futaba reciever replacements

[SweetAccord]

Did you look at the links I posted? If Hobby King don't have them no one will.

[longballlumber]

This is all good for the FAST system.

Does anyone make a receiver to match the Futaba - 2.4GHz - S-FHSS system??

Larry

Why? The Futaba OEM FHSS stuff is very reasonable in cost.

[NativePaul]

Sweetaccord.
Yes, more susceptible in a lot of ways. Your never having a problem with it doesn't disprove that, my dad never crashed his car when driving home from the pub when it was legal to do so, but that doesn't make his drink driving as safe as me taking a taxi.

Frequency hopping can be overrated when applied to a small part of the band, but can also offer significant advantages implemented correctly, and it is not just the hopping that makes FASST superior.

I think you have been misinformed about FASST, while there are some hopping protocols out there that operate on limited parts of the 2.4 band Futaba's FHSS being one (along with JR/Spektrum's DSM2, WFly, FlyDream, Corona). Futaba's FASST however (along with FrSky, Sanwa/Airtronics FHSS3, Sprektrm's DSMX, JR's DMSS, Multiplex's M-link) utilises the whole of the legal 2.4ghz band.

Assan's narrower bandwidth allows for 83 channels whereas FASST uses 36 wider bandwidth channels. If there is a tight spike of interferance it is much less likely to affect the wider FASST channel. If however the interferance takes out a whole channel of each (if it is wide enough to take a FASST channel it would actually cover 2 ASSAN channels) there is a 1 in 83 chance of it hitting the channel the ASSAN is on and taking out the ASSAN's link, and a 1 in 36 chance of it hitting the FASST's channel, which sounds really bad, but the FASST's dual antennas are not just 2 antenna on the same receiving circuit to avoid getting atenuated by engines, motors, batteries, etc between than and the TX, they are attached to their own separate internal receiver and the chances of them both being on the same channel are to take out the FASST's link is 1 in 1296, a significant improvement.

Then there is the hopping, FASST doesn't hang around waiting for a bad signal like some, so it doesn't have to look to find a new channel, it constantly changes channels at 500hz whether dirty or not, so even if that 1296-1 chance comes up all is not over, as it will only lose the link for 1/500th of a second before switching to a new channel.

You seem to be using brownout is a different context to the one I know, which is when the supply voltage dips below somethings minimum operating voltage and it temporarily ceases to function. I think I addressed what you meant in my hopping paragraph, but ironically the minimum operating voltage is one area that the ASSAN does actually beat FASST. ASSAN has the lowest operating voltage that I have seen at 2.3v, whereas FASST needs 2.6v, both reboot quickly. The one that brought brownouts to the fore was Spektrum, which needed 3.5v and their older RX could take several seconds to reboot, making a crash likely if it happened (recent units boot quickly, I don't know if they need less voltage now too as there have been generational changes since, but it was not in the initial "fix"). I have not heard of any brownout issues with RX that need <3.2v.

ASSAN may be good enough for you, it may be good enough for me, and you are right about diminishing returns, But ASSAN does not offer as reliable an RF link as Futaba FASST (with the exception of their Gunther8 FASST compatible RX).

Due to the possible consequences of a failed RF link, I want the best link available whether overkill or not. Even real Futaba RXs are only a small proportion of my total boat cost, so for me it is not worth skimping on.


Larry.
All the talk is about FASST because the OP's 3PM-X is FASST not S-FHSS. There are a couple of S-FHSS compatible RX that I know of, FrSky do the Delta8, and Orange do the GR400S. There are also a few Futaba FHSS compatible RXs, and as far as I know all the S-FHSS TXs can be switched between S-FHSS and FHSS, as the protocol is nearly the same, S-FHSS just allows failsafe on all channels instead of just the throttle, and a choice of either more than 4 channels(up to 8), or high speed mode for digital servos.

[SweetAccord]

In theory and in practice, a good FHSS system will keep working long after many 2-frequency DSSS systems have locked out. However, that's not the whole story and it's not all that cut and dry.

Because the FHSS systems are using much (or all) of the band, there are situations where they can be badly affected while a DSSS system is not affected at all. I've seen it. This can occur if the band is heavily congested except for a small portion and the DSSS system chooses that portion on which to operate without any issues. The DSSS signals are allocated to the clean part of the band and thus provide faultless communications, while the FHSS one loses a good percentage of its data to noise because it's hopping through interference.

It's rare but it can happen cause I've seen it.

[NativePaul]

True, that can happen. If 35 of the 36 channels available are dirty, that FASST will be noticeably very slow slow and laggy (I don't know the protocol well enough to say if it starts skipping known dirty channels, but assuming not which is the worst case), it may only getting updated 14 times a second which is getting on for a quarter of the normal speed servos run at.

I know I would prefer a slower radio to one that doesn't work though. (JR/Spektrum seem to agree as they must have spent phenomenal amounts of money switching from a single channel with clean start (DSM), to a 2 channel DSSS (DSM2), and now to a full channel hopper (DSMX/DMSS)

Are ASSAN actually delivering a 2 channel DSSS system now? I must admit I was basing what I have said on it not being, though I still much prefer a full channel hopper to a 2 channel DSSS. It was always advertised and specified as such, but spectrum analysis of the first couple of generations showed they were only broadcasting on 1 frequency which never moved, and was always the same one whether dirty at switch on or not. I don't know anyone with a set to test it and googling brings up lots of old posts complaining about it. Maybe they fixed it so the complaints stopped, or maybe people didn't like being lied to and stopped buying it. Have you seen any recent spectrum analysis?

[SweetAccord]

True, that can happen. If 35 of the 36 channels available are dirty, that FASST will be noticeably very slow slow and laggy, as it may only getting updated 14 times a second which is a quarter of the speed analog servos run at(I don't know the protocol well enough to say if it starts skipping known dirty channels, but assuming not which is the worst case), the chances are high that ASSAN would have stopped working altogether long before the channels was that bad though.

Are ASSAN actually delivering a 2 channel DSSS system now? I must admit I was basing what I have said on it not being, though I still prefer a full channel hopper 20 a 2 channel DSSS. It was always advertised and speced as such, but spectrum analysis of the first couple of generations showed they were only broadcasting on 1 frequency that never moved, and was always the same one whether dirty or not. I don't know anyone with a set to test it and googling brings up lots of old posts complaining about it. Maybe they fixed it so the complaints stopped, or maybe people didn't like being lied to and stopped buying it. Have you seen recent spectrum analysis?

I have the first generation. I know ASSAN has made improvements but I have not looked into the new versions as I never had any issues with the first generation.