Turn and bank interference
Moderators: John Dean, Moderator
Turn and bank interference
I got the Esqual flying a couple of weeks back and one of the snags was the radio interference.
I improved the cable run off the dipole which made things better but finally discovered most of the problem is from the old fashioned electric turn and bank.
I picked up some hash from it when the panel was on test in the workshop and screened the supply and that improved things somewhat. The addition of the engine running has excited the whole thing and it's not acceptable, disconnect the T+B and all is OK.
I have the radio on a supply smoother and the headset/mic leads are all isolated and screened.
Same set up that the Jab has and it's a really sweet radio.
Ideas/comments, thanks Clive
I improved the cable run off the dipole which made things better but finally discovered most of the problem is from the old fashioned electric turn and bank.
I picked up some hash from it when the panel was on test in the workshop and screened the supply and that improved things somewhat. The addition of the engine running has excited the whole thing and it's not acceptable, disconnect the T+B and all is OK.
I have the radio on a supply smoother and the headset/mic leads are all isolated and screened.
Same set up that the Jab has and it's a really sweet radio.
Ideas/comments, thanks Clive
Ferrite beads?
Any particular type of bead?
I've heard of these used before but have never tried them.
Ta, Clive
I've heard of these used before but have never tried them.
Ta, Clive
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Choke
I have the radio on an inductive choke smoother so the interference isn't coming up the power lead into the radio, I think it's radiating back down the supply from the T+B and then getting picked up as RF though the radio aerial. Is that possible?
CJ
CJ
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- Mike Cross
- Site Admin
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If any of you want ferrite beads drop me a PM with your address and Il'll be happy to post you a couple. I end up with plenty spare at work. They are designed to simply clip onto the wire. Form a loop in the wire and clip on to it so the wire passes through the bead and then loops round and goes though again. I recommend a nylon tie-wrap round it to ensure it doesn't come loose and it will be a good idea to tie wrap it to a support so its weight is not dangling on the wire.
030881
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How about a new Turn & Slip/Bank/Co-ordinator?
Or get the existing one serviced?
Or have a hunt on eBay and the small ads for a replacement.
Not the cheapest options, granted, but if the gyro's motor is that noisy then I'd always wonder how long it will go for anyway.
I'm not just being flippant. In the past I've avoided expenditure and made do only to finally give in. Almost always I've thought afterwards, "why didn't I do this ages ago"!
Or get the existing one serviced?
Or have a hunt on eBay and the small ads for a replacement.
Not the cheapest options, granted, but if the gyro's motor is that noisy then I'd always wonder how long it will go for anyway.
I'm not just being flippant. In the past I've avoided expenditure and made do only to finally give in. Almost always I've thought afterwards, "why didn't I do this ages ago"!
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.
If the good Lord had intended man to fly, He would have given him more money.
It's new!
The T+B is new but was noisy the first time I powered it up. Got it from Light Aero.
The lads on the Jabiru owners have come up with similar suggestions, from Ralf:
If the T/B has a DC brush type motor a good way to reduce noise is fit a diode across the terminals for reverse shunt ie. the cathode (stripe) of diode to +ve terminal.
Diode can be 1N4004 thru 7 series. Adding a 0.1 capacitor across as well will finish the job.
I got this info from an IEEE publication in the 70s and it has worked for me on several generations of vehicles including electric radiator fans and fuel pumps. Can't be used on reversible motors (except ahead of the switch).
Ralph
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I have an EMI fitted to the radio + intercom supply. Thanks for the offer Mike, I just ordered some beads and a capacitor from Paul at partsforaircraft (cheap and arrived 18hrs later).
I'm still at work till middle of next week but will report back on progress as soon as I get home and start soldering.
Thanks again, Regards, Clive
The lads on the Jabiru owners have come up with similar suggestions, from Ralf:
If the T/B has a DC brush type motor a good way to reduce noise is fit a diode across the terminals for reverse shunt ie. the cathode (stripe) of diode to +ve terminal.
Diode can be 1N4004 thru 7 series. Adding a 0.1 capacitor across as well will finish the job.
I got this info from an IEEE publication in the 70s and it has worked for me on several generations of vehicles including electric radiator fans and fuel pumps. Can't be used on reversible motors (except ahead of the switch).
Ralph
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I have an EMI fitted to the radio + intercom supply. Thanks for the offer Mike, I just ordered some beads and a capacitor from Paul at partsforaircraft (cheap and arrived 18hrs later).
I'm still at work till middle of next week but will report back on progress as soon as I get home and start soldering.
Thanks again, Regards, Clive
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If this is a new T&B which is producing EMI, then you should contact the vendor and the manufacturer and notify them of the product defect. I am sure that neither of them want to sell a product that is unsatisfactory. EMI generation would not normally be tested in a production environment, but it should have been tested to be EMI compliant when the part was certified.
For the benefit of the rest of us, what make is this instrument?
For the benefit of the rest of us, what make is this instrument?
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Falcon indeed
Yep, it's a cheap Falcon import. I bought it 3 years ago so no joy with the supplier. I've spoken to light aero about another instrument out the batch and it was too long ago, and I can't say I blame them.
With these chinese things I think yer takes yer chance, I've been lucky in the past, a guy in the hanagr had three from Harry and they all had to go back. This was within the first year so Harry did the right thing. another guy's died the other week so I've had it apart and squirted some 3 in 1 in and it's up and running now.
Home in 2 days so will see, might stick it on a separate battery and let it run for 24 hours before I wire it in with all its jewelry.
Ta, Clive
With these chinese things I think yer takes yer chance, I've been lucky in the past, a guy in the hanagr had three from Harry and they all had to go back. This was within the first year so Harry did the right thing. another guy's died the other week so I've had it apart and squirted some 3 in 1 in and it's up and running now.
Home in 2 days so will see, might stick it on a separate battery and let it run for 24 hours before I wire it in with all its jewelry.
Ta, Clive