Range issue, could use some help
04-04-2005 | 01:51 PM
#1
Range issue, could use some help
On my isobar went out to do a range check and here's the info I got and am confused.
Using PCM 10 channel the older style 955 dual conversion
with antenae off the 10x radio could only get about 15 feet from the airplane before failsafe engine on or off.
with regular 9 channel fm receiver could get about 60 feet antenae off.
The FM failed the "50 paces" test, but did pass 45 paces.
I moved the antenae on each receiver in every direction imagineable.
This is with a Merlin "FADEC" ecu. The throttle cable from teh ECU does have that ferrite coil thingy.
The pump is mounted about 12 inches from the receiver, the ecu is same distance away. The pump and ecu are mounted two inches apart, but I'm not sure the ECU has anything to do with it as with the turbine off (but not unplugged, didn't think to try that) still failed.
Some thoughts? I can take a picture of the install tonight if it will help.
Sean
PS, Wocket, I already know your suggestion, but I just bought a second 10x so don't see more than 10 channels in the near future
Using PCM 10 channel the older style 955 dual conversion
with antenae off the 10x radio could only get about 15 feet from the airplane before failsafe engine on or off.
with regular 9 channel fm receiver could get about 60 feet antenae off.
The FM failed the "50 paces" test, but did pass 45 paces.
I moved the antenae on each receiver in every direction imagineable.
This is with a Merlin "FADEC" ecu. The throttle cable from teh ECU does have that ferrite coil thingy.
The pump is mounted about 12 inches from the receiver, the ecu is same distance away. The pump and ecu are mounted two inches apart, but I'm not sure the ECU has anything to do with it as with the turbine off (but not unplugged, didn't think to try that) still failed.
Some thoughts? I can take a picture of the install tonight if it will help.
Sean
PS, Wocket, I already know your suggestion, but I just bought a second 10x so don't see more than 10 channels in the near future
04-04-2005 | 02:28 PM
#3
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RE: Range issue, could use some help
I thought the 955 was a single conversion and the 945 was a dual conversion.
Are you using any match boxes? We had one that went bad and we couldn't get more than about 20 feet away before going into failsafe.
Start unplugging leads from your RX one at a time to see if you can isolate any of those items as the cause. Make sure all of your battery leads are run as far as possible away from the fuel pump wiring.
Are you using any match boxes? We had one that went bad and we couldn't get more than about 20 feet away before going into failsafe.
Start unplugging leads from your RX one at a time to see if you can isolate any of those items as the cause. Make sure all of your battery leads are run as far as possible away from the fuel pump wiring.
04-04-2005 | 02:53 PM
#4
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RE: Range issue, could use some help
Gotta agree with Dan:
(a) the 955 is single conversion, 945 is dual
(b) in general the approach should be to start unplugging stuff until you make a difference. When you do see a difference though, don't just assume that the last thing you unplugged was necessarily the culprit - i.e if you unplug your ECU followed by 4 servos before you see an improvement, then don't just assume the last servo to be unplugged was it - plug the other components back in again to confirm whether the problem lies with the last item unplugged, or is a more insiduous compound problem.
Gordon
04-04-2005 | 03:11 PM
#6
RE: Range issue, could use some help
No match boxes. Nine channels used
throttle
aileron
elevator with a Y (8611's one reversed)
Rudder
Gear (regular robart mechanical) with servo
Flap servo 1 8411
Brakes (clippard momentary push button type)
Flap servo 2 (I think on this channel, again 8411
Steering servo aux 4.
No match box was necessary, although my last isobar had two.
throttle
aileron
elevator with a Y (8611's one reversed)
Rudder
Gear (regular robart mechanical) with servo
Flap servo 1 8411
Brakes (clippard momentary push button type)
Flap servo 2 (I think on this channel, again 8411
Steering servo aux 4.
No match box was necessary, although my last isobar had two.
04-04-2005 | 05:36 PM
#9
RE: Range issue, could use some help
I'm on a LIPO pack through a regulator, same setup I had in my Eurofighter, same setup I had in my F-15. I just don't get it, but will try to isolate by suggestions above. Weird that 6 volt would do that, what was your solution?
04-04-2005 | 05:57 PM
#10
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RE: Range issue, could use some help
There was a thread on here a couple of years ago about range problems. Several people stated that they had had range problems on 5 cell nicad packs that went away by just adding a regulator or dropping down to a 4 cell pack. The problem seemed to be related to the pack being fresh off the charger and thus quite a bit more than 6V.
I know a lot of guys are using unregulated 5 cell packs with no problems, but evidently it can cause problems in some setups. I wouldn't think that a LiPo or LiIon pack regulated at 6V would cause the same range problem, but you might want to try a nicad pack just for grins.
I know a lot of guys are using unregulated 5 cell packs with no problems, but evidently it can cause problems in some setups. I wouldn't think that a LiPo or LiIon pack regulated at 6V would cause the same range problem, but you might want to try a nicad pack just for grins.
04-04-2005 | 06:06 PM
#13
RE: Range issue, could use some help
I did that also on Saturday. But I have categorically on every airplane I've ever ranged checked been able to get 50 to 55 paces with my 10x with no antenae. This time I got 12 steps. To me, that's just a freaken problem any way you cut it. I did range check it with the antenae on and I did get 50 paces roughly with the antenae on, but to me, it's just masking a problem and I'm not willing to fly the jet with that.
I will say that with the FM receiver, I decided to try a test flight with the 40 paces no antenae but unfortunately my airplane veered off the runway on take off, threw gear and other parts off the airplane, so the day was lost anyway. I actually made a whole new wing for the airplane yesterday and will have it back in the condition it was before this weekend, but since I'm going through the airplane all over again, thought I'd go ahead and work the range issue as best as can be done.
I will say that with the FM receiver, I decided to try a test flight with the 40 paces no antenae but unfortunately my airplane veered off the runway on take off, threw gear and other parts off the airplane, so the day was lost anyway. I actually made a whole new wing for the airplane yesterday and will have it back in the condition it was before this weekend, but since I'm going through the airplane all over again, thought I'd go ahead and work the range issue as best as can be done.
04-04-2005 | 06:15 PM
#14
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RE: Range issue, could use some help
Sean,
All the stupid questions...was it a good RX before you put in in the bar? With all the rough handling of installation (plugs in/plugs out..drop it a couple of times when it falls out of the fuse etc it may be broken) Just ask me how I know these things. Another thing that I didnt know until recently is the dual conversion rx's require a special crystal, if you've changed crystals check that. I always range check with the TX antenna installed but down with the RX antenna and the TX antenna pointed at each other (the worst possible case). After I get a good check there I do a antenna up and walk as far away as it will work.(Thats why Seguin is a good place to test fly..you can walk all the way to Gonzales for your range check. Then I start all over again with the motor running and compare. My idea is if I cant see my airplane any more it is a good check. For this one I place the running motor between me and the RX antenna to get the worst case, again with the RX antenna pointed at the TX. If you dont get a good check with the ecu/pump/motor off I would call it your Rx, especially with the antenna out of the airplane. Another thing is set the plane on a plastic box,table etc to get it away from the ground for the motor off checks. I suspect a broken/loose crystal in the RX. For my Hawk I'm trying a Revolution antenna mounted inside the fuse, no range check yet though, gotta get my motor back and installed first.
Tom
All the stupid questions...was it a good RX before you put in in the bar? With all the rough handling of installation (plugs in/plugs out..drop it a couple of times when it falls out of the fuse etc it may be broken) Just ask me how I know these things. Another thing that I didnt know until recently is the dual conversion rx's require a special crystal, if you've changed crystals check that. I always range check with the TX antenna installed but down with the RX antenna and the TX antenna pointed at each other (the worst possible case). After I get a good check there I do a antenna up and walk as far away as it will work.(Thats why Seguin is a good place to test fly..you can walk all the way to Gonzales for your range check. Then I start all over again with the motor running and compare. My idea is if I cant see my airplane any more it is a good check. For this one I place the running motor between me and the RX antenna to get the worst case, again with the RX antenna pointed at the TX. If you dont get a good check with the ecu/pump/motor off I would call it your Rx, especially with the antenna out of the airplane. Another thing is set the plane on a plastic box,table etc to get it away from the ground for the motor off checks. I suspect a broken/loose crystal in the RX. For my Hawk I'm trying a Revolution antenna mounted inside the fuse, no range check yet though, gotta get my motor back and installed first.
Tom
04-04-2005 | 07:43 PM
#15
RE: Range issue, could use some help
Sean, have you changed the receiver to determine if the problem is on it or something related to
the airframe installation? another way to test a receiver is installing it on a cheap plane. if it
could return to base, the rx is OK. if not, you have already got rid of the problem.
p.s. don't point the test plane south!
Enrique
the airframe installation? another way to test a receiver is installing it on a cheap plane. if it
could return to base, the rx is OK. if not, you have already got rid of the problem.
p.s. don't point the test plane south!
Enrique
04-04-2005 | 07:47 PM
#16
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From: SeaTac - Angle Lake, WA
RE: Range issue, could use some help
Question for everyone in this thread, What kind of antenna is being used and how is it routed?
I had all kinds of noise and range problems with my jet until switching to a Revolution Whip and it all cleared up. Wondering if this may be the same thing? The pump and ECU bleed with RF and if your antenna is anywhere close to those two items it could possibly explain the difficulty.
My 2 cents...
Cheers,
I had all kinds of noise and range problems with my jet until switching to a Revolution Whip and it all cleared up. Wondering if this may be the same thing? The pump and ECU bleed with RF and if your antenna is anywhere close to those two items it could possibly explain the difficulty.
My 2 cents...
Cheers,
04-04-2005 | 08:41 PM
#18
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RE: Range issue, could use some help
Do a good range check with the ECU unplugged! With your receiver / airplane about 3 feet above the ground on an wood / plastic stand You should be able to walk about 100 paces or about 300 feet, in any case not less than 225 feet. And yes that is with the antenna removed on the 10X! If you want to have the antenna screwed in place fully collapsed then your looking at about 200 paces or 600 plus feet! Turn the transmitter in all directions and see no fail-safes.
If you can't get this kind of baseline range check send the junk receiver and transmitter module in for match tuning & alignment. Ask them to not send it back until it will range check at least the 300 / 600 feet. This crap about 50 or 100 feet is just that... radio manufactures and more importantly resellers advertise those low distances because.... they want fewer returns for warranty repair!! Beg my pardon but I call um like I see um...
OK, then do the same test with ECU plugged in..... what distances do you get?
Then start the turbine and run-up to full power.... do the same test... never but never fly if the degradation is more than about 25% in distance.... use a whip antenna move the fuel pump farther away from any receiver wiring or antenna.... until you can get no more than a 25% degradation in range from your established baseline...
If you really want to get serious do the range check with the transmitter antenna fully extended. The normal best baseline will be about 1/2 mile! Yep thats way farther than you can see to fly! The average radio / RF link will get at least 2000 feet or slightly less than 4 tens of a mile. In no case should you fly if this full extended range check at full power checks out at less than about 1600 feet!
Lee H. DeMary
AMA 36099
If you can't get this kind of baseline range check send the junk receiver and transmitter module in for match tuning & alignment. Ask them to not send it back until it will range check at least the 300 / 600 feet. This crap about 50 or 100 feet is just that... radio manufactures and more importantly resellers advertise those low distances because.... they want fewer returns for warranty repair!! Beg my pardon but I call um like I see um...
OK, then do the same test with ECU plugged in..... what distances do you get?
Then start the turbine and run-up to full power.... do the same test... never but never fly if the degradation is more than about 25% in distance.... use a whip antenna move the fuel pump farther away from any receiver wiring or antenna.... until you can get no more than a 25% degradation in range from your established baseline...
If you really want to get serious do the range check with the transmitter antenna fully extended. The normal best baseline will be about 1/2 mile! Yep thats way farther than you can see to fly! The average radio / RF link will get at least 2000 feet or slightly less than 4 tens of a mile. In no case should you fly if this full extended range check at full power checks out at less than about 1600 feet!
Lee H. DeMary
AMA 36099
04-04-2005 | 09:36 PM
#19
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RE: Range issue, could use some help
Lee has hit it on the range check. Start with the ECU unplugged and see where you are at. If the receiver antenna was coiled up during the check then that could be the biggest problem. I am really hoping that pic was taken during the gear up process and you didn't forget to unwrap the antenna.
Also my first guess is try a new receiver. I am not able to tell if that is a 940 receiver, but if it is they were not necessarily known for being the best in that series. The old 950 (even though a single conversion receiver) was much better in the turbine environment over the 940. The newer 945 is ten times better than the old 940. I would try switching to one of the newer receivers and see what you get. I normally see at least 100 paces with engine running and antenna removed from the tranasmitter. But I will say that I am at a very clean RF field.
I have no experience with the Merlin you are running but am guessing the ECU probably isn't the big culprit here. I am staying with the receiver right now as my guess.
Also my first guess is try a new receiver. I am not able to tell if that is a 940 receiver, but if it is they were not necessarily known for being the best in that series. The old 950 (even though a single conversion receiver) was much better in the turbine environment over the 940. The newer 945 is ten times better than the old 940. I would try switching to one of the newer receivers and see what you get. I normally see at least 100 paces with engine running and antenna removed from the tranasmitter. But I will say that I am at a very clean RF field.
I have no experience with the Merlin you are running but am guessing the ECU probably isn't the big culprit here. I am staying with the receiver right now as my guess.
04-04-2005 | 09:41 PM
#20
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RE: Range issue, could use some help
Well Sean, you did indeed squelch my first suggestion! See if you can eliminate pi_s poor antenna routing by using a non-conductive rod (a wood dowel perhaps) to put the antenna vertical, as in a full length whip, and placed away from ECU, batteries, servos, etc.
I would not think the issue is with the FADEC. I have never had any radio issue with them with the MPX 12 channel stuff. Always a chance that you got a bad one that is bleeding some weird RF. Can you increase the range by unplugging the ECU?
I would not think the issue is with the FADEC. I have never had any radio issue with them with the MPX 12 channel stuff. Always a chance that you got a bad one that is bleeding some weird RF. Can you increase the range by unplugging the ECU?
04-04-2005 | 10:56 PM
#21
RE: Range issue, could use some help
Ok, I have narrowed it down. I switched crystals, switched receivers, switched transmitters etc. All having the same effect. Then I simply unplugged everything but the elevator, no effect elevator sits there and jiggles a little bit and sometimes had to do with my personal proximity to the model.
Then I grabbed a hitec receiver and pluged a battery in it and a digital servo and started waving the receiver all around the model while my transmitter sat on the table across the room (on).
No servo glitch no nothing till I started waving it around the control panel I built (for photo you might need to go over to isobar build thread. This is the first time I've used a clippard brake valve, but on that panel I have the following and I could not narrow it down to each item (but I will when I start taking them out of the panel one at a time). I have there a robart retract valve, a small hitec 85 bb metal servo, a hitec 5645 digital servo to hit the BVM made clippard control deal for brakes. I also have a jetcat fuel filter on my propane line (which I did notice the glitch happened for sure when I touched the filter with the hitec receiver) I also have my propane solenoid and fuel solenoid on that panel. I'll see if I can get a pic up of this tomorrow evening. I may be able to post some video as well. But it appears I have some RF stuff coming off this panel for sure cause if I put the receiver on the ass of the airplane, no glitch no nothing.
And yes, I had the ant. installed as per my old Isobar, a loop forward towards the nose, and looped around and back so the whole ant. was in the nose, however, that was the first thing I pulled out when I failed, I put that ant in every direction but up as Wocket suggested. I know it is an older style receiver, but it has been sent to JR and was tuned to my module, but, something about two receivers on different channels suggests it's THIS install rather than anything else as I've indicated above.
Then I grabbed a hitec receiver and pluged a battery in it and a digital servo and started waving the receiver all around the model while my transmitter sat on the table across the room (on).
No servo glitch no nothing till I started waving it around the control panel I built (for photo you might need to go over to isobar build thread. This is the first time I've used a clippard brake valve, but on that panel I have the following and I could not narrow it down to each item (but I will when I start taking them out of the panel one at a time). I have there a robart retract valve, a small hitec 85 bb metal servo, a hitec 5645 digital servo to hit the BVM made clippard control deal for brakes. I also have a jetcat fuel filter on my propane line (which I did notice the glitch happened for sure when I touched the filter with the hitec receiver) I also have my propane solenoid and fuel solenoid on that panel. I'll see if I can get a pic up of this tomorrow evening. I may be able to post some video as well. But it appears I have some RF stuff coming off this panel for sure cause if I put the receiver on the ass of the airplane, no glitch no nothing.
And yes, I had the ant. installed as per my old Isobar, a loop forward towards the nose, and looped around and back so the whole ant. was in the nose, however, that was the first thing I pulled out when I failed, I put that ant in every direction but up as Wocket suggested. I know it is an older style receiver, but it has been sent to JR and was tuned to my module, but, something about two receivers on different channels suggests it's THIS install rather than anything else as I've indicated above.
04-05-2005 | 12:03 AM
#22
RE: Range issue, could use some help
Sean, You said:
How did you REVERSE the 8611? I have a buddy who builds a lot of "turn-key" IMAC airplanes for guys and he told me that those Y-harnesses that can reverse a servo can cause range problems. He won't install them any more. I had a serious lock-out in the air with my little Viggen. Luckily I was able to get it back and go through it. I removed the Y-harness and re-programmed one Hitec servo on one flap to be reversed. I also changed the RX AND module...........the problem went away! I know that I changed a lot, to say that it was the harness, but that's my $.02 worth.
Good luck,
John
ORIGINAL: seanreit
No match boxes. Nine channels used
throttle
aileron
elevator with a Y (8611's one reversed)
Rudder
Gear (regular robart mechanical) with servo
Flap servo 1 8411
Brakes (clippard momentary push button type)
Flap servo 2 (I think on this channel, again 8411
Steering servo aux 4.
No match box was necessary, although my last isobar had two.
No match boxes. Nine channels used
throttle
aileron
elevator with a Y (8611's one reversed)
Rudder
Gear (regular robart mechanical) with servo
Flap servo 1 8411
Brakes (clippard momentary push button type)
Flap servo 2 (I think on this channel, again 8411
Steering servo aux 4.
No match box was necessary, although my last isobar had two.
How did you REVERSE the 8611? I have a buddy who builds a lot of "turn-key" IMAC airplanes for guys and he told me that those Y-harnesses that can reverse a servo can cause range problems. He won't install them any more. I had a serious lock-out in the air with my little Viggen. Luckily I was able to get it back and go through it. I removed the Y-harness and re-programmed one Hitec servo on one flap to be reversed. I also changed the RX AND module...........the problem went away! I know that I changed a lot, to say that it was the harness, but that's my $.02 worth.
Good luck,
John
04-05-2005 | 06:17 AM
#23
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RE: Range issue, could use some help
ORIGINAL: seanreit
Ok, I have narrowed it down. I switched crystals, switched receivers, switched transmitters etc. All having the same effect. Then I simply unplugged everything but the elevator, no effect elevator sits there and jiggles a little bit and sometimes had to do with my personal proximity to the model.
Then I grabbed a hitec receiver and pluged a battery in it and a digital servo and started waving the receiver all around the model while my transmitter sat on the table across the room (on).
No servo glitch no nothing till I started waving it around the control panel I built (for photo you might need to go over to isobar build thread. This is the first time I've used a clippard brake valve, but on that panel I have the following and I could not narrow it down to each item (but I will when I start taking them out of the panel one at a time). I have there a robart retract valve, a small hitec 85 bb metal servo, a hitec 5645 digital servo to hit the BVM made clippard control deal for brakes. I also have a jetcat fuel filter on my propane line (which I did notice the glitch happened for sure when I touched the filter with the hitec receiver) I also have my propane solenoid and fuel solenoid on that panel. I'll see if I can get a pic up of this tomorrow evening. I may be able to post some video as well. But it appears I have some RF stuff coming off this panel for sure cause if I put the receiver on the ass of the airplane, no glitch no nothing.
And yes, I had the ant. installed as per my old Isobar, a loop forward towards the nose, and looped around and back so the whole ant. was in the nose, however, that was the first thing I pulled out when I failed, I put that ant in every direction but up as Wocket suggested. I know it is an older style receiver, but it has been sent to JR and was tuned to my module, but, something about two receivers on different channels suggests it's THIS install rather than anything else as I've indicated above.
Ok, I have narrowed it down. I switched crystals, switched receivers, switched transmitters etc. All having the same effect. Then I simply unplugged everything but the elevator, no effect elevator sits there and jiggles a little bit and sometimes had to do with my personal proximity to the model.
Then I grabbed a hitec receiver and pluged a battery in it and a digital servo and started waving the receiver all around the model while my transmitter sat on the table across the room (on).
No servo glitch no nothing till I started waving it around the control panel I built (for photo you might need to go over to isobar build thread. This is the first time I've used a clippard brake valve, but on that panel I have the following and I could not narrow it down to each item (but I will when I start taking them out of the panel one at a time). I have there a robart retract valve, a small hitec 85 bb metal servo, a hitec 5645 digital servo to hit the BVM made clippard control deal for brakes. I also have a jetcat fuel filter on my propane line (which I did notice the glitch happened for sure when I touched the filter with the hitec receiver) I also have my propane solenoid and fuel solenoid on that panel. I'll see if I can get a pic up of this tomorrow evening. I may be able to post some video as well. But it appears I have some RF stuff coming off this panel for sure cause if I put the receiver on the ass of the airplane, no glitch no nothing.
And yes, I had the ant. installed as per my old Isobar, a loop forward towards the nose, and looped around and back so the whole ant. was in the nose, however, that was the first thing I pulled out when I failed, I put that ant in every direction but up as Wocket suggested. I know it is an older style receiver, but it has been sent to JR and was tuned to my module, but, something about two receivers on different channels suggests it's THIS install rather than anything else as I've indicated above.
Then after you establish the fact that your baseline is within normal range, go directly to rec. antenna placement. Hang the receiver antenna out of the airplane as far as possible and do a range check, is there a difference now? Receiver antenna and pump location should be as far apart as possible! I would be surprised if the receiver antenna re-location wouldn't make a big change. Keep in mind no more than a 25% degradation from baseline..
Lee
04-05-2005 | 06:31 AM
#24
RE: Range issue, could use some help
John, I bought a "reversed" 8611, I would never use a reversing device, however, sometimes I reverse a servo by creating a mix in my radio. On this jet there was no need to do that as I simply bought the "right" servo in the first place.
Lee, I wish I could answer your question, but I'm not sure I understand it. Can you elaborate on what you mean by baseline?
Lee, I wish I could answer your question, but I'm not sure I understand it. Can you elaborate on what you mean by baseline?
04-05-2005 | 06:35 AM
#25
RE: Range issue, could use some help
ok, you edited the question and it is now within my understanding. With the PCM receiver the baseline was 12 steps, while previously on all airplanes it was a miniumum of 50 to 55 paces. With PPM, last night simply placing the transmitter on a table maybe 20 feet from the airplane with an 8103 transmitter ant. down, I was getting servo jitter in the airplane with the ant. in some positions but not all positions. Then I started the test by placing a receiver and a servo all over the airplane to help determine where the noise was coming from. Tonight I will start removing items from my control panel to see when the noise goes away.
Sean
Sean
