Today's Message Index:
----------------------
1. 01:54 AM - Re: We can't build our own avionics (jetboy)
2. 04:57 AM - Re: We can't build our own avionics ()
3. 05:22 AM - Re: We can't build our own avionics (Ed Anderson)
4. 06:32 AM - Re: We can't build our own avionics (dwieck@cafes.net)
5. 06:36 AM - Re: Re: We can't build our own avionics (Michael Hinchcliff)
6. 07:45 AM - Re: off topic--2 batteries, one alternator (Robert L. Nuckolls, III)
7. 10:31 AM - Wiring Diag for GTX327 (Norman Stapelberg)
8. 11:37 AM - Re: Wiring Diag for GTX327 (Gaye and Vaughn)
9. 01:11 PM - Re: Re: We can't build our own avionics (Ernest Christley)
10. 03:15 PM - Attitude gyro problem. (Puckett, Gregory [DENTK])
11. 03:35 PM - Odessey Battery Capacity Test (Charles Brame)
12. 04:28 PM - Re: Attitude gyro problem. (S. Ramirez)
13. 05:05 PM - Re: AeroElectric-List Digest: 18 Msgs - 05/21/07 (Lee Logan)
14. 05:49 PM - Re: Attitude gyro problem. (Puckett, Gregory [DENTK])
15. 06:36 PM - Ni-Cad Capacity check (raymondj)
16. 08:33 PM - High VSWR reading on my antenna lead (James Beeghly)
17. 09:40 PM - Re: Re: We can't build our own avionics (Robert L. Nuckolls, III)
18. 09:44 PM - Re: High VSWR reading on my antenna lead (Robert L. Nuckolls, III)
19. 10:07 PM - Dual circuit for J3300 EFI (Peter Harris)
20. 11:15 PM - Can Rotax be self exciting? ()
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: We can't build our own avionics |
Articles like that just increase the challenge....
http://lea.hamradio.si/~s53mv/avionics/avionics.html
deserves congratulations for putting so much together.
--------
Ralph - CH701 / 2200a
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=114124#114124
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: We can't build our own avionics |
Ernest:
Ditto, that is what I got out of the article as well, but.......
I was waiting for him to say if you work on your avionics the terrorist
will win.
None of this applies to experimentals except for may be ELT's and
transponders. Yes FCC is another story. Gray area? Yes.
However, I disagree w/ your EAA comment. They do more than any
group for all GA, especially experimental. EAA is 100's more active
AOPA which is in the pocket of the aviation industry and
than manufactures.
Don't Bash EAA, simply write and send the editor your complaints.
Further contact EAA legal and tell them you think that this article
is full of fallacies. The EAA single handily rights the wrongs of the
FAA that misinterprets FAR's and makes up inconcistant policy
as they go. They will research it and tell you the law, not make it
up.
I just can't emphasise how much the EAA protects our right to fly
and build.
Sincerely George ATP/CFI-II-ME/MSME
>From: Ernest Christley <echristley@nc.rr.com>
>Subject: AeroElectric-List: We can't build our own avionics
>
>The latest Sport Aviation has an article that attempts to explain why
>we can't work on our own avionics. There's some mental gymnastic
>type 'logic' (the author basically states that "none of this applies" early
>in the article) and some outright fallacies (a normal person can't
>solder surface mount devices) amongst lots of exaggeration (repairing
>a board would require a resistor or diode from the same lot used in
>the original construction), a preachy style, and lots of bogeymen in
>the form of the FAA and the FCC. There's even a veiled attack of
>Jim Weir's audio panel. What is it with these people and their can't
>do attitudes?
>
>Can we rise up in unison and tell the EAA that if this is all the help
>we're going to get to please go back to actively ignoring us?
---------------------------------
Be a better Globetrotter. Get better travel answers from someone who knows.
Yahoo! Answers - Check it out.
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: We can't build our own avionics |
That's interesting, Dennis.
Way back a long time ago, I got a Commercial Radio telephone and Telegraph
operators license from the FCC - 16 years old at the time, thinking I could
get a job as radio operator aboard a US registered ship which at that time
were required by law to have a radio telegraph operator on board. But, as
soon as I got my ticket, they changed the law and they were no longer
required - so no career as a merchant ship radio operator {:>)
But, it sounds like I could legally build my transmitter (not that I would
want to).
Ed
----- Original Message -----
From: "Dennis Wieck" <dwieck@cafes.net>
Sent: Monday, May 21, 2007 9:27 PM
Subject: Re: AeroElectric-List: We can't build our own avionics
>
> Rob Housman wrote:
>> <robh@hyperion-ef.com>
>>
>> No problem with the FCC on "homebuilt" radios.
>
> Depends on how you are using them. It is still OK to build ham radios (
> and kits are still available just not from Heathkit any more)
> Until the demise of it's
>> electronics kit business sometime in the mid-1980s Heathkit produced many
>> ham radio transmitter and receiver kits which were very popular with ham
>> radio operators. Other than the required license for operating a
>> transmitter, the FCC imposed no restrictions on the amateur radio
>> builders.
>
> The FCC will not let you build an aircraft transmitter or work on one. You
> have to have a GROL ( General Radiotelephone Operator License) or at least
> be signed off by someone with one.
>
> Here is a summary of when you need a commercial license (GROL):
>
> "You need a commercial radio operator license to repair and maintain the
> following:
>
> * All ship radio and radar stations.
> * All coast stations.
> * All hand carried units used to communicate with ships and coast
> stations on marine frequencies.
> * All aircraft stations and aeronautical ground stations
> * including hand-carried portable units) used to communicate with
> aircraft.
> * International fixed public radiotelephone and radiotelegraph
> stations."
>
> this is not just a FCC requirement but an international requirement.
>
>
> Dennis
>
>
>
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: We can't build our own avionics |
That's interesting, Dennis.
Way back a long time ago, I got a Commercial Radio telephone and Telegraph
operators license from the FCC - 16 years old at the time, thinking I could get
a
job as radio operator aboard a US registered ship which at that time were
required by law to have a radio telegraph operator on board. But, as soon as
I
got my ticket, they changed the law and they were no longer required - so no
career as a merchant ship radio operator {:>)
But, it sounds like I could legally build my transmitter (not that I would want
to).
Sort of. You would have to have it approved by the FCC.
Sec. 87.39 Equipment acceptable for licensing.
Transmitters listed in this part must be certificated for a
particular use by the Commission based upon technical requirements
contained in subpart D of this part.
All of this does not mean you cant build some of your own avionics, just that
anything that transmits would require a license.
Dennis
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: We can't build our own avionics |
Although I don't always see things the way gmcjetpilot "George" sees
them, I must agree with him on his stance about the EAA. If the EAA was
to be a purely "experimenters" organization, it would be a very, very
small group. Don't forget that plans built and kit built planes are
STILL experimental as well. Without the EAA, we might not have nearly
as many folks building their own electrical systems for OBAM aircraft.
The EAA constantly reminds me that I can do it and it's worth it. I
challenge you to tell me of another organization that better supports
our efforts with OBAM aircraft. Just becuase the EAA is imperfect does
not mean they're the enemy.
Now with that said, I will have to agree with many other's opinion that
the EAA does not support a lot of electrical systems knowledge. It
would be nice to have somebody volunteer to present a series of FACTUAL
lectures at AirVenture to futher the cuase (hint, hint). As of right
now, the only folks who regularly present electrical systems subject
matter at AirVenture are from Blue Moutain avionics. I think they have
a few good ideas, but have a very different approach to aircraft
electical systems than 'lectic Bob. I prefer Bob's roll-your own method,
which is why I'm here. This group fills the gap.
----- Original Message -----
From: gmcjetpilot@yahoo.com
To: aeroelectric-list@matronics.com
Sent: Tuesday, May 22, 2007 6:52 AM
Subject: AeroElectric-List: Re: We can't build our own avionics
Ernest:
Ditto, that is what I got out of the article as well, but.......
I was waiting for him to say if you work on your avionics the
terrorist
will win.
None of this applies to experimentals except for may be ELT's and
transponders. Yes FCC is another story. Gray area? Yes.
However, I disagree w/ your EAA comment. They do more than any
group for all GA, especially experimental. EAA is 100's more active
AOPA which is in the pocket of the aviation industry and
than manufactures.
Don't Bash EAA, simply write and send the editor your complaints.
Further contact EAA legal and tell them you think that this article
is full of fallacies. The EAA single handily rights the wrongs of the
FAA that misinterprets FAR's and makes up inconcistant policy
as they go. They will research it and tell you the law, not make it
up.
I just can't emphasise how much the EAA protects our right to fly
and build.
Sincerely George ATP/CFI-II-ME/MSME
>From: Ernest Christley <echristley@nc.rr.com>
>Subject: AeroElectric-List: We can't build our own avionics
>
>The latest Sport Aviation has an article that attempts to explain why
>we can't work on our own avionics. There's some mental gymnastic
>type 'logic' (the author basically states that "none of this applies"
early
>in the article) and some outright fallacies (a normal person can't
>solder surface mount devices) amongst lots of exaggeration (repairing
>a board would require a resistor or diode from the same lot used in
>the original construction), a preachy style, and lots of bogeymen in
>the form of the FAA and the FCC. There's even a veiled attack of
>Jim Weir's audio panel. What is it with these people and their can't
>do attitudes?
>
>Can we rise up in unison and tell the EAA that if this is all the
help
>we're going to get to please go back to actively ignoring us?
-------------------------------------------------------------------------
-----
Be a better Globetrotter. Get better travel answers from someone who
knows.
Yahoo! Answers - Check it out.
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: off topic--2 batteries, one alternator |
At 11:43 PM 5/21/2007 -0400, you wrote:
>
>I have a boat I am wanting to hook up a second battery for running on-board
>equipment and charge from the same 25 amp alternator of the motor. Thinking
>about paralleling the batteries with a diode separating the starting battery
>through positive lead, isolating it from the load of the on board equipment.
>Should there be a concern of overcharging or more likely undercharging the
>second battery? See anything wrong with this simple system?
It can be simpler yet. Assuming you have useful instrumentation/
warning systems aboard (most important . . . a low volts warning
light) then you can simple hook both batteries on line during
normal operations through a switch. See marine suppliers for
OFF, 1, 2, BOTH battery switches.
Distribute loads unique to each battery from battery busses
that are not switched. During normal operations (engine running,
low volts warning light out), the battery switch is at
BOTH. If the light comes on, move the battery switch as-desired
and keep on truck'n.
See:
http://www.aeroelectric.com/Pictures/Switches/Battery_Switches/
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Wiring Diag for GTX327 |
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 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Wiring Diag for GTX327 |
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 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: We can't build our own avionics |
Michael Hinchcliff wrote:
> The EAA constantly reminds me that I can do it and it's worth it. I
> challenge you to tell me of another organization that better supports
> our efforts with OBAM aircraft.
"You CAN do it. Just buy the parts from any of our vendors and plug
them in. See how nice that looks? You're such a sweet boy, Michael.
No, you can do that part, Michael. That's to difficult for you. You
have to have a kit to that. Look at all the pretty advertisements. You
wouldn't want to fly in something that looks like you built it at home
would you? Of course not. You just need to buy some things, because
they're too hard for you."
I can do without that sort of support, thank you. The article was
exactly that patronizing, and was solely written to dissuade people who
might consider obtaining the skills to build their own. How someone
could insult such a large group of people at once is beyond me.
> Just becuase the EAA is imperfect does not mean they're the enemy.
>
Any person, group, or organization that would choose to reign in the
creativity or industry of homebuilders are to be marked enemy. Any
claim that "you can't" that is not backed by instructions in simple
physics must be met with fierceness and without prejudice.
The guy claimed that you can't solder surface mount device, for Pete's
sake. I worked in a custom electronics shop as a technician for four
years. After it passed through the oven, my job was to test the board.
The most prevalent problem was that one of the devices was never put on,
or was broken off. After testing, I would put a replacement part back
on...WITH A HANDHELD SOLDERING IRON. Two lead parts were easy (tin one
pad, stick the part to that side, then solder the other side), but I
regularly repaired 40-pin, high-density IC's (lots of flux, drag a ball
of molten solder across the leads...that one takes some practice). For
someone to claim that is isn't possible to do at home is insulting,
creates an oppressive can't-do atmosphere, and is most definitely not
supportive. We are not sheep to be lined up by the EAA to be fleeced by
their vendors.
Now, I've got to put-up or shut-up. The can't-doers have had their
say. The can-doers deserve equal air time. I've built one of Jim
Weir's audio panel kits, and a display for an engine monitor. I've also
experimented with some techniques for building LED position and tail
lights. I know a few others I know have projects that would be perfect
for putting the lie to this article. I'm volunteering to write an
article entitled "Yes We Can" (I reluctantly will leave off the Da**-It,
but it deserves to be there). I will specifically be trying to drive
home the point that the EAA has no place trying to pointlessly limit
what can be done. I have some data on what the FCC will allow. But I'd
like to add pictures of components that others have built that
specifically counter the no-you-can't points, and give descriptions of
how it is accomplished. I'd like a few list members to volunteer as
editors to help me avoid making a complete fool of myself. I would like
to make a timely response, so please don't hesitate to speak up.
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Attitude gyro problem. |
Help!! My attitude indicator is driving me nuts!
The attitude indicator is a RC Allen RCA26AK2 (14v electric) with 8deg
tilt installed in my RV-8.
>From the first flight, the indicator showed signs of what I thought was
precession. During constant altitude standard rate turns, when rolling
out to wings level the indicator would show up to 10deg bank in the
opposite direction. While turning at standard rate level altitude, after
90 deg of hdg change in one direction the indicator would show up to
5deg of false climb and 5deg of false descent when in the other
direction. BTW, the indicator does not show any bank during turns on the
ground.
I thought, well this thing has been sitting for some time, the bearings
must be bad. I sent the indicator back to Kelly Mfg for repair, they
replaced the bearings and recalibrated. After reinstalling, I still had
the same problem. I suspected that the repair was not sufficient and
sent it back again with no fault found. I still had the same problem in
the airplane after reinstalling.
I checked some things with the A/C such as actual panel tilt, voltage at
the instrument with respect to the instrument ground, noise on the power
in. The only thing I found was that my actual panel tilt was more like
5.5 deg and not 8. I shimmed the instrument so that it was exactly 8 deg
and it did not help the problem at all. I thought for sure, something
must be wrong with the instrument. Kelly mfg agreed to exchange it for a
new manufacture instrument. I still have the same problem with the new
instrument.
I then thought, even though it's a spinning hunk of mass, something must
be interfering with it. I wrapped the case in mu-metal, turned off all
electrical equipment in the panel including both alternators and you
guessed it, I still have the problem. WTF....
What else could possibly be causing this????
Thanks in advance,
Greg
Message 11
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | 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
Message 12
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Attitude gyro problem. |
Greg,
Measure the voltage at the unit, not at the battery, and report back.
Simon Ramirez, Aerocanard Builder
LEZ N-44LZ
Oviedo, FL 32765 USA
Copyright C 2007
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Puckett,
Gregory [DENTK]
Sent: Tuesday, May 22, 2007 6:13 PM
Subject: AeroElectric-List: Attitude gyro problem.
Help!! My attitude indicator is driving me nuts!
The attitude indicator is a RC Allen RCA26AK2 (14v electric) with 8deg tilt
installed in my RV-8.
>From the first flight, the indicator showed signs of what I thought was
precession. During constant altitude standard rate turns, when rolling out
to wings level the indicator would show up to 10deg bank in the opposite
direction. While turning at standard rate level altitude, after 90 deg of
hdg change in one direction the indicator would show up to 5deg of false
climb and 5deg of false descent when in the other direction. BTW, the
indicator does not show any bank during turns on the ground.
I thought, well this thing has been sitting for some time, the bearings must
be bad. I sent the indicator back to Kelly Mfg for repair, they replaced the
bearings and recalibrated. After reinstalling, I still had the same problem.
I suspected that the repair was not sufficient and sent it back again with
no fault found. I still had the same problem in the airplane after
reinstalling.
I checked some things with the A/C such as actual panel tilt, voltage at the
instrument with respect to the instrument ground, noise on the power in. The
only thing I found was that my actual panel tilt was more like 5.5 deg and
not 8. I shimmed the instrument so that it was exactly 8 deg and it did not
help the problem at all. I thought for sure, something must be wrong with
the instrument. Kelly mfg agreed to exchange it for a new manufacture
instrument. I still have the same problem with the new instrument.
I then thought, even though it's a spinning hunk of mass, something must be
interfering with it. I wrapped the case in mu-metal, turned off all
electrical equipment in the panel including both alternators and you guessed
it, I still have the problem. WTF..
What else could possibly be causing this????
Thanks in advance,
Greg
Message 13
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: AeroElectric-List Digest: 18 Msgs - 05/21/07 |
How would the FCC know your aircraft radio (TSO'd or otherwise) was broken?
If it fails, you (or someone) must fix it before it can be used again. The
next time you use it, it will have had to have been fixed. How would the
FCC know it was ever broken to even be able to ask, "who fixed it"?
Lee...
Message 14
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | RE: Attitude gyro problem. |
Hey Simon,
Thanks for the response.
When I say
> voltage at the instrument with respect to the instrument ground.
I meant what you said, at the backshell of the indicator, while in flight. It was
reading .2 volts less that the buss voltage with 5 mv of ripple with the alternator
online. To me, that seemed in the reasonable range.
Greg
p.s. I did notice today that the panel cutout had almost a 1 deg error in roll
with respect to the main spar that I corrected by elongating the holes in the
panel. I can't believe something like that could be the answer and unfortunately,
the weather was too crappy to fly and see. Let me know if you can think of
anything else to try.
Message 15
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Ni-Cad Capacity check |
Does anyone have a schematic for a capacity checker for small batteries like
Ni-Cads, etc.
Thanks,
Raymond Julian
Kettle River, MN.
do not archive
Message 16
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | High VSWR reading on my antenna lead |
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><head><meta name="Generator" content="PSI HTML/CSS Generator"/>
<style type="text/css"><!--
body{font-family:'Arial';font-size:11pt;font-color:'#000000';}
LI{display:list-item;margin:0.00in;}
p{display:block;margin:0.00in;}
body{}
--></style>
</head><BODY BGCOLOR="#F0F0F0" ><div><SPAN style="font-size:11pt;">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.  </SPAN></div>
<div> </div>
<div><SPAN style="font-size:11pt;">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.</SPAN></div>
<div> </div>
<div><SPAN style="font-size:11pt;">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.</SPAN></div>
<div> </div>
<div><SPAN style="font-size:11pt;">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.
 </SPAN></div>
<div> </div>
<div><SPAN style="font-size:11pt;">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.)  </SPAN></div>
<div> </div>
<div><SPAN style="font-size:11pt;">Does anyone have any suggestions for what
to consider next?  As you can no doubt tell, I am new to this.
 Thanks.</SPAN></div>
<div> </div>
<div><SPAN style="font-size:11pt;">Jim Beeghly</SPAN></div>
<pre><b><font size=2 color="#000000" face="courier new,courier">
</b></font></pre></body></html>
Message 17
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: We can't build our own avionics |
At 08:33 AM 5/22/2007 -0500, you wrote:
<snip>
Now with that said, I will have to agree with many other's opinion that the
EAA does not support a lot of electrical systems knowledge. It would be
nice to have somebody volunteer to present a series of FACTUAL lectures at
AirVenture to futher the cuase (hint, hint). As of right now, the only
folks who regularly present electrical systems subject matter at AirVenture
are from Blue Moutain avionics. I think they have a few good ideas, but
have a very different approach to aircraft electical systems than 'lectic
Bob. I prefer Bob's roll-your own method, which is why I'm here. This
group fills the gap.
I attended OSH for 12 years running and produced two
seminars every year . . . a one-hour gig during the day
and an evening session that ended when the EAA folks came
out and pulled the plug. I also wrote about a dozen articles
for Sport Aviation.
Long 'bout fall of '98, Cox sent me an article
written by one Mr. Paul Burgher. He said a number of
folks had looked it over and thought some of the ideas
were "fishy" . . . I read the article, did a two page
review on it and returned it to Sport Aviation and
recommended that it not be published.
Nevertheless, about May of 1999, the article pops up
in Sport Aviation anyhow. Mr. Burgher took issue with
my review and apparently, somebody in the EAA hierarchy
agreed with him and directed the magazine to publish the
thing anyhow.
So given that I was mentioned in the article, I felt that
it was only fitting that I explain myself . . .
which I did and published on AeroElectric.com
http://aeroelectric.com/articles/rules/review.html
I decided that it was not a good use of my time to
swim upstream in that current so I ceased donating
the articles to the 'cause'.
A few years later, the new editor (Spangler?) wrote
me an e-mail or called after somebody turned him on
to the critical review of Burgher's piece. He expressed
some dismay that such poorly written material would be
printed in the EAA's flagship publication. I told him I might
be interested in writing for SA again but that a decent
article took 8-10 hours. He said that he now had a budget
to pay for good work. I told him I'd dig through the
works in progress and finish up one or more for his
consideration.
A few days later, I got a call from him asking if I
had anything I could do quickly. Seems someone on tap
for the next issue wasn't going to perform and he needed
a piece in a hurry. So, I went to the keyboard and turned
some test data I had on AA alkaline cells into an article.
http://www.aeroelectric.com/articles/AA_Bat_Test.pdf
I guess it filled the bill. It appeared in the next issue
of SA. However, in years since, no remuneration has been
received from SA nor have I had any requests to continue
the relationship. In the mean time, other articles of
questionable pedigree have been published. Like this
little jewel . . .
http://www.aeroelectric.com/articles/Wired_for_Disaster.pdf
I've since decided that my time is better spent here
on the List than massaging the folks at Sport Aviation.
It's sad but typical of many publishing ventures that
graduated up from 4 pages of mimeographed hard data
and no advertising to 150 pages of 4-color, computer
aided, gee-whiz graphics, lots of advertising and
management that believes one should have a certain
number of but not too many pages of "knowledge" to
print along with the ads.
Last time I counted pages in an issue of SA, I think it
was about 130 pages long and I found 10 pages of information
on how to build airplanes. This was certainly not Paul's
vision of what the magazine should be . . . nonetheless,
that's where it is today.
I went to OSH a couple of years ago and did a couple
of gigs at some kit-dinners. I don't recall if I got a
slot in the tents or not . . . I think they offered me
an early slot early in the week. If I accepted it, there
weren't many folks there yet. No hard feelings but certainly
a sense of sadness to watch it devolve over the years.
Bob . . .
Message 18
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: High VSWR reading on my antenna lead |
At 10:33 PM 5/22/2007 -0500, you 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.
First, go to Radio Shack and get the stuff to build one of these:
http://www.aeroelectric.com/Pictures/Tools/DummyLoad.jpg
Use it to replace the antenna connection on the output of
the SWR meter and see if it shows 1:1 SWR. If not, the meter
is bad. If so, the antenna (or more probably) the coax connectors
at one end or the other . . . but your duplicated experiment
on two different antennas suggests that meter is bad.
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
Message 19
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Dual circuit for J3300 EFI |
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
Message 20
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Can Rotax be self exciting? |
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
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|