---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 07/29/08: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:00 AM - Re: Re: BnC Continuous Duty Contactor 12 v (Ken) 2. 05:04 AM - AT150 Interrogation Light (fox5flyer) 3. 08:27 AM - Re: AT150 Interrogation Light (Matt Prather) 4. 09:20 AM - Re: AT150 Interrogation Light (Ron Quillin) 5. 02:04 PM - Re: AT150 Interrogation Light (Bill Boyd) 6. 02:45 PM - Capacitors for trim servos? (Ralph Finch) 7. 05:03 PM - Re: Capacitors for trim servos? (Eric M. Jones) 8. 05:38 PM - Re: BnC Continuous Duty Contactor 12 v (Robert L. Nuckolls, III) 9. 06:08 PM - Re: Re: BnC Continuous Duty Contactor 12 v (Robert L. Nuckolls, III) 10. 06:08 PM - Re: Re: Z-19/RB Question (Robert L. Nuckolls, III) 11. 06:11 PM - Re: Re: BnC Continuous Duty Contactor 12 v (Robert L. Nuckolls, III) 12. 06:21 PM - Re: Capacitors for trim servos? (Robert L. Nuckolls, III) 13. 06:36 PM - Re: Grounding of com antenna on Tube and Fabric airframe (Robert L. Nuckolls, III) 14. 09:29 PM - Re: PMag Preflight Check (Michael T. Ice) 15. 10:27 PM - Re: PMag Preflight Check (Rob Stapleton, Jr.) ________________________________ Message 1 _____________________________________ Time: 05:00:51 AM PST US From: Ken Subject: Re: AeroElectric-List: Re: BnC Continuous Duty Contactor 12 v The Trombetta mentioned below looks like a type 70 in an expensive package to me. In a nutshell my thoughts on the type 70 criticism are: some of it is true, most of it is irrelevant. Type 70 contactors are widely available, affordable, and no real risk with aeroelectric architecture except perhaps for a B lead overvoltage interupter with an IR alternator. Sure I might have to replace one of mine in my lifetime. I think I have a spare $14. unit in stock from the local hardware store but I'd also expect to find one at most any airport if needed. However if Eric or anyone wanted to suggest a particular "cheap" or value priced Omron part number or series, I would check it out for cost effectiveness and reasonable availability and interchangeability. Lots of discussion in the archives Michael but I would not hesitate to use the type 70's in a new design for the time being. Better stuff is available at a price but I haven't seen anything that has a cost and availability of interest to me yet. Ken Jeffrey W. Skiba wrote: > > I looked at some of those below and found this in the process: > http://www.trombetta.com/cm/pdfs/defender-family.pdf > > > Anybody use one of these? > Looks like they can be had for fairly cheap and have some type of TVS > (Transient Volt Suppression) built in! > Looks like it's a little heavier than some of the more expensive ones, so I > guess that's the trade off for cost. > > Thoughts? > > Jeff. > > > > I have railed against these Type-70 contactors for years. But they are > almost obsolete. Most electronics distributors have dropped them from their > lines. > > Problems-- > > 1) Low Temperature rating. Only 122F max. You could land at Furnace Creek in > Death Valley in May and take off in October. Maybe. This is primarily due to > the Nylon innards. This is a drop-dead reason to avoid the part. > > 2) Not sealed. Not dust proof, or fuel proof. > > 3) Low interrupt capacity. > > 4) High hold current---16 ohm coil. Almost one amp. > > 5) Low hold force. The specifications call for specific orientation. 2G > rating? > > 6) Wildly wrong for B&C to use coil suppression diodes on these. This causes > short lifetimes on the B&C parts. > > 7) Not designed to open against voltages above 36 volts. (So forget the > B-lead applications) > > See: www.stancor.com > > There are better ways to go. Omron's line of automotive contactors (CHEAP) > and Kilovac's EV200 series, Blue Sea 9012, Gigavac's GX-11. Expensive but > preferred. > > Can you use them? Sure. Should you use them?....not on my bird, Bubela. > > Better yet, avoid all contactors and use manual switches if you can. > > ________________________________ Message 2 _____________________________________ Time: 05:04:08 AM PST US From: "fox5flyer" Subject: AeroElectric-List: AT150 Interrogation Light I have a Narco AT150 transponder in a Kitfox 5 with the antenna on the belly with a 5.5" ground plate. It seems to be working fine according to ATC. Good data and the mode C is accurate. However, the interrogation light is on steady, rather than blinking as the radar sweeps past it. It used to be just fine, but at some point it began to act differently where it would flicker, especially on the ground. Now, if the engine is off and I activate it, the interrogation light comes on for a few seconds, then turns off. I believe that's how it's supposed to act. However, when flying, it seems to come on steady and stay that way with an occasional flicker during flight. As I said, ATC says it's working fine. Has anyone seen this? Any idea what my problem is? Several times I've removed it, cleaned and lubed the contacts, and replaced it with the same results. Since it's working fine, I'm not to worried about it, but I'd like to get this light working like it's supposed to. Thanks for any help offered. Deke ________________________________ Message 3 _____________________________________ Time: 08:27:49 AM PST US Subject: Re: AeroElectric-List: AT150 Interrogation Light From: "Matt Prather" Maybe you have something in the airplane generating noise which causes the transponder to reply - even though it wasn't interrogated by an actual radar signal. How's the audio in your comm radio? Any new noise? Off the top of my head, maybe you have a bad spark plug wire, or alternator diode or something like that. Does your engine have dual ignition systems? If yes, does the transponder behave the same way on each of them separately? Can you turn the alternator off and still run the txp from battery (as a test)? I doubt you have a DME in a Kitfox, but they operate in the same band as the transponder so might be a source of interference. As a long shot, possibly your cell phone is setting it off. Did you get a new phone? Does it misbehave with the phone turned off? I can't recall if the AT150 has a remote ident button, but maybe the wire that connects that circuit isn't isolated properly. I think those work by grounding the wire. Vibration might cause that wire to rub against ground. In reality, the pin in the shell connector for that function probably doesn't even have a wire in it, so that's probably not the issue. Maybe the reply discrimination circuit is messed up in your txp. Possibly a radio shop has a loaner unit you could swap into the tray. Or maybe they can test the unit for that functionality. Regards, Matt- > I have a Narco AT150 transponder in a Kitfox 5 with the antenna on the > belly with a 5.5" ground plate. It seems to be working fine according to > ATC. Good data and the mode C is accurate. However, the interrogation > light is on steady, rather than blinking as the radar sweeps past it. It > used to be just fine, but at some point it began to act differently where > it would flicker, especially on the ground. Now, if the engine is off and > I activate it, the interrogation light comes on for a few seconds, then > turns off. I believe that's how it's supposed to act. However, when > flying, it seems to come on steady and stay that way with an occasional > flicker during flight. As I said, ATC says it's working fine. > Has anyone seen this? Any idea what my problem is? Several times I've > removed it, cleaned and lubed the contacts, and replaced it with the same > results. Since it's working fine, I'm not to worried about it, but I'd > like to get this light working like it's supposed to. > Thanks for any help offered. > Deke > ________________________________ Message 4 _____________________________________ Time: 09:20:11 AM PST US Subject: Re: AeroElectric-List: AT150 Interrogation Light From: Ron Quillin Matt, Deke, I was thinking many of the same things, but given ATC was reporting his unit was 'normal', I discounted them, as I would have thought they would have complained of excessive replies or ident's making a mess of their sereens. IIRC, the 150, unlike the 50, does have a remote ident pin. I'll look in my SM tonight as see if there may be a some failure to the light circuit only, doesn't seem likely, but... If the unit is in an area with many ADSB units and/or heavy radar coverage, it could actually be interrogated at some high rate and the reply light is working normally. One would expect it to be a bit quieter on the ground, out of sight of multiple radar sites but perhaps still seeing ADSB inquires. However, Deke reports a change. Has anything else changed within the AC that may give a clue? I agree, a bench check at a radio shop or exchange unit should be near the top of things to try. Ron Q. At 08:22 7/29/2008, you wrote: > >Maybe you have something in the airplane generating noise which causes the >transponder to reply - even though it wasn't interrogated by an actual >radar signal. How's the audio in your comm radio? Any new noise? Off >the top of my head, maybe you have a bad spark plug wire, or alternator >diode or something like that. Does your engine have dual ignition >systems? If yes, does the transponder behave the same way on each of them >separately? Can you turn the alternator off and still run the txp from >battery (as a test)? I doubt you have a DME in a Kitfox, but they operate >in the same band as the transponder so might be a source of interference. > >As a long shot, possibly your cell phone is setting it off. Did you get a >new phone? Does it misbehave with the phone turned off? > >I can't recall if the AT150 has a remote ident button, but maybe the wire >that connects that circuit isn't isolated properly. I think those work by >grounding the wire. Vibration might cause that wire to rub against >ground. In reality, the pin in the shell connector for that function >probably doesn't even have a wire in it, so that's probably not the issue. > >Maybe the reply discrimination circuit is messed up in your txp. Possibly >a radio shop has a loaner unit you could swap into the tray. Or maybe >they can test the unit for that functionality. > > >Regards, > >Matt- > > > > I have a Narco AT150 transponder in a Kitfox 5 with the antenna on the > > belly with a 5.5" ground plate. It seems to be working fine according to > > ATC. Good data and the mode C is accurate. However, the interrogation > > light is on steady, rather than blinking as the radar sweeps past it. It > > used to be just fine, but at some point it began to act differently where > > it would flicker, especially on the ground. Now, if the engine is off and > > I activate it, the interrogation light comes on for a few seconds, then > > turns off. I believe that's how it's supposed to act. However, when > > flying, it seems to come on steady and stay that way with an occasional > > flicker during flight. As I said, ATC says it's working fine. > > Has anyone seen this? Any idea what my problem is? Several times I've > > removed it, cleaned and lubed the contacts, and replaced it with the same > > results. Since it's working fine, I'm not to worried about it, but I'd > > like to get this light working like it's supposed to. > > Thanks for any help offered. > > Deke > > > > ________________________________ Message 5 _____________________________________ Time: 02:04:12 PM PST US From: "Bill Boyd" Subject: Re: AeroElectric-List: AT150 Interrogation Light My Garmin xponder does that whenever both Pmags are powered up. If I kill one side, it behaves normally again. If I kill the other side, the problem remains. ATC seems to see me okay most of the time while this is going on. Strange, indeed. Makes it hard to see true interrogation hits. -Bill B On Tue, Jul 29, 2008 at 12:13 PM, Ron Quillin wrote: > > Matt, Deke, > > I was thinking many of the same things, but given ATC was reporting his > unit was 'normal', I discounted them, as I would have thought they would > have complained of excessive replies or ident's making a mess of their > sereens. IIRC, the 150, unlike the 50, does have a remote ident pin. I'll > look in my SM tonight as see if there may be a some failure to the light > circuit only, doesn't seem likely, but... > > If the unit is in an area with many ADSB units and/or heavy radar coverage, > it could actually be interrogated at some high rate and the reply light is > working normally. One would expect it to be a bit quieter on the ground, > out of sight of multiple radar sites but perhaps still seeing ADSB inquires. > However, Deke reports a change. Has anything else changed within the AC > that may give a clue? > > I agree, a bench check at a radio shop or exchange unit should be near the > top of things to try. > > Ron Q. > > At 08:22 7/29/2008, you wrote: > >> mprather@spro.net> >> >> Maybe you have something in the airplane generating noise which causes the >> transponder to reply - even though it wasn't interrogated by an actual >> radar signal. How's the audio in your comm radio? Any new noise? Off >> the top of my head, maybe you have a bad spark plug wire, or alternator >> diode or something like that. Does your engine have dual ignition >> systems? If yes, does the transponder behave the same way on each of them >> separately? Can you turn the alternator off and still run the txp from >> battery (as a test)? I doubt you have a DME in a Kitfox, but they operate >> in the same band as the transponder so might be a source of interference. >> >> As a long shot, possibly your cell phone is setting it off. Did you get a >> new phone? Does it misbehave with the phone turned off? >> >> I can't recall if the AT150 has a remote ident button, but maybe the wire >> that connects that circuit isn't isolated properly. I think those work by >> grounding the wire. Vibration might cause that wire to rub against >> ground. In reality, the pin in the shell connector for that function >> probably doesn't even have a wire in it, so that's probably not the issue. >> >> Maybe the reply discrimination circuit is messed up in your txp. Possibly >> a radio shop has a loaner unit you could swap into the tray. Or maybe >> they can test the unit for that functionality. >> >> >> Regards, >> >> Matt- >> >> >> >> > I have a Narco AT150 transponder in a Kitfox 5 with the antenna on the >> > belly with a 5.5" ground plate. It seems to be working fine according >> to >> > ATC. Good data and the mode C is accurate. However, the interrogation >> > light is on steady, rather than blinking as the radar sweeps past it. >> It >> > used to be just fine, but at some point it began to act differently >> where >> > it would flicker, especially on the ground. Now, if the engine is off >> and >> > I activate it, the interrogation light comes on for a few seconds, then >> > turns off. I believe that's how it's supposed to act. However, when >> > flying, it seems to come on steady and stay that way with an occasional >> > flicker during flight. As I said, ATC says it's working fine. >> > Has anyone seen this? Any idea what my problem is? Several times I've >> > removed it, cleaned and lubed the contacts, and replaced it with the >> same >> > results. Since it's working fine, I'm not to worried about it, but I'd >> > like to get this light working like it's supposed to. >> > Thanks for any help offered. >> > Deke >> > >> >> >> >> > > ________________________________ Message 6 _____________________________________ Time: 02:45:26 PM PST US From: "Ralph Finch" Subject: AeroElectric-List: Capacitors for trim servos? Hey...not trying to start an argument but as an electronic nobody, these two advices about caps seem to recommend very different cap sizes (uF). How to resolve? Ralph Finch -----Original Message----- From: Robert L. Nuckolls, III Sent: Monday, July 14, 2008 8:00 AM Subject: Re: AeroElectric-List: Trim noise in Audio speaker Try the .22 uF capacitor first 272-1070. Try the pair of 272-1436 if the first doesn't work. These need to be tied into the harness as close as practical . . . 2-3 inches outside actuator housing. -----Original Message----- From: Eric M. Jones Sent: Monday, July 28, 2008 6:43 AM Subject: AeroElectric-List: Re: Connectors for trim servos? 2) Noise suppressor capacitors are easy to add. One .01 uF ceramic across the motor brushes and one 0.1 uF ceramic from each brush to ground (which you might want to add) is a standard approach. Keep the leads critically short. ________________________________ Message 7 _____________________________________ Time: 05:03:24 PM PST US Subject: AeroElectric-List: Re: Capacitors for trim servos? From: "Eric M. Jones" In motors of this size, 0.1uF ceramic caps will do. If caps get below 0.005uF they may not be so effective, above 0.2 they are getting physically big. But the critical thing is to keep the leads short, and use ceramic caps for their stability, lifetime and voltage withstand. Often schematics differ since they indicate how the prototype was built. In wideband noise filtering (as opposed to ripple filtering or timing applications) more is usually better. Sometimes the exact values are critical, sometimes not so much. In this case, not so much. Just use 0.1 uFs 50V ceramic disk caps. Even Radio Shack has them..... -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones@charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=195654#195654 ________________________________ Message 8 _____________________________________ Time: 05:38:07 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: BnC Continuous Duty Contactor 12 v > >I am using it as a battery contactor but with a Very High out alternator, >200amps ..... So I am thinking I need to find a bigger contactor ? or my >other thought - guess was maybe to run TWO Stancor 70-902 contactors in >parallel ? with the extra wires also... but concern here is that something I >haven't thought of will smoke something if both are not closed ? No paralleling . . . it's not practical. Yes . . . you need a contactor rated for the task. In the el-cheeso line of contactors, the Stancore 586-902 is rated for this service and should be a good value. See: http://aeroelectric.com/Mfgr_Data/Contactors/Stancor-WhiteRogers/Stancor_586-Series.pdf You can get these for about $50 from Allied Electronics at: http://tinyurl.com/5bxtnm If you're interested in "stepping up", these are equally suited to the task: Cutler-Hammer 6041H105 http://aeroelectric.com/Mfgr_Data/Contactors/Eaton_CH/6041SeriesPowerRelays.pdf or Tyco Killvac EV200 http://aeroelectric.com/Mfgr_Data/Contactors/Tyco_Kilovac/ev200.pdf Be advised that some builder's have reported noise from the "power saver" feature on the EV-200 that required filtering. Easy to do should it become necessary. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 9 _____________________________________ Time: 06:08:16 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: BnC Continuous Duty Contactor 12 v At 07:33 AM 7/28/2008 -0700, you wrote: > >I have railed against these Type-70 contactors for years. But they are >almost obsolete. Most electronics distributors have dropped them from >their lines. > >Problems-- > >1) Low Temperature rating. Only 122F max. You could land at Furnace Creek >in Death Valley in May and take off in October. Maybe. This is primarily >due to the Nylon innards. This is a drop-dead reason to avoid the part. > >2) Not sealed. Not dust proof, or fuel proof. Neither are most of the switches, contactors, even alternators that have been used with great success for decades. >3) Low interrupt capacity. But they're never asked to interrupt anything but normal pre-parking currents in aircraft . . . maybe 10A? For a time, the TC aircraft industry attempted to use the intermittent duty versions of these contactors for starter control service and found them unsatisfactory. However, they have proven a good value (I didn't say lasts forever) in light aircraft battery contactor service. In other words, the 8x more expensive 6041H series mil spec contactors did not last even 4x as long. Given the exceedingly light duty cycles expected from these devices the way we use them (in failure tolerant systems) they are of good value. >4) High hold current---16 ohm coil. Almost one amp. Which is not an issue as long as the alternator is running . . . you have power to burn. When the alternator is not running, this device is turned off for endurance mode operations. >5) Low hold force. The specifications call for specific orientation. > 2G rating? I've tested these at over 12g. Where do you find any recommendations with respect to g-loading. I can tell you that the vertical orientation is to reduce potential for moisture ingress due to coindensation and/or splash . . . as you've noted, they are not sealed. As a battery contactor, they are closed in all phases of flight and exceedingly difficult to force open with g-loads. >6) Wildly wrong for B&C to use coil suppression diodes on these. This >causes short lifetimes on the B&C parts. I've also demonstrated that this is not true. >7) Not designed to open against voltages above 36 volts. (So forget the >B-lead applications) True . . . and not recommended to routinely SWITCH such loads but will be just fine as suggested on the third page of: http://aeroelectric.com/articles/Adapting_IR_Alternators_to_Aircraft.pdf where we will routinely switch the alternator ON and OFF at will without exceeding the contactors rated operating conditions. >See: www.stancor.com > >There are better ways to go. Omron's line of automotive contactors (CHEAP) >and Kilovac's EV200 series, Blue Sea 9012, Gigavac's GX-11. Expensive but >preferred. Preference is another matter entirely . . . and when it comes to preferences, I'll concede to anyone's desires. I've even cited alternatives that include the Kilovac EV200. But let us not resort to generating climates of fear on the part of the neophyte airplane builders. The track record on this part for return on investment has been exemplary. >Can you use them? Sure. Should you use them?....not on my bird, Bubela. By all means sir . . . >Better yet, avoid all contactors and use manual switches if you can. This IS a stretch Eric. It's true that contactors are the most highly stressed devices on an airplane after generators and followed by alternators. It's also true that they are a significant maintenance item on EVERY airplane from the C-150 through the Hawkers. But so are tires, batteries, generators, etc. The artfully crafted system tolerates these service life limitations without placing the aircraft or occupants at risk. Can we really recommend that anyone resort to manually operated high current switches (bring high current conductors within reach of pilot) just to avoid a service-life issue on a 100-our a year airplane? >"Facts do not cease to exist because they are ignored." > ---Aldous Huxley Absolutely! Please separate deeply held beliefs from demonstrable fact. I have outlined the facts . . . which of these do you find to be in error? Bob . . . ________________________________ Message 10 ____________________________________ Time: 06:08:49 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z-19/RB Question At 07:19 AM 7/28/2008 -0700, you wrote: > >Bob, > >Understood, that EBus switch is ALTERNATE path to powering the EBus. And >as you said, turn it on, check ATIS are all good preflight procedures to >test this path. > >I just wanted to confirm that once you are started and the alternator is >running smoothly, it would do no harm to leave the EBus switch turned on >(closed) during normal operations. No harm at all. This part of the design philosophy. No mis-ositioning of switches places any part of the system at-risk for failure. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 11 ____________________________________ Time: 06:11:18 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Re: BnC Continuous Duty Contactor 12 v At 10:31 PM 7/28/2008 -0500, you wrote: > >I looked at some of those below and found this in the process: >http://www.trombetta.com/cm/pdfs/defender-family.pdf > > >Anybody use one of these? >Looks like they can be had for fairly cheap and have some type of TVS >(Transient Volt Suppression) built in! >Looks like it's a little heavier than some of the more expensive ones, so I >guess that's the trade off for cost. These should be entirely suitable for use as battery contactors in the OBAM aircraft. Bob . . . ________________________________ Message 12 ____________________________________ Time: 06:21:43 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Capacitors for trim servos? At 02:39 PM 7/29/2008 -0700, you wrote: > >Hey...not trying to start an argument but as an electronic nobody, these two >advices about caps seem to recommend very different cap sizes (uF). How to >resolve? > >Ralph Finch We have a first-hand report that the pair of 272-1436 capacitors back to back "did the job". Would something else work as well? Probably. My selection of "try it" parts was based on availability of parts for a quick look-see. Given that the motor is at the end of long, small gage wires, inrush at the switches due to "too large" capacity is mitigated. But if you'd like to conduct a science experiment an test other sizes, we'd be interested in the results. This is always a bit of a crap-shoot. Noise issues are a unsatisfactory combination of noise intensity, attenuation in the conduction pathway, and noise susceptibility. When working qualification issues in the lab, we have benefit of calibrated equipment with which we can put numbers on all three variables. Once the combination finds it's way to your airplane, the most you can tell us is that the noise exists and you find it unacceptable. The first thing to try is reduce the signal at the source. The next thing to try is increase attenuation in the coupling mode. The last thing you can do is reduce the susceptibility in the victim. For the moment, our brute-force experiment to reduce it to acceptable levels at the source were successful. Is it the optimum solution? Got a few $thousand$ to spend, we can take it to the lab and find out. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 13 ____________________________________ Time: 06:36:05 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Grounding of com antenna on Tube and Fabric airframe At 11:16 AM 7/28/2008 -0700, you wrote: > >I have a Kitfox 7 that I just had inspected (I have 1 hour on it so far) >and am having issues with my transmission and reception quality and >effectiveness. Here is a brief description of my problem: > >When at the airport (taxing, and in the pattern) my radio seems to work >fine with the exception of an intermittent static blip every two seconds >or so. As I get farther out, the intermittent blip becomes more >pronounced to the point that my transmission and reception is horrible >(transmission is worse than reception though by a long shot). Basically, >my communications become unintelligible around 4-5 miles out. I >originally didn't have a ground plane other than the mounting plate for >the antenna (which the manual says is fine) so I added one on the advice >of a couple people and the problem has not changed a bit. > >Here is a question: Does the antenna itself have to be electrically >bonded to the airframe? I think the answer is yes and according to the >maker of my antenna, mine is through the mounting hardware. However, the >builder's manual says to remove any fabric and grind down the powder >coating under the antenna to get a good bond. Would this be my >problem? Would the issues I have described be symptomatic of a poorly >grounded antenna? I know just enough about electronics to be dangerous so >any help and advice would be greatly appreciated. > >I guess I should state that I have checked my antenna cable for continuity >and it all checks out and the shielding is completely isolated. Also, my >radio is clear of all other noise such as engine, alternator, etc. The first thing to do is get an antenna analyzer of some type hooked to your feedline at the transceiver end and see what it says. This is not an absolute test of performance but it IS an absolute test of non-performance. High SWR says something is seriously wrong without telling you exactly what it is. Another experiment you can try is substitute a test antenna. Get some brass shim stock from machine shop or sheet from Hobby Lobby/local hardware store. Thinner the better. Wrap a piece around the strut of your airplane 1/2 way out to the wing attach. Secure with rubber banding or wraps of plastic tape around the brass . . . don't get the tape goo on your paint. Take a piece of coax (RG58 will do) and remove outer jacket and shield to expose 20" of inner insulation and conductor. This is the "antenna". Do this . . . http://aeroelectric.com/articles/shldwire/shldwire.html Cut shield pigtail to about 1/2" and tack solder to brass. Tape coax down strut and bring into cabin at trailing edge of door or through window. Install coax connector and attach to transceiver. I've built dozens of these antennas to make temporary installation on ferry aircraft and they've performed well without having to drill holes and/or make more complex installations on the a/c. If THIS antenna works "better", then you'll need to investigate the mounted antenna more closely. If not, then the problem is in the radio. That "every two seconds" thing is a bit buggy . . . antennas don't tell time worth a hoot but electronics is much better at it. Bob . . . ________________________________ Message 14 ____________________________________ Time: 09:29:53 PM PST US From: "Michael T. Ice" Subject: Re: AeroElectric-List: PMag Preflight Check Darwin, Mike Ice from Alaska here. Just getting ready to test fly the 9. I have a p and an e mag. Do you have any further recommendations for testing/checking these models before flight, i.e., run up. Mike ----- Original Message ----- From: Darwin N. Barrie To: aeroelectric-list@matronics.com Sent: Monday, August 20, 2007 4:12 PM Subject: Re: AeroElectric-List: PMag Preflight Check I have two pmags, total time now 265 hours. This includes one replacement and both sent in for updates during the annual. After each reinstall I check to insure the mags were working at my idle setting. Both were. I didn't take the time to adjust the idle abnormally low to find the cut off of each Pmag. (I did the first time) As long as they work at my idle setting I was happy. I have my panel set up so everything to start works from Left to Right and reverse for shut down. My process is as follows, Pmag switched breakers, ON, Master On, full rich yada yada yada. On run up, RPM 1700, key switch on both. Check left, back to Both, Check Right, back to Both. Done deal. If there is a problem you'll know there. Why do anything different? During the one failure I had in flight (an internal magnet failure of my left Pmag) I switched to the Right mag and proceeded on safely. If you have a sudden rise in temps, rough running, loss of power, switch mags to isolate and find out if it is a mag issue. I firmly believe people are getting them in the set up mode and messing up the timing. Set them up and leave them alone!!! Darwin N. Barrie Chandler AZ ________________________________ Message 15 ____________________________________ Time: 10:27:46 PM PST US From: "Rob Stapleton, Jr." Subject: RE: AeroElectric-List: PMag Preflight Check Mike, Rob from the Chapter here. Good luck on the test flights, keep us posted. RS Rob Stapleton, Photojournalist Anchorage, Alaska 907-230-9425 KL2AN Skype:rob.stapleton.jr IM Windows Live Messenger: foto@alaska.net -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Michael T. Ice Sent: Tuesday, July 29, 2008 8:21 PM Subject: Re: AeroElectric-List: PMag Preflight Check Darwin, Mike Ice from Alaska here. Just getting ready to test fly the 9. I have a p and an e mag. Do you have any further recommendations for testing/checking these models before flight, i.e., run up. Mike ----- Original Message ----- From: Darwin N. Barrie Sent: Monday, August 20, 2007 4:12 PM Subject: Re: AeroElectric-List: PMag Preflight Check I have two pmags, total time now 265 hours. This includes one replacement and both sent in for updates during the annual. After each reinstall I check to insure the mags were working at my idle setting. Both were. I didn't take the time to adjust the idle abnormally low to find the cut off of each Pmag. (I did the first time) As long as they work at my idle setting I was happy. I have my panel set up so everything to start works from Left to Right and reverse for shut down. My process is as follows, Pmag switched breakers, ON, Master On, full rich yada yada yada. On run up, RPM 1700, key switch on both. Check left, back to Both, Check Right, back to Both. Done deal. If there is a problem you'll know there. Why do anything different? During the one failure I had in flight (an internal magnet failure of my left Pmag) I switched to the Right mag and proceeded on safely. If you have a sudden rise in temps, rough running, loss of power, switch mags to isolate and find out if it is a mag issue. I firmly believe people are getting them in the set up mode and messing up the timing. Set them up and leave them alone!!! Darwin N. Barrie Chandler AZ ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.