Today's Message Index:
----------------------
1. 01:00 AM - Re: building a hall-effect ammeter (Brian Lloyd)
2. 02:20 AM - Re: Re: Grounding lugs and transponder radiation (FLYaDIVE@aol.com)
3. 02:32 AM - Re: External Power and electrical system isolation (FLYaDIVE@aol.com)
4. 04:52 AM - microphone noise (Ken)
5. 06:07 AM - Re: microphone noise (Charlie England)
6. 06:30 AM - Re: External Power and electrical system ()
7. 07:10 AM - Re: microphone noise (FLYaDIVE@aol.com)
8. 09:05 AM - Re: External Power and electrical system (Brian Lloyd)
9. 07:03 PM - Help needed: continued strobe noise & weak radio (luckymacy@comcast.net (lucky))
10. 08:38 PM - Re: Help needed: continued strobe noise & weak radio (Hopperdhh@aol.com)
11. 08:41 PM - Re: Help needed: continued strobe noise & weak radio (Hopperdhh@aol.com)
12. 08:42 PM - Re: Help needed: continued strobe noise & weak radio (B Tomm)
Message 1
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| Subject: | Re: building a hall-effect ammeter |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
On Jul 14, 2006, at 3:20 PM, Dale Ensing wrote:
> --> AeroElectric-List message posted by: "Dale Ensing"
> <densing@carolina.rr.com>
>
> Brian,
> Is this available as a kit?
I don't know. I just found the article. You probably need to use the
info in the article to find out.
> Dale Ensing
>
>
>> --> AeroElectric-List message posted by: Brian Lloyd <brian-
>> yak@lloyd.com>
>>
>> FYI: http://www.siliconchip.com.au/cms/A_30551/article.html
>>
>> Brian Lloyd
>>
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 2
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| Subject: | Re: Grounding lugs and transponder radiation |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 7/12/06 7:45:08 PM Eastern Daylight Time, n3eu@comcast.net
writes:
> > The signal is radiated only from the shaft of the antenna.
>
> A couple theoretical texts I have suggest it radiates only from the base
of
> the antenna. Has to do with 90-deg phase lag, current and voltage, I
think.
> The vertical element is there merely to resonate.
>
> Dunno also, but the ball has been alleged to be either a capacity hat, or
to
> have proverse effect on radiating pattern. One such allegation came from
a
> retired, aircraft antenna engineer I know. But he thinks my questions are
> often inane! [Wink]
>
> Fred F.
=================================
Fred - Group:
If people think that the ball does not radiate cut it off. Better yet TOUCH
it and see if you get an RF Burn! Want to get a bit more scientific? Make up
or obtain a second antennas and check the SWR with and without the ball. SWR
will be higher without the ball.
As I stated before ... If it is metal and it is attached to the antenna it is
part of the radiating medium of the antenna.
As far as Lead Vs Lag ... Current Vs Voltage ... ELI the ICE man ... [The
previous are all theories taught in electronics and physics.] Who gives a
Dittlie-Womp. That is all theory in Capacitive Reactance - Inductive Reactance
and
Wave Length. It only matters when obtaining the correct impedance for
matching the antenna to the transmission line and the transmission line to the
transponder (in this case). Bottom Line ... IT RADIATES. Check out SMITH Charts
and that other guy's charts I can't remember right now.
It is NOT a capacitive hat ... It is NOT a loading coil ... Again as I stated
it is for eliminating Corona Effect and the dissipation of static.
Barry
"Chop'd Liver"
Message 3
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| Subject: | Re: External Power and electrical system isolation |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 7/13/06 3:59:57 PM Eastern Daylight Time,
michele.delsol@microsigma.fr writes:
> What do you guys suggest isolate my electrical system when external power
> is hot or just hook it up onto the battery via a relay?
>
> Thanks,
> Michele Delsol
> RV8 Fuselage
==========================
Michele:
The first question you have to ask yourself is: "What do I want the external
power for?"
If your answer is STARTING then all that is required is a connection - relay
to act as a MASTER RELAY and supply power to the Starter Relay and conversely
to the STARTER. Isolating the rest of the panel and electronics. You can get
that circuit from any GA manual Cessna, Piper or Grumman. That to me is the
K.I.S.S. M.E. principal. Now if you want a THREE function power hookup source
for:
1 - Running a handheld or GPS
2 - Running your electronics for testing, or
3 - Doing a LOW LEVEL charge, such as charging the battery using a solar
panel ... The just hook up a cigarette lighter directly to the battery.
This is the system I have hooked up in the RV-6A.
It is GREAT when you have an electrical problem and have to shut down the
MASTER. It gives you power for the GPS [Navigation] and a handheld
[Communication]. Oh, did you remember to install a quick disconnect for the antenna
so you
can hook up the handheld?
Barry
"Chop'd Liver"
Message 4
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| Subject: | microphone noise |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Good day.
I've tried a couple of headsets but I have a lot of static whenever I
key the transmit button with the headset microphone plugged in. I can
hear it on my headset and it is being transmitted. No static if I key it
with the mic unplugged. So it would seem that the mic is picking up
cockpit noise. However clasping my hand over the boom mic or changing
its orientation does not change the static which seems to suggest it is
not cockpit noise. Any suggestions?
This is an Icomm A-200 radio and an intercom but bypassing the intercom
with its "pilot/all" switch doesn't change anything. The headset jacks
are mounted in a plastic box. Separate shielded wires are used for the
mic and the earphones with the shields carrying the grounds.
thanks
Ken
Message 5
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| Subject: | Re: microphone noise |
--> AeroElectric-List message posted by: Charlie England <ceengland@bellsouth.net>
Ken wrote:
> --> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>
> Good day.
>
> I've tried a couple of headsets but I have a lot of static whenever I
> key the transmit button with the headset microphone plugged in. I can
> hear it on my headset and it is being transmitted. No static if I key
> it with the mic unplugged. So it would seem that the mic is picking up
> cockpit noise. However clasping my hand over the boom mic or changing
> its orientation does not change the static which seems to suggest it
> is not cockpit noise. Any suggestions?
>
> This is an Icomm A-200 radio and an intercom but bypassing the
> intercom with its "pilot/all" switch doesn't change anything. The
> headset jacks are mounted in a plastic box. Separate shielded wires
> are used for the mic and the earphones with the shields carrying the
> grounds.
>
> thanks
> Ken
If you have a noisy cockpit, covering the mic with your hand probably
won't make much difference.
Is it electronic static or cockpit noise?
Does it change in pitch with engine rpm? (ignition or alternator)
Is it quiet it you key the mic with the master & all accessories on but
without the engine running? (cockpit noise)
If it's there with the engine & all other accessories off, you might
have radio problems.
If it's there but quieter & no pitch change with the engine idling, it's
probably cockpit noise.
Message 6
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| Subject: | Re: External Power and electrical system |
--> AeroElectric-List message posted by: <chaztuna@adelphia.net>
> >--> AeroElectric-List message posted by: =?iso-8859-1?Q?Mich=E8le_MS?=
> ><michele.delsol@microsigma.fr>
> >
> >Listers,
> >
> >I have been planning on adding external power to my system (one alternator,
> >one battery, PMag IO360). My original design was pretty simple, hook it
> >straight onto the battery such as one does when jump starting a car.
>> Then I added a relay so that the external power terminals would not be hot
when not connected to external power.
Michele,
Earlier you said that you intended to place your battery on the right side behind
the firewall. It seems to me, that in this location, you can access the battery
on your RV8 by simply opening the front baggage door and reaching down.
With this location, why add weight and complexity when there is such a simple
and obvious solution? What am I missing?
Charlie Kuss
Message 7
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| Subject: | Re: microphone noise |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 7/15/06 7:55:03 AM Eastern Daylight Time,
klehman@albedo.net writes:
> Good day.
>
> I've tried a couple of headsets but I have a lot of static whenever I
> key the transmit button with the headset microphone plugged in. I can
> hear it on my headset and it is being transmitted. No static if I key it
> with the mic unplugged. So it would seem that the mic is picking up
> cockpit noise. However clasping my hand over the boom mic or changing
> its orientation does not change the static which seems to suggest it is
> not cockpit noise. Any suggestions?
>
> This is an Icomm A-200 radio and an intercom but bypassing the intercom
> with its "pilot/all" switch doesn't change anything. The headset jacks
> are mounted in a plastic box. Separate shielded wires are used for the
> mic and the earphones with the shields carrying the grounds.
>
> thanks
> Ken
============================
Ken:
You have a good question ... Problem their ... My next question in the
diagnosis would be:
Is the static their when you use any other Headset - Mic Jacks?
If not then the problem is only associated with the Mic Jack you are using.
If the problem still exists on ALL jacks then you have to go back to the
common points - PTT Switch, Intercom and Radio.
Barry
"Chop'd Liver"
"When all the possibilities are eliminated then the only thing left is the
probability"
Message 8
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| Subject: | Re: External Power and electrical system |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
It can be difficult to effectively asses one's needs when doing an
initial design. For the most part, whenever I have said to myself, "I
won't need that," I have found that indeed I eventually needed "that".
As others have said, there are three reasons for ground power:
1. starting the engine when the battery charge is too low;
2. to operate the electrical equipment on the ground without
discharging the battery;
3. to charge the battery.
If I were going to craft a ground-power plug I would ensure that it
was usable for all three functions.
Now for an anecdote. At OSH in 2000 I was supposed to fly my CJ6A in
the mass warbird formation on Friday. (I had already flown on opening
day on Wednesday as I recall.) At the proper time we hopped in our
airplanes. It was at that moment I discovered that someone had been
in my airplane and had turned on every switch, including the battery
master. My battery was dead. If I had had a ground power plug I might
have been able to put an initial charge on the battery and start the
engine and still fly in the shoe. As it was, I couldn't.
I considered trying to get some jumpers in there but, as the battery
was back in the empennage under the baggage compartment floor, it was
inconvenient and a rogue jumper cable was likely to do damage to
something. So I very carefully pulled the battery and hauled it up to
the warbird maintenance area were we were able to put it on a charger.
Several hours later the battery was charged and I was in the process
of reinstalling it. I was being extremely careful to keep the
terminal from touching any of the control cables but it was dark back
in there. I had avoided the rudder and elevator control cables but
missed seeing the much smaller trim cable. Of course I managed to get
the trim cable across the battery terminals. The trim cable failed
with a most satisfactory flash and bang. (Yes, the damned thing
literally exploded in my face.) I bashed my head against a bulkhead
and uttered the immortal words. I managed to extricate my temporarily-
blinded eyes from the baggage compartment only to have the pilot next
to me say, "So Sparky, having a bit of trouble, are we?" From then on
my call-sign was "Sparky".
So, yes, I want my ground power plug to be able to do it all. I
consider it to be a safety issue now.
Brian Lloyd 361 Catterline Way
brian-yak AT lloyd DOT com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
Message 9
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| Subject: | Help needed: continued strobe noise & weak radio |
--> AeroElectric-List message posted by: luckymacy@comcast.net (lucky)
I have two "comm" issues that I haven't been able to debug to completion yet.
I'm using an Xcom 760 radio with their pre-made harness.
1) I still hear my strobes in my headset even when they are grounded with the radio
ground and even when I put power noise filters on. However, the Radio Shack
noise filters reference on Bob's web site were reported to me to be no longer
carried by them. So I used the only ones I could find locally which were
sold by Pep Boys and the capacitor was 4700 uF instead of 2200 uF like Radio Shack
apparently was.
More specifically, the strobe noise is relatively faint until I select the Push
to Talk button. Then it gets pretty loud. Some feedback going on there. Looking
for ideas from this list.
Should the capacitor specs have made a big difference on the effectiveness overall
of the noise filter? It made no measurable difference regardless of whether
I installed it just before the radio or out at the strobe's power supply just
before the AC +14v entered the power supply. I even reversed direction of
the filter and it didn't matter one iota. Really bummed out about this turn of
events since I thought they'd at least have made some observable difference
based upon stuff in the archives.
2) The second overall problem is that the radio still is reported to me by other
pilots as weak when I get much beyond a couple of miles and breaks up in the
pattern a lot. I'm guessing it's because I can't put out enough consistent
power to break their squelch consistently. When on the actual ground taxiing
around, if there's a crown or "hill" between me and another airplane on the ground
forget it. They can't hear me or vice a versa.
When I check my radio with a handheld on the ground I seem to be just fine for
the relatively close distances I've tried even when the plane is inside an open
hangar and come in just as loud on the hand held as anyone else is. It also
doesn't matter whether or not the strobes are powered on or not as far as whether
or not the range/strength improves. ie, even with them off the lack of range
doesn't improve.
I swapped the cable between the radio and the antenna and it made no difference.
I bought my antenna from Van's but didn't do any kind of post install test
besides checking it out with my comm radio and a hand held and it seemed fine
at the time...
Instead of using RG-58 I bought two pre-made RG-400 cables. What should the center
conductor's resistance read end to end? ~58 Ohms, right? My actual reading
bounces all over the place no matter how stable I am in trying to read it.
Strange. Also, there doesn't seem to be a short between the center conductor
and the plug itself when I check it with a multimeter so I'm guessing the plugs
were installed correctly.
Things I have left to try is just buy a pre-made 12' RG-58 cable from radio shack
and try it instead of the RG-400 cables. Also, I don't have a spare comm antenna
but I think RS carries a replacement 800 Mhz scanner antenna with the right
BNC connector that I can just temporarily use just to see if makes any difference
at all.
Any ideas from the list?
Message 10
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| Subject: | Re: Help needed: continued strobe noise & weak radio |
In a message dated 7/15/2006 10:05:43 P.M. Eastern Daylight Time,
luckymacy@comcast.net writes:
Instead of using RG-58 I bought two pre-made RG-400 cables. What should the
center conductor's resistance read end to end? ~58 Ohms, right? My actual
reading bounces all over the place no matter how stable I am in trying to
read it. Strange. Also, there doesn't seem to be a short between the center
conductor and the plug itself when I check it with a multimeter so I'm guessing
the plugs were installed correctly.
No, with a DC meter the cable should read very low resistance from end to
end on the center conductor. You should measure an open from center conductor
to shield. And you should measure a short from end to end on the outer
shield of the fittings. It sounds like you may have a bad (loose) connection.
The 50 ohms refers to the high frequency characteristic impedance of the cable.
That is the ratio of voltage to current in the cable is (or should be) 50
ohms while it is conducting RF.
Things I have left to try is just buy a pre-made 12' RG-58 cable from radio
shack and try it instead of the RG-400 cables. Also, I don't have a spare
comm antenna but I think RS carries a replacement 800 Mhz scanner antenna with
the right BNC connector that I can just temporarily use just to see if makes
any difference at all.
Forget trying to use the 800 MHz antenna on the VHF Aircraft Band -- not a
good idea at all.
Any ideas from the list?
I recommend finding a ham operator with an MFJ-259B or similar type
instrument that will measure the SWR of your antenna system. That is, check out
your
feedline and antenna. Try to determine if the antenna is OK then check
antenna and feedline together, etc.
Make sure the antenna is grounded to the aircraft skin by measuring from the
coax fitting with the coax disconnected to the skin with a DC ohmmeter. You
should measure a short.
Hope this helps,
Dan Hopper
K9WEK
RV-7A
Message 11
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| Subject: | Re: Help needed: continued strobe noise & weak radio |
In a message dated 7/15/2006 10:05:43 P.M. Eastern Daylight Time,
luckymacy@comcast.net writes:
swapped the cable between the radio and the antenna and it made no
difference. I bought my antenna from Van's but didn't do any kind of post install
test besides checking it out with my comm radio and a hand held and it seemed
fine at the time...
It seems to me like I had to put some star washers between the antenna and
skin to make connection there. The antenna must be grounded to the aircraft
skin.
Dan Hopper
RV-7A
Message 12
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| Subject: | Help needed: continued strobe noise & weak radio |
--> AeroElectric-List message posted by: "B Tomm" <fvalarm@rapidnet.net>
Lucky,
I'm don't know the definitive answer to your problems but here are a couple
thoughts. This problem will most certainly take some time and investigation
to solve.
Sounds like the radio is not transmitting at enough power. If this is
caused by a bad cable, it can be tested for continuity with a handheld
ohmmeter but will not be 58 ohms. The center conductor should read almost 0
ohms end to end. Also test it to see that there is NO conductivity
(infinite ohms) between the center conductor and the outer shield. Do these
tests with both ends disconnected from the radio and antenna. Repeat the
test for no continuity between the center and ground with the antenna
installed
If you need 2200uF and all you have is 4700uF, put two in series to yield
2350uF. This will get you closer.
If when you key the mic you get more strobe noise, most likely you are
getting noise introduced via the activated mic line or through the radio
itself. The mic wiring should be checked for proper isolation. Check to see
that the mic jacks are NOT grounded at the jack. Check to see that the mic
line is not run close and parallel to any wiring going to/from the strobe
power supply.
You might try to transmit with the same antenna and cable using a handheld
radio. If the range improves, then the Xcom radio is suspect. If the range
is the same, try the handheld with it's own antenna. If the handheld and
it's own antenna is better, there is likely a problem with the aircraft
antenna. Is the aircraft antenna on the belly or top?
I would think that these two problems are separate issues, but you never
know.
Bevan
RV7A finish kit.
-----Original Message-----
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of lucky
Sent: Saturday, July 15, 2006 6:54 PM
--> AeroElectric-List message posted by: luckymacy@comcast.net (lucky)
I have two "comm" issues that I haven't been able to debug to completion
yet. I'm using an Xcom 760 radio with their pre-made harness.
1) I still hear my strobes in my headset even when they are grounded with
the radio ground and even when I put power noise filters on. However, the
Radio Shack noise filters reference on Bob's web site were reported to me to
be no longer carried by them. So I used the only ones I could find locally
which were sold by Pep Boys and the capacitor was 4700 uF instead of 2200 uF
like Radio Shack apparently was.
More specifically, the strobe noise is relatively faint until I select the
Push to Talk button. Then it gets pretty loud. Some feedback going on
there. Looking for ideas from this list.
Should the capacitor specs have made a big difference on the effectiveness
overall of the noise filter? It made no measurable difference regardless of
whether I installed it just before the radio or out at the strobe's power
supply just before the AC +14v entered the power supply. I even reversed
direction of the filter and it didn't matter one iota. Really bummed out
about this turn of events since I thought they'd at least have made some
observable difference based upon stuff in the archives.
2) The second overall problem is that the radio still is reported to me by
other pilots as weak when I get much beyond a couple of miles and breaks up
in the pattern a lot. I'm guessing it's because I can't put out enough
consistent power to break their squelch consistently. When on the actual
ground taxiing around, if there's a crown or "hill" between me and another
airplane on the ground forget it. They can't hear me or vice a versa.
When I check my radio with a handheld on the ground I seem to be just fine
for the relatively close distances I've tried even when the plane is inside
an open hangar and come in just as loud on the hand held as anyone else is.
It also doesn't matter whether or not the strobes are powered on or not as
far as whether or not the range/strength improves. ie, even with them off
the lack of range doesn't improve.
I swapped the cable between the radio and the antenna and it made no
difference. I bought my antenna from Van's but didn't do any kind of post
install test besides checking it out with my comm radio and a hand held and
it seemed fine at the time...
Instead of using RG-58 I bought two pre-made RG-400 cables. What should the
center conductor's resistance read end to end? ~58 Ohms, right? My actual
reading bounces all over the place no matter how stable I am in trying to
read it. Strange. Also, there doesn't seem to be a short between the
center conductor and the plug itself when I check it with a multimeter so
I'm guessing the plugs were installed correctly.
Things I have left to try is just buy a pre-made 12' RG-58 cable from radio
shack and try it instead of the RG-400 cables. Also, I don't have a spare
comm antenna but I think RS carries a replacement 800 Mhz scanner antenna
with the right BNC connector that I can just temporarily use just to see if
makes any difference at all.
Any ideas from the list?
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