Today's Message Index:
----------------------
1. 10:55 AM - Cross talk problem (jonlaury)
2. 12:12 PM - Re: Cross talk problem (Daniel Hooper)
3. 06:25 PM - Re: Com and Nav Radio and Antenna Questions (Robert L. Nuckolls, III)
4. 07:16 PM - Re: Com and Nav Radio and Antenna Questions (Don)
5. 08:52 PM - Re: Com and Nav Radio and Antenna Questions (Robert L. Nuckolls, III)
6. 09:22 PM - Re: Com and Nav Radio and Antenna Questions (Don)
7. 09:27 PM - Re: Com and Nav Radio and Antenna Questions (Don)
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: | Cross talk problem |
Listers.
I have installed an EyeBeam mini in my composite airframe. Unfortunately I do not
have a schematic of the unit, but it uses capacitance (touch) to control the
on/off function and dimming.
The shielded, twisted pair power and ground wire cable parallel unshielded, untwisted
wires to the 4 ohm 1.25" x 1.75" cabin speaker for a distance of about
5' . At that point the cabin speaker pair becomes a twisted and shielded cable.
The two cables parallel each other for an additional 12'. The shield for the
speaker is grounded at the audio panel and the shield for the EB is grounded
at the ship's single point ground bus.
The problem:
When I key the microphone, the EB turns on. If I key it again, the EB begins flashing
uncontrollably. It is unresponsive to the dimming control and the on/off
switch. The only way to stop the flashing is to disconnect the EB from power.
The EB works as intended when connected to battery power independent of the
ship's electrical system.
Attempts at a solution:
Thinking that the the magnetic field of the speaker magnet may be causing the problem,
the speaker was disconnected and the mic was keyed. The EB exhibited the
same uncontrollable flashing upon keying the microphone.
Any ideas on what's happening and/or how to fix it?
Thanks,
John
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=365744#365744
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: Cross talk problem |
Try keying the mic without the comm radio on. Chances are it's RF interference.
If that's the case, get a clamp-on ferrite kit and start experimenting.
Touch technology can be very sensitive to RF interference, and that could be leaking
into the power lines from a number of places. For a start, I would recommend
putting a ferrite right at the power input to the light. Another reasonable
place to try is on the speaker line, where it meets the lighting power.
These are made to go around a set of wires (power and ground, power ground and
serial comm) so you should only need one for a given set of wires. ie one for
the speaker wires, one for the EB power lines. They're pretty cheap, so you can
easily pick a few to try out.
To pick some appropriate ones:
Digikey.com
search "ferrite"
Under "Filters" pick "Ferrite Cores and Cables for Wiring (469 Items)
Under "Filter Type" pick "Round Cable, Snap On"
Check the "In Stock" box
Press "Apply Filters"
Pick some with reasonable outer diameters (OD) and inner diameters (ID) that will
fit around your wiring. There are a lot of variables in ferrite selection still,
but in general when choosing between them, higher impedance is better for
you.
--Daniel
On Feb 6, 2012, at 12:47 PM, jonlaury wrote:
>
> Listers.
> I have installed an EyeBeam mini in my composite airframe. Unfortunately I do
not have a schematic of the unit, but it uses capacitance (touch) to control
the on/off function and dimming.
>
> The shielded, twisted pair power and ground wire cable parallel unshielded, untwisted
wires to the 4 ohm 1.25" x 1.75" cabin speaker for a distance of about
5' . At that point the cabin speaker pair becomes a twisted and shielded cable.
The two cables parallel each other for an additional 12'. The shield for
the speaker is grounded at the audio panel and the shield for the EB is grounded
at the ship's single point ground bus.
>
> The problem:
> When I key the microphone, the EB turns on. If I key it again, the EB begins
flashing uncontrollably. It is unresponsive to the dimming control and the on/off
switch. The only way to stop the flashing is to disconnect the EB from power.
The EB works as intended when connected to battery power independent of the
ship's electrical system.
>
> Attempts at a solution:
> Thinking that the the magnetic field of the speaker magnet may be causing the
problem, the speaker was disconnected and the mic was keyed. The EB exhibited
the same uncontrollable flashing upon keying the microphone.
>
> Any ideas on what's happening and/or how to fix it?
>
> Thanks,
> John
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=365744#365744
>
>
>
>
>
>
>
>
>
>
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: | Com and Nav Radio and Antenna Questions |
At 07:20 PM 2/5/2012, you wrote:
This will not break the bank, will purchase one. It does not mention
the ability to excite the feedline and antenna for setting up vor so
U will need help in doing that.
This is a self contained antenna analyzer. It features
a variable frequency oscillator that provides a test
signal source over a 2 to 170 Mhz range. There is a
counter that displays the oscillator's present frequency.
Finally, there is an array of detectors upon which a
ratiometric analysis is conducted to deduce the resistive
and reactive components of the antenna and display them.
Instruction manual can be found here:
http://www.mfjenterprises.com/pdffiles/MFJ-259B.pdf
While not a laboratory grade instrument, it's
a lot of bang for the buck.
The wingtip antenna you talk about in the connection is a slightly
modified Archer. Archer mounts them to the fiberglass wing tip and
sandwiches it between the glass and the wing root for the ground. I
am looking for the instructions that came with the unit and will send
them to you as soon as I find them.
Yeah, Bob was a little incensed when the folks
at Van's published dimensional details on his
first RV wingtip offerings (and I repeated them
in the 'Connection). Bottom line is that the antenna
is simply a gamma-matched monopole of which there
are many variations on a theme. The now arcane
'sled runner' marker beacon antennas on the belly
are a good example.
Once you have an MFJ259 in hand, you can both
trim overall length of the Archer design to
desired center frequency, you could also adjust
the gamma-match and tuning capacitor for optimum
performance too.
While this might be an intellectually satisfying
exercise (Hams can get downright pedantic in
their quest for the Holy-SWR), it would be hard
to observe much difference in performance between
an Archer cookie-cutter installation and one that
has be tuned to technical Nirvana.
I would like to be able to get one of these. To work in each wing
tip for my two vors. I have an APRS (2meter Jpole in one wingtip
that may make it impossible to get the Archer to work.
Why a j-pole? That's an awfully big antenna for
a line-of sight application. Why not the simple
vertical whisker?
I will ask the additional questions after I send you the Archer instructions.
Got the data package. What's your question?
Bob . . .
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: | Com and Nav Radio and Antenna Questions |
I would like to be able to get one of these. To work in each wing
tip for my two vors. I have an APRS (2meter Jpole in one wingtip
that may make it impossible to get the Archer to work.
Why a j-pole? That's an awfully big antenna for
a line-of sight application. Why not the simple
vertical whisker?
Lack of room on the bottom of the AC. Most of the RV's with ATRS installed
use the JPOLE.
One Nav in the right wing with a splitter should work fine.
I will ask the additional questions after I send you the Archer
instructions.
Got the data package. What's your question?
Had to do with why the antenna needed to be as far forward as possible. I
6hink that is to keep the lighting wires that have to run forward after
going halt way up the leading edge "looking like part of the antenna". Also
why the marker beacon antennadid not drain energy to ground. Figured out
that there is no ground plane so no drain to ground.
Thanks for the help and I will let you know what the people at xcom say
about the Pitts radio. Bought the MFJ and I guess I missed the RF signal
generator in the advertisement.
Don
Bob . . .
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: | Com and Nav Radio and Antenna Questions |
>Lack of room on the bottom of the AC. Most of the RV's with ATRS installed
>use the JPOLE.
But that's a 3/4 wavelength antenna. Where do you
stretch out 60" of antenna?
Bob . . .
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: | Com and Nav Radio and Antenna Questions |
But that's a 3/4 wavelength antenna. Where do you
stretch out 60" of antenna?
With a slight curve it fits in an RV wingtip. The versions that most RV'ers
are using is between 57 and 59 inches long and works fine with a continuous
bow frow front to rear.
Don
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: | Com and Nav Radio and Antenna Questions |
But that's a 3/4 wavelength antenna. Where do you
stretch out 60" of antenna?
These are the twin lead 300ohm TV cable type and the basic shape of mine is
half an elipse.
Don
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! --
|