Futaba range [Archive]

A.T.

Jun 07, 2003, 04:01 AM

No definite distance, depends on several factors. Range check each time
before use to ensure there has been no significant reduction from earlier
tests. Futaba 2CR, 2DR and 2ER 2ch are simply cosmetic case changes. Results
achieved vary as a number of new sets on 27 and 29 MHz recently tested, all
with 122JE RX had a variance in range testing between 12 and 25 paces.
Results appeared to relate mainly to each RX. Xtals were interchanged
(within same 27 or 29 band) and individual RX displayed similar range each
time with a different TX. Two older sets held on 75 MHz have a 6 pace
difference in range test, swapping RX xtals highlighted problem RX.
The following is a good guide bearing in mind that the distances recommended
relate to more expensive higher powered multi channel FM systems.

1.
refer to range tests for PCM (also applies to PPM & AM except you do not
see the
failsafe actuate) at =
http://www.horizonhobby.com/articles/1079.asp
includes extra articles on PCM Range Testing, Comprehensive Testing, Why
PCM, 7 Simple Steps, What's Good Range?,Variables, Range Testing Stories,
Download Your Own Log.
2.
Quote from Terry Rance's (Service Manager at Macgregor Industries) "Radio
Range Testing", article in the RCM&E 10 Sept.97
"It is not necessary to verify the range with the TX aerial fully extended
as a check with the TX in the retracted position will give representative
results. As a rough approximation the range on the ground with the aerial up
will be ten times that obtained with the aerial down although, of course, if
the retracted aerial is particularly long or short, this will affect the
figure.
Since transmissions from other transmitters in the vicinity can affect the
result, the test should take place with only the test TX operating. Ideally
a clear open field should be used as a test area, but a test along a road or
a path will be satisfactory provided that an allowance is made for the
localised signal distorting effects of parked cars and other large metal
objects.
IT TAKES TWO = Two people are needed for the test. One should take the TX
with the aerial retracted and operate it as if flying the model, moving a
control stick to operate a servo in the model. The other should walk away
from the side of the person holding the TX, with the model held at right
angles to the direction of walking so that the TX and RX aerials are
approximately parallel. With the model at waist height, a range of at least
70 paces should be obtained and can be verified by observing the servo or
control surface on the model. The servo should smoothly follow the TX
commands without chattering or hesitation. If the model is held lower, the
range obtained will be less and if the model is held higher the range will
be more. Pointing the RX aerial at the TX will dramatically reduce the
range.
TWO DIMENSIONAL = The radio signals are emitted from the side of the TX
aerial. Only a very small signal is sent out from the top, along the
aerial's axis. Similarly, The RX picks up the strongest signal when it's
full length is exposed to the TX. If the RX aerial is held in a straight
line and pointed at the TX, only the diameter of the RX wire is available to
pick up the signal and the result will be a very short range. For these
reasons we recommend that the TX aerial is not pointed at the model and the
RX aerial is arranged in two dimensions so that whichever way the model
turns, there is always a good length of exposed RX aerial to pick up the
signal. Taking the end of the RX aerial to the top of the tail fin is
strongly recommended. The ground absorbs radio signals and makes them
weaker. As a model moves away from the ground, the available TX signal gets
much stronger and because of this the air range might be two or three times
the ground range."

see also http://homepages.ihug.co.nz/~atong/
and scroll down to = "Radio Systems, Accessories, Alterations and FAQ" for
"Range Test - Futaba answers.
Range Test - JR answers. (If defaults to Horizon home page, check archives
3.24.01)
PCM vs PPM. AM vs FM.
Radio Interference Primer " and further articles.

regards
Alan T.

Alan's Hobby Web Links
http://homepages.ihug.co.nz/~atong/
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"MarioG" <mario.glozinic@vz.tel.hr> wrote in message
news:bbqv0a$f18b$4@as201.hinet.hr...
> Hi guys !
> I need some assistance, please.
> Can anyone tell me the range of Futba 2DR two channel radio ( 75 Mhz) ??
> Any help is wellcome.
>
> TIA,
> best regards,
> Mario
>
>
>
>