Today's Message Index:
----------------------
1. 04:47 AM - Re: High VSWR reading on my antenna lead (Robert Feldtman)
2. 05:46 AM - Re: Can Rotax be self exciting? (Robert L. Nuckolls, III)
3. 05:57 AM - Re: High VSWR reading on my antenna lead (Kevin Horton)
4. 06:07 AM - Re: Ni-Cad Capacity check (Robert L. Nuckolls, III)
5. 06:16 AM - Re: High VSWR reading on my antenna lead (Alan Adamson)
6. 06:18 AM - Re: High VSWR reading on my antenna lead (luckymacy@comcast.net (lucky))
7. 06:25 AM - Re: Ni-Cad Capacity check (Christopher Stone)
8. 07:10 AM - Re: High VSWR reading on my antenna lead (Robert L. Nuckolls, III)
9. 07:45 AM - Re: High VSWR reading on my antenna lead (Rob Turk)
10. 08:03 AM - Re: Odessey Battery Capacity Test (Tinne maha)
11. 08:12 AM - Re: Dual circuit for J3300 EFI (Robert L. Nuckolls, III)
12. 09:35 AM - Off Topic- Was : Re: We can't build our own avionics (John Burnaby)
13. 10:07 AM - Re: Off Topic- Was : Re: We can't build our own avionics (Hinde, Frank George (Corvallis))
14. 10:26 AM - Re: Off Topic- Was : Re: We can't build our own avionics (Walter Fellows)
15. 10:59 AM - Re: Off Topic- Was : Re: We can't build our own avionics (Ernest Christley)
16. 11:27 AM - Blowing fuses (Glaeser, Dennis A)
17. 12:31 PM - Re: Wiring Diag for GTX327 (Norman Stapelberg)
18. 03:04 PM - Re: Dual circuit for J3300 EFI (Peter Harris)
Message 1
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Subject: | Re: High VSWR reading on my antenna lead |
borrow a known good meter from a ham in the area. make sure you set the
forward power to exactly full deflection, then read the reflected power. you
may have the gain set way too high. If it is 9 to one the radio would have
detected this on it's own and decreased the power. I suspect the meter is
bad or you don't have it adjusted right. get a ham to help you. Don't spend
more money - get a ham to help you
bobf
W5RF and glastar owner
ps - don't do it in the hangar - too much metal. roll it outside away from
the hanger more than 30 feet or so
On 5/22/07, James Beeghly <jbeeghly@earthlink.net> wrote:
>
> In the process of building up the avionics for our Wag Aero Super Sport I
> reached that point where I was ready to power up the used King KY 97A Comm.
> I had fabricated about a 10 - 12 foot long antenna lead using RG-400 and
> BNC connectors purchased from B&C (and assembled with a RCT-2 coax crimping
> tool also from B&C) to connect the comm to a used Cessna antenna (came from
> a 172.) I plugged in the headset, turned on the radio, and all seemed well.
> I listened (from inside the hanger) to airport traffic. I briefly keyed
> the mike and heard myself on the scanner across the hanger.
>
> Then I turned off the radio and connected a DAIWA CN 720B SWR meter in the
> antenna circuit. this involved undoing the BNC connector from the back of
> the tray (The tray itself is fitted with a bulkhead type of female BNC
> connector so this was no problem.) The 720 B is a cross needle meter rated
> up to 150 MHz and with a 5 watt range at the lower end. It has two SO-239
> connectors on the back, one marked antenna and one transmitter. I had
> gotten converters to use BNC connectors and had purchased a radio shack
> premade RG-58 cable, about 6 feet long, to patch the meter to the radio.
> The antenna lead connected to the Antenna connector on the 720 B.
>
> My understanding (I bought this meter on E-bay and do not yet have a
> manual - one is ordered) is that reading VSWR is a matter of pushing
> transmit and finding the VSWR line corresponding to where the two needles
> intersect as they measure forward and reflected watts. If this is correct,
> my system has a VSWR of 9 or 10. Needless to say, I did not hold the
> transmit button down for long.
>
> I know that I am looking for a VSWR as close to 1 as possible, so this is
> not acceptable. I don't quite know what to do next. I do not see a way to
> calibrate the meter. My understanding is that this kind of meter is not
> supposed to need calibration. I do not see what I could have done wrong in
> constructing the antenna lead to get this kind of VSWR.
>
> I did try another experiment. I took my JVC handheld, and put the meter
> between it and the whip antenna. There was barely enough power to read
> VSWR, but it was still in the 9 or 10 range. I then measured VSWR using the
> JVC feeding the antenna lead and Cessna antenna. The reading for forward
> power was clearly improved, but the VSWR was still at the same high level.
> These results make me wonder if there isn't something wrong with the meter
> (or my measuring technique.)
>
> Does anyone have any suggestions for what to consider next? As you can no
> doubt tell, I am new to this. Thanks.
>
> Jim Beeghly
>
> *
>
>
> *
>
>
Message 2
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Subject: | Re: Can Rotax be self exciting? |
At 06:14 AM 5/23/2007 +0000, you wrote:
>
>Could Z-16 (Rotax 912/914 System) incorporate self excitation feature as
>seen in Z25 (note 25) and be self exciting and maintain overvoltage
>protection?
>
>Thx.
>Ron Parigoris
Probably. But this is based on a schematic deduced
by individuals who disassembled a Ducati regulator.
The regulator topology is very close to that of the
regulator sold by B&C so assuming that our presumptions
are accurate and that the diagram has not changed,
the answer would be yes.
Bottom line is that the repeatable experiment rules.
Try it, see what results you get and then let us know
one way or another.
Bob . . .
Message 3
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Subject: | Re: High VSWR reading on my antenna lead |
Will a VSWR meter designed for the ham radio band produce valid results with aviation
Com frequencies?
Kevin Horton
On Wed, 23 May 2007 06:45:39 -0500
"Robert Feldtman" <bobf@feldtman.com> wrote:
> borrow a known good meter from a ham in the area. make sure you set the
> forward power to exactly full deflection, then read the reflected power. you
> may have the gain set way too high. If it is 9 to one the radio would have
> detected this on it's own and decreased the power. I suspect the meter is
> bad or you don't have it adjusted right. get a ham to help you. Don't spend
> more money - get a ham to help you
>
> bobf
> W5RF and glastar owner
>
> ps - don't do it in the hangar - too much metal. roll it outside away from
> the hanger more than 30 feet or so
>
> On 5/22/07, James Beeghly <jbeeghly@earthlink.net> wrote:
> >
> > In the process of building up the avionics for our Wag Aero Super Sport I
> > reached that point where I was ready to power up the used King KY 97A Comm.
> > I had fabricated about a 10 - 12 foot long antenna lead using RG-400 and
> > BNC connectors purchased from B&C (and assembled with a RCT-2 coax crimping
> > tool also from B&C) to connect the comm to a used Cessna antenna (came from
> > a 172.) I plugged in the headset, turned on the radio, and all seemed well.
> > I listened (from inside the hanger) to airport traffic. I briefly keyed
> > the mike and heard myself on the scanner across the hanger.
> >
> > Then I turned off the radio and connected a DAIWA CN 720B SWR meter in the
> > antenna circuit. this involved undoing the BNC connector from the back of
> > the tray (The tray itself is fitted with a bulkhead type of female BNC
> > connector so this was no problem.) The 720 B is a cross needle meter rated
> > up to 150 MHz and with a 5 watt range at the lower end. It has two SO-239
> > connectors on the back, one marked antenna and one transmitter. I had
> > gotten converters to use BNC connectors and had purchased a radio shack
> > premade RG-58 cable, about 6 feet long, to patch the meter to the radio.
> > The antenna lead connected to the Antenna connector on the 720 B.
> >
> > My understanding (I bought this meter on E-bay and do not yet have a
> > manual - one is ordered) is that reading VSWR is a matter of pushing
> > transmit and finding the VSWR line corresponding to where the two needles
> > intersect as they measure forward and reflected watts. If this is correct,
> > my system has a VSWR of 9 or 10. Needless to say, I did not hold the
> > transmit button down for long.
> >
> > I know that I am looking for a VSWR as close to 1 as possible, so this is
> > not acceptable. I don't quite know what to do next. I do not see a way to
> > calibrate the meter. My understanding is that this kind of meter is not
> > supposed to need calibration. I do not see what I could have done wrong in
> > constructing the antenna lead to get this kind of VSWR.
> >
> > I did try another experiment. I took my JVC handheld, and put the meter
> > between it and the whip antenna. There was barely enough power to read
> > VSWR, but it was still in the 9 or 10 range. I then measured VSWR using the
> > JVC feeding the antenna lead and Cessna antenna. The reading for forward
> > power was clearly improved, but the VSWR was still at the same high level.
> > These results make me wonder if there isn't something wrong with the meter
> > (or my measuring technique.)
> >
> > Does anyone have any suggestions for what to consider next? As you can no
> > doubt tell, I am new to this. Thanks.
> >
> > Jim Beeghly
> >
> > *
> >
> >
> > *
> >
> >
>
Message 4
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Subject: | Re: Ni-Cad Capacity check |
At 08:33 PM 5/22/2007 -0500, you wrote:
>
>Does anyone have a schematic for a capacity checker for small batteries like
>Ni-Cads, etc.
I have a product under development that will do the task
you're asking about. It's a 2.5 x 4 inch etched circuit
board offered in three versions. They hold 4AA,
2AA-2AAA or 4AAA cells and runs them down under a
fixed loading condition. When discharge is completed,
the time that each cell supported its load is reported
by means of voltage readings taken with your shop
mulitimeter. This device will be offered on my website
for about $40.
In the mean time, you might consider this product:
http://westmountainradio.com/CBA_ham.htm
I have one of these and find it quite useful in a
variety of battery studies. It's also been used to
measure and plot data (voltage vs. time) for the
evaluation of a number of battery chargers. See
this example:
http://www.aeroelectric.com/Pictures/Curves/schumacher_3.jpg
In terms of it's utility and versatility, the
West Mountain Radio product is well worth the money.
It's flexibility allows testing of any cells or array
of cells over discharge current ranges of many amps down
to tens of milliamps.
Finally, the task is simple but the implementation
for a roll-yer-own cap-meter is $time$ consuming.
The goal is to craft a device that applies a load
and records the time that a cell supports that load.
My personal preference for mulit-cell evaluation uses
a data acquisition module from Weeder Technology
analog data input module
http://www.weedtech.com/wtadc-m.pdf
teamed with a computer running a Basic program that
measures and records data with respect to time for
later analysis. This is the technique used for
crafting the article at:
http://www.aeroelectric.com/articles/AA_Bat_Test.pdf
. . . except that the data acquisition module
used in this test was different than the device
suggested above.
The minimum $time$ route is the West Mountain Radio
product with the AEC cap meter coming in second place.
But if you'd like to acquire some REAL number gathering
capabilities for both battery testing and a host of
other applications, the Weeder Tech/Junk Computer approach
offers a ton of capability for a very low investment.
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
Message 5
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Subject: | High VSWR reading on my antenna lead |
Kevin, the Ham Radio *band*, is a very large frequency spectrum :)....
However, something designed for VHF and in Ham Speak, 2 meters, will work
just fine.
As a side note. Most SWR meters are DC-Daylite and should work just fine.
There are units like a "bird wattmeter" that have specific "slugs" for
specific power settings and frequencies, but if you have an SWR meter that
simply measures forward and reverse power, you should be fine.
Alan
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Kevin
Horton
Sent: Wednesday, May 23, 2007 8:56 AM
Subject: Re: AeroElectric-List: High VSWR reading on my antenna lead
--> <khorton01@rogers.com>
Will a VSWR meter designed for the ham radio band produce valid results with
aviation Com frequencies?
Kevin Horton
On Wed, 23 May 2007 06:45:39 -0500
"Robert Feldtman" <bobf@feldtman.com> wrote:
> borrow a known good meter from a ham in the area. make sure you set
> the forward power to exactly full deflection, then read the reflected
> power. you may have the gain set way too high. If it is 9 to one the
> radio would have detected this on it's own and decreased the power. I
> suspect the meter is bad or you don't have it adjusted right. get a
> ham to help you. Don't spend more money - get a ham to help you
>
> bobf
> W5RF and glastar owner
>
> ps - don't do it in the hangar - too much metal. roll it outside away
> from the hanger more than 30 feet or so
>
> On 5/22/07, James Beeghly <jbeeghly@earthlink.net> wrote:
> >
> > In the process of building up the avionics for our Wag Aero Super
> > Sport I reached that point where I was ready to power up the used King
KY 97A Comm.
> > I had fabricated about a 10 - 12 foot long antenna lead using
> > RG-400 and BNC connectors purchased from B&C (and assembled with a
> > RCT-2 coax crimping tool also from B&C) to connect the comm to a
> > used Cessna antenna (came from a 172.) I plugged in the headset, turned
on the radio, and all seemed well.
> > I listened (from inside the hanger) to airport traffic. I briefly
> > keyed the mike and heard myself on the scanner across the hanger.
> >
> > Then I turned off the radio and connected a DAIWA CN 720B SWR meter
> > in the antenna circuit. this involved undoing the BNC connector
> > from the back of the tray (The tray itself is fitted with a bulkhead
> > type of female BNC connector so this was no problem.) The 720 B is a
> > cross needle meter rated up to 150 MHz and with a 5 watt range at
> > the lower end. It has two SO-239 connectors on the back, one marked
> > antenna and one transmitter. I had gotten converters to use BNC
> > connectors and had purchased a radio shack premade RG-58 cable, about 6
feet long, to patch the meter to the radio.
> > The antenna lead connected to the Antenna connector on the 720 B.
> >
> > My understanding (I bought this meter on E-bay and do not yet have a
> > manual - one is ordered) is that reading VSWR is a matter of pushing
> > transmit and finding the VSWR line corresponding to where the two
> > needles intersect as they measure forward and reflected watts. If
> > this is correct, my system has a VSWR of 9 or 10. Needless to say,
> > I did not hold the transmit button down for long.
> >
> > I know that I am looking for a VSWR as close to 1 as possible, so
> > this is not acceptable. I don't quite know what to do next. I do
> > not see a way to calibrate the meter. My understanding is that this
kind of meter is not
> > supposed to need calibration. I do not see what I could have done
wrong in
> > constructing the antenna lead to get this kind of VSWR.
> >
> > I did try another experiment. I took my JVC handheld, and put the
> > meter between it and the whip antenna. There was barely enough
> > power to read VSWR, but it was still in the 9 or 10 range. I then
> > measured VSWR using the JVC feeding the antenna lead and Cessna
> > antenna. The reading for forward power was clearly improved, but the
VSWR was still at the same high level.
> > These results make me wonder if there isn't something wrong with the
> > meter (or my measuring technique.)
> >
> > Does anyone have any suggestions for what to consider next? As you
> > can no doubt tell, I am new to this. Thanks.
> >
> > Jim Beeghly
> >
> > *
> >
> >
> > *
> >
> >
>
Message 6
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Subject: | Re: High VSWR reading on my antenna lead |
Worked for us. Exact numbers are going to be incorrect but the relative deflection
is still valid. ie, it will still read toward the "bad" end if there's a
lot of reflection and read more towards the "good" end of the scale after you
fix a problem but won't tell you just how good your SWR really is if you are
anal about your exact number...
-------------- Original message --------------
From: Kevin Horton <khorton01@rogers.com>
>
> Will a VSWR meter designed for the ham radio band produce valid results with
> aviation Com frequencies?
>
> Kevin Horton
>
> On Wed, 23 May 2007 06:45:39 -0500
> "Robert Feldtman" wrote:
>
> > borrow a known good meter from a ham in the area. make sure you set the
> > forward power to exactly full deflection, then read the reflected power. you
> > may have the gain set way too high. If it is 9 to one the radio would have
> > detected this on it's own and decreased the power. I suspect the meter is
> > bad or you don't have it adjusted right. get a ham to help you. Don't spend
> > more money - get a ham to help you
> >
> > bobf
> > W5RF and glastar owner
> >
> > ps - don't do it in the hangar - too much metal. roll it outside away from
> > the hanger more than 30 feet or so
> >
> > On 5/22/07, James Beeghly wrote:
> > >
> > > In the process of building up the avionics for our Wag Aero Super Sport I
> > > reached that point where I was ready to power up the used King KY 97A Comm.
> > > I had fabricated about a 10 - 12 foot long antenna lead using RG-400 and
> > > BNC connectors purchased from B&C (and assembled with a RCT-2 coax crimping
> > > tool also from B&C) to connect the comm to a used Cessna antenna (came from
> > > a 172.) I plugged in the headset, turned on the radio, and all seemed well.
> > > I listened (from inside the hanger) to airport traffic. I briefly keyed
> > > the mike and heard myself on the scanner across the hanger.
> > >
> > > Then I turned off the radio and connected a DAIWA CN 720B SWR meter in the
> > > antenna circuit. this involved undoing the BNC connector from the back of
> > > the tray (The tray itself is fitted with a bulkhead type of female BNC
> > > connector so this was no problem.) The 720 B is a cross needle meter rated
> > > up to 150 MHz and with a 5 watt range at the lower end. It has two SO-239
> > > connectors on the back, one marked antenna and one transmitter. I had
> > > gotten converters to use BNC connectors and had purchased a radio shack
> > > premade RG-58 cable, about 6 feet long, to patch the meter to the radio.
> > > The antenna lead connected to the Antenna connector on the 720 B.
> > >
> > > My understanding (I bought this meter on E-bay and do not yet have a
> > > manual - one is ordered) is that reading VSWR is a matter of pushing
> > > transmit and finding the VSWR line corresponding to where the two needles
> > > intersect as they measure forward and reflected watts. If this is correct,
> > > my system has a VSWR of 9 or 10. Needless to say, I did not hold the
> > > transmit button down for long.
> > >
> > > I know that I am looking for a VSWR as close to 1 as possible, so this is
> > > not acceptable. I don't quite know what to do next. I do not see a way to
> > > calibrate the meter. My understanding is that this kind of meter is not
> > > supposed to need calibration. I do not see what I could have done wrong in
> > > constructing the antenna lead to get this kind of VSWR.
> > >
> > > I did try another experiment. I took my JVC handheld, and put the meter
> > > between it and the whip antenna. There was barely enough power to read
> > > VSWR, but it was still in the 9 or 10 range. I then measured VSWR using the
> > > JVC feeding the antenna lead and Cessna antenna. The reading for forward
> > > power was clearly improved, but the VSWR was still at the same high level.
> > > These results make me wonder if there isn't something wrong with the meter
> > > (or my measuring technique.)
> > >
> > > Does anyone have any suggestions for what to consider next? As you can no
> > > doubt tell, I am new to this. Thanks.
> > >
> > > Jim Beeghly
> > >
> > > *
> > >
> > >
> > > *
> > >
> > >
> >
>
>
>
>
<html><body>
<DIV>Worked for us. Exact numbers are going to be incorrect but the relative deflection
is still valid. ie, it will still read toward the "bad" end if
there's a lot of reflection and read more towards the "good"
end of the scale after you fix a problem but won't tell you
just how good your SWR really is if you are anal about your exact number...</DIV>
<DIV> </DIV>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px
solid">-------------- Original message -------------- <BR>From: Kevin Horton
<khorton01@rogers.com> <BR><BR>> --> AeroElectric-List message posted
by: Kevin Horton <KHORTON01@ROGERS.COM><BR>> <BR>> Will a VSWR meter
designed for the ham radio band produce valid results with <BR>> aviation
Com frequencies? <BR>> <BR>> Kevin Horton <BR>> <BR>> On Wed, 23
May 2007 06:45:39 -0500 <BR>> "Robert Feldtman" <BOBF@FELDTMAN.COM>wrote: <BR>>
<BR>> > borrow a known good meter from a ham in the area. make sure
you set the <BR>> > forward power to exactly full deflection, then read
the reflected power. you <BR>> > may have the gain set way too high.
If it is 9 to one the radio would have <BR>> > detected this on it's own
and decreased the power. I suspect the meter is <BR>> > bad or you don't
have it adjusted right. get a ham to help you. Don
't spe
nd <BR>> > more money - get a ham to help you <BR>> > <BR>> >
bobf <BR>> > W5RF and glastar owner <BR>> > <BR>> > ps - don't
do it in the hangar - too much metal. roll it outside away from <BR>> >
the hanger more than 30 feet or so <BR>> > <BR>> > On 5/22/07,
James Beeghly <JBEEGHLY@EARTHLINK.NET>wrote: <BR>> > > <BR>> >
> In the process of building up the avionics for our Wag Aero Super Sport
I <BR>> > > reached that point where I was ready to power up the used
King KY 97A Comm. <BR>> > > I had fabricated about a 10 - 12 foot long
antenna lead using RG-400 and <BR>> > > BNC connectors purchased from
B&C (and assembled with a RCT-2 coax crimping <BR>> > > tool
also from B&C) to connect the comm to a used Cessna antenna (came from <BR>>
> > a 172.) I plugged in the headset, turned on the radio, and all
seemed well. <BR>> > > I listened (from ins
ide th
e hanger) to airport traffic. I briefly keyed <BR>> > > the mike and heard
myself on the scanner across the hanger. <BR>> > > <BR>> >
> Then I turned off the radio and connected a DAIWA CN 720B SWR meter in the
<BR>> > > antenna circuit. this involved undoing the BNC connector
from the back of <BR>> > > the tray (The tray itself is fitted with
a bulkhead type of female BNC <BR>> > > connector so this was no problem.)
The 720 B is a cross needle meter rated <BR>> > > up to 150 MHz
and with a 5 watt range at the lower end. It has two SO-239 <BR>> > >
connectors on the back, one marked antenna and one transmitter. I had <BR>>
> > gotten converters to use BNC connectors and had purchased a radio
shack <BR>> > > premade RG-58 cable, about 6 feet long, to patch the
meter to the radio. <BR>> > > The antenna lead connected to the Antenna
connector on the 720 B. <BR>> > > <BR>&g
t; >
; > My understanding (I bought this meter on E-bay and do not yet have a <BR>>
> > manual - one is ordered) is that reading VSWR is a matter of pushing
<BR>> > > transmit and finding the VSWR line corresponding to
where the two needles <BR>> > > intersect as they measure forward and
reflected watts. If this is correct, <BR>> > > my system has a VSWR
of 9 or 10. Needless to say, I did not hold the <BR>> > > transmit button
down for long. <BR>> > > <BR>> > > I know that I am looking
for a VSWR as close to 1 as possible, so this is <BR>> > > not acceptable.
I don't quite know what to do next. I do not see a way to <BR>>
> > calibrate the meter. My understanding is that this kind of meter is
not <BR>> > > supposed to need calibration. I do not see what I could
have done wrong in <BR>> > > constructing the antenna lead to get this
kind of VSWR. <BR>> > > <BR>> > >
; I di
=====
<pre><b><font size=2 color="#000000" face="courier new,courier">
</b></font></pre></body></html>
Message 7
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Subject: | Re: Ni-Cad Capacity check |
>
>>
>>Does anyone have a schematic for a capacity checker for small batteries like
>>Ni-Cads, etc.
>
>Here is a link to a NiCad/NiMh capacity tester. Not as capable as the West Mountain
product but less money and self contained. I have used the tester and
it performs as advertised.
http://www.siriuselectronics.com/index.php?main_page=product_info&cPath=1&products_id=123
Chris Stone
Message 8
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Subject: | Re: High VSWR reading on my antenna lead |
At 08:55 AM 5/23/2007 -0400, you wrote:
>
>Will a VSWR meter designed for the ham radio band produce valid results
>with aviation Com frequencies?
>
>Kevin Horton
Some do, some don't. I recall a lot of wasted $time$ many moons
ago when building a new colinear array for use on our repeater
installation at the 1200 foot platform of KTVH in Hutchinson
KS. See:
http://www.aeroelectric.com/Pictures/Misc/KTVH.gif
Glen Brasch and I worked for several days bending aluminum drilling
brackets, bolting elements and cutting coax for the feedline transformers.
Each step of the way was checked with a reflectometer style SWR
meter . . .
http://www.aeroelectric.com/Pictures/Tools/SWR/SWR_Sometimes_4.jpg
http://en.wikipedia.org/wiki/SWR_meter
. . . and we thought we were doing really good work as each step
of the process produced an excellent SWR reading. Imagine our
dismay when the assembled array tested with anther meter
( A Bird Model 43)
http://www.aeroelectric.com/Pictures/Tools/Bird_43.jpg
called it less than the best we should expect. Bottom line
is that there are easy mistakes to be made in the design
and assembly of many test instruments with those crafted
for use at high RF frequencies being strong candidates
for obtuse behavior. Just 'cause the label says so don't
make it so.
I dumped my $low$ reflectometer in the trash and bought
a Bird. If it's important to know what the numbers are,
its a safe bet to go with the repeatable experiments like
Tektronix, HP, Bird, Fluke, etc. This doesn't mean you
can't find good value in other brands . . . but if there
is doubt and the expenditure of $time$ is a critical part
of your efforts, the repeatable experiments are often the
most economical choices in spite of their higher prices
off-the-shelf.
Here's a montage of examples for repeatable experiments
-AND- experiments to be tested for repeatability in
the world of RF instrumentation . . .
http://www.aeroelectric.com/Pictures/Tools/SWR/
Bob . . .
Message 9
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Subject: | Re: High VSWR reading on my antenna lead |
That depends on the frequency range it's designed for. If it's for 0-30MHz
(most el-cheapo VSWR's and CB stuff) then there's a big chance that it won't
work. If you get one designed for 2m (144-148MHz) then you should have no
problems gettng an accurate VSWR reading. Power readings will most likely be
unreliable though, except if you use something professional like the Bird
model that Bob mentioned.
Rob
----- Original Message -----
From: "Kevin Horton" <khorton01@rogers.com>
Sent: Wednesday, May 23, 2007 2:55 PM
Subject: Re: AeroElectric-List: High VSWR reading on my antenna lead
> <khorton01@rogers.com>
>
> Will a VSWR meter designed for the ham radio band produce valid results
> with aviation Com frequencies?
>
> Kevin Horton
>
> On Wed, 23 May 2007 06:45:39 -0500
> "Robert Feldtman" <bobf@feldtman.com> wrote:
>
>> borrow a known good meter from a ham in the area. make sure you set the
>> forward power to exactly full deflection, then read the reflected power.
>> you
>> may have the gain set way too high. If it is 9 to one the radio would
>> have
>> detected this on it's own and decreased the power. I suspect the meter is
>> bad or you don't have it adjusted right. get a ham to help you. Don't
>> spend
>> more money - get a ham to help you
>>
>> bobf
>> W5RF and glastar owner
>>
>> ps - don't do it in the hangar - too much metal. roll it outside away
>> from
>> the hanger more than 30 feet or so
>>
>> On 5/22/07, James Beeghly <jbeeghly@earthlink.net> wrote:
>> >
>> > In the process of building up the avionics for our Wag Aero Super Sport
>> > I
>> > reached that point where I was ready to power up the used King KY 97A
>> > Comm.
>> > I had fabricated about a 10 - 12 foot long antenna lead using RG-400
>> > and
>> > BNC connectors purchased from B&C (and assembled with a RCT-2 coax
>> > crimping
>> > tool also from B&C) to connect the comm to a used Cessna antenna (came
>> > from
>> > a 172.) I plugged in the headset, turned on the radio, and all seemed
>> > well.
>> > I listened (from inside the hanger) to airport traffic. I briefly
>> > keyed
>> > the mike and heard myself on the scanner across the hanger.
>> >
>> > Then I turned off the radio and connected a DAIWA CN 720B SWR meter in
>> > the
>> > antenna circuit. this involved undoing the BNC connector from the back
>> > of
>> > the tray (The tray itself is fitted with a bulkhead type of female BNC
>> > connector so this was no problem.) The 720 B is a cross needle meter
>> > rated
>> > up to 150 MHz and with a 5 watt range at the lower end. It has two
>> > SO-239
>> > connectors on the back, one marked antenna and one transmitter. I had
>> > gotten converters to use BNC connectors and had purchased a radio shack
>> > premade RG-58 cable, about 6 feet long, to patch the meter to the
>> > radio.
>> > The antenna lead connected to the Antenna connector on the 720 B.
>> >
>> > My understanding (I bought this meter on E-bay and do not yet have a
>> > manual - one is ordered) is that reading VSWR is a matter of pushing
>> > transmit and finding the VSWR line corresponding to where the two
>> > needles
>> > intersect as they measure forward and reflected watts. If this is
>> > correct,
>> > my system has a VSWR of 9 or 10. Needless to say, I did not hold the
>> > transmit button down for long.
>> >
>> > I know that I am looking for a VSWR as close to 1 as possible, so this
>> > is
>> > not acceptable. I don't quite know what to do next. I do not see a
>> > way to
>> > calibrate the meter. My understanding is that this kind of meter is
>> > not
>> > supposed to need calibration. I do not see what I could have done
>> > wrong in
>> > constructing the antenna lead to get this kind of VSWR.
>> >
>> > I did try another experiment. I took my JVC handheld, and put the
>> > meter
>> > between it and the whip antenna. There was barely enough power to read
>> > VSWR, but it was still in the 9 or 10 range. I then measured VSWR
>> > using the
>> > JVC feeding the antenna lead and Cessna antenna. The reading for
>> > forward
>> > power was clearly improved, but the VSWR was still at the same high
>> > level.
>> > These results make me wonder if there isn't something wrong with the
>> > meter
>> > (or my measuring technique.)
>> >
>> > Does anyone have any suggestions for what to consider next? As you can
>> > no
>> > doubt tell, I am new to this. Thanks.
>> >
>> > Jim Beeghly
>> >
>> > *
>> >
>> >
>> > *
>> >
>> >
>>
>
>
>
Message 10
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Subject: | Re: Odessey Battery Capacity Test |
I don't get it...........I thought the purpose of the capacity test was to
see how long the ship's battery could power the essential bus & stay above
10.5 Volts. If the amount of time this takes is within the pilot's zone of
comfort (i.e. enough to land safely), then the battery is deemed sufficient.
Any battery's ability to start an engine is tested at each startup.
Assuming the above is true, I don't see what this particular test
accomplished. Can someone explain what I'm missing?
Thanks,
Grant
Time: 03:35:28 PM PST US
From: Charles Brame <chasb@satx.rr.com>
Subject: AeroElectric-List: Odessey Battery Capacity Test
Based on the recent discussions of battery capacity, I decided to put
my six year old Odessey PC-680 battery through a poor man's capacity
test. I started with a fully charged battery which read 12.7 volts at
the beginning of the test. I turned on my aircraft main bus with all
the avionics, gyros, engine monitor (VM-1000), instruments, and
instrument lights - ON. The electronic ignition, nav lights, and
strobes were left OFF (aircraft on the ground.) After 20 minutes the
voltage was down to 12.1 volts. The engine was then started (cold
start and it took two tries to get it going.) The electronic ignition
and electric boost pump were turned ON; however, the alternator was
intentionally left OFF. The engine was run for three or four minutes
and shut down. The aircraft then sat for another 35 minutes with the
main bus, avionics, etc., left ON though the ignition and boost pump
were turned OFF. The lowest battery voltage was 11.4 volts. After a
full hour of battery only operation, the engine was again started
with no problems. The alternator was turned on after the second
engine start and the bus voltage read 13.8. (I forgot to check the
amperage, which is basically an alternator loadmeter.) The engine was
only run for about three minutes. After engine shutdown, the battery
voltage was back up to 12.4 and the test ended.
Pretty good battery I think. Based on the age of my PC-680, I really
didn't expect this kind of performance.
Charlie Brame
RV-6A N11CB
San Antonio
_________________________________________________________________
More photos, more messages, more storageget 2GB with Windows Live Hotmail.
Message 11
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Subject: | Re: Dual circuit for J3300 EFI |
It would be MUCH faster if you could sketch your
changes for scanning and posting to the List. I'm
not sure the images in my head based on your words
match the reality of your proposal.
Bob . . .
At 03:05 PM 5/23/2007 +1000, you wrote:
>
>
>First a big thank you Bob for the PM self exciting feature and the crowbar
>CB tripper. Watching the voltmeter stay up, and running the electronic
>ignition all with the master switch off was too much and I had to go home
>and have a couple of beers to celebrate it. Clever stuff.
>
>I have been finishing installation of a dual circuit based on Z-21A but I
>have wandered astray a bit as follows:
>
>
>1. Re Z21-A I have connected the starter relay direct to the
>battery and not via the battery contactor. I am using the battery
>contactor only to interrupt the charging current (and to close the
>alternator relay.) I did this only because I do not know the logic for
>running the starter current through two series relays ?
>
>2. I have retained the DPST master switch to isolate battery from
>alternator from main bus. This master connects the battery contactor which
>connects the alternator relay and it connects the main bus.
>
>3. I have earthed the alternator relay coil and action it from the
>master switch through the battery contactor. I was thinking that the
>current from a failed regulator will otherwise go to earth through the
>master switch ? But how much current to expect here, I guess it is limited
>by the coil resistance. The method I have used saves another wire routed
>out to the engine bay.
>
>4. For the ebus I just had to use those two big diodes which
>access either the battery or the alternator or both (normally both) each
>with a green LED signal light. Z21-A offers power from battery plus
>alternator , or from battery but can not be switched to run from
>alternator only. So What ? Well it just appealed to me to be able to
>choose which power source in any emergency and the green lights are a feel
>good feature.
>
>
>I am offering this amendment fully expecting a flame out and ready to eat
>humble pie and learn some more, mean time I will stay off the beer.
>
>Circuit details follow :
>
>Peter
>
>
>image002.jpg
>
>
>incoming mail is certified Virus Free.
>Checked by AVG.
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
Message 12
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Subject: | Re: Off Topic- Was : Re: We can't build our own avionics |
Despite the dearth of applicable information for homebuilders in SA, and
that AOPA Pilot unabashedly promotes trainer aircraft that cost more
than my house, I still pay my dues to support the EAA and AOPA. I do
this because general aviation is under assault on myriad fronts. The
public perception of private aircraft is one of exclusivity, an arena
reserved for the wealthy. Anything that excludes the lazy and
unimaginative, that celebrates creativity, possibility and industry, is
frightening to a lot of people because it challenges them to shut-off
the TV and learn something. That takes effort and I think,
unfortunately, most people don't want to stray very far from the comfort
zone of what they know and repeat. It's easier to dismiss homebuilders
and non-commercial pilots as crazy than to go to the airport and talk to
one about flying and building.
Inspite of the condescending, cornball, syrupy image of a family affair
promoted by the EAA, I support the organization because I am convinced
that private aviation and legal homebuilding would simply vanish without
the cumulative efforts of AOPA and EAA. The two organizations are
microphones for a collective voice, amplifying the message of our
passionate group. They are the glue that keeps our spinning, aviating
world cohesive, staving off the centrifugal forces that would fragment
us into meaningless pieces. Without them, I fear, the few letters that
may arrive on congressional desks, supportive and protective of our
passion, will be drowned in a tide seeking conformity and banality. So,
I say send in your dues, and let the EAA and AOPA put on the smiley face
and the suit that allows us to do the putative job of the EAA;
experimenting, sharing information, camaraderie, and advancing aviation
technology.
Do not Archive
Message 13
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Subject: | Re: Off Topic- Was : Re: We can't build our own avionics |
Excellent thoughts John,
Yes I too support the AOPA for the same reason, sure they are "beating
the beehive" with a big stick but if they didn't the airlines would just
roll right over us with their user fees and we'd be grounded in short
order.
The sad thing is we may still loose but we're much stronger together and
if AOPA gives us a voice in Washington then they are more than worth my
$40.
Frank
Do not archive
________________________________
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John
Burnaby
Sent: Wednesday, May 23, 2007 10:10 AM
Subject: AeroElectric-List: Off Topic- Was : Re: We can't build our own
avionics
Despite the dearth of applicable information for homebuilders in SA, and
that AOPA Pilot unabashedly promotes trainer aircraft that cost more
than my house, I still pay my dues to support the EAA and AOPA. I do
this because general aviation is under assault on myriad fronts. The
public perception of private aircraft is one of exclusivity, an arena
reserved for the wealthy. Anything that excludes the lazy and
unimaginative, that celebrates creativity, possibility and industry, is
frightening to a lot of people because it challenges them to shut-off
the TV and learn something. That takes effort and I think,
unfortunately, most people don't want to stray very far from the comfort
zone of what they know and repeat. It's easier to dismiss homebuilders
and non-commercial pilots as crazy than to go to the airport and talk to
one about flying and building.
Inspite of the condescending, cornball, syrupy image of a family affair
promoted by the EAA, I support the organization because I am convinced
that private aviation and legal homebuilding would simply vanish without
the cumulative efforts of AOPA and EAA. The two organizations are
microphones for a collective voice, amplifying the message of our
passionate group. They are the glue that keeps our spinning, aviating
world cohesive, staving off the centrifugal forces that would fragment
us into meaningless pieces. Without them, I fear, the few letters that
may arrive on congressional desks, supportive and protective of our
passion, will be drowned in a tide seeking conformity and banality. So,
I say send in your dues, and let the EAA and AOPA put on the smiley face
and the suit that allows us to do the putative job of the EAA;
experimenting, sharing information, camaraderie, and advancing aviation
technology.
Do not Archive
Message 14
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Subject: | Re: Off Topic- Was : Re: We can't build our own avionics |
Very well said and I support both organizations. However I cannot help but
feeling sad when a 130 page issue of SA contains only a few pages related to
building as pointed out by Bob. On the bright side we would not have had
this forum back in in good ol days when SA was mostly about building and SA
never ever got into the aircraft electrical systems in the way this forum
does. I would like to say thanks to Bob for that. Bob's remarks on Greg of
BMA were appreciated as well, it is good to have multiple views eventhough
the people expressing them might be a bit abrasive.
On 5/23/07, John Burnaby <jonlaury@impulse.net> wrote:
>
> Despite the dearth of applicable information for homebuilders in SA, and
> that AOPA Pilot unabashedly promotes trainer aircraft that cost more than my
> house, I still pay my dues to support the EAA and AOPA. I do this because
> general aviation is under assault on myriad fronts. The public
> perception of private aircraft is one of exclusivity, an arena reserved for
> the wealthy. Anything that excludes the lazy and unimaginative, that
> celebrates creativity, possibility and industry, is frightening to a lot of
> people because it challenges them to shut-off the TV and learn something.
> That takes effort and I think, unfortunately, most people don't want to
> stray very far from the comfort zone of what they know and repeat. It's
> easier to dismiss homebuilders and non-commercial pilots as crazy than to go
> to the airport and talk to one about flying and building.
> Inspite of the condescending, cornball, syrupy image of a family affair
> promoted by the EAA, I support the organization because I am convinced that
> private aviation and legal homebuilding would simply vanish without the
> cumulative efforts of AOPA and EAA. The two organizations are microphones
> for a collective voice, amplifying the message of our passionate group. They
> are the glue that keeps our spinning, aviating world cohesive, staving off
> the centrifugal forces that would fragment us into
> meaningless pieces. Without them, I fear, the few letters that may arrive on
> congressional desks, supportive and protective of our passion, will be
> drowned in a tide seeking conformity and banality. So, I say send in your
> dues, and let the EAA and AOPA put on the smiley face and the suit that
> allows us to do the putative job of the EAA; experimenting, sharing
> information, camaraderie, and advancing aviation technology.
>
> Do not Archive
>
> *
>
>
> *
>
>
Message 15
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Subject: | Re: Off Topic- Was : Re: We can't build our own avionics |
John Burnaby wrote:
> Despite the dearth of applicable information for homebuilders in SA,
> and that AOPA Pilot unabashedly promotes trainer aircraft that cost
> more than my house, I still pay my dues to support the EAA and AOPA. I
> do this because general aviation is under assault on myriad
> fronts. The public perception of private aircraft is one of
> exclusivity, an arena reserved for the wealthy. Anything that excludes
> the lazy and unimaginative, that celebrates creativity, possibility
> and industry, is frightening to a lot of people because it challenges
> them to shut-off the TV and learn something. That takes effort and I
> think, unfortunately, most people don't want to stray very far from
> the comfort zone of what they know and repeat. It's easier to dismiss
> homebuilders and non-commercial pilots as crazy than to go to the
> airport and talk to one about flying and building.
> Inspite of the condescending, cornball, syrupy image of a family
> affair promoted by the EAA, I support the organization because I am
> convinced that private aviation and legal homebuilding would simply
> vanish without the cumulative efforts of AOPA and EAA. The two
> organizations are microphones for a collective voice, amplifying the
> message of our passionate group. They are the glue that keeps our
> spinning, aviating world cohesive, staving off the centrifugal forces
> that would fragment us into meaningless pieces. Without them, I fear,
> the few letters that may arrive on congressional desks, supportive and
> protective of our passion, will be drowned in a tide seeking
> conformity and banality. So, I say send in your dues, and let the EAA
> and AOPA put on the smiley face and the suit that allows us to do the
> putative job of the EAA; experimenting, sharing information,
> camaraderie, and advancing aviation technology.
Good words, John. EAA and AOPA do provide necessary functions, but they
will spin off into the mind-numbed, TV-viewing masses if we let them.
The subject article being a prime example. The only response is to
scream until the usurpers who would lead us down that path scurry back
into their holes.
I don't want to write a freakin' article. I want to build my airplane,
and have EAA provide me with some help in that goal. That attitude
places me dead square in the middle of the MTV generation. "My needs.
My needs," I cry, along with the rest of the mind-numbed. And I'm not
alone. Builder's everywhere are hunkered down in their garages,
expecting someone else to look after their interests. But we can't do
that. We all want a revolution, where the productive, intelligent, and
demonstrably capable come out on top, but we want someone else to lead
and fight the battles.
That won't happen. The president of the organization has never built
anything. The leadership can't find the funds to build a friggin' WIND
TUNNEL, but there's cash enough to purchase and operate a P-51 for said
president to have joy rides in. Meanwhile, has the CAFE Foundation done
ANYTHING since getting a mogas STC for certified planes? These are not
the priorities of experimenters trying to expand on the best we know how
to do. You aren't fighting an organization of experimenters gone
astray. You're fighting a rising wave of conformity and banality
washing in from the outside and threatening to swamp us all. They try
to tell us that the EAA has grown to be something larger than it used to
be. I say that it has shrunk to be much less, nothing more than the
Disneyland of airplanes.
If we let the nonsense published in the subject article go unanswered,
then our collective voice will be saying that we're not capable of
building an entire airplane. We need to be circumvented and have
artificial fences erected around us. It may be to late. The
condescending cornballs may have won already, in which case legal
homebuilding as we know it will eventually vanish. "Homebuilding" will
amount to nothing more than showing up for a two week 'quick-build'
vacation at a kit factory, where you install your selection of off the
shelf components in a pre-molded shell of an aircraft. Of course, you
can a Lindsy at a flyin, because you chose the best paint scheme from
those available.
Bob fought back till he lost interest. I know others who simply have no
interest in such activities. However, I've generated a LOT of
inter-activity in builders from my local chapter by just sending out a
lunch invitation by email. If not for that interest, I'd drop my EAA
membership this year. I have little more than a couple articles in me,
but I'll give what I have. If the cornballs have won, I'll look to
organize and join "HAA!" (Homebuilder's Aviation Alliance...we laugh at
you!)
Message 16
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Bob,
I'd asked this question a week ago and never got a reply that offered a
plausible explanation, so I'm trying again...
I have a Z-19 (2 batt, 1 alt) architecture, modified a bit for a Subaru
engine, with rear mounted Odyssey batteries. I have 2 lighter
receptacles on the panel, each wired to a battery hot bus through a 10a
fuse. I attached a couple of lighter plugs on my Battery Tender Jr. as
a convenient way to charge the batteries.
The Problem: I can insert and remove a 'hot' charger plug to one battery
at a time with no problem. However once I insert both plugs (and both
batteries are charging), and then remove one plug, the fuse on the other
circuit blows. This is a repeatable experiment. Once both plugs are
inserted, the only way I can remove them is to either unplug the
charger, or unplug the charging plugs from the charger (the output wire
has a plug to enable different endings to be attached).
Can you explain the physics of why the fuse blows when one plug is
removed?
Thanks,
Dennis Glaeser
RV-7A
Rochester Hills, MI
Message 17
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Subject: | Wiring Diag for GTX327 |
Thanks to all that responded I did not realise that it would be so
simple.
Thanks again
Norman
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Gaye
and Vaughn
Sent: 22 May 2007 08:36 PM
Subject: Re: AeroElectric-List: Wiring Diag for GTX327
<vaughnray@bvunet.net>
Here is a link to the installation manual that I found.....Vaughn
http://aviation.vortex.is/install/Garmin%20Install%20manuals/GTX-327.pdf
----- Original Message -----
From: "Norman Stapelberg" <norshel@mweb.co.za>
Sent: Tuesday, May 22, 2007 1:29 PM
Subject: AeroElectric-List: Wiring Diag for GTX327
> <norshel@mweb.co.za>
>
> I wonder if some could help out, I am busy fitting a Garmin GTX327
> Transponder in a friends plane, as luck would have it he has misplaced
> the manuals I have managed to download the operation manual, but am
some
> what stuck for the wiring side.
>
> Thanks
>
> Norman Stapelberg
> South Africa
> RV7 Fuselage 50%
>
>
>
Message 18
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Subject: | Dual circuit for J3300 EFI |
Bob, Sorry about my attachment, the scan att is not accepted on the Yahoo
lists I know best.
I should correct item 3 below, pls disregard my reference to the coil
resistance which is shunted by the crowbar, I hope that helps to make more
sense?
But I am curious to know how much current to expect through the crowbar if
the regulator fails. I can still remember a boiling battery and think about
the amount of energy to be wasted through the crowbar.
Thanks,
Peter
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Thursday, 24 May 2007 2:12 AM
Subject: Re: AeroElectric-List: Dual circuit for J3300 EFI
It would be MUCH faster if you could sketch your
changes for scanning and posting to the List. I'm
not sure the images in my head based on your words
match the reality of your proposal.
Bob . . .
At 03:05 PM 5/23/2007 +1000, you wrote:
>
>
>First a big thank you Bob for the PM self exciting feature and the crowbar
>CB tripper. Watching the voltmeter stay up, and running the electronic
>ignition all with the master switch off was too much and I had to go home
>and have a couple of beers to celebrate it. Clever stuff.
>
>I have been finishing installation of a dual circuit based on Z-21A but I
>have wandered astray a bit as follows:
>
>
>1. Re Z21-A I have connected the starter relay direct to the
>battery and not via the battery contactor. I am using the battery
>contactor only to interrupt the charging current (and to close the
>alternator relay.) I did this only because I do not know the logic for
>running the starter current through two series relays ?
>
>2. I have retained the DPST master switch to isolate battery from
>alternator from main bus. This master connects the battery contactor which
>connects the alternator relay and it connects the main bus.
>
>3. I have earthed the alternator relay coil and action it from the
>master switch through the battery contactor. I was thinking that the
>current from a failed regulator will otherwise go to earth through the
>master switch ? But how much current to expect here, I guess it is limited
>by the coil resistance. The method I have used saves another wire routed
>out to the engine bay.
>
>4. For the ebus I just had to use those two big diodes which
>access either the battery or the alternator or both (normally both) each
>with a green LED signal light. Z21-A offers power from battery plus
>alternator , or from battery but can not be switched to run from
>alternator only. So What ? Well it just appealed to me to be able to
>choose which power source in any emergency and the green lights are a feel
>good feature.
>
>
>I am offering this amendment fully expecting a flame out and ready to eat
>humble pie and learn some more, mean time I will stay off the beer.
>
>Circuit details follow :
>
>Peter
>
>
>image002.jpg
>
>
>incoming mail is certified Virus Free.
>Checked by AVG.
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
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