testing and screening IBC

yesterdays testing

setout to measure the affect of IBC noise on the radio setup and see what could be done to improve it.


we are hopefully going to use a "tophat" style antenna which should give us good range in a small package inital testing qualitivly proved the idea (ie it worked fine) now we are putting some numbers to it and seeing what can be done to improve it.



Rx batt voltage 5.4V, Tx bat voltage 17.4V



Testing was conducted using a servo and commanding it to traverse smoothly from stop to stop. Signal strength was rated out of 5

5 - perfect signal
4 - slight interuptions - mostly noticablle only in the sound of the servo drive
3 - intermittant drive - servo visibly twitching
2 - poor drive - servo still travels but with much inteference
1 - unusablle - servo movement eratic
0 - no servo movement


Results

Antenna Orientation	IBC	Range	Signal Str	Notes
Series : 1	Tuning antenna, no sheilding on IBC, Photos 1,2
90	Off	15m	3	See Photo 1 for detail
0	Off	27	5	there seemed to be some blockage near the gate signal strength dropps off quite quickly there see photo 3
0	On	15	3	signal degridation is abrupt, 5 - 0 over about 1.5 meters
90	On	3	2	possibly an optimistic result, the rx had better line of sight than normal
Series : 2	Alumium foil wrapping photo 4 sheild connected to -ve Vbat
0	off	31	3	baseline
90	on	9	3
0	on	25	3
Series : 3	Steel Shield (basic wrap) sheild connected to -ve Vbat Photo 5
0	off	37	3	baseline
90	off	18	3	baseline
0	on	9	3	the steel posed a large LOS obstruction which might inhibit it signifigantly
90	on	9	3	same signal strength with 0 and 90 deg antenna
Series : 4a	Steel Shield (basic wrap) sheild connected to -ve Vbat, reciever is connected to IBC for the first time in the test series, note BEC is *off* rx is running on its own battery, driving a rs550 drill motor
0	off	1.5	2	some LOS issues here
90	off	1	2
Series : 4b	Steel Shield (basic wrap) sheild connected to -ve Vbat, same as above using stock antenna photos 7
0	off	6	2
Series : 5	Complete steel sheild, IBC optically isolated from reciever, tophat antenna 7
0	On	15	3
90	On	12	3

the optically isolated complete steel housing gives us the best isolation from the RFI from the IBC.

note that with the transmitter *off* if the ibc was switched on next to the reciever the servo started jerking around all over the place, it was reduced with the steel sheild but not eliminated.