Model Forum / Radio Controlled / Land Models / May 2006

Sorry, but in this situation size does matter.  Mass has little to do with
it.  If you would like to put your theory about mass to practise take your
receiver antenna and scrunch it up into a little ball and tape it down
inside your truck some where and see what happens to your range, even better
do it with the transmitter antenna down and if your theory is correct you
should be able to get full range with the failsafe disconnected of course.

also requires a tuned antenna and needs it to be fully extended for best
performance.

Most RC transmitters new and old have a built in preload circuit of some
sort to reduce the effect of needing a tuned antenna system like they do in
CB transmitters.  Thus having a preloaded circuit you don't have to worry
about overloading the circuit as much as you would with a CB transmitter if
you have no antenna connected or the antenna partially extended.  There is
also the understanding that in low power devices like RC transmitters that
the circuit does not need protection from overload because the voltage is
never a constant and power output of the transmitter is not high enough to
cause effective damage to the unit.  We're talking about <100 mili-watts for
a RC transmitter as apposed to a CB transmitter of 4+ watts (40X greater
power).

An example of this preload in the antenna circuit is simply put, if you
don't have this circuit your antenna would have to be approx. 11 meters long
if you were using a 27Mhz RC transmitter.

Take a CB antenna and fold it in half and bad things happen the same thing
applies to RC transmitters but not to the same extent as a CB transmitter
because of the lower power output and preloading circuit.

One thing that is relevant is if you use your RC transmitter with no antenna
or the antenna down you will consume more battery power, of course given
that a Futaba 3PM has a current drain of 250mA or less means little or
nothing to a set of 2600ma rechargeable batteries but to a set of Alkaline
that are rated at 500ma it means a lot.

Its mostly about SWR, VSWR or ISWR, here is a article relating to what your
talking about above.  The last paragraph of the article relates directly to
what you guys are talking about with RC transmitters.

http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci852555,00.html

Hope this helps, one thing I no doesn't is getting the relevant information
from RC manufacturers about the power output and circuitry of the radio
equipment.  I'm actually surprised the US government doesn't require this
information to be included in the manuals specially where digital and high
frequency (microwave) transmitters are becoming more common and the effect
of radiation from these transmitters could cause health problems in
children.

Cheers
Richard

NO - that's wrong! More power would be required if the antenna were
shortened!!

What changes the frequency in your FM or AM radio - think about it - a
length of wire is lengthened! will it change the frequency. If I were to
change the length of the antenna wire, would the frequency change or bleed
over into another freq. -  How about the receiver ie does this work for the
receiver as well eg if I cut an inch off my receiver wire!!!

OMFG, if it isn't Dark Night = Mr. kiddie porn himself !!!  you been
diddling with them little boys...  <drops and shakes head in disgust>   I
suspect you came in here to prey on the youngsters!!