Futaba 2.4GHz with caution

[Chris Dowsett]

After researching various blogs for the most suitable 2.4GHz gear to buy I opted for FASST as I have an 'FF9' TX.    I am now happily flying with a TM-7 TX module  and R607FS RX.  The TX module has a serial number listed in the Futaba USA service advisory list  http://www.2.4gigahertz.com/techsupport/service-advisory-tm7-7c-6ex.html 

Any digital electronics has a habit of hanging up on you from time to time.  We just have to stay in control .  It helps to know what to look for - like time to boot up... ...and how to avoid it.

The Futaba advisory (which we have not got in Europe yet) tells you what to look for with FASST gear.

Here is a scenario I am trying to avoid with my FF9 / FASST.  

Beat the boot up time.  It is possible when recycling the TX power after swapping from PCM to PPM ( FASST requires PPM).  The FF9 can prompts you to re-cycle the power if you swap to a different model memory.  DON'T - you may loose your unique identity.

If you intend flying a mix of 35MHz and 2.4GhHz it is best to select model memory, switch the power off, change the RF module and then switch the power on.

[Chris Dowsett]

If any one else has thoughts on scenarios I would like to hear them. John Cole has summarised the Futaba situation concisely and I agree with it (see)

 Futaba's announcement is I think consistent with two scenarios:

1. Some of the Txs NEVER had their ID set correctly, AND there's the Zero-Over-write issue.

2. All Txs had their IDs set correctly BUT there is the Zero-Over-write issue AND some Txs were zeroed accidentally in the factory.

2 seems more plausible as it only requires one fault!

Whatever causes a Zero-Over-write it will be something that the TX operator does.  If it happens the RX will have to be re-locked. So it should be obvious something has happened.  Think about it.

[Chris Dowsett]

I thought there would be more cautionary tips from fliers.  We are taking part in the same revolution!

Here is #2 - Applies to Futaba, Spectrum and other makes of 2.4GHz gear:-

When you do a range check to the limit recommended in the operating instructions hold the stub aerial on the transmitter whilst waggling a stick.  If you still have control walk further away but stop when you loose it.   When you lost it keep waggling the stick and move your hand away from the aerial.

Is the delay before you are back in control fast enough?

[David Ashby - Moderator]

I haven't range tested like that Chris - I've got a humble 6EX 2.4 but I've not had a problem with it and have been using it for nearly a year now in my electric models across 5 x R606 receivers - no glitches, no problems at all. 

Do I recall that modules were unaffected by by the recent problems? Still what you say makes sense re changing modules.

[Chris Dowsett]

What happens when you fly out range matters so any flier should.  The simple test is a good demonstrator.

My experience is the similar to yours David.  No problems. 

My understanding modules ( bought in the UK ) were affected.  Any could have a defaulted ID so I need to be careful.  If there is a "zero overwrite issue" it could have occurred in the factory as well as the field.   So we all need to take care (TX's or modules).

I have no first hand experience of any issue but there is nothing wrong with taking precautions - 2.4GHz is new to R/C.

NB Assume you meant "modules were unaffected" and "changing models". 

[Dr1deck]

I have a Futaba T7 ,on the box it states Software version2, however it had an 07 serial number and I was still concerned, I contacted Ripmax who replied as follows:----------------Please disregard the Futaba serial number. It has no significance in the UK.If your transmitter is a Futaba T7CP and it has a Ripmax serial number then it will not have any problems with the ID code.You do not have to take any special precautions when turning the transmitter off or be concerned if the battery runs flat.All T7CP transmitters sold in the UK (with a Ripmax serial number) will have version 2 firmware installed and cannot lose their correct ID code under any operating conditions.RegardsJim MeierFutaba Service Department
Ripmax Ltd
241 Green Street
Enfield
Middlesex
EN3 7SJ
England

[Chris Dowsett]

Thanks Steve.  Welcome news.  If you have a Futaba T7CP, as Jim describes in your quote, there is NO "zero overwrite" issue.  It would be very re-assuring to know how you get on after the first 10 flights or so.

My transmitter module TM7 has the 07 serial number but it is a Futaba number there is no Ripmax number.  I have had 121 flights with my Phase 6 but only the last 3 were with 2.4GHz.  Just waiting for an easterly wind.

The only cautionary note added so far concerns trim changes in roll and elevation.  Probably due to change from PCM to PPM and a lighter RX.  Couldn't be the RF change (35MHz PCM to 2.54GHz PPM).

[Chris Dowsett]

I have just had a response from Ripmax concerning use of the TM7 (plug in TX module).  I am basically worried about the "Zero-Over-Write" issue hence Jim Meier's answer:-

All R607fs and R617FS receivers should have an ID=0 code if they are new out of the box and have not been linked to a transmitter before. You will need to check with your supplier that this is the case.All TM7 modules with a 07xxx serial number should be regarded as suspect and should be used with caution as per the advise on our website. I am still not sure about the 08xxx serial numbers yet. It's likely that they are fixed but I have not yet had that confirmed by Futaba.Best RegardsJim Meier

Jim's comment is helpful so I shall be buying an R617FS "new out of box".  The idea is to check that my TM7 has not zero coded itself.  If it has not then I will re-lock the new RX to the TM7 to get a second ship flying. 

[Chris Dowsett]

The new R617FS has arrived.  As described in my last post it should have an ID=0.   This means if it does not work "out of the box" with my TM7 then the latter is OK. 

 SO WHAT HAPPENED?    It did not work!  Great my TM7 is safe to fly with.

Caution #3  Interesting discovery.  The green light flashes on the R617FS when it wants to bond. 

Could indicate it has ID = 0.  I cannot go back to check if the R607FS does the same thing.  There is no mention in the user guide (1M23N19801).

Once the "Easy Link" button is pressed the flashing stops green LED on the RX becomes steady.  When the TX is off the RX LED changes to red.  

Next thing is a comparative range check waggling sticks and whiskers.  Anyone who has experience of 35MHz, mobile phones and WiFi knows how much more fickle 2.4GHz can be. 

Back in a week, or so.  Anyone confirm when/if  their Futuba RX had a flashing green? 

[Frank Latham]

What are the differences between the R607 and R617 FS receivers please?

I am in the US at the moment and a set with 607 is on offer 15 quid cheaper than one with a 617.

[Chris Dowsett]

No real differences found yet though I am told there is a different component supplier. 

I am wondering if both have a flashing green led before bonding. 

Both R607FS and R617FS have been flying without problems but I feel more confident about the R607FS having had more flights with it.  Also I am not sure if the low power range/failsafe check is as good for the latter but I am still researching a good test method.  Not as easy to do as 35MHz.

[YakMad]

The 617 rx is supposed to have higher quality components as Futaba were unable to source 607 components for a short while and produced the 617 instead but now have kept both going?? and the signals are sent to the servos in a different order which is supposed to suit heli's better. I am using both rx's with no problems although I have had one of my 3 TM-7 modules replaced as it had a zero GUID, I checked it with a new RX as described above.

[Frank Latham]

Thanks for the info guys. I guess  that I may follow the price!

Do you happen to know whether you can use a 35MHz Tx  linked to a 2.4GHz set as a buddy box?

I'm guessing "No" but it would be nice...

ciao

Frank 

[Former Member]

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[Frank Latham]

Thanks Eric.

Now what do you do when a range test gives a less than "good" result?

Can anything be done to improve the signal?

aye! 

 Frank

[Chris Dowsett]

As far as I know one has come up with a foolproof range test for 2.4GHz yet so I am not sure what "good" result means.  

The book says "approximately 30 - 50 paces... ...without losing control"

Range checked the 617 today and got 43 paces.  Worst case conditions: model at ground level,  one whisker pointing to the tail & other whisker pointing straight up,  finger pressing low power button whilst hoping red light is on, walking backwards, waggling the stick, watching a control surface waiting for the fatal hesitation,etc, etc.  Walk forwards until the controls are crisp. Do a masking test.  Then pace it back to the model.

Had a trimming flight next.  Going from PCM to PPM seems to produce a shift in trims.  No loss of control.

A typical flight next to push the envelope.  No loss of control. 43 paces is OK for the moment

If you want a scare try comparing 'low power 2.4' with retracted aerial 35MHz.

[YakMad]

I flew my Cularis (ep powered)at the weekend with a  607rx out to a tiny speck with no loss of control, something I rarely did on 35mhz (glitches) so I am more than happy with the range. You just have to remember that ensure as best possible the aerials are not blanked eg behind a battery pack. when in flight to ensure you get the best range possible, this sometime involves more care ful planing than we would have done on 35 mhz.

[Chris Dowsett]

YakMad wrote (see)

..607rx out to a tiny speck with no loss of control...

Air range is good but how does this translate to ground range - less than 30 paces? - more than 50 paces?

There is the opportunity with 2.4 to make the ground range check easy enough to do as a pre-flight test.  This would make optimisation a lot easier. 

[Former Member]

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[Chris Dowsett]

It would cost you a doughnut and a cup of coffee Eric.   Add a quote so we can all read it.

I am taking the easiest approach.  Swapping the 35Mhz RX for 2.4GHz.  Stuffing one whisker in the tube the 35Hz aerial was fitted.  Adding a second tube for the other whisker at 90deg.  I get a ground range inside the maker's specification and no problems in the air.

[Former Member]

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[260 Flyer]

So the worst case scenario is with the Tx antenna pointing at your plane which is directly overhead in a vertical dive toward you with the motor, batteries etc shielding the Rx antenna.

[Former Member]

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[Chris Dowsett]

Thanks Eric and I like doughnuts.  Rob seems to prefer dunking rather than savourying  them.

 There are several good points you make the most relevant I think is :-

"..the signal spreads out evenly all round except for where your body is blocking it. "

It is covered by my suggestion for a ground range test (see)

Here is #2 ....

When you do a range check to the limit recommended in the operating instructions hold the stub aerial on the transmitter whilst waggling a stick.  If you still have control walk further away but stop when you loose it.   When you (have) lost it (again) keep waggling the stick and move your hand away from the aerial.

Is the delay before you are back in control fast enough?

 

Taking your doughnut analogy a bit further.  I cannot think of any case, except when doing a ground range check, when the pilot's body would be between the TX and RX.  Other peoples' bodies are another matter.  Think of my hand as holding the doughnut and representing a ring of fellow fliers.

Reasonable? 

We have to assume the signal can be blocked,  need to check the RX  masks the loss of signal but returns control quickly. Can you better #2? 

[Former Member]

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