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So I have been slowly preparing for my journey to Oshkosh. Several things on my list but the top of the list is having power for my iPad and Stratus should I need it. (I already have power for my ICON A24 radio so I'm good there)
I know that the stratus and the iPad both require high amp USB power more specifically 2.1 Amp at 5 V so not just any charger will do the trick. So like any good bargain hunter I went to amazon. I had troubles finding 2 port 2.1 A each port cigarette chargers so I ended up with two of these Battery Tender 2.1 A usb chargers that I attached to my battery with an inline fuse.
http://www.amazon.com/dp/B00DJ5KEF4/?tag=skimlinks_replacement-20
$20 and 2 days later (with the adapter cord and fuse) I had them in hand and routed them in my plane to my pleasure and boom easy power both devices charge happily. So I decided that I'd leave them plugged in so they're always charging during flight. I set off on a test flight when them installed and soon as I turned on the radio I noticed that there was a lot of static on the radio. I figured it was hot mic'd after a while it didn't go away and it was also on the AWOS as well. I switched to a couple of over freq and found it there too. So I just started turning up the squelch. It took 100% squelch to get it off the radio
. I unplugged the chargers and bam static went away squelch down to 40% or less. Classic EMI (Electro-Magnetic Interference).
So here's the problem. (Caution EE nerd stuff here I am an AE not a EE so this is my basic understanding) As stated above we need 5V for our phones, tablets, accessory etc. To get there from 12-14 volts that our system run at we need to drop them using a DC to DC converter. There are several ways of doing this. One way is to use a transformer, but they are power hungry and have expensive components. Another way is to use a micro processor in between and actually convert the DC to DC by way of an AC (Alternating Current) micro controller. So this is small light and cheap thus why everyone does it. So now you have a DC signal going into a micro controller which only takes what it needs to make it 5V from 12 by oscillating the signal (buck converter). On the back side you get a seemingly constant DC signal. By using the micro controller to make an AC signal you naturally get Radio Frequency that comes along with it cause its oscillating. The best part is the cord you plug into it becomes an antenna Sweet Right! No not really! .
So I scoured the aircraft forums and found there are of course others that have had this problem mostly RV dudes. A fair amount of them were able to kill it with the ferrite chokes (you know those weird bumps on all of your computer chords). But that hasn't worked for my for reasons which I hypothesize later. I also found a Ham radio forum that had soldered a bypass capacitor between the two output signals coming out of the chargers. So I tried that with zero good results. The idea there is the capacitors only work on AC signals not DC so they should absorb the AC freq. Note: I may not have used the incorrect capacitors here AKA still doing more research.
Finally I tried another charger that everyone says is good made by Scosche http://www.amazon.com/dp/B0077PM3KG/?tag=skimlinks_replacement-20 This one is a two port 2.1 amp each charger but it still has the problem.
So I think (hypothesis) part of my problem is that my Advanced Aircraft Electronic Antenna http://www.advancedaircraft.com/ that is just behind my seat is A) really sensitive, B) not outside the aircraft thus not getting the shielding of the aluminum panels and such that spam cans get thus the ferrite chokes working.
So alas I don't have an answer yet except to buy an >10,000 mah external battery pack for like $30 on amazon with a two port 2.1 amp charging outlets. Problem here is I don't know if the basic battery pack has a DC to AC to DC coverter too or are they just native 5 volts ? I would guess they have a regulator of some type to keep the juice exactly at 5V oh hell I don't know. If you have any ideas let me know if not this was just a really long informational session for those who might have the problem.
I know that the stratus and the iPad both require high amp USB power more specifically 2.1 Amp at 5 V so not just any charger will do the trick. So like any good bargain hunter I went to amazon. I had troubles finding 2 port 2.1 A each port cigarette chargers so I ended up with two of these Battery Tender 2.1 A usb chargers that I attached to my battery with an inline fuse.
http://www.amazon.com/dp/B00DJ5KEF4/?tag=skimlinks_replacement-20
$20 and 2 days later (with the adapter cord and fuse) I had them in hand and routed them in my plane to my pleasure and boom easy power both devices charge happily. So I decided that I'd leave them plugged in so they're always charging during flight. I set off on a test flight when them installed and soon as I turned on the radio I noticed that there was a lot of static on the radio. I figured it was hot mic'd after a while it didn't go away and it was also on the AWOS as well. I switched to a couple of over freq and found it there too. So I just started turning up the squelch. It took 100% squelch to get it off the radio
. I unplugged the chargers and bam static went away squelch down to 40% or less. Classic EMI (Electro-Magnetic Interference). So here's the problem. (Caution EE nerd stuff here I am an AE not a EE so this is my basic understanding) As stated above we need 5V for our phones, tablets, accessory etc. To get there from 12-14 volts that our system run at we need to drop them using a DC to DC converter. There are several ways of doing this. One way is to use a transformer, but they are power hungry and have expensive components. Another way is to use a micro processor in between and actually convert the DC to DC by way of an AC (Alternating Current) micro controller. So this is small light and cheap thus why everyone does it. So now you have a DC signal going into a micro controller which only takes what it needs to make it 5V from 12 by oscillating the signal (buck converter). On the back side you get a seemingly constant DC signal. By using the micro controller to make an AC signal you naturally get Radio Frequency that comes along with it cause its oscillating. The best part is the cord you plug into it becomes an antenna Sweet Right!
No not really! .So I scoured the aircraft forums and found there are of course others that have had this problem mostly RV dudes. A fair amount of them were able to kill it with the ferrite chokes (you know those weird bumps on all of your computer chords). But that hasn't worked for my for reasons which I hypothesize later. I also found a Ham radio forum that had soldered a bypass capacitor between the two output signals coming out of the chargers. So I tried that with zero good results. The idea there is the capacitors only work on AC signals not DC so they should absorb the AC freq. Note: I may not have used the incorrect capacitors here AKA still doing more research.
Finally I tried another charger that everyone says is good made by Scosche http://www.amazon.com/dp/B0077PM3KG/?tag=skimlinks_replacement-20 This one is a two port 2.1 amp each charger but it still has the problem.
So I think (hypothesis) part of my problem is that my Advanced Aircraft Electronic Antenna http://www.advancedaircraft.com/ that is just behind my seat is A) really sensitive, B) not outside the aircraft thus not getting the shielding of the aluminum panels and such that spam cans get thus the ferrite chokes working.
So alas I don't have an answer yet except to buy an >10,000 mah external battery pack for like $30 on amazon with a two port 2.1 amp charging outlets. Problem here is I don't know if the basic battery pack has a DC to AC to DC coverter too or are they just native 5 volts ? I would guess they have a regulator of some type to keep the juice exactly at 5V oh hell I don't know. If you have any ideas let me know if not this was just a really long informational session for those who might have the problem.
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