Re-read precisely what I have previously written; when normal airborne
range is diminished due to limiting factors like CF, a ground range test
becomes difficult to measure reliably and state that indeed one is safe
to fly to maximum range with headroom to spare.
Airborne systems that have no limiting RF factors, like a sailplane made
from glass that ground-ranges (antenna-down) to some recognized
acceptable value, make ground range-testing a simpler task with
definable results that are repeatable. This is what makes ground-testing
a viable means of ensuring adequate control.
The factors that limit sensitivity within a CF boom are not equal in all
directions, even with the antenna on the periphery. RF factors like
reflectivity or directionality make a ground test difficult to define,
let alone repeatable. In one position you may see <100ft, in a slightly
different orientation you may observe <50Ft.
You could model the CF boom on the all-glass model and "still" get
accurate and repeatable results by just shortening that configuration's
antenna element. However you can not compare the two results because
they represent different physical conditions that are limiting sensitivity.
To clarify the ground range test on aircraft with compromized range as a
result of CF; once you determine that you have acceptable range while
airborne, you can get a bit of a handle on what the ground range is, but
you need to test in precisely the same manner each time, in the exact
same location, holding the aircraft the same way, etc etc and you still
couldn't gaurantee repeatability because of changes out of your control
(like parked cars, other EMI/RFI, etc).
Bill's Email wrote:
So if I understand you correctly, a ground range test has little, if
any, correlation to airborne range. If it did, then there would be an
empirical formula that would allow me to relate the two. But what I see
you saying is that each installation is unique and therefore you cannot
provide a mathematical relationship due to an essentially infinite
number of variables. Essentially it is an equation with no solution.
Simon Van Leeuwen wrote:
I wish I could, life would be simple, but (again) given that each
install is different you need to find the airborne limits for your
aircraft, that is if the range on the ground is less than 100ft (again
- relative to your radio system). Add to this my vision is rated @
20/10, what you distignuish at 20/20 I see at a much further distance.
This is what I meant that you need to put in the legwork to find out.
What turns out to be functional is different for each install when the
limiting factors include situations like carbon fiber booms that are
enveloping the antenna element...
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Simon Van Leeuwen
RADIUS SYSTEMS
PnP SYSTEMS - The E-Harness of Choice
Cogito Ergo Zooom
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