FrSky....Christmas in July

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Re: FrSky....Christmas in July

Postby jet760 » Wed Jul 21, 2010 5:42 am

Hi Guys
They say in there manual that the range test is up to 30m with the current system. (telemetry) 1/30th the power.
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Re: FrSky....Christmas in July

Postby Whiteprop » Wed Jul 21, 2010 7:35 pm

RCModelReviews wrote:The DIY module uses a switch-mode regulator so adding an inductive choke to the positive line may make a big difference. As many turns as you can fit around a ferrite core ought to do it.


I've added chokes, capacitors, lowered the B+ line to 6VDC and lowered the amplitude of the PPM signal, I've wrapped the module and antenna in copper foil, twisted the B+ line and common together. At this point I'm pretty much done. As I stated before the ripple on the +9.6vdc line and PPM line is modulated and is causing the servos to jog back and forth around neutral just a small amount. The +9.6vdc and PPM is completely clean and smooth without the module removed from the circuit. Again,...when the module is placed in power reduction mode the modulated ripple reduces from approx. 300mv to less than 100mv and the servos are completely stable. There's no doubt in my mind that the prolem is being generated by the module itself...I don't know if this is the nature of the beast or if I have a defective unit. Too bad...this thing has so much range in power reduction mode, you could probably fly it that way.......Kidding!

I put an email into FrSky....will be interesting to see if I get a response. Am I the Lone Ranger on this thing?? Has anyone else out there played around with these modules?
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Re: FrSky....Christmas in July

Postby JMP_blackfoot » Wed Jul 21, 2010 8:02 pm

duplicate, sorry!
Last edited by JMP_blackfoot on Wed Jul 21, 2010 8:09 pm, edited 1 time in total.
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Re: FrSky....Christmas in July

Postby JMP_blackfoot » Wed Jul 21, 2010 8:04 pm

Just another thought. Have you tried another power source?
I mean, either a bench power supply or a different battery.
I had no trouble with converting my home made Supertef transmitter (http://home.nordnet.fr/~fthobois/autres.htm), but it does use a regulated voltage to the coder.
And when doing the 4-cell modification to my FlySky (Turnigy, etc...) transmitter, I found that the battery box contacts were creating ripple on the power supply.
Maybe the internal resistance of your battery is a factor in the problem. 300 mV seems a fair lot.
Or could it be that the power switch is resistive. Do you see ripple across it? A capacitor across it?
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Re: FrSky....Christmas in July

Postby RCModelReviews » Wed Jul 21, 2010 10:03 pm

A low ESM capacitor of sufficient size should remove the ripple and you can use a series resistor before the cap to further increase the smoothing, so long as the voltage across the capacitor doesn't dip below 6V or so.

It does sound as if the caps on your encoder board have gone dry over the years if the module is putting that much ripple on the V+
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Re: FrSky....Christmas in July

Postby Whiteprop » Wed Jul 21, 2010 11:23 pm

JMP_blackfoot wrote:Just another thought. Have you tried another power source?
I mean, either a bench power supply or a different battery.
I had no trouble with converting my home made Supertef transmitter (http://home.nordnet.fr/~fthobois/autres.htm), but it does use a regulated voltage to the coder.
And when doing the 4-cell modification to my FlySky (Turnigy, etc...) transmitter, I found that the battery box contacts were creating ripple on the power supply.
Maybe the internal resistance of your battery is a factor in the problem. 300 mV seems a fair lot.
Or could it be that the power switch is resistive. Do you see ripple across it? A capacitor across it?


You sir, are a very intelligent individual. I took the battery box apart and found that they are doing something a little unusual...they use 2 separate 4.8 volt battery packs with 4 leads leaving the battery box..... going up to the on/off switch and join the two together to form +9.6vdc when the system is energized. I isolated the +9.6vdc bus from the switch and wired in an external 9.6vdc nicad pack. No strange modulated ripple!!!....nice clean waveform!!!, no buzzing servos!!! Apparently the original Proline transmitter charger was comprised of 2 separate 4.8vdc chargers. I'm going to install a 9.6vdc nicad pack and rewire the switch to accept a conventional 9.6vdc charger. Thanks very much for your tenacity and help on this. My thanks also to the gentleman that is responsible for RC Model Reviews and this forum.... I think his name is Bruce....obviously another pretty sharp individual.

I now have an old Proline RF deck that I have no use for. Drop me an email patrickrel@hotmail.com
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Re: FrSky....Christmas in July

Postby RCModelReviews » Wed Jul 21, 2010 11:53 pm

Whiteprop wrote: My thanks also to the gentleman that is responsible for RC Model Reviews and this forum.... I think his name is Bruce....obviously another pretty sharp individual.

Blush! :oops:

Just spread the word about RCModelReviews so others can benefit too!
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Re: FrSky....Christmas in July

Postby JMP_blackfoot » Thu Jul 22, 2010 12:12 am

Thanks for the compliment, it is Christmas in July after all !!!
As we say in my mother tongue: "Tout est bien qui finit bien"
I made my first radio in 1963, and have been making them ever since.
One receiver I had made (single-channel super-regen in these early days) worked for a while, then started misbehaving and became unusable. I took it apart and made another according to a different design with the same transistors, etc.. This second one worked fine at first, but soon misbehaved too. I made a third one, same story....
They were powered by the same 4.5V flat lamp battery. It just happened that the battery was almost dead and would recover while I made a new receiver !!!
Lesson learned: make sure of the power supply first.
While working as tech support for Rank Xerox, I even had two cases of customers complaining that their machine did not work, only to find upon my questioning that the machine wasn't plugged to the mains!
In your case, I really should have thought of it earlier.

PS1: Both Bruce and I seem to be the kind to not give up on a challenge like this.
PS2: Email on its way.
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Re: FrSky....Christmas in July

Postby Whiteprop » Thu Jul 22, 2010 1:43 am

Just for the record, I just received an email from Frsky after sending them an email early this morning describing the problem. Their suggestions were:
1 Relocate the module/antenna to best avoid the encoder circuitry.
2 Shorten the Supply, PPM, and Common line as much as possible.
3 Try another power supply (Battery Pack)

In my opinion, very prompt and effective customer tech support. Their #3 suggestion..the battery pack, nailed the problem right on the head!

I'm Sold!!!

I now have 2 out of 2 very nicely operating systems and definately will be buying more. Will be posting from time to time reporting on how the systems are doing in actual use in the testbed aircraft.

Thanks again to all that weighed in on this particular problem.
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Re: FrSky....Christmas in July

Postby JMP_blackfoot » Thu Jul 22, 2010 1:10 pm

Now you could continue the update of your Proline transmitter by fitting a new computer encoder like the Microstar 2000:
http://mstar2k.com/index.php?option=com ... &Itemid=11
and have all the bells and whistles of modern technology. It deserves it !
Also see:
http://www.qsl.net/k5bcq/MS2K/MS2K.html


Happy flying!
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