It has merit Tom. Although the epoxy matrix will sorta of insulate, the
wire would still have to be (electrically) insulated fromt he CF, one
could employ 28awg or smaller solid core motor lead which is used in
motor windings (very tough varnish).
The proper way to build it would be to look at return losses with a
network analyzer, determining center frequency and bandwidth. This could
be modeled (antenna software), but the CF boom would itself have to be
modeled first.
If it functioned adequately, then it might be possible to build the unit
into every boom during the molding process. However a fair amount of
testing would have to confirm that a cross section of OEM RX's would
respond adequately to such an antenna.
I have yet to be stymied when inserting the OEM antenna within the
confines of carbon booms (including the Pike versions) and not modify it
such that it works adequately. Again, this requires sophisticated
equipment to actaully measure operating frequency. B/W, and gain.
The biggest problem is that most folks do not have any conception of
what the minimum (antenna down) range is viable for their particular
radio system. Some folks do have a good understanding of this, but only
after taking the time to experiment.
No matter what, although you could develop an integrated base-loaded
style antenna, but it would I think be different enough from
installation to installation, plus different RX's, plus different wiring
configurations (the rest of the control system wiring plays an important
role) would make it work for your isntallation but not others.
Booms are usually long enough to allow a full 1/4 wave, this offers the
best reciprocity. However there is a possibility that the boom itself
may enhance a based-loaded design that could be superior. Modeling
(using S/W) would still not be adequate, actual prototypes would confirm
or deny performance...
Tom Broeski wrote:
What would be the results if you wrapped copper wire antenna around the
base of the boom and ran it out a bit. Would it by like base loading?
Would it prevent signal blocking by the boom? Is a slightly wrapped
antenna (couple turns down the boom length) better than a straight taped
one.
I tried inside the boom, in a tube and just taping the antenna to the
boom. Got about 130 ft (Stylus with no antenna) before the picolario
stopped announcing on all occasions. I have a couple picolarios and
this one never said "attention", so it' probably an older one. Will try
another one to test Skip's method.
I will also try a "sticky antenna" from RC Direct and see what it does.
Tom
----- Original Message ----- From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>; <[email protected]>
Sent: Friday, February 17, 2006 1:49 PM
Subject: Re: [RCSE] Molded Supra Antenna Placement - bottom placement
I updated George's pulse emmission detecotr (PED) design as one of my
final
projects years ago. For me these devices are critical to setting up a new
aircraft. They are especially useful where CF is employed, gas
engines, etc.
Although diagnostic by nature, in aircraft where I have them employed
full
time, they have prevented serious failures by just observing the recorded
results after every landing.
The Picalario idea is a good one; essentially the same thing. Most
folks are
just plain not aware how many times the RF link has failed on any
given flight
until they actaully witness it for themselves. Non-believers become
believers
in very short order. You can not see EMI/RFI, until it gets past the
point of
being serious in nature...
Quoting [EMAIL PROTECTED]:
In a message dated 2/16/2006 11:49:14 P.M. Eastern Standard Time,
[EMAIL PROTECTED] writes:
I tried the thick walled plastic tube along the tailboom - works
but only what I consider to be very marginal range (approx 120 feet).
DARN! I was hoping Hartmut/Dave/Simon were on to something, but I
guess
we're still groping around.
The next time you do a range test, plug up your Picalario - that nice
itty-bitty lady in there will likely start saying "ATTENTION!" before
you
start
seeing the controls twitch (particularly if you set the sensitivity
up) so
you
won't have to walk so far/strain your eyes/get muddy. Then, (for those
antenna configurations in which you have the MOST confidence,
PLEASE!) fly
the
airplane and keep track of of the number of "ATTENTION!"s (glitch/pulse
omission
reports) vs flight time for comparison. That might take a
pencil/notepad/assistant (or other talent, writing with your toes
comes to
mind), since AFAIK
the Pic doesn't keep that data in memory (HELP Hartmut!). There are
other
such (older & new) sensors out there that do (I've got one I bought
from
Mark
Schwing (EMS) someplace, and RC guru George Steiner had DIY articles
on such
in
RCM). If enough folks do this and (carefully!) report the results, we
might start to get a stochastic (yeh, eye are an injenyr two!)
insight into
the
practical effects of carbon structure vs antenna performance, since the
application of more elegant em theory is (as yet, apparently)
inconclusive.
Maybe
Gordy could do something REALLY useful by compiling the data. Might
be more
helpful than the "I wrapped my antenna around a pair of needle-nose
pliers
and never had a problem" approach. Good Lift!
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--
Simon Van Leeuwen
RADIUS SYSTEMS
PnP SYSTEMS - The E-Harness of Choice
Cogito Ergo Zooom
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