TX antenna question

TX antenna question

Post by t.. » Sat, 28 Aug 1999 04:00:00



Hi everyone,

I've got a new Futaba 6AH heli transmitter. I've also got a sim. The
question is ... is it not a good idea to run the transmitter for
extended periods of time with the antenna collapsed?

In the good old days (flying fixed wing models) I had often heard that
the OUTPUT TRANSISTOR would become heat damaged running the transmitter
with the antenna down (something about expected resistance in the
feedback path). Is this still true?

Should I move my seat back 3 feet from the screen and pull out the
antenna??

regards,
tob

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TX antenna question

Post by SIMP » Sat, 28 Aug 1999 04:00:00


When using the sim, the transmitter is not actually sending radio waves so you
don't have to extend the antenna. Remember not turn on your Tx, just plug in
the trainer cord.

Phillip

 
 
 

TX antenna question

Post by Penguin » Sat, 28 Aug 1999 04:00:00


I have heard that you should never turn on the TX with the antenna REMOVED, but
never heard of any concern with it collapsed.

My 2 cents worth.

 
 
 

TX antenna question

Post by Joe Klabni » Sat, 28 Aug 1999 04:00:00


Quote:

> I have heard that you should never turn on the TX with the antenna REMOVED, but
> never heard of any concern with it collapsed.

> My 2 cents worth.

You are correct, you should never turn on any transmitter be it RC, CB
or any radio transmitting device with out the correct load attached to
it. To put it into simple terms, just think of all this energy being
generated with no where for it to go except back into the transmitting
circuit, poof there goes your circuit. As for the collapsed antenna, you
have a load there so it does not do any harm to the circuit.

Joe...

 
 
 

TX antenna question

Post by Dutc » Sat, 28 Aug 1999 04:00:00



 As for the collapsed antenna, you

Quote:
> have a load there so it does not do any harm to the circuit.

> Joe...

Actually, the collapsed antenna does not present a load because transmitter
antennas are matched to the transmitting frequency by having the correct
length, ie. extended.
Dutch
 
 
 

TX antenna question

Post by Joe Klabni » Sun, 29 Aug 1999 04:00:00


Quote:




>  As for the collapsed antenna, you
> > have a load there so it does not do any harm to the circuit.

> > Joe...

> Actually, the collapsed antenna does not present a load because transmitter
> antennas are matched to the transmitting frequency by having the correct
> length, ie. extended.
> Dutch

Actually you do have a load there, I am quite aware of the mismatching
of the antenna length, however power is being radiated out from that
transmitter. It can cause a problem in a very long term use, but how
many people go around with the antennas collapsed for long periods of
time. If this where a problem then the manufacturers would be making all
the transmitters with base loaded antennas(like the ugly duck) to keep
everyone from damaging your transmitters. Also the output power is
directly proportional to the life of running your transmitter with out a
load.

Joe...