FrSky FASST Rx's Technical Question - RC Groups
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Dec 06, 2012, 08:32 AM
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FrSky FASST Rx's Technical Question


Hi

Does anyone know if the FrSky FASST Rx's have the same level of interference rejection circuitry/filters as the original Futaba FASST Rx's. I'm not a technical RC guy so I hope I've worded this correctly.

Thanks.
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Dec 06, 2012, 10:09 AM
Radio? Screwdriver!
Quote:
Originally Posted by ThermalBoy
Hi

Does anyone know if the FrSky FASST Rx's have the same level of interference rejection circuitry/filters as the original Futaba FASST Rx's. I'm not a technical RC guy so I hope I've worded this correctly.

Thanks.
Apart from the RF matching circuitry (which the values used depend on the PCB layout), the rest of the interference rejection and filtering is done by the RF IC. RF matching, with the correct tools and knowledge, is relatively straight forward to do (i.e. a Textbook exercise). This IC is the same manufacturer as used in both FrSky FASST and Futaba FASST receivers. The only difference is that Futaba pay to have their company name etched onto the IC.

So in a nut shell, yes, expect very similar levels of performance with the FrSky receivers.

Si.
Dec 07, 2012, 04:13 AM
Registered User
Quote:
Originally Posted by SimonChambers
Apart from the RF matching circuitry (which the values used depend on the PCB layout), the rest of the interference rejection and filtering is done by the RF IC. RF matching, with the correct tools and knowledge, is relatively straight forward to do (i.e. a Textbook exercise). This IC is the same manufacturer as used in both FrSky FASST and Futaba FASST receivers. The only difference is that Futaba pay to have their company name etched onto the IC.

So in a nut shell, yes, expect very similar levels of performance with the FrSky receivers.

Si.
Thanks Simon for the info.

Comes as a bit of a surprise to find out that the Futaba "Custom IC'" is nothing more than another manufacturers IC with their name stamped on it. More than one person has told me that the ommision of the Interference Rejection Circuitry/Filters in the FrSky FASST Rx's were the reason they are so cheap compared to the real Futaba Rx's. Obviously this is cleary not true.
Dec 07, 2012, 06:02 AM
Registered User
I dare to disagree a bit here... The RF circuit, i.e. the 2724 transceiver, the same used as Frsky in their FASST compatible, is a general usage circuit, a commodity I could say, and is not hidden under Futaba sign even in original FASST receivers.
The one stamped as Futaba is the receiver MCU, the chip who runs FH code, different from Futaba and Frsky, but doing same job, FASST implementation.
Actually, the RF circuit text can't even be read without disassembling the Futaba original receiver, because it is faced internally in a dual PCB board setup. It was the origin of the Futaba receivers overheating issue in the last summers, because it's not a military rated chip, but a commercial one, maximum 60 C degrees, easily to reach in a hot summer, under a black canopy. And so bad buried in the receiver, without any airflow.
Dec 07, 2012, 09:50 AM
Registered User
Quote:
Originally Posted by RENATOA
I dare to disagree a bit here... The RF circuit, i.e. the 2724 transceiver, the same used as Frsky in their FASST compatible, is a general usage circuit, a commodity I could say, and is not hidden under Futaba sign even in original FASST receivers.
The one stamped as Futaba is the receiver MCU, the chip who runs FH code, different from Futaba and Frsky, but doing same job, FASST implementation.
Actually, the RF circuit text can't even be read without disassembling the Futaba original receiver, because it is faced internally in a dual PCB board setup. It was the origin of the Futaba receivers overheating issue in the last summers, because it's not a military rated chip, but a commercial one, maximum 60 C degrees, easily to reach in a hot summer, under a black canopy. And so bad buried in the receiver, without any airflow.
Renatoa

For a non technical guy like myself, are you saying that in your opinion the FrSky FASST Rx's are as good as the genuine Futaba FASST Rx's in terms of quality of the radio link and interference suppression at great range, say 1-1.5 km?

Thanks
Dec 07, 2012, 09:55 AM
Registered User
Not using it personally, but my FPV fellows using them says it is a notch better, in the manufacturer margin, as in 2.5km vs 2km the original.
What is really stellar is the failsafe support !
The FPV autopilots requires a failsafe level on an upper channel, usually ch5, to trigger return home when lost link. The genuine Futaba receivers up to 6ch are missing this feature, they implement only throttle cut and neutral on all other channels. The ch7-8 models featuring programable failsafe are stinky expensive to be considered for this task, I am talking about FPV planes costing less than such receiver !
Dec 07, 2012, 10:24 AM
A man with too many toys
Quote:
Originally Posted by RENATOA
Not using it personally, but my FPV fellows using them says it is a notch better, in the manufacturer margin, as in 2.5km vs 2km the original.
I have also heard that. I will be getting a couple of the TFR8SB receivers soon but they will be used for helicopters.

.
Dec 15, 2012, 11:46 AM
Registered User
RC Man, please send me a PM via email. Like to ask you a couple of questions. Thanks.
Mar 06, 2015, 06:34 AM
Registered User
sea_owl's Avatar
"Custom " Futaba IC chip is likely DF36087FPV (IC MCU 16BIT 56KB FLASH 64LQFP), you can easily find it at DigiKey for $10
Mar 08, 2015, 01:37 PM
AKA 8178 - MIke Dailey
Jet_Flyer's Avatar
I'm using some FrSky TFR6-A FASST receivers with my Futaba 12FG and they work quite well. I run them bound in Multi mode and use the 12FG fail safe settings. From my experience the only Futaba feature they do not support is the low voltage fail safe that most Futaba receivers have.

I upgraded my old Futaba 9C with the FrSky telemetry module and I'm using the D8R-II Plus - 8 receivers with it. They have built in support for settable low voltage warnings and low signal alarms.

I buy all my FrSky stuff from Aloft Hobbies because of their great service.


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