Problem:SubTech Subsafe & FMA receiver

[chips]

I'll start with my working WTC. WTC #1 is controlled by Futaba 4 channel transmitter,and has a Novak XXTra synthesized receiver, and a SubTech Subsafe. The SubSafe works fine with the Novak receiver, it blows the ballast tank if there is a signal loss.

I'm working on another WTC for a WWII GATO fleetboat. I'm using the same Fuatba tx. I have a FMA M5 receiver (tuned for a Futaba system) that I plan to install in the new WTC #2, along with the SubSafe. I connected the ballast tank servo directly to the FMA rx and verified that it works; when I install the SubSafe in-line between the rx and servo, the servo operates when the tx is turned on. When I turn off the tx, the SubSafe doesn't move the servo to blow ballast.

I took the SuSafe from WTC #2, and plugged it into WTC #1 (Novak rx) - it works as designed. When I plugged WTC #1 SubSafe into the FMA rx, it doesn't blow ballast. The problem seems to be with the FMA rx. Any ideas on what the problem is and how to correct it it?

Both SubSafe units work as designed when connected to a Futaba R127DF rx. The Futaba TX and all 3 rx are tuned to Channel 83 FM. All testing was done on the workbench with the tx and rx less than 3 feet apart; all batteries were recently charged.



Edited By chips on 1103776740

[anonymous]

The only thing I can

The only thing I can suggest here is that I've never had much luck with the FMA recievers. They are usual signal loss death when used in my airplanes but maybe I just had a streak of bad luck with them.

I only use Hitec recievers now as they are close to bullet proof and I have yet to have one fail. It does sound to me that the FMA RX is the problem.

Sorry I couldn't be more help. And I don't mean to bad rap FMA but as said I had trouble with them.

Steve

[bigdave]

Hi Bob,
I have used

Hi Bob,
I have used FMA receivers for years with no problems. I am using a M5 in my 1/72 Type V11c with a Subtech SES-2 which has a failsafe built into it and it works fine. I also use the M5 in my micro helicopters with no problems. You may want to contact Subtech and FMA and explain the problem. That is a weird one. Good Luck, Dave.

[anonymous]

Hi Dave,

Maybe it's the field

Hi Dave,

Maybe it's the field I fly at. Heavy traffic there being a pulic city field.

I'm using a Hitec Feather on the Kilo and despite the 500 ft range I'm having good results. But that's in my pool. Maybe his FMA is out of tune. It happens sometimes.

Steve

[chips]

Dave,

I contacted FMA, and

Dave,

I contacted FMA, and received their reply today -

I think the problem is the M5 has last good frame hold failsafe. If you turn your transmitter off or have signal loss due to interference, the servos will remain at the last position before the receiver goes into failsafe. Once your transmitter is turned on or signal is regained, the receiver picks up where it left off (if you will).

I sent them a follow up email asking if the M5 last good frame hold can be disabled or turned off. I'll be putting a Novak XXtra synthesized rx in the WTC and use the M5 as a target.

Follow up from FMA is that the M5 last good frame hold is built into the rx and cannot be disabled.



Edited By chips on 1104121198

[craigf]

Another possibility for a synthesized

Another possibility for a synthesized receiver that I've tested works fine with the SubTech AFS, so presume with the similar SubSafe. I was going to use the XXtra, but the Sombra Shadow-1 just became available at that time. It's 6 channel (ch. 1-4 and any 2 of ch. 5-7) synthesized 50/72/75MHz bands, smaller than XXtra (8g), and cheaper I believe (US$70 I think, at least in Canada it's lots cheaper than XXtra). DSP, auto shift select, learns profile of your TX signal to help avoid "hits" even if on same freq, ultra narrow band (5kHz), no servo jitter/craziness on loss of TX signal (but not last frame hold), etc. etc., all good stuff. You can find more info and places that sell it in U.S. on RCGroups "Radio" forum, check a recent thread about "small synthesized RX" or similar.