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A few antenna / magnetic / carbon / RF / battery questions
#1
So, a couple questions regarding RF/electrical interference.  I'm designing a rocket with some pretty tight quarters, and wondering about a couple of potential issues.  I know that carbon fiber blocks RF signals and so it's not a good idea to encase trackers and such (at least the antennas) inside carbon airframes.  But.....

* I've got a 7 inch antenna (TeleMini V1) that's going up inside a fiberglass nosecone.  However, the altimeter itself and about the first 3/4" or so of the antenna will be inside the airframe, which will be carbon fiber.  Will having that short section of antenna "inside" the airframe be a problem do you think?  Anyone run something similar, and if so, did it work or was it a problem?

* I'm also utilizing a Featherweight magnetic switch.  It will be located adjacent to (and quite close to) the antenna.  Will this be a problem?  Any interference issues?

* The LiPo battery (110mAh, 3.7v) will also be located very close to the antenna - again, should I be concerned about this?

OK, technically that's five questions, not "a couple", I know.  But regardless, any answers/advice are appreciated.
Thanks,
s6
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#2
S6,
The magnetic switch should not be an issue at the power your transmitting.
The airframe and the battery are going to attenuate the signal.
How much, is impossible to determine so you will have to test your setup.
Build it and test the range.
Also be sure to put matches on your altimeter so you know if it tried to fire the outputs.
Only heard of that type of electrical interference once but ya never know.
Also be aware of the Fresnel zone of your signal.
You can't just put it on the yard and drive up the block.
You have to put it up high, maybe a parking garage or a hill you can see from a distance.
Good luck sounds like an interesting project.
[Image: sigpic867_3.gif]
Robert DeHate
AMW/ProX
www.amwprox.com
TRA TAP #9956
NAR L3CC #75198
Largest single flight 81,267Ns! [Image: yikes.gif]
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#3
[quote pid='2807' dateline='1447209943']

Robert,
   thanks for the feedback.
I'm not sure what you mean by "Fresnel zone of signal" - can you clarify?

s6
[/quote]
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#4
https://en.wikipedia.org/wiki/Fresnel_zone
John S.
NAR #96911
TRA #15253
MDRA
Level 1, 2014-Mar-15 -- Aerotech Sumo, H133BS
Level 2, 2014-Jun-21 -- Giant Leap Vertical Assault, J240RL
Level 3, 2016-03-12 -- MAC Performance Radial Flyer, M1101WH, 13,028 feet
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#5
John just gave details.
It's basically your radio waves getting absorbed by the ground.
[Image: sigpic867_3.gif]
Robert DeHate
AMW/ProX
www.amwprox.com
TRA TAP #9956
NAR L3CC #75198
Largest single flight 81,267Ns! [Image: yikes.gif]
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