RF Filter required?
 

I'm ready to try a Castle Creations HV85 with my Futaba 14MZ on 50 MHz. Wondering if I need a filter between the receiver and ESC? Had none with the Jeti stuff.

Jim O

RE: RF Filter required?
 

Jim,
I have the same setup, and I have the filter on mine. The reason is, I needed the filter on the Jeti setup and just left it in place. Since then I have
gone to the 2.4 and still use the filter. So I guess what I am saying is, it is now just insurance for me.

RE: RF Filter required?
 

Hi Jim,

I use one with HV85 and 12Z on 2.4. Not sure if I really need it, but since the filter has the proper length to reach between ESC and receiver, and I have one anyway, so instead of using the extension, I put the filter there... :-)

Kevin

RE: RF Filter required?
 

I am using one on mine, I didn't try it without it however. One thing, you'll have to remove the filter if you plan on hooking it up to the PC programming link. Mine didn't work with the filter in between the PC and the controller.

RE: RF Filter required?
 

I have one in my setup. I had radio glitch few months ago, a friend loan me one and the glitch disappered. Maybe just coincidence, but I feel more comfortable with it.... still, I'm not sure it is required.:D

Luke

RE: RF Filter required?
 

Again,just one's personal experience(all with CC 85HV):
35Mhz-no filter-occasional ,short, fail-safe episodes.
35Mhz-filter -no fail-safe episodes.
2.4 Ghz-no filter no problems(only thing -had one dodgy motor battery which would drop below the progammed 30V low cut-off and the CC "simulated" the fail-safe low throttle)
All the above with pretty standard F3A electric set-ups.

Just one other observation-not my scene, but there are quite a few electric helicopters in my club there were so many glitches on 35 Mhz,whatever else was in the radio set-up, that almost without exception, all the flyers changed to 2.4Ghz which solved the problems....

RE: RF Filter required?
 

Jim,

I haven't used a filter as of yet. I had "zero" problems up until I put together this Element. I am getting glitches quite often now. I just sent in all my equipment to Airtronics and got it back Friday. Took the Element out flying today and nearly lost her on the first flight. I started getting the glitches when I moved the esc forward under the motor at the front of the chin cowl opening (which was about 20 flights ago). I took some things apart tonight, and saw that the Esc to rec wire was chafing against the carbon fiber mount for the Esc and had broke through the shielding on the signal part of the wire (touching the carbon fiber). I'm wondering if this was my issue. I will test again tomorrow (well, today now).... I will also take some garbage bags just in case.. lol

Chris

RE: RF Filter required?
 

Chris' experience is what I would expect. If you move the esc closer to the noise generator (i.e. motor) then it will couple more onto the signal line coming from the rx. It might have been made worse by contacting carbon fiber. Even though the lines from the rx are opto isolated (assuming there is no other noise path from the motor connection) in the HV85 you can still couple onto the input lines if you are close enough to the motor. I don't think it would make much difference what RF band your rx is working on, but it probably has a lot more to do with how it is designed in the first place. The motor isn't throwing off much energy in the 72 or 35mhz range (some distant harmonic of the switching frequency) so I think what we experience is noise on the signal and voltage line to the esc which cause problems at the rx. Most of the rx's out there seem to share a common power bus across all the servos so if noise gets onto the power line and signal line then it can affect the rx and all servos connected to it. So, to be safe, I decided to hook up the filter. I guess an opto isolated interface to the esc would achieve the same result as long as the isolator where far enough away so that the noise wouldn't couple onto the rx lines. That is basically how the optoisolated ignition kill switches work on large aircraft. The noisy ignition line is connected to the isolator. It does not allow the ignition noise to ride to the rx on the leads. It has the added benefit of being a kill switch. Too bad it is just an on/off. A real optoisolated throttle control would be neat. Run a fiber optic line to the esc from a sending unit that is located near the rx......

RE: RF Filter required?
 

Which filter did you use?

It's funny, I've had 5 or 6 2m electrics now, and this is the only one I've had issues with. Might need to add one to it.

Thanks,

C

RE: RF Filter required?
 

Good question. I must admit that I don't know which filter I am using. It was in my Pinnacle when I bought it and I carried it forward into my Passport. I'll hunt around and see if I can figure it out.

RE: RF Filter required?
 

No worries. It's a futaba choke. I remember that's what Tom had in it.

Chris

RE: RF Filter required?
 

Chris,

I've used the filter/choke from Cermark with no problems at all and I'm also using the Futaba one (now)... no problems all around, but then again, I'm on 2.4.

RE: RF Filter required?
 

Okay guys,
the above posts assume one knows what a "filter" is and what it does. I'm assuming it helps with interference. I have an Astro 60 with an Astro 204D esc. I'm running 10 A123s and pulling 30 amps. I'm also using an external BEC. I'm getting what appears to be RF interference, would a "filter" help? By the way, I have caps running between adjacent brush posts, but none crossing to an opposing brush.
Walt

RE: RF Filter required?
 

It helps with intereference caused by your electric motor. Here's a link to one: http://www3.towerhobbies.com/cgi-bin...&I=LXDKP6&P=SM

RE: RF Filter required?
 

thanks for the lead. 20 bucks isn't a bad investment against a $500 plane.
Walt

RE: RF Filter required?
 

Thanks guys, I ordered one.

Jim O

RE: RF Filter required?
 

Luke,..... You're welcome

Jim, I posted the same question on this forum (04/03/2008). Almost every post advocated using it as added insurance against interference.
There was one interesting post that took the view that the filter was masking a basic installation problem and the correction of the installation problem would mean you don't need the filter. This post also advocated twisting the ESC wires to eliminate interference. I'm not an expert in the area so I run a filter as cheap insurance.

Terry

RE: RF Filter required?
 

Chasing small throttle burps and short duration holds can be very pesky.

From my experience (using Castle 45HV and 85HV and a variety of JR PCM recievers and 2.4 recievers) -
- a choke on the ESC lead next to the ESC rarely helps.
- a choke on the ESC lead next to the RX helps the majority of the time.
- moving wires and components around to better isolate them helps on occasion.
- rotating the receiver 90 degrees (in any direction or axis) may help (or hurt).
- type of choke really doesn't matter much - I ended up using an 18" aileron extension woven around itself in a small circle - cheapest and lightest choke, and worked as well as anything else.

Once I changed to 2.4, I've not used a choke, and not found any reason to use one.

Regards,

Dave