Best way to do a range check.
08-08-2003, 03:39 PM
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Best way to do a range check.
In your opinion, what's the best way to do a range check for a new jet. Is it different if I use a whip antenna?
Thanks
Russ
Thanks
Russ
08-08-2003, 04:21 PM
#2
Best way to do a range check.
set the fail safe on your radio to push something out that you will be able to see from far away. Take your antennae off your radio and start walking. When you see whatever you fail safed pop up, you've exceeded the range. It appears that 50 to 60 regular steps appears to be acceptable among most modelers.
08-08-2003, 05:09 PM
#3
Best way to do a range check.
I think its important to mention that the range check should be done first with the engine off, and then with the engine running (also run it up to full power). A difference of more than 10% or so between the two is cause for a delay in flying to track down the problem. This is especially true with turbines because the ECU, fuel pump, and the engine itself can cause electrical noise and thus decreased range, but I would think its a good idea on a DF too because the vibration of the engine could cause electrical noise as well. Clearly this procedure requires a helper, but I wouldn't fly a jet without doing it...
Bob
Bob
08-09-2003, 05:54 AM
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Best way to do a range check.
Hi the only addition to the above I do is to turn the aircraft through 360 deg. at each phase. This seems to avoid potential masking particularly with the aerial inside the a/c.
Ian
Ian
08-09-2003, 11:39 AM
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Best way to do a range check.
Lee DeMary, where are ya when we need ya? Lee is the undisputed range check expert. If ya wanna do the best range check to really validate your installation, you need to do the full length antenna, full range check. Support the model on a non conducting table, up off of the ground to get out of ground clutter, and have a buddy communicate with ya of FRS radios or cell phones. Also be sure to check different orientations (as mentioned above), with engine off & running. It takes time, but there is no surer way!
08-11-2003, 02:49 AM
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Ooops flying all weekend -----
Originally posted by woketman
Lee DeMary, where are ya when we need ya? Lee is the undisputed range check expert. If ya wanna do the best range check to really validate your installation, you need to do the full length antenna, full range check. Support the model on a non conducting table, up off of the ground to get out of ground clutter, and have a buddy communicate with ya of FRS radios or cell phones. Also be sure to check different orientations (as mentioned above), with engine off & running. It takes time, but there is no surer way!
Lee DeMary, where are ya when we need ya? Lee is the undisputed range check expert. If ya wanna do the best range check to really validate your installation, you need to do the full length antenna, full range check. Support the model on a non conducting table, up off of the ground to get out of ground clutter, and have a buddy communicate with ya of FRS radios or cell phones. Also be sure to check different orientations (as mentioned above), with engine off & running. It takes time, but there is no surer way!
Send me an e-mail if you want a little reading and a few more detailed ideas on the "Real Range Check" ---- I am glad to see people are still checking and double checking before blasting off! I've seen to many great aircraft destroyed because a good range check wasn't done before taking to the sky. The little extra time it takes to make sure all is OK ---- before the first flight --- is well worth it!
Lee H. DeMary
[email protected]
AMA 36099
08-12-2003, 03:45 AM
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Best way to do a range check.
It is important to know that each radio manufacturer has a different opinion on how to perform the range check, and how many steps or feet are required. When I called JR they recommended no less than 65 paces with the antenna out. On a turbin aircraft the ck should be performed with the engine running. I put the engine on a little above idle and walk untill the engine shuts off. Trust me when that happens, your out of range. You will also notice a difference ( we do anyway) between a JR 955 and JR 945 reciever. The 955 being single conversion and the 945 being duel conversion. Its our expierence tha the 945 is superior in range cks on turbins and giant scale and giant warbirds to the 955 reciever. Airtronics has a different method and recommends no less than 150Feet. Oh well, the point is, IMO you should call the manufacturer if in doubt..... Ray Blair
08-12-2003, 10:38 AM
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The Real Range Check!
Hello Ray and others,
Radio manufactures do suggest different ways to do a range check ---------- I submit there is only one way to really do it correctly ----- to know for SURE that you have the strongest RF link possible, and one that will be reliable! Find below my notes on the Real Range Check -----------------
Range Check Preliminaries
The only way I have found to do a range check that you can be very sure is accurate, is with the transmitter antenna fully extended, and the aircraft supported on a (non metallic) stand that places the model about 2 ½ to 3 feet above the ground. Obviously this method has its logistical problems, you must have a friend, cell phones, and a ½ mile stretch of flat land you can easily move back and forth on, and is fairly isolated. With those prerequisites taken care of a very accurate reliable range check is a forgone conclusion.
There are a couple of radios that I am familiar enough with to be able to quote ground ranges with either the antenna removed "JR 10X" or antenna fully collapsed on the Futaba 9Z series. For these two types of Radio systems shorter distances will allow a slightly easier range check procedure.
NOTE: I still would do at least one Full antenna extended range check to verify all is OK.
With all RFI generating devices operating i.e. turbine running 300 feet is what you’re looking for. Some radio / turbine combinations are so poorly matched and setup that 100 to 120 feet is the maximum distance obtainable and still have a perfect RF link. You must in my opinion do whatever is necessary to get a minimum of 220 feet distance with a perfect RF link.
In the procedures below, I will describe the method that I use when doing a range check for a Turbine Powered Model Jet aircraft. The same range check methodology will work with any type of model. The ECU (electronic control unit) controls the operating parameters for the Jet turbine motor, most ECU's emit RFI (Radio Frequency Interference), other turbine components may create EMI (electro magnetic interference) i.e. the pump motor, electric fuel valves, etc. If you are checking other types of aircraft, powered let's say with a gasoline motor just substitute whatever on-board interference producing equipment your model might have, with the activation of the ECU, and starting of the turbine, in the range check described below.
Other methods of range checking, for instance, with the transmitter antenna collapsed, antenna off, or only one stage of antenna out, may be presumed to be adequate by some people, and even manufactures. I have found this type of range check certainly does not produce reliable distances that can in anyway be considered universal considering all radio brands! For example you ask one fellow and he says you should get at least 150 feet with the antenna off. O.K., but you own a Futaba, and you can’t take the antenna Off. The closest we could get to being universal, would be to quote ranges with ONE stage only extended. Well no one I know flies with the radio antenna that way number one, and number two, I’m not sure the RF radiation is the same amongst differing brands of radios with one stage of antenna extended. I haven’t had time to test enough different brands of radios to know for sure. The best and most universal range check is only done with the transmitter antenna fully extended. I don’t know about you, but when your model aircraft, a turbine powered Jet as an example, can cost more than 10 percent of the average annual income, it’s really better to know for sure, don’t you think
THE “REAL” RANGE CHECK!
1, With your model aircraft on a (non metallic) stand, approximately 2 1/2 or 3 feet off the ground, "preset your fail safe settings" too Elev. full up deflection and throttle to idle position.
NOTE: If you don't have a radio with a fail safe system, the movement of any control surface, even the slightest, can be substituted below for the full up or ratcheted movement of the elevator surface that is displayed when a PCM radio system begins to fail it's RF link. At this time set your (PCM) radio fail-safe so you have a full up elevator and throttle to idle reaction for a fail-safe condition.
2. Turn your transmitter ON and then your receiver only, at this time do not plug in the ECU power source. Then OFF the transmitter to check the fail-safe reaction of your Elev, it should be full up. If the fail-safe is working properly plug your ECU in, turn your transmitter and receiver ON and start your turbine, per all safety regulations, check to make sure the throttle fail safe is working. That's easy just turn OFF the transmitter the turbine should stay running and the Elev. should go to full up. If all is OK, shut the turbine down, and unplug the ECU.
3. Fully extend the transmitters antenna turning the transmitter and receiver ON. Have your friend drive out to a point 1/2 mile away, with the transmitter. He should be able to, while standing some distance form his vehicle, turn all around pointing the antenna up and down, away and pointed at you, and while doing that (little dance) have a solid RF link. You watch the Elev. closely for any full up deflections and also ask him to move the Elev. up and down fast, and evenly, you should see No lock outs or even small ratcheted movements during fast up and down Elev. movements. If your radio does not work perfectly at this distance, transmitter pointed all directions, then you are starting out with a radio that has some range problems, it needs alignment and tuning or has poor batteries!
You might have to go out even farther than 1/2 a mile, I have seen some radios get out as far as 8 tenths of a mile in this phase of the range check. The point is to find out what the maximum range is with just the radio and it's servo's operating. We will call this the "Baseline" NO ECU PLUGGED IN range.
4. Now plug in the ECU (turbine powered aircraft) or ( turn on strobe lights, camera's, start & run Gasoline engines (G-62s, etc.) turn on anything that may cause on-board RFI / EMI, and do the same check! Ok, all is still "perfect" and we are at the 1/2 mile or better range excellent!
If your aircraft is equipped with a turbine engine, per manufactures instructions, AMA wavier regulations, start you turbine. Yes, start your turbine with your buddy at the Baseline Max range. It’s kinda neat to do. If your radio locks up during the "start sequence" the turbine will continue to ramp up and complete its startup all by itself. "Remember", we set the fail safe to a throttle idle setting. Depending on the type of turbine you have, there maybe some momentary lockouts during the start sequence, some turbines have an electric starter motor that begins the ramp up, emitting even more RFI / EMI. If your radio locks up during the "start sequence only", and then comes back on line fully after ramp up all is fine. So now with everything on-board operating, do you still have a perfect RF link with a range of no less than 1/2 a mile or more?? Ok now go to full power!! – you still have a perfect RF link? If so you’re good to go! In the finial analysis what we are looking for is as close to zero difference in range between ECU unplugged and the turbine operating. If there is zero difference in range all you have to do now is go fly, you can be fully confident you have the best RF link our radio systems of today can provide.
5. You say there is a problem my radio locks up when I plugged in the ECU, or when the turbine started, and it wouldn’t come out of fail safe! If that is the case have your friend walk or drive back to-wards you until your radio comes back on-line solid! Have your friend do the transmitter dance again, if you can’t get a clean (lock out free) radio check at a "Minimum" of 4 tenths of a mile don’t fly until you correct what is wrong!
Fixing a bad RF link / short Range Check!
When turbine or other types of motors are running and you can’t get a clean range check of at least 4 tenths of a mile, you have a problem! If you own other receivers on different channels, try them or try routing the antenna to different locations. You might even try a WIP antenna (loaded or not). Try changing the Jux-a-position of the ECU, pump, ECU battery, electronic valves and your receiver. Try changing the receiver antenna type and location. It is possible one of these changes will improve the range enough to fix the problem. Try the complete range check from the start, that means with the motor shutdown. If you are running a turbine motor you will have to go clear back to step 3. If your radio now checks out fine at this distance, but locks up when you plug in the ECU, and or start the turbine you have a case of on-board EMI / RFI. Confronted with this dilemma you only have a few choices. If you find that despite all your efforts you still can’t get an adequate range check there is a great little tool that might help! The little Icom R-2 scanner. Refer to Joel’s Web site that will tell you how to obtain and use the R-2.
URL http://www.charlesriverrc.org/articl...r_icomicr2.htm
No room on in this posting to include my method of using the R-2 as a poor mans spectrum Analyzer if anyone is intestested I will post my notes on that in another posting.
Lee H. DeMary
AMA 36099
Radio manufactures do suggest different ways to do a range check ---------- I submit there is only one way to really do it correctly ----- to know for SURE that you have the strongest RF link possible, and one that will be reliable! Find below my notes on the Real Range Check -----------------
Range Check Preliminaries
The only way I have found to do a range check that you can be very sure is accurate, is with the transmitter antenna fully extended, and the aircraft supported on a (non metallic) stand that places the model about 2 ½ to 3 feet above the ground. Obviously this method has its logistical problems, you must have a friend, cell phones, and a ½ mile stretch of flat land you can easily move back and forth on, and is fairly isolated. With those prerequisites taken care of a very accurate reliable range check is a forgone conclusion.
There are a couple of radios that I am familiar enough with to be able to quote ground ranges with either the antenna removed "JR 10X" or antenna fully collapsed on the Futaba 9Z series. For these two types of Radio systems shorter distances will allow a slightly easier range check procedure.
NOTE: I still would do at least one Full antenna extended range check to verify all is OK.
With all RFI generating devices operating i.e. turbine running 300 feet is what you’re looking for. Some radio / turbine combinations are so poorly matched and setup that 100 to 120 feet is the maximum distance obtainable and still have a perfect RF link. You must in my opinion do whatever is necessary to get a minimum of 220 feet distance with a perfect RF link.
In the procedures below, I will describe the method that I use when doing a range check for a Turbine Powered Model Jet aircraft. The same range check methodology will work with any type of model. The ECU (electronic control unit) controls the operating parameters for the Jet turbine motor, most ECU's emit RFI (Radio Frequency Interference), other turbine components may create EMI (electro magnetic interference) i.e. the pump motor, electric fuel valves, etc. If you are checking other types of aircraft, powered let's say with a gasoline motor just substitute whatever on-board interference producing equipment your model might have, with the activation of the ECU, and starting of the turbine, in the range check described below.
Other methods of range checking, for instance, with the transmitter antenna collapsed, antenna off, or only one stage of antenna out, may be presumed to be adequate by some people, and even manufactures. I have found this type of range check certainly does not produce reliable distances that can in anyway be considered universal considering all radio brands! For example you ask one fellow and he says you should get at least 150 feet with the antenna off. O.K., but you own a Futaba, and you can’t take the antenna Off. The closest we could get to being universal, would be to quote ranges with ONE stage only extended. Well no one I know flies with the radio antenna that way number one, and number two, I’m not sure the RF radiation is the same amongst differing brands of radios with one stage of antenna extended. I haven’t had time to test enough different brands of radios to know for sure. The best and most universal range check is only done with the transmitter antenna fully extended. I don’t know about you, but when your model aircraft, a turbine powered Jet as an example, can cost more than 10 percent of the average annual income, it’s really better to know for sure, don’t you think
THE “REAL” RANGE CHECK!
1, With your model aircraft on a (non metallic) stand, approximately 2 1/2 or 3 feet off the ground, "preset your fail safe settings" too Elev. full up deflection and throttle to idle position.
NOTE: If you don't have a radio with a fail safe system, the movement of any control surface, even the slightest, can be substituted below for the full up or ratcheted movement of the elevator surface that is displayed when a PCM radio system begins to fail it's RF link. At this time set your (PCM) radio fail-safe so you have a full up elevator and throttle to idle reaction for a fail-safe condition.
2. Turn your transmitter ON and then your receiver only, at this time do not plug in the ECU power source. Then OFF the transmitter to check the fail-safe reaction of your Elev, it should be full up. If the fail-safe is working properly plug your ECU in, turn your transmitter and receiver ON and start your turbine, per all safety regulations, check to make sure the throttle fail safe is working. That's easy just turn OFF the transmitter the turbine should stay running and the Elev. should go to full up. If all is OK, shut the turbine down, and unplug the ECU.
3. Fully extend the transmitters antenna turning the transmitter and receiver ON. Have your friend drive out to a point 1/2 mile away, with the transmitter. He should be able to, while standing some distance form his vehicle, turn all around pointing the antenna up and down, away and pointed at you, and while doing that (little dance) have a solid RF link. You watch the Elev. closely for any full up deflections and also ask him to move the Elev. up and down fast, and evenly, you should see No lock outs or even small ratcheted movements during fast up and down Elev. movements. If your radio does not work perfectly at this distance, transmitter pointed all directions, then you are starting out with a radio that has some range problems, it needs alignment and tuning or has poor batteries!
You might have to go out even farther than 1/2 a mile, I have seen some radios get out as far as 8 tenths of a mile in this phase of the range check. The point is to find out what the maximum range is with just the radio and it's servo's operating. We will call this the "Baseline" NO ECU PLUGGED IN range.
4. Now plug in the ECU (turbine powered aircraft) or ( turn on strobe lights, camera's, start & run Gasoline engines (G-62s, etc.) turn on anything that may cause on-board RFI / EMI, and do the same check! Ok, all is still "perfect" and we are at the 1/2 mile or better range excellent!
If your aircraft is equipped with a turbine engine, per manufactures instructions, AMA wavier regulations, start you turbine. Yes, start your turbine with your buddy at the Baseline Max range. It’s kinda neat to do. If your radio locks up during the "start sequence" the turbine will continue to ramp up and complete its startup all by itself. "Remember", we set the fail safe to a throttle idle setting. Depending on the type of turbine you have, there maybe some momentary lockouts during the start sequence, some turbines have an electric starter motor that begins the ramp up, emitting even more RFI / EMI. If your radio locks up during the "start sequence only", and then comes back on line fully after ramp up all is fine. So now with everything on-board operating, do you still have a perfect RF link with a range of no less than 1/2 a mile or more?? Ok now go to full power!! – you still have a perfect RF link? If so you’re good to go! In the finial analysis what we are looking for is as close to zero difference in range between ECU unplugged and the turbine operating. If there is zero difference in range all you have to do now is go fly, you can be fully confident you have the best RF link our radio systems of today can provide.
5. You say there is a problem my radio locks up when I plugged in the ECU, or when the turbine started, and it wouldn’t come out of fail safe! If that is the case have your friend walk or drive back to-wards you until your radio comes back on-line solid! Have your friend do the transmitter dance again, if you can’t get a clean (lock out free) radio check at a "Minimum" of 4 tenths of a mile don’t fly until you correct what is wrong!
Fixing a bad RF link / short Range Check!
When turbine or other types of motors are running and you can’t get a clean range check of at least 4 tenths of a mile, you have a problem! If you own other receivers on different channels, try them or try routing the antenna to different locations. You might even try a WIP antenna (loaded or not). Try changing the Jux-a-position of the ECU, pump, ECU battery, electronic valves and your receiver. Try changing the receiver antenna type and location. It is possible one of these changes will improve the range enough to fix the problem. Try the complete range check from the start, that means with the motor shutdown. If you are running a turbine motor you will have to go clear back to step 3. If your radio now checks out fine at this distance, but locks up when you plug in the ECU, and or start the turbine you have a case of on-board EMI / RFI. Confronted with this dilemma you only have a few choices. If you find that despite all your efforts you still can’t get an adequate range check there is a great little tool that might help! The little Icom R-2 scanner. Refer to Joel’s Web site that will tell you how to obtain and use the R-2.
URL http://www.charlesriverrc.org/articl...r_icomicr2.htm
No room on in this posting to include my method of using the R-2 as a poor mans spectrum Analyzer if anyone is intestested I will post my notes on that in another posting.
Lee H. DeMary
AMA 36099
