Blueadventures Posted October 3, 2023 Share Posted October 3, 2023 1 hour ago, RFguy said: Unless you have a sick Alternator Regulator, I dont think it should need the capacitor. Well, I had a colleague the other week and was IDENTICAL symptoms- and it was the connector.... I'd be looking there. TX was fine. Loosening the screws can tell you if you have some sort of microphonic in the radio. BTW when you say "It's a screw in antenna. Antenna is in the tail fin." - Jabiru factory dipole antennas in the tail are not screw on antennas- what are you referring to ? I would expect that wiring in a capacitor 22,000 size would not damage anything and at worst would be a waste of about $20 and at best may improve the situation??? RF, your reply comment is appreciated, thanks mate. 1 Link to comment Share on other sites More sharing options...
RFguy Posted October 3, 2023 Share Posted October 3, 2023 The only reason I would be hesitant of that size is that you want to make sure it is not being SWITCHED IN. IE it's always across the bbattery and NOT being switched by a contactor . Why? Because a capacitor that size will be a infinite current sink when power is applied- this will tend to lessen the lifespace of any relay contacts or switching contacts. IE a bad idea. Also if there is a fault condition, the capacitor will be ablwe to supply zillions of amps (briefly) . So, suggest avoid using it. If there is alternator noise, that will be some different problem. Some instruments are suceptible to noise, and this should have their power supply LC line filter. You WONT get static like being mentioned here for any likely Jab reason . glen 1 1 1 Link to comment Share on other sites More sharing options...
shajen Posted October 3, 2023 Author Share Posted October 3, 2023 RFGuy, I was referring to the connection on the aerial lead going into the radio. It just screws into the back of the brick part of the Trig radio. There isn’t any 90degrees connection. Hey, I’m learning such a lot here! Next week, or when the weather settles down, I’ll be seeing the avionics man again and will bring up your suggestions. if I’m still struggling to get this problem sorted, can I arrange for you to have a look? im considering the MGL singles for engine monitoring, but no room for another hole, so was thinking I’d get a gauge that showed RPM also and use that slot. Thoughts on this? Link to comment Share on other sites More sharing options...
RFguy Posted October 5, 2023 Share Posted October 5, 2023 I think MGL is always a good option, they do listen to their customers, also. Maybe can take a look but we're along way from that yet, lots of things still to check. My guess is vibration related. Oh, BTW though WHAT is the 12V bus voltage at 1000RPM, 1500 , 2000, and 2300RPM ???? I've seen a regulator putting out excessive voltages causing voltage spike protectors start to act and putting lots of noise on the 12V... 1 Link to comment Share on other sites More sharing options...
shajen Posted October 5, 2023 Author Share Posted October 5, 2023 New regulator, should be ok? we are going there on Saturday, so will check the voltages. Will also check the vibration issue you suggested. Thanks again! I will get this problem sorted out!!! Jenny Link to comment Share on other sites More sharing options...
shajen Posted October 11, 2023 Author Share Posted October 11, 2023 RFGuy, a question for you. Is a dc to dc converter the same as a noise suppressor? Heres where I’m up to now … I’ve sent the radio back to Trig, they suggested they would check the modulation and adjust the receiving if necessary. I’ve borrowed my friends trig radio, same issues, so we’ve fitted some ferrite beads to the radio wires and the regulator. Did actually make a difference. We also checked the VSWR and all good there. Now one person who has done a bit of avionics suggested an automotive noise suppressor, while another friend who just enjoys electronics, suggested the dc to dc converter. Would love you thoughts again please? But it does seem to be the right track. PS, I’m also going to get my hearing checked, just in case some of the issue is me! Hahaha Jenny Link to comment Share on other sites More sharing options...
Blueadventures Posted October 11, 2023 Share Posted October 11, 2023 Long shot here; are your ignition ground wires shieled and the shield grounded at only one end? Link to comment Share on other sites More sharing options...
shajen Posted October 11, 2023 Author Share Posted October 11, 2023 No, the ignition wires aren’t shielded. Spoke to Jabiru about them and the say they have always been like that. They don’t think that should be an issue 1 Link to comment Share on other sites More sharing options...
Blueadventures Posted October 11, 2023 Share Posted October 11, 2023 2 hours ago, shajen said: No, the ignition wires aren’t shielded. Spoke to Jabiru about them and the say they have always been like that. They don’t think that should be an issue Have you read their manual about radio interference? They mention about the need to have all wires through firewall as shielded wire. Link to comment Share on other sites More sharing options...
Tasmag Posted October 11, 2023 Share Posted October 11, 2023 13 hours ago, Blueadventures said: Long shot here; are your ignition ground wires shieled and the shield grounded at only one end? The easiest way to achieve this is to use a single core shielded wire, connect the shield to ground at the engine and the wire to the mag. Then switch these two to ground the mag. When engine is running the shield is grounded. Link to comment Share on other sites More sharing options...
shajen Posted October 11, 2023 Author Share Posted October 11, 2023 Actually Tasmag, that is something my friend suggested the other day, but we forgot to do. I think you’re all on the right track now as it has to be either a shielding and/or earthing issue.. Everything, wiring, connectors, aerial, antennae, vibration has all been checked from firewall backwards. Now need to look at engine side of the firewall. The Ferrite beads helped, so hopefully some checking and adjusting of earthing points and shielding will solve this. I’m learning so much too.! Link to comment Share on other sites More sharing options...
RFguy Posted October 11, 2023 Share Posted October 11, 2023 A few good ideas by others, but Jabiru engines norrmally dont have too many problems.... hence I'm looking for a fault, or something specific to your installation. A DC DC convertor is not a noise suppressor. DCDC converters are more are noise generators... I do not think your problem has anything to do with the 12V bus noise UNLESS you have a sick alternator regulator... (which I have seen and do the same thing) Still need this info : WHAT is the 12V bus voltage at 1000RPM, 1500 , 2000, and 2300RPM ???? 1 Link to comment Share on other sites More sharing options...
RFguy Posted October 11, 2023 Share Posted October 11, 2023 and when you say , new regulator- new since new radio ? Link to comment Share on other sites More sharing options...
shajen Posted October 11, 2023 Author Share Posted October 11, 2023 Rf guy, new regulator fitted with new engine at the same time as new radio. checked voltages yesterday, 1000rpm 14.4, runups at 2000 14.4 and 2300 about the same. All what is expected, nothing higher or spiking, and nothing below 14. Link to comment Share on other sites More sharing options...
RFguy Posted October 11, 2023 Share Posted October 11, 2023 1000 rpm 14.4 is suspect high. a Jabiru does not charge below 1200-1500 RPM. I would expect < 13.2 unless it has been on charge. A rat is smelt. With all avionics on and 1000 RPM, I would expect < 13.5. New engine- remind me , what engine ? what sort of battery ??? Was 14.4 with avionics on , landing light on ? Doesnt seem usual behaviour, 1 Link to comment Share on other sites More sharing options...
RFguy Posted October 11, 2023 Share Posted October 11, 2023 (edited) AND.... further more- where is your voltage monitor source from- that sounds like it is connected to a DCDC converter somewhere !!! The DCDC converter will usually take varying voltage and convert to a constant voltage. I smell a rat !! I smell a noisy DCDC converter rat !! Edited October 11, 2023 by RFguy 1 Link to comment Share on other sites More sharing options...
Blueadventures Posted October 11, 2023 Share Posted October 11, 2023 11 hours ago, Blueadventures said: Have you read their manual about radio interference? They mention about the need to have all wires through firewall as shielded wire. Have you worked through this section of the Jabiru manual 'Radio Frequency (RF) Noise Reduction'? Link to comment Share on other sites More sharing options...
RFguy Posted October 11, 2023 Share Posted October 11, 2023 (edited) Mike said - "Have you worked through this section of the Jabiru manual 'Radio Frequency (RF) Noise Reduction'?" footnote- I dont think that's useful at this point, but a good point for folk without access to me. Edited October 11, 2023 by RFguy 1 Link to comment Share on other sites More sharing options...
shajen Posted October 12, 2023 Author Share Posted October 12, 2023 Blue adventures, yes I have looked at it, and I think there has been more than one issue. The ferrite clamps have actually reduced some of the noise. The noise is now more that the noise from the engine overrides what I can hear at higher rpm. I’m probably not describing it very accurately. 1 Link to comment Share on other sites More sharing options...
shajen Posted October 12, 2023 Author Share Posted October 12, 2023 RFGuy, I’m not sure about DCDC converters. I’ll have to ask someone where to look. I bet in the end it will be something like you say, fairly simple, but wrong thing in the wrong place! will get back to you next week when I’m back there. Link to comment Share on other sites More sharing options...
RFguy Posted October 12, 2023 Share Posted October 12, 2023 Pretty sure you have a DCDC converter in there, that does not need to be in there... could be some of the trouble, Highly unusual to have the voltage fixed like that, if the voltage aint varying, you have a DCDC conv in there and it should be removed, the system does NOT need it. Where did this aircraft come from ? IE non direct from factory I guess Link to comment Share on other sites More sharing options...
shajen Posted October 12, 2023 Author Share Posted October 12, 2023 RFGuy, it’s a Gen 4 3300 engine. Battery is 18 months old, think it’s called Full River. It is the correct one for my engine. Link to comment Share on other sites More sharing options...
RFguy Posted October 12, 2023 Share Posted October 12, 2023 OK, is a lead acid battery, not any sort of ltihium battery ? anyway, the DCDC converter needs to be found and removed (it will run avionics so it wil need ot be bypassed) Be sure to look in the log maintenance books to find out WHY it was installed, is a good idea first. But it is absolutely NOT required. Link to comment Share on other sites More sharing options...
shajen Posted October 12, 2023 Author Share Posted October 12, 2023 Sealed, lead acid. Haha, my maint book had NOTHING in it until I bought it. Spent heaps getting all the SDs etc up to date and getting everything “right”. Taken 18 months! He had all sorts of weird stuff in the dash such as house electrical wire! Anyway, will check next time I’m over there! So glad there are people on this forum willing to give advice:)) Link to comment Share on other sites More sharing options...
Blueadventures Posted October 12, 2023 Share Posted October 12, 2023 Maybe post some images of under the dash and engine compartment, showing the wiring and the items there. Link to comment Share on other sites More sharing options...
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