MODEL RADIO CONTROL ELECTRONICS 
Another norcim web page covering some intriguing test data of many
commercial radio control receivers. If you are into technical facts and figures
of R/C systems, then this page begins to show just how ‘technically good’ various
makes of receivers are. The following test data investigates probably the most
important quality of a model radio control receiver, that of ‘sensitivity’.
This determines how far away the receiver can operate a model without loss of
the radio link.
RECEIVER TEST DATA commercial receiver
range testing by Radio Guru Dave McQue.
..
BACK TO RADIO4 page of the norcim web site.
BACK TO RADIO1 first page of the norcim web
site.
THERE’S A
RADIO6 NOW! History of model control
systems plus circuits.
BACK TO RADIO3
Tx circuitry, electric glider, input from NASA, Multi-chan failsafe
BACK TO RADIO2 40mhZ Tx /Rx notes, PCM
system, speed control, Tony’s website
IN THE DISTANT PAST! When micron sold radio control kits for
a living, samples of the kits used to be tested and compared with commercially
available units of the day. One of the primary tests, involved comparing the
range of different units, which in turn gave a degree of satisfaction when the
kit samples were up there with the best at that time! As there was a field at
the rear of the workshop, range testing was very practical. With a nicad,
receiver and servo in a plastic box, the number of paces away from the Tx
(antenna collapsed) before servo ‘noise’ from the box could be heard. (non
visible jitter) This was noted. Then a further number of paces were taken to
loose transmitter control altogether, this was also noted. These tests were
ongoing as new circuitry was tried and new commercial equipment became
available to compare. All our kits were PPM type so little notice was given to
the PCM equipment that was evolving. Looking back, this kind of testing
invariably took place on hot summer days with little wind! I wonder why? (said,
he, carrying a model and can of fuel!).
I have recently, been chatting with UK Radio Guru, Dave McQue,
who has been doing some more up to date commercial receiver testing for
the RCC (Radio Control Council). I Managed also to get a copy of his
results which make interesting reading! I’ll let Dave explain his more
scientific approach to receiver sensitivity (than pacing out on the flying
field!) and I’ll comment on his findings and notes later.
Over
to Dave……..
RADIO CONTROL RECEIVER TESTING DATA
9/2003 D. McQue
RECEIVER TESTS SEPTEMBER TO NOV 2003
Purpose :- To
measure the various receivers’ sensitivity using a Signal generator and dummy
antenna.
Apparatus :-
Panasonic Signal Generator VP819A modulated by the “Buddy Box’’ output from
a Futaba T8UPS with its RF output switched off. Or JR X-3810 for JR PCM RX
tests.
Regulated Power supply set to 5 Volts. 500 mA analogue meter.
Dummy antenna to terminate the 50-Ohm cable from the Signal generator
and simulate a 1m-model antenna. Made from a 47R Ohm resistor in series with a
3.9-Ohm resistor. The output taken from the junction, via a 4.7 pf capacitor to
the RX ant input with its wire antenna disconnected. (as shown in Fig 7a)
A Hitec HS-615 servo was plugged into the Aileron Channel.
Results :-
Note the signal level for control
is where servo twitching is just apparent for PPM receivers. At this point
there is a large servo current draw of more than 250mA.
Abbreviations :- SC = Single Conversion, DC= Dual
Conversion. PPM=Pulse Position
Modulation, PCM=Pulse Code Modulation
|
MAKE/MODEL
OF RECEIVER |
CONVERSION
TYPE |
MODULATION
TYPE |
MIN SIGNAL
LEVEL FOR <20 MA SERVO CURRENT (uV) |
MIN SIGNAL
LEVEL FOR CONTROL OF SERVOS (uV) |
|
DALASY |
|
|
|
|
|
MINI/NANO |
SC |
PPM |
350 |
35 |
|
FUTABA |
|
|
|
|
|
FP-R138DF |
DC |
PPM |
79 |
7.9 |
|
R149DP |
DC |
PCM |
2.5 |
2.5 |
|
R116IIP |
SC |
PCM |
2.5 |
2.5 |
|
GWS |
|
|
|
|
|
GWRD-8 |
DC |
PPM |
350 |
35 |
|
HITEC |
|
|
|
|
|
FEATHER |
SC |
PPM |
350 |
35 |
|
HFS-04 MG |
SC |
PPM |
50 |
2.5 |
|
ELECTRON 6 |
DC |
PPM |
20 |
2 * |
|
JETI |
|
|
|
|
|
REX4 PLUS |
SC |
PPM |
28 |
3.5 ** |
|
REX5 |
SC |
PPM |
35 |
5 ** |
|
JR |
|
|
|
|
|
NER-326X |
SC |
PPM |
55 |
10 |
|
NER-D940S |
DC |
PCM |
1.8 |
1.8 |
|
MICRON |
|
|
|
|
|
FET-7 |
DC |
PPM |
176 |
17.6 |
|
MINI-3371 |
SC |
PPM |
45 |
4.5 |
|
STD-3361 |
SC |
PPM |
176 |
17.6 |
|
FET-7 DSP |
DC |
PPM |
14 |
7 |
|
MULTIPLEX |
|
|
|
|
|
MINI DS-IPD |
DC |
PPM |
8.8 |
2.8 |
|
P SUNG |
|
|
|
|
|
SR4F |
SC |
PPM |
700 |
88 |
|
SANWA |
|
|
|
|
|
RX515 |
SC |
PPM |
8.85 |
1.24 |
|
RX611 |
SC |
PPM |
27.9 |
3.9 |
|
ACT |
DC |
PPM |
442 |
44.2 |
|
SHULTZE |
|
|
|
|
|
ALPHA 840S |
SC |
PPM |
28 |
2.8 |
|
WEBRA |
|