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
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Subject: | 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.
>
> <emjones@charter.net>
>
> 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
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Subject: | 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
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Subject: | Re: AT150 Interrogation Light |
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
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Subject: | Re: AT150 Interrogation Light |
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
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Subject: | Re: 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 <rjquillin@gmail.com> 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
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Subject: | 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
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Subject: | Re: Capacitors for trim servos? |
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
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Subject: | 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
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Subject: | 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 . . .
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Subject: | 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- )
----------------------------------------
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Subject: | 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
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Subject: | Re: 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
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Subject: | Re: 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
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Subject: | Re: 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
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Subject: | 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 <mailto:ktlkrn@cox.net>
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
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