Today's Message Index:
----------------------
1. 04:34 AM - Re: GPS Antennas (Dennis O'Connor)
2. 05:33 AM - FW: Over-voltage protection (Gary Casey)
3. 08:15 AM - Re: two stage blower (Robert L. Nuckolls, III)
4. 05:42 PM - Do I need a battery contactor? (Sam Hoskins)
5. 06:04 PM - OV Module Problems (Robert Kellar)
6. 06:06 PM - OV Module (Robert Kellar)
7. 08:57 PM - Re: Perm magnet alternator & fuel pump (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: GPS Antennas |
--> AeroElectric-List message posted by: "Dennis O'Connor" <doconnor@chartermi.net>
Dave, Norm is correct that cloud attenuation is a minor player in GPS,
however it is not a zero player, as he is wont to think, in a receiver with
minimal parallel processing going on, which was what started the thread...
I was making the point that if you already have a low signal to noise ratio
due to a poor antenna and a high temperature receiver front end (Teff), so
that you are near that -152dBm threshold, that a couple dB of rain
attenuation will be enough to push your signal integration time beyond the
number of receivers you have... (20 dB was just an irritation factor)
Certainly, you can add parallel receivers and make up for the worsened S/N
ratio, which is why the 12 channels in the higher end units perform
better... Indoor GPS units on your belt to provide personnel location
tracking within the building will soon be common because the units will have
massive parallel channel capability to make up for low S/N ratios...
Or, the building may have a local corrections transmitter... Who knows how
the market will shake out...
Anyway, cloud cover is not a benign as may be thought... I have done some
moon bounce in years past (ham radio) and heavy, wet clouds do interfere
significantly.. Also, the small TV dishes such as Dish Network, et. al.,
will lose signal lock in the presence of heavy precip... Ask any of your
friends who have one...
Denny
----- Original Message -----
From: "David Lundquist" <lundquist@ieee.org>
Subject: Re: AeroElectric-List: GPS Antennas
> --> AeroElectric-List message posted by: David Lundquist
<lundquist@ieee.org>
>
> After seeing this message I did some digging around in a few textbooks I
had
> here. I really wasn't able to find much and the little I did find seemed
to
> indicate that the attenuation due to rain or clouds at GPS frequencies
> should be VERY small. Nothing even approaching a few dB. More like a few
> hundreths of a dB which of course would have no real effect.
>
> Now that I've started in on this I'd be curious if anybody else has any
hard
> info on the effect of clouds and water vapor. I'll keep looking and post
> anything interesting I find.
>
> Dave Lundquist
> '77 C150
> RV-6 Wings
> ----- Original Message -----
> From: "Dennis O'Connor" <doconnor@chartermi.net>
> To: <aeroelectric-list@matronics.com>
> Subject: Re: AeroElectric-List: GPS Antennas
>
>
> > --> AeroElectric-List message posted by: "Dennis O'Connor"
> <doconnor@chartermi.net>
> >
> > Bob, I have to take exception to your statement that clouds make no
> > difference... A thick layer of clouds does absorb energy from the
> satellite
> > signals.. If you have a good antenna and therefore a good signal to
noise
> > ratio you will not notice it... But if your receiver s/n ratio is
marginal
> > for what ever reason, a few more dB of loss will make a difference...
> >
> > Denny
> > ----- Original Message -----
> > From: <BobsV35B@aol.com>
> > To: <aeroelectric-list@matronics.com>
> > Subject: Re: AeroElectric-List: GPS Antennas
> >
> >
> > > --> AeroElectric-List message posted by: BobsV35B@aol.com
> > >
> > > In a message dated 12/30/02 7:36:06 PM Central Standard Time,
> > > Whollo80@aol.com writes:
> > >
> > > > I'm using a Garmin 90 and sometimes lose coverage on cloudy days.
> Would
> > > > using
> > > > one of the externally mounted antennas improve my coverage?
Everything
> > that
> > > > I
> > > > see in Aircraft Spruce is a little bit on the expensive side. Any
> > thoughts?
> > >
> > > Good Evening Bill,
> > >
> > > The clouds should have absolutely nothing to do with your GPS
coverage.
> > > However, getting a full view of the sky is always a good idea. The 90
> was
> > a
> > > good unit in it's day and still has the capability of providing useful
> > > information, but the technology curve is still rising quite steeply on
> > such
> > > equipment. You might consider upgrading to something like the Garmin
> 196.
> > >
> > > Any remote antenna that will allow a better view of the sky will make
> the
> > 90
> > > work a bit better. I don't know whether an active antenna will help
> with
> > the
> > > 90 or not, but why don't you call the Garmin service number? I have
> found
> > > them to be easy to get hold of and full of good information.
> > >
> > > I added an active antenna for use with my Trimble 2000 Approach Plus.
> > That
> > > old antique had it's performance noticeably improved by the addition.
> > >
> > > Look up Garmin at: <A HREF="www.garmin.com">www.garmin.com
> > >
> > > They have data there as to the phone numbers to call.
> > >
> > > Happy Skies,
> > >
> > > Old Bob
> > >
> > >
> >
> >
>
>
Message 2
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| Subject: | FW: Over-voltage protection |
--> AeroElectric-List message posted by: "Gary Casey" <glcasey@adelphia.net>
Pardon the repetition, but I didn't see my original message or any replies
on the list - It may not have gotten there.
-----Original Message-----
From: Gary Casey [mailto:glcasey@adelphia.net]
Subject: Over-voltage protection
In reading all the submissions about over-voltage protection I have come up
with a question. It is based on the assumption that the only failure that
can cause an over-voltage condition is that of the voltage regulator,
assuming that the regulator is external or otherwise not internally powered.
The typical over-voltage protection circuit is in series with the regulator
and disconnects the power feed to the field. I'm assuming that the
protection device could be on either side of the regulator. Question: Why
not just install a second regulator in series with the first? The second
one could be adjusted to a somewhat higher voltage than the first one and
could be designed to provide an output for a warning light if it came on
line. Therefore, a (primary) regulator failure would result in a system
voltage of, say, 15 volts instead of 14 and a warning indicator. Nothing
would have to be done by the pilot and he could complete his flight without
worry of running out of battery. This would seem like a more elegant
solution than to just kill the alternator if the voltage regulator fails,
which only replaces one emergency with another less urgent one.
Gary Casey
Message 3
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| Subject: | Re: two stage blower |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:22 PM 1/1/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: Sam Buchanan <sbuc@hiwaay.net>
>
>
>"Robert L. Nuckolls, III" wrote:
> >
> > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <bob.nuckolls@cox.net>
><snip>
> > I'll suggest that your airplane wont be "finished"
> > until perhaps 100 hours after first flight . . .
><snip>
>
>
>How 'bout ~440 hrs and still "buildin' the plane"?? ;-)
>
>Sam Buchanan (RV-6, probably never will be finished as long as I am
>flying it)
Aren't you glad you don't own a 172? It's really
great when a useful tool can evolve with the
times, technology and acquisition of new ideas.
Bob . . .
Message 4
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| Subject: | Do I need a battery contactor? |
--> AeroElectric-List message posted by: "Sam Hoskins" <shoskins@globaleyes.net>
I have the traditional split rocker master switch. Do I need a contactor, or can
I get rid of it?
Armstrong starter.
Aircraft: Q-200
Powrplant: Continental O-200
Alternator: 200G
Devices:
Nav lights (rarely used)
Strobes (rarerly used)
Nav Comm
Transponder
Fuel transfer pump
T&B
Handheld GPS
Message 5
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| Subject: | OV Module Problems |
--> AeroElectric-List message posted by: "Robert Kellar" <rkellar@attbi.com>
What follows is my original e-mail to Bob through his web site, his answer and
questions, my response and finally at the bottom of the message is the new information
regarding the tripping of the breaker...
Comments/Questions: I am using your voltage regulator LR3B-14 in my
RV6. Purchased 2 years ago. Worked wonderfully until 2 months ago. On
multiple occasions the 5A fuse from the bus to the master switch to
terminal 6 blows.
This fuse should have been a circuit breaker . . . all of our
installation drawings show a breaker used with any form of
crowbar overvoltage protection.
When not blown the voltage regulator functions perfectly 20+ amps
charge then cycles down to less than 5 amps for flight. Usually the
fuse lasts for 1 hr or less and then with the next flight, as I take off the
fuse will blow and the blinking warning light comes on. Replace the
fuse and I can fly again for awhile. I have inspected everything in the
panel, wires, connections etc looking for a possible short or failure. My
question is...Is there anything internal to the unit that could cause
this intermittent failure? If not, I will continue my investigation of
all the wire out to the alternator looking for a possible intermittent
short.
Do you have a voltmeter in the airplane? What does it read
just before the ov system trips?
Thank you for your response and all the help provided on the net and
in your electical manual and diagrams.
>
> My pleasure sir.
>
> I will invite you to join us on the AeroElectric List
> to continue this and similar discussions. It's useful to
> share the information with as many folks as possible.
> You can join at . . .
Thank you for you quick response. I missed the part about the breaker in
the instructions. I'll install a breaker and fly some more and then let you
know here on the list. Re: Voltage before the fuse blows...I am too busy
flying the takeoff to notice. I'll bring a passenger to monitor this value.
Bob Kellar
Jan 2, 03
Bob, After installing a 5 amp breaker, I went flying today with an observer with
the following results. Start up and taxi, runup all trouble free. I placed
various loads, lights radios, strobes etc. onto the bus without any problems.
Good charge at 13 + volts even during idle. Take off started and just about
at 100 ft. of altitude the breaker popped and the yellow blinking light came
on. The observer reported no change in the volt meter until the breaker popped
and it of course dropped to 10-12 volts. She noted that the amp meter had
suddenly flicked full to charge just before the breaker popped. I unloaded the
system bus completely, reset the breaker and then restarted to apply the load.
No problems at all. We flew for awhile and then landed, shut down, restarted
and took off, this time without any problems. Regualator and alternator continued
to work well for the 30 min. of additional flight. The unit was purchased
from you 5/4/99 with first flight 10/4/01. As I noted above I have about
100 hours on the airplane and no problems until the last 15 hours. Any suggestions
regarding diagnostics or fixes would be greately appreciated. Bob Kellar
Message 6
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--> AeroElectric-List message posted by: "Robert Kellar" <rkellar@attbi.com>
What follows is my original e-mail to Bob through his web site, his answer and
questions, my response and finally at the bottom of the message is the new information
regarding the tripping of the breaker...
Comments/Questions: I am using your voltage regulator LR3B-14 in my
RV6. Purchased 2 years ago. Worked wonderfully until 2 months ago. On
multiple occasions the 5A fuse from the bus to the master switch to
terminal 6 blows.
This fuse should have been a circuit breaker . . . all of our
installation drawings show a breaker used with any form of
crowbar overvoltage protection.
When not blown the voltage regulator functions perfectly 20+ amps
charge then cycles down to less than 5 amps for flight. Usually the
fuse lasts for 1 hr or less and then with the next flight, as I take off the
fuse will blow and the blinking warning light comes on. Replace the
fuse and I can fly again for awhile. I have inspected everything in the
panel, wires, connections etc looking for a possible short or failure. My
question is...Is there anything internal to the unit that could cause
this intermittent failure? If not, I will continue my investigation of
all the wire out to the alternator looking for a possible intermittent
short.
Do you have a voltmeter in the airplane? What does it read
just before the ov system trips?
Thank you for your response and all the help provided on the net and
in your electical manual and diagrams.
>
> My pleasure sir.
>
> I will invite you to join us on the AeroElectric List
> to continue this and similar discussions. It's useful to
> share the information with as many folks as possible.
> You can join at . . .
Thank you for you quick response. I missed the part about the breaker in
the instructions. I'll install a breaker and fly some more and then let you
know here on the list. Re: Voltage before the fuse blows...I am too busy
flying the takeoff to notice. I'll bring a passenger to monitor this value.
Bob Kellar
Jan 2, 03
Bob, After installing a 5 amp breaker, I went flying today with an observer with
the following results. Start up and taxi, runup all trouble free. I placed
various loads, lights radios, strobes etc. onto the bus without any problems.
Good charge at 13 + volts even during idle. Take off started and just about
at 100 ft. of altitude the breaker popped and the yellow blinking light came
on. The observer reported no change in the volt meter until the breaker popped
and it of course dropped to 10-12 volts. She noted that the amp meter had
suddenly flicked full to charge just before the breaker popped. I unloaded the
system bus completely, reset the breaker and then restarted to apply the load.
No problems at all. We flew for awhile and then landed, shut down, restarted
and took off, this time without any problems. Regualator and alternator continued
to work well for the 30 min. of additional flight. The unit was purchased
from you 5/4/99 with first flight 10/4/01. As I noted above I have about
100 hours on the airplane and no problems until the last 15 hours. Any suggestions
regarding diagnostics or fixes would be greately appreciated. Bob Kellar
Message 7
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| Subject: | Re: Perm magnet alternator & fuel pump |
trouble
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:39 PM 1/1/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Sam Hoskins"
><shoskins@globaleyes.net>
>
>About 15 years ago I installed the B&C 14 amp PM alternator on my Quickie
>Q-200 powered by a Continental O-200. After I flew the aircraft a couple
>of years, I found a wierd condition. My Facet fuel transfer pump would
>not pump while airborne. It would seem to work on the ground, but not in
>the air. I replaced the fuel pump but it still occurred. Finally, I
>replaced the battery (I do not use a starter), and that corrected the
>problem. A couple of years later when my battery again went bad, the same
>problem occurred. Installed a new battery and the fuel pump worked fine.
>
>This made me nervous (I really need that transfer pump) so when I had an
>opportunity to swap out a standard O-200 alternator and regulator for the
>B&C unit (even steven) I did it.
>
>I now want to convert back to the B&C, and I will be using an RG
>battery. I never did figure out exactly why this occurred. Could it have
>something to do with filtering of the alternator output? In my new
>installation I will be installing the B&C regulator, with the new addition
>of the crowbar OV protection and the filtering capacitor.
>
>Should this take care of it? What do you think?
>
>Thanks! BTW, my O-200 alternator and regulator are for sale on eBay,
>right now. Auction # 1876166436.
I suspect the pump (which I believe is solid state
electronics to control motor coil) may be sensitive
to the severe ripple voltage that is present with
the permanent alternators. If install the recommended
filter capacitor and change the battery out regularly
this should not be a problem.
If you didn't use the battery for cranking, then I
suspect it was a rather small battery that was getting
beat up pretty badly with the ripple current from the
alternator. A 17 a.h. battery should be able to put up
with this abuse pretty well but periodic capacity checks
or yearly change-out is very much in order . . .
Bob . . .
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