[TowerTalk] If you had a choice

[David Gilbert]

Those $300 quad-copters might not have the beef to handle the task, but 
I'm pretty sure that the more expensive octo-copter machines (about 
$3500) could.  They can lift upwards of 2 kilograms, and they not only 
can be controlled from the ground they can be pre-programmed to navigate 
whatever path you want via their own onboard GPS.  I think it would take 
a pretty stiff wind to throw them off course.  The biggest downside to 
using them might be battery life, but pretty much the entire measurement 
process could be automated so that it didn't require much air time.  It 
might even be possible for such a machine to lift its own power cord for 
supply from the ground if the measurement protocol allowed for a fixed 
X-Y position (i.e., the antenna could be rotated).

But in general, this should be possible:

*  pre-programmed, GPS controlled flight plan consisting of concentric 
rings at multiple heights in a spherical configuration.

*  onboard field strength detector with a small sense antenna

*  onboard transmitter to send back real time signal strength readings 
and GPS coordinates to a ground based receiver feeding a laptop for data 
collection.

I suspect that if someone wanted to get fancy they could feed the test 
antenna with broadband noise (pulsed for recognition) and put an SDR in 
the copter.   There are some interesting possibilities out there ....

73,
Dave   AB7E




On 10/17/2012 1:02 PM, Jim Lux wrote:
>>
>>> A fun thing might be to use one of those little quad-copter things
>>> to fly an orbit around an antenna at various altitudes while making
>>> measurements.
>>
>> I doubt that those devices have sufficient operating height to make
>> practical far field elevation plots - even at one mile which is still
>> not completely in the "far field" on some bands.
>
> I have a 1/3 scale R/C powered parachute  that I was going to use for 
> this kind of thing: GPS and 3 axis short dipole antennas with a 
> receiver (like RELEDOP from SRI), but it has a whole lot of other 
> practical problems... For instance, the little quad copters (and my 
> powered parachute) can't move fast enough to overcome a decent wind.
>
> Some folks in the UK have done this with flying a probe on a tethered 
> balloon.  (and of course, SRI's RELEDOP is a probe towed by a helicopter)
>