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RC Radios, Transmitters, Receivers, Servos, gyros Discussion all about rc radios, transmitters, receivers, servos, etc.

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Old 05-01-2012, 06:57 AM   #1
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Unhappy Losing my confidence in Spektrum

My giant scale Cessna 182. It sure was a beautiful aircraft. Now it's in a bag, and I'm pretty sure I can thank Spektrum. This is the second plane I've lost on Spektrum.

I have a DX6i, and when I first got it, I loved it. I was a really big Spektrum fan for a long time. Now I'm losing my confidence.

The first was a small L-39. Pulling out of a shallow dive there was no reponse. I could hear the edf unit still running at my commanded power setting, but there was simply no response to stick inputs. Flew itself at high speed into a bush ripping it to pieces, but the fusealage was still intact except for the nose wich was ripped out due the battery continuing flight after the aircraft had stopped. After retrieval, the radio system worked fine. Totally unexplainable loss of control. Rx was a 6110e (before DSMX). Since I was one of only two people airborne, and the other guy was on 72mHz, I doubt DSMX would have made any difference. This happened right in front of me at only 100ft seperation between me and the aircraft. It was not a transmitter antenna orientation issue. I learned that lesson long ago. I always fly with my transmitter antenna pointed straight up overhead.

My giant 182 was purpose built for reliability. I invested a huge amount of money and took every precaution I could afford. I used an AR6210-X with satellite. (I understand that using an X receiver with a non-X transmitter means you are still flying regular old DSM2.) Antennas were oriented in 90 degree offset planes and were placed against the fuse side and bottom so only a 1/16 sheet of balsa and the monokote separated the antennas from the signal.. I used a 6V 2200mAh Nimh receiver battery to not rely on the BEC of the ESC in case the ESC fried. The receiver battery was charged up the night before the flight and showed 7.02V after a 6 hour .2mAh trickle. (I had done a 16 hr on it the previous week and only flew the plane twice after that charge.) The receiver was 2 feet away from the ESC and 1 foot away from the closest battery wire. Every extension wire coupling was tested with an ohmmeter after using CA to make sure no separation could possibly occur. The servos were not high current draw. Hitec HS-485HB. (It was, after all, only a Cessna and not a 3D monster so it didn't need anything more). The on/off/charge switch was tested before installation for any voltage drop across the contacts and only extremely minimal amounts could be detected, when I could detect any at all. Wire guage was ample to carry the current. Receiver was checked before and after each flight (all 5 I got to make) for blinkies with no indications of a problem.

Until last weekend. Airborne for 2 minutes and turning base for a touch and go, stick inputs became meaningless. The aircraft was flying itself, and as we all know, that is a bad thing. I prayed to regain control but could only watch as it rolled over and augered in. Hard. There was nothing left of the receiver battery to test, but I know it was in very good shape and could have easily supported 2 or 3 flights that day if not 10 were I a reckless builder and pilot. The receiver, however, in the rear cargo area, survived completely with all its connections perfectly intact including the one to the shredded end which used to be soldered onto the receiver battery. Bench testing today showed the receiver to be working perfectly. All servos tested fine as well eliminating a stuck or shorted servo that would draw huge current. Again, a totally unexplainable loss of control.

(BTW, I'm impressed with the Hitec HS-485HB. After a total loss high speed impact crash, not one of them even popped a tooth much less needed rebuilding with a new gearset.)

So I'm losing my confidence in Spektrum. Your pre-flight check should NOT have to contain a step wherein you remind yourself that even though you do everything right, there's still a 1/2% chance that you'll simply be disconnected from your aircraft and have to watch it be destroyed.

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Old 05-01-2012, 09:39 AM   #2
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I had the same type of thing happen to me, but I decided it was the off brand receiver, not the radio. To be honest I am all that impressed with the spectrum stuff, especially when a full range with satelite is roughly half the range of my $10 parkflyer knock off.

I had been doing touch and goes all day, probably at least an hour, ran through a few batteries. I was landing in about a 45 degree crosswind (I enjoy crosswind landings.) And I let go of the rudder a bit to let it weathervane a bit, and it just kept turning, and turning, and turning. I was glad I had no power onto the motor, because every control I had was completely dead. My father was sure I was just blaming a glitch, untill as I was walking up to the plane, still no movement. I knocked off the landing gear, but nothing else was damaged. I was actually flairing it, if I hadn't been, I think the plane would have landed itself. Turning the radio on and off several times did nothing. Unpluging and plugging the battery for the plane in instantly gave me servo movement. I did several range tests, even though I knew it wasn't range related. It was maybe 40 ft away when it went awol.

I didn't think to check my battery voltage, but I did a full power pull for 30 seconds, with no noticeable degriation. I figure I still had half my flying to do before I would hit lvc (3.7v's). Where I had my hands off, no motor pull and no servo movement, I don't see how it could have been a brown out. Although I am using the esc bec to power the receiver. So I guess it is possible that the bec overheated.

Other people on this forum brought up that the software on the receiver can hang up, but has a program to watch it, so it will restart on failure. I'm guessing my $10 receiver doesn't have this feature or it didn't work. I had probably close to 50 hours on it without a glitch. For now, I have swapped back to a spectrum brand 6 channel parkflyer. Thi is just my little eflight alpha 450 trainer.
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Old 05-01-2012, 05:02 PM   #3
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I've got a suspicion that many of the radio failures that get blamed on spektrum gear are in fact due to inadequate BEC power on ESC's if the power from the BEC fails then you have no control regardless of brand of radio gear. A stalled or faulty servo can also cause even a good BEC too shut down. A faulty servo was the cause of the only radio failure I've ever experienced with Spektrum gear.

I've no idea if this was the cause of your accidents but it may be premature to just the the conclusion that it was a Spektrum problem.

What ESC's / BEC's were you using?

Steve
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Old 05-01-2012, 05:19 PM   #4
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Anything small I'll fly with Spektrum. Anything large I fly with Futaba ONLY. Been in this hobby a long time, have seen and been involved with out of control planes. Anything over a pound gets the best I can afford. Futaba has been in the 2.4 business with cranes for around 30 years. If they trust their stuff to lift up hundreds of thousands of pounds when people's lives are on the line that's good enough for me.

I don't work for nor am I involved with Futaba in any way. Just my 0.02 worth.

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Old 05-01-2012, 05:20 PM   #5
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I would copy and paste exactly what you wrote into an email to customer support at Spektrum. They are known for taking customer feedback seriously and I'm sure they'll offer to bring your tx/rx in for investigation and possibly repair/software upgrade free of charge.

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Old 05-01-2012, 05:50 PM   #6
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Originally Posted by NJSwede View Post
I would copy and paste exactly what you wrote into an email to customer support at Spektrum. They are known for taking customer feedback seriously and I'm sure they'll offer to bring your tx/rx in for investigation and possibly repair/software upgrade free of charge.
What about his planes? The word that I really dislike from a manufacture is going to be .......Sorry.

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Old 05-01-2012, 05:52 PM   #7
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Originally Posted by airmail wf View Post
Anything small I'll fly with Spektrum. Anything large I fly with Futaba ONLY. Been in this hobby a long time, have seen and been involved with out of control planes. Anything over a pound gets the best I can afford. Futaba has been in the 2.4 business with cranes for around 30 years. If they trust their stuff to lift up hundreds of thousands of pounds when people's lives are on the line that's good enough for me.

I don't work for nor am I involved with Futaba in any way. Just my 0.02 worth.
Airmail,

Thanks for posting. I'm one of the few Futaba guys in our club and sometimes feel like the lone wolf. Somethings are reversed between Futaba and Spektrum so I'm careful about asking a programming question to a Spektrum pilot or answering a programming question.
What's a plus value in Spektrum can be a minus value for Futaba.

I do think Futaba might have dropped the ball with the masses a few years back. More or less a price point thing. Seemed they focused more on the high end. Kind of like Mercedes owners versus Ford owners.

No doubt there's lots of really good computer radios out there and I'm never critical of what someone else is using. Spektrum has some nice creature features like model id. I have the 6EX which is as basic as it gets for the Fasst TX series. Next up will be probably be the 8FG or if I win the lottery, the 14MZ.

Great quality, can't go wrong with Futaba

Nice to know I'm not alone !

Hawk

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Old 05-01-2012, 05:55 PM   #8
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There has been stories about Spektrum helping people in various ways to get back in the air. I only have second hand accounts, but if you search Wattflyer, you'll find a few. My only point is that it's worth five minutes of effort to reach out to Spektrum and ask them what they are willing to do to make things right. Not trying to be a fan boy here.

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Old 05-01-2012, 06:43 PM   #9
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Your losses are tragic. I've used Spektrum since the DX-7 hit the market, and I had only one loss, likely due to a badly planned power system. I now use a DX-8 and love it. But, I also use a Hitec A-9, and probably would for anything over two pounds or so: not because I've had an issue, but because I fear one based on reports like this one.

Again, your losses are tragic.
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Old 05-01-2012, 07:00 PM   #10
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First off, sorry for your loss. I have the Top Flite Gold edition Cessna 182 ARF as well. Gorgeous plane.

The only thing I see that you did not do was to do a load test on the receiver battery.

I lost a 1/4 scale beauty one day with a full charged 6v battery for the receiver. I too was pissed about my DSM setup that had even been upgraded to DSMX both Tx and Rx. I was ready to kick that damn transmitter across the field.

I went out to retrieve the plane and once I got it back started looking for other culprits. Rx batter fully charged but when placed under a 1.5 amp load voltage dropped to 2.8v. Bad cell in the pack. This happened about 4 minutes into the flight.

Now I run redundant A123 packs for the radio gear.

I found my confidence once again in DSMx and just got back from SEFF, lessons learned, and no lockouts or mishaps. Flew all day and well into the night most days and there was 402 pilots that showed up to fly, play with boats, and run cars all over the grounds. Not to mention all the cell phone, Mi-fi- Wi-Fi, Satellite TV, FPV flyers and all other sorts of electrical noise. Not a single issue the entire week.

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Old 05-01-2012, 07:23 PM   #11
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My problem with spectrum, its not new technology, its not even really special in anyway. But it is cheap. It feels cheap, its made in the same types of places the $10 receiver is, and I think the $10 might be better. It definately is on price and range. If I had a ubec on the plane or battery pack to blame spectrum completely, I would feel differently about it. I didn't have a servo bind, I didn't have low voltage. I seriously doubt a brown out could have happened. But then again, if that's what spektrum blames it on and everyone else buys it, that's the way it is.

My esc's bec changed from 5.02v's to 4.98v's with full throttle on a low battery and all 4 micro servo's moving for over 30 seconds. Just for fun I tested it with some old full sized futaba servo's, and it droped a bit more, but it was still over 4.90v's. Really not sure how much weight I want to add to a less then 2 pound park flyer to feel like my spectrum gear is safe. If everything else on the plane functions perfectly well and only the radio "browns out", then who's fault is it really? I don't think any of us go out to fly expecting a brown out or not trying to prevent it, if its a 1/4 scale or a parkflyer. Imagine if my plane was wot when I lost my plane or if it was at a feild with others?

Part of the reason I swapped to the $10 receiver, I could hear my motor taking forever to respond to inputs when it was far away. This tipped me off to the fact that my servo's were getting jittery, and I could easily see my plane (6channel spektrum dsm2 full range with satelite) further hen I could fly it. The $10 receiver fixed this, and there is evidence of it happening with my parkflyer spectrum receiver. I would rather fly close then see if I can lose radio signal where I might have a hard time flying the plane. Range test is the same 31-33 paces as the full range. I've gotten over 50 for the $10 one, without jitter or a drop in response, and called that good enough.

My radio is a dx6I, spectrum brand batteries always fully charged when I go out, with a new antenna. Unless there is a problem with the radio, which I doubt.
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Old 05-01-2012, 08:20 PM   #12
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Originally Posted by dahawk View Post
Airmail,

Thanks for posting. I'm one of the few Futaba guys in our club and sometimes feel like the lone wolf. Somethings are reversed between Futaba and Spektrum so I'm careful about asking a programming question to a Spektrum pilot or answering a programming question.
What's a plus value in Spektrum can be a minus value for Futaba.

I do think Futaba might have dropped the ball with the masses a few years back. More or less a price point thing. Seemed they focused more on the high end. Kind of like Mercedes owners versus Ford owners.

No doubt there's lots of really good computer radios out there and I'm never critical of what someone else is using. Spektrum has some nice creature features like model id. I have the 6EX which is as basic as it gets for the Fasst TX series. Next up will be probably be the 8FG or if I win the lottery, the 14MZ.

Great quality, can't go wrong with Futaba

Nice to know I'm not alone !

Hawk
Hawk you are hardly alone. Futaba sells a lot of radios. I have tried many radios and I still have different ones. My first radio was a futaba about 30 years ago. It cost me if I remember correctly about 300 dollars. I still us this radio with an XPS module. I waited for the 8FG radio from Futaba to come out with because it uses the high end software. This radio I got for $425. I fully expect to get 30 years out of this one also. My reasoning was purely because of Futaba's quality and the fact they have been working with 2.4 for so many years in there crane division. One other thing Futaba is such a big company they make their own chips for there radios. So they control all their quality. Thats a big plus when I'm flying something that can cause harm to someone.

I would never let anyone bother me because I use something different then they do. We would be riding horses to work and cleaning up crap from city streets if that were the case.

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Old 05-01-2012, 09:14 PM   #13
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Originally Posted by JetPlaneFlyer View Post
I've got a suspicion that many of the radio failures that get blamed on spektrum gear are in fact due to inadequate BEC power on ESC's if the power from the BEC fails then you have no control regardless of brand of radio gear. A stalled or faulty servo can also cause even a good BEC too shut down. A faulty servo was the cause of the only radio failure I've ever experienced with Spektrum gear.

I've no idea if this was the cause of your accidents but it may be premature to just the the conclusion that it was a Spektrum problem.

What ESC's / BEC's were you using?

Steve
Go back and read first guys post - he was using SEPARATE Rx pack .... NOT a BEC.

One point though - I disagree with his antena orientation statement of straight UP antena ... I have been informed by a radio tech and also via reading various forums that a 2.4Ghz antena should be horizontal in line with top of Tx as that is usually the orientation horizontal of the models Rx antena.

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Old 05-01-2012, 09:24 PM   #14
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Originally Posted by airmail wf View Post
............................. Futaba has been in the 2.4 business with cranes for around 30 years. If they trust their stuff to lift up hundreds of thousands of pounds when people's lives are on the line that's good enough for me. ................
Sorry to burst the bubble - but do you honestly think Futaba was first, is the only Co. involved in heavy lift control ?

I work with heavy lift Marine stuff incl. radio controlled grabs and cranes ... to be honest I've never seen Futaba name on any ... JR yes ... and many other labels ... Futie ? Nope.

Must keep an eye out for it !!

Oh - I was a Futaba fanatic till I got my JR Propo in the 1980's ....

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Old 05-01-2012, 09:27 PM   #15
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You never want to point the antenna at the plane. ALL antennas (of this type anyway) have a null straight "up". 72 mHz, 35 mHZ also have that problem. In the old days before we had "no code hams", we all learned that for VHF/UHF operations


People have a natural tendency to point the antenna at the plane. "Bending" it 90 degrees makes it pretty un-natural to do that.

I haven't seen any RF studies that show 90 is better than anything else (but I bend mine at 90 when it comes out of the case anyway)

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Old 05-01-2012, 09:44 PM   #16
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Originally Posted by Old Fart View Post
You never want to point the antenna at the plane. ALL antennas (of this type anyway) have a null straight "up". 72 mHz, 35 mHZ also have that problem. In the old days before we had "no code hams", we all learned that for VHF/UHF operations


People have a natural tendency to point the antenna at the plane. "Bending" it 90 degrees makes it pretty un-natural to do that.

I haven't seen any RF studies that show 90 is better than anything else (but I bend mine at 90 when it comes out of the case anyway)
How it was put to me was to consider the usual attitude of the Rx antena and my Tx antena should parellel it. Of course we know that the model will fly all sorts of attitudes but we normal sport flyers usually spend more time on the level than most ... OK if a 3D - then antena is vertical ?

Funny in the days 35mHz .... very few radios allowed you to alter antena out of Tx ... there were a few where pilots tended to fly on trays etc. and the Tx was flat ... then they angled their antenas vertical !! Well the guys I saw did !!

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Old 05-01-2012, 09:49 PM   #17
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Even parallelling might not put you in the optimum part of the signal (but as a simple default, you're better off with the TX and RX antennas im parallel then perpendicular). Going back to my school days (yes Bill - radio HAD been invented), I remember the instructor comparing antenna radiation patern for a vertical antenna to a water sprinkler (the simple hose end type). Not much if anything straight up - but a donut like pattern if viewed from the side. Antenna gain affects how "steep" of "shallow" the pattern is also. Google "RF angle of radiation" some time if you're REALLY bored (why I was a power engineer and not an RF engineer)

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Old 05-01-2012, 11:10 PM   #18
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Originally Posted by solentlife View Post
Sorry to burst the bubble - but do you honestly think Futaba was first, is the only Co. involved in heavy lift control ?

I work with heavy lift Marine stuff incl. radio controlled grabs and cranes ... to be honest I've never seen Futaba name on any ... JR yes ... and many other labels ... Futie ? Nope.

Must keep an eye out for it !!

Oh - I was a Futaba fanatic till I got my JR Propo in the 1980's ....
Read the post "I DIDN"T SAY Futaba was first at anything. If you are going to quote me please be correct. I could care less what the Marines use or what you use or see or fail to see. I stated my opinion and my experiences to the OP. If you have or think you have something better to use or experiences with something you think is better then state it. But please don't put words in my mouth (or post). Thank You.

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Old 05-02-2012, 12:58 AM   #19
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So tell us e-pilot, how do you normally point your Tx antenna and which way was it pointing at the time of the crashes?

What is the wing span of the small L-39 and the giant scale Cessna 182?
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Old 05-02-2012, 01:03 AM   #20
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e-pilot was your DX6i recalled? They had an issue with POT's on some models.
http://www.horizonhobby.com/products...ode-2-SPMR6610

Sorry for your loss. They all have expiration dates but that stinks.

Mike
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Old 05-02-2012, 01:14 AM   #21
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Originally Posted by firemanbill View Post
First off, sorry for your loss. I have the Top Flite Gold edition Cessna 182 ARF as well. Gorgeous plane.

The only thing I see that you did not do was to do a load test on the receiver battery.

I lost a 1/4 scale beauty one day with a full charged 6v battery for the receiver. I too was pissed about my DSM setup that had even been upgraded to DSMX both Tx and Rx. I was ready to kick that damn transmitter across the field.

I went out to retrieve the plane and once I got it back started looking for other culprits. Rx batter fully charged but when placed under a 1.5 amp load voltage dropped to 2.8v. Bad cell in the pack. This happened about 4 minutes into the flight.

Now I run redundant A123 packs for the radio gear.

I found my confidence once again in DSMx and just got back from SEFF, lessons learned, and no lockouts or mishaps. Flew all day and well into the night most days and there was 402 pilots that showed up to fly, play with boats, and run cars all over the grounds. Not to mention all the cell phone, Mi-fi- Wi-Fi, Satellite TV, FPV flyers and all other sorts of electrical noise. Not a single issue the entire week.

Thanks for your experience, firemanbill. You are correct I didn't load test the rx batt, but I really wish I had as no matter the result of the test I would know definitively what the cause of the crash was. If the battery tested bad (and I was dumb enough to fly anyway, oh well, my bad, but if it tested good, then I'd know it was radio related and I could just start shopping for a Hitec or a Futaba or whatever. It's the 'not knowing' that is driving me crazy at the moment.

Also thanks for your DSMx experience. I was ready to scratch everything Spektrum off my list but maybe I'll take a second look at the new DX8-X. The cost of re-equipping my entire hangar with X receivers is a bit frightening at this point, though. Especially right after watching my $1000 investment turn into $2 of spare parts...
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Old 05-02-2012, 01:23 AM   #22
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Originally Posted by rcers View Post
e-pilot was your DX6i recalled? They had an issue with POT's on some models.
http://www.horizonhobby.com/products...ode-2-SPMR6610

Sorry for your loss. They all have expiration dates but that stinks.

Mike
Thanks Mike.

My Dx6i was not part of the recall. I found out about the recall after the L-39 went down and was actually glad to hear about the recall as it would explain what happened. Sadly, my model was not one of the runs that had to be recalled so I was left with no explanation for that crash either.

P.S. The L-39 at left is still flying - the one that went down was a great planes park foamie.
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Old 05-02-2012, 01:34 AM   #23
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Originally Posted by Turner View Post
So tell us e-pilot, how do you normally point your Tx antenna and which way was it pointing at the time of the crashes?

What is the wing span of the small L-39 and the giant scale Cessna 182?

I always point the transmitter antenna up. The signal radiates in a doughnut shaped pattern from the sides of the antenna, not the top. Pointing your antenna at your aircraft is a good way to lose contact cause you're flying 'in the doughnut hole" where there is very little signal.

The small L-39 was the great planes park foamie, the Cessna was a Top-Flite at 81"
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Old 05-02-2012, 01:39 AM   #24
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I never had a single failure with my 72mhz futaba radio. This is about my 4th, although minor with spektrum.
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Old 05-02-2012, 02:13 AM   #25
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Originally Posted by e-pilot View Post
Thanks Mike.

My Dx6i was not part of the recall. I found out about the recall after the L-39 went down and was actually glad to hear about the recall as it would explain what happened. Sadly, my model was not one of the runs that had to be recalled so I was left with no explanation for that crash either.

P.S. The L-39 at left is still flying - the one that went down was a great planes park foamie.
Time for the TX to go off to Horizon for a check. They are good folks. It does not appear you have power issues, I suspect the TX.

Mike
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