Per_N

Hi
Didn't find any forum that match this question so I hope this is ok.
In the beginning I have used Hitec radio with Hitec Rx and there have never been any problem. But I bought a new radio Futaba FF8 (Need more memory and functions). And now my problem start. Some people say that never mix different brands and some say that there is ok. I used Futaba crystal in my Futaba radio and Hitec Crystal in the Hitec Rx. First day i tryed the range it whas supperior no problem at all. At least 150 feet:s range with the antenna push in. (could fine the word for that). Next time I should fly end up in a crash because of range problem. Now my range is about 150 feet with the antenna full extruded? Have tryed with more Rx and there is the same. Can any one tell me how this could change from one day to another? I don't believe there is something wrong with the Tx. How many of you out there is using Futaba Tx with Hitec Rx and what kind of crystals do you use.

Sorry for broken English.

Regards
Per
Sweden

PJ_TankPilot

I have 3 Futaba Tx and have used about 20 Hitec Rx with Hitec Xtals. I also use FMA M4 Rx with Hitec Xtals for small stuff.
If I have ever had a compatibility problem, I don’t know about it.
All receivers that use Futaba shift should work fine.

I would start looking at the Tx. I had a Futaba Tx behave the way you describe. The antenna wire had come unplugged.

Mluvara

My Feedback: (10)

Per,

I would look at your transmitter side like PJ_Tankpilot mentioned. Something might be amiss there.

I also moved this discussion from pylon to the radio forum where it might be better answered.

Regards,
Michael

Steve Lewin

I use several Hitec Rxs with my FF8 (35MHz like I guess yours is) and get I excellent range on all of them. It's definitely a transmitter fault. The most likely problem is that the antenna is not firmly screwed in (they do sometimes come loose).

Other than that is the battery fully charged ? Is the RF module on the back clipped in correctly ? Also check that the pins it connects to aren't loose.

If it's not one of those it needs to go in for repair.

Steve

Per_N

I should take a look at the Tx under the cover. This transmitter is not a new one, so I will talk to my friend who sold it.

(Yes Stewe, it's 35 Mhz)

I come back and let you know if I found some answers.


Per

bushwhacker

try cleaning your aerial. telescopic aerials can suffer from poor contacts between sections due to dirt build up. This can dramatically affect range and detune the aerial.

One chap informed me that he regularly lubricated his TX aerial which can also cause problems.

Steve Lewin

Indeed. Most lubricants are also pretty good insulators, not something you need between the sections of an antenna. Oils also tend to capture dirt. I fairly regularly *clean* mine and check it's still screwed up tight but that's all.

Steve

Per_N

I Haven't clean the antenna yet, but it's look ok. No dirtier than others. And it's not possible to unscrew this antenna. Under the cover all seems ok to. Next step i should do is to try with another xtals.

Anybody with more suggestion ?


Regards Per

transmission_dr

My Feedback: (1)

Hi,

If you clean your transmitter antenna, clean it with alcohol. DO NOT LUBRICATE IT. Oil will gather dirt and insolate the sections from each other and can cause the kind of problem you are having.

I agree with others comments that this is most likely a transmitter problem, rather than a compatibility problem.

HTH

Jerry

bushwhacker

Somebody should suggest to manufacturers that they return to the use of RF meters as used in the 70's. If the batteries are low or a xtal is dead low/no RF.

In this age of computerised manufacturing, and often side-lining older methods and wiser staff, company's forget the important things in the name of "progress".

FLYBOY

My Feedback: (11)

Was the range that caused the crash or could it have been something else? What happened in the crash, did the radio stop working? What did the plane do? What were you doing just before the crash? Many people blame it on the radio right away, when it was something else entirely. Might consider that. The other thing it coule be is a broken antena that is making contact sometimes and not others in the receiver.

Per_N

The peculiar thing is that I had range 5 seconds before when I was further away. The problem came when the plane was coming to me. I shut down the throttle but it's still rapidly open and closing the throttle and aileron + elevator was jumping around. Not much I can do, I manage to move up the nose before hitting the ground. So the damage was only the firewall that broke lose.

Thanks for your support, have not find any solution yet.

Per

bushwhacker

The symptom you are describing suggests an intermittent loss of tx signal. The jittering surfaces may be due to loss of command signals.

Sounds like there must be a bad connection. Check the internal aerial connection, the battery pack, or there may be a bad joint (dry joint). Also check for black wire (-ve) corrosion.

Intermittent faults are usually the most difficult to locate. In the interests of safety it would be best to get your system checked by an authorised agent.

Steve Lewin

If you haven't yet checked that the pins that the RF module connects to are securely soldered I suggest you do it now ! Bad solder joints on those pins was a known fault with some older FF8s. The symptoms are exactly as you describe.

The bracket that the antenna fixes into has also been known to come loose and that also gives similar symptoms.

Steve

Per_N

I have check inside the radio and have'nt find anything wrong.
I bend the pins a little on the module only.
Today I did a range test and it seems to be ok again??

This frighten me to use this radio. This failure could happen anytime at all. I don't like to lose contact with my Quickie running at 175Mph

I do regular test before I fly with this radio.

Per

hilleyja

My Feedback: (3)

Are you absolutely sure your initial problem was due to range -- afer all you said you range checked at 150' (don't get better than that).

If you really started to have measureable problems after the crash then it doesn't take a PHD to suspect damage to the airplane's flight pack, especially the RX crystal.

As far as compatibility, there is absolutely no problem using a Futaba TX and a Hitec flight pack -- 90% of my airplanes fall into this category. I have a couple of airplanes with the opposite -- I have Futaba RXs and use a Hitec Eclipse 7 (Spectrum) to control them.

The only problems I have had over the years could easily be attributed to bad switches (I now only use double-pole switches) and on one occasion I ran into difficulty with an FMA RX with my Hitec Eclipse 7.

transmission_dr

My Feedback: (1)

Per,

I would suggest that you send the whole package to a sevice center to be checked out. They will vibrate everything and an intermittent part will show up in the vibration check.


I had a brand new Futaba that would only act up very occasionallly. Cost me two VERY expensive airplanes before I wised up and sent it back to Futaba. Turned out to be a bad transmitter module.

HTH

Jerry