Jeremy,
Thanks for the info. I just placed what should be my final order
with Mouser with expected delivery for tomorrow. I will now have
black/red/white/blue/grey colors of the 2843/19 Teflon wire. I
assembled an entire harness yesterday and got comfortable with the
crimper and used a large optical magnifier to inspect the crimped
terminals. I am confident this combination of wire/crimps/connectors
is about the best we can do for this size.
The RX antenna, referencing the Wiki it says the antenna connection
is weak and should be strengthened. I want to know what exactly this
is referring to. The wire antenna is passing through a PCB hole,
upward to the solder point so at initial inspection it appears to be
strain relieved. I am curious what would break, the wire strands in
the antenna just outside the RX PCB? Or is it more possible the
antenna will actually break off the solder joint? Just curious.
I have disappointing news about the new Male Wire-to-Wire Molex
connectors, Mouser appeared to carry them but it appears to be more
like they have them in their database only. I was only able to get a
handful of 2 conductor housings and no male crimpable terminals. The
rest are backordered with insane shipping times into the next year! I
will begin searching for these with spare time and see what we can't
come up with, I would really like to make some disconnects in my
harnesses for flexibility.
Regards,
Matthew Currie
address@hidden wrote:
Just run the antenna out the wing and it'll be far and
perpendicular from everything. I've found that the Berg works better
with a wire antenna cut to some random length than with a base loaded
antenna. Don't know why, I read somewhere that the Berg does some
automatic impedence matching magic and I noticed that it comes with a
random length antenna (newer versions are 1m).
-- Matthew Currie <address@hidden> wrote:
Jeremy,
Sounds about right. Just as a side note I am almost SURE they are
using some thin conformal coating on this receiver. It was difficult
to get reflow and it gave off an odd odor. There also appear to be
drops of something in between closely spaced components, etc.. I am not
absolutely sure but it made me wonder. You are right that
impedance-wise, this circuit could be less susceptible to the affects
of moisture but then I had never considered moisture mucking with RF
circuitry =) I will be abandoning the coating and already had some
suitable lightweight shrink set aside I had used for building small
battery packs. I also plan on using some surplus 1206 SMT ferrite
chokes which I used to filter ~ 72MHz and coming up with a clever way
to incorporate them in series with this wiring for a more bulletproof
link. I used to use these in other RC products I designed and they
made a dramatic difference to glitching.
On a somewhat related note. Would it be more suitable to use a 1/4"
whip or something out of solid rod and make an antenna that could get
perpendicular faster instead of running past every transceiver in th
plane? Only thinking out loud here. I have a few of those tiny tuned
antennas meant for parkflyers which turn the 30+" wire into a 4"
antenna at the expense of a quoted 10% range as well.
Regards,
Matthew
address@hidden wrote:
The IR sensors use very large value resistors that are easily
affected by humidity but the receiver does not rely on such things.
Also 72MHz is a pretty low frequency and not so sensitive to detuning.
Lastly, Castle Creations doesn't coat these receivers and they know a
lot more about it than we do. :)
Just slap some heat shrink on it, keep it away from the GPS, and
try to keep the antenna perpendicular to other antennas.
-- Matthew Currie <address@hidden>
wrote:
Group,
I will be modifying the Berg 4L receiver tonight and was curious if
there is any reason why I should _not_ coat the entire assembly in an
Aerosol Silicone Conformal Coating for protection mechanically and
problems of moisture in foggier weather, etc. While I realize the IR
sensors may be of limited use in rain / fog I sure don't want the weak
link to be something I can correct for now. My only reasons for being
cautious would be RF detuning, contamination, etc.
Regards,
Matthew Currie
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