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Aerial check - a timely reminder


Andy Green
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I lost by Chevron last saturday, beyond a repair even worse than I could cope with.

Took off, and on the climb out went into fail save, throttle to idle and I watch it plough in.

This is the first time ever I've had a failsafe kick in, so was a bit surprised.

Retrieved the model and the radio was still working, got the bits back to the pits, put the radio in range check mode, and got a bout 5 steps.

Tried another model, and the same - about 5 steps. So it was the Transmitter.

Now I don't have a cheap set - in fact its probably the most expensive set in the world, and has been faultless for the past 3 years.

Its always in its case when not in use, never had the aerial unclip so a bit surprised to find this:

18mz-aerial.jpg


Looks like the arial wire has broken through. I have a new one on order, so will only know for sure once fitted.

Check yours now and do a range check!

Andy

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Bad news Andy always sorry to hear about that sort of thing. I must admit that those aerials that twist and bend worry me. I must admit those movable TX aerials scare me I am always concerned about the number of people who get their transmitters out and immediately adjust the aerial. There are so many opinions about where both TX and rx aerials should point and I have seen some horrendous things done to receive aerials like bending at right angles close to the case

On my DX8 I tend to keep the aerial parallel to the top of the case and even had one guy walk up to me when flying and move the aerial round. There was so much I could have said but refrained instead just said please don't ever touch my transmitter again especially when I am flying it. It's amazing that those who have all the theories are the same ones who have radio problems and for ever blaming interference

Anyway don't scrap the model yet until you have slept on the feasibility of repair and thanks for posting the heads up on aerials Andy

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WHY OH WHY! - Why don't Tx Manufacturers now incorporate the aerial into the handle nowadays - now we are encouraged to have the Tx aerial parallel to the horizon - or is it a copyright thing? I must say I worry about the rather delicate Tx aerial hinged connection on my Cockpit and Dx7. Does anyone replace aerials, if so, how often?

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Looks like a pinch point at the break on the coax - wonder how it got like that? Can't see too well, but is the smaller bit to the left of the fracture part of the cable, or an exit guide? Just had a look at the cable through the folding joint on my DX7 and the wire has quite a gentle radius to go around with a bit of slack in it as well. I wonder if your cable was installed tight and hence stressing it around a very tight radius when folding/unfolding? I'd send it back to the service agent saying that this had cost you an expensive model, quite apart from the safety aspect, and is not what you expect  from an a top end bit of kit.

Got to be honest, I hate the design of these aerials and I leave mine alone - folded parallel to the top of the tranny.

 

Edited By Cuban8 on 04/08/2015 17:38:11

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I have and always have the tx aerial at right angles to the to top of the transmitter. My gear, by the way is Futaba 14SG.

A pal of mine severely damaged his jet-powered Hawk when on finals. His aerial was parallel to the top of the case and pointing directly at the Hawk. Signal lost to the rx and the motor shut down. His observer called 'Flame-Out. He did not call out loudly enough and my pal, not hearing the call, lowered flaps and u/c - result drag = OH! NO! Too low to recover. Punched the u/c through the wings and the nose wheel ripped out of the fuz. Very expensive.... Wata mistaka to maka.

The manual for the 14SG states (page 14 and not in very good English) 'If you have a transmitter at an angle of a figure, an antenna will be good to use it , bending 90 degrees. It is not good for there to be a model on flight in the direction of the tip of the antenna.

Edited By Barrie Dav 2 on 04/08/2015 17:40:52

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Hi Andy thanks for the heads up on this.

I've just checked mine and it seems(?) okay,

The cable on mine is a light grey colour and it has a small amount of flex.

It's not as old as your transmitter, approx. 2 years old, maybe Futaba picked up on this?

Definitely have a close inspection/tear down, before I go flying again!

img_1599.jpg

Regards,

Simon.

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So from the second photo it's a single length of mini coax. Seems to me that the cable has fractured on the lower edge of the black plastic probably because not enough of a radius has been allowed for. Can't think how else you'd get that type of damage. Manufacturing fault?

Worse thing you can do to any type of coax.

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I had remove the aerial assembly, but have put it back as it was to show how I found it - looks like the aerial goes the wrong way around the screw pillar, such that there is no give.

18mz-aerial-2.jpg

18mz-aerial-3.jpg

I have a new one on order, so will be careful how it goes back together.

Not sure there is anything I can do - let Ripmax know maybe, but no expectations.

Andy

 

Edited By Andy Green on 04/08/2015 18:50:35

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Posted by Barrie Dav 2 on 04/08/2015 17:39:12:

The manual for the 14SG states (page 14 and not in very good English) 'If you have a transmitter at an angle of a figure, an antenna will be good to use it , bending 90 degrees. It is not good for there to be a model on flight in the direction of the tip of the antenna.

"Chinglish" at it's finest... Quite what a beginner would make of that, I'm really not sure. The final sentence is just about understandable, especially if you already know what they're trying to say. But I'm not at all sure what the first sentence is trying to say!

I'm sure Futaba manuals used to be written in English that was at least readable, even if they didn't always explain things in the best possible way - leaving the door open for the likes of Don Edberg and Anne-Marie Cross to produce superior third-party instruction manuals.

Is it really beyond the ability of Futaba to get one of their people in Futaba Inc to re-write the first draft of the manual in "proper" English (even if it's American English)?

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At least the Futaba manual is in chinglish When I bought my JR x378 the manual it came with was in Japanese, written in Japanese script. Macgregors had attempted to cobble up an A4 typed sheet of instructions which was frankly useless. Strange because it was possible to download a very excellent manual complete with all diagrams from a US web site, Tower hobbies I believe. The RCM&E review of that radio had mentioned the manual issue but I had assumed they had gotten hold of an early import and by the time it reached the LMS it would have been sorted

I recently bought a second hand PCM9X interestingly 2 manuals came with it English and Japanese, whether or not the English one originally came with it I know not.

AS for Futaba the manuals for the T6J and T8J seem to be in good English, although they do both seem to have the same ambiguous gibberish about battery types and voltages and to what level to set the low voltage alarm.

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Posted by gangster on 04/08/2015 23:19:55:

AS for Futaba the manuals for the T6J and T8J seem to be in good English, although they do both seem to have the same ambiguous gibberish about battery types and voltages and to what level to set the low voltage alarm.

From page 15 of the 6J manual:

"If using four AA Alkaline (dry cell) batteries, the alarm should be set to 4.2 volts. If utilizing a five cell NiCd/NiMH transmitter battery, select the 5.0V setting."

Seems clear enough to me. Have I missed something?

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Posted by gangster on 04/08/2015 23:19:55:

AS for Futaba the manuals for the T6J and T8J seem to be in good English, although they do both seem to have the same ambiguous gibberish about battery types and voltages and to what level to set the low voltage alarm.

From page 15 of the 6J manual:

"If using four AA Alkaline (dry cell) batteries, the alarm should be set to 4.2 volts. If utilizing a five cell NiCd/NiMH transmitter battery, select the 5.0V setting."

Seems clear enough to me. Have I missed something?

Hi Wright stuff

Well I think the whole thing is a muddle and its not the first time its been mentioned on this Forum

Unless something has changed in the last two years

The manual states it can either run on 4 x Alkaline or 5 rechargeables. It is wired for a charger but only has space for 4 cells. As far as I know Ripmax never supplied a rechargeable pack. To fit a third party 5 cell pack required butchery of the back. Hardly satisfactory.? Still not satisfactory to have to use a third party battery There was vague reference on the web to a different back but was that ever available in the UK. Also 4x alkali cells is 6 volts, I would be nervous about setting the alarm to 4.2, I dont think that would give much time to land. I only owned a 6j for a few weeks before changing for a 8J

Now as far as the 8j is concerned the manual says similar things and speaks of a 5 cell rechargeable Futaba pack, now as far as I can see from looking on the web and speaking to a couple of suppliers no such animal is available in the UK Ripmax seem to supply a 4.8V flat AA rechargeable pack.

Having said that I have used the 4.8V pack with alarm set to 4.2 for two years, and it works fine and lasts for ages. But at least the book is in english!

Like mentioned in an earlier thread Futaba seems to have lost the will to live.

 

Edited By gangster on 05/08/2015 16:27:43

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