angle. If the transmitter were left standing upright (no human - antenna at 90 degrees to the ground) the null point would be close to the line of sight along the antenna (directly above). Quoting Arne Ansper [EMAIL PROTECTED]: On Fri, 13 Aug 2004, Simon Van Leeuwen wrote: Hi Anker, As you are refering to the transmitter antenna, you can include your body and the surrounding ground making up the GNDplane. As a result, the premise that the worst point of radiation os off the end of (directly in line) the antenna element is not true. These extra factors have the null point somewhere above the plane of the antenna element... Can you please clarify it. Are you saying that the worst position for the TX antenna is when it is sighting below the model? And best position is when it is pointed straight up? Arne Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
Guys, The system is made to work with less than optimal antenna position. If we could all have RF transparent planes with the right structure for mounting a precision cut antenna, then great, like the man said, we could all fly our planes even further past that mile we can't see them at anymore anyway. The fact is people have done all sorts of wacky things with their antennas that work. Things you can't even change will effect your antenna performance. How you hold you hold your transmitter relative to your body and the ground, how wet the ground is, how the antenna in your plane shakes around as you maneuver around. Yes, it is important to leave that ~ 1 meter length of wire on your receiver, and try to keep it away from other conductive materials. But if you need to fold it around on your wing to make it fit, do it, it'll probably work. Just be sure to test (range check) your arrangement before sending it up the winch, and have fun. :) -Charles RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
I have an old Xterminator Pro fuselage with an XP3 aileron wing that had terrible glitch problems. I ran the antenna inside the boom, wrapped around the boom and straight down the boom and nothing worked. I finally glued a piece of very thin music wire to the back of the wing inside the aileron cutout with foam safe CA.. The cutout is about 1/8 wide and the wire doesn't come even close to getting in the way of the aileron. I glued it inside the wing opposite the throwing peg to help with the balance of the wing. I cut off a piece of the original antenna the same length as the music wire and soldered the music wire to the part that was left. I cut off one pin of a Dean's connector and put in in a break in the antenna so I could unplug it when I took the wing off. If you did this on a new build, you could just use a connector for your ailerons that had one more pin and plug everything in at once. The good newsSince putting the antenna in the wing, I haven't had a single glitch. Before putting it there I was getting hit 4 or 5 times a flight. Buddy Roos -Original Message- From: Jared [mailto:[EMAIL PROTECTED] Sent: Friday, August 13, 2004 10:45 AM To: [EMAIL PROTECTED] Subject: RE: [RCSE] Antenna Info All, Thanks for all the fast replies! Looks like I'm just going to throw out the T thing and do a single wire in one of the wings :) Any suggestions on doing this? Do I actually need to route a tunnel or if I use a fairly small wire, .02 diameter, could I get away with just laying it on top/bottom of the foam? Jared RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
RE: [RCSE] Antenna Info
Wow...never thought this thread would grow to be this long! Antenna theory is too much...I'm going to go back to my elementary school days and just fly paper planes and maybe some control line if I get really ambitious :) come to think of it at the last club meeting I couldn't even get a boomerang to work...maybe I'll just stick to things that don't fly :) O.k., that probably won't happen! Again, thanks to everyone that responded! Jared (head spinning with antennas) RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
