Call it entrenched fuddyduddy-ism from the old days, but I still cringe at the thought of running a Tx with the antenna down. Sure, nowadays it's "safe" and people do it all the time.. like back-driving a servo and it doesn't strip the output gear, but evokes the very same "yeeee-ech" feeling.
In the old days, transmitter antenna matching was a major deal. And when solid state CBs came along, i worked replacing a ton of fried finals in those, and that's where this latter-day "yeee-ech" factor comes from.
Old myth or not.... the fact is that RF energy is usually matched into the Tx antenna. This way you get MAXIMUM output power and a minimum of reflected power. With CB and ham radio gear the output stages are powerful enough to self destruct if abused. RC transmitters are relatively low power and will almost certainly survive some abuse.
However.... why chance it ? There may be only a slim chance of damaging the PA transistor due to overheating but there is still a chance. It may be a long slow degradation process that finally reveals itself when your highly prized model goes in at top speed, as long as it doesn't go into the other guys fiddling around in the pits then it won't really matter !
You could run your car without an air filter on the engine and go round boasting that you have done 1,000 miles in it and NEVER had a problem. Using air filters is therefore not necessary but is just an urban myth.
I have seen recommendations for removing the crystal, and thus disabling RF output, when using the transmitter on flight simulators with the aerial retracted for long periods. Output transistors are matched into the antenna so that they "see" a suitable load. Cause a mismatch, or heaven forbid, remove the antenna and there is NO suitable impedance match.... the outgoing RF will either be far less than it should be, or in the case of no antenna at all.... virtually none ! There have been fatalities already with guys using good equipment, the authorities are going to be really impressed at any fatality caused by some dimwit flying without a Tx antenna !
Hmmmmmmm, I guess you are a troll.... surely no one is actually this daft ?
If there is an insistence on a certain polarisation of the Tx antenna then doen't that only make sense if the receive antenna also has the same polarisation ??? Doesn't a simple whip antenna have both vertical and horizontal radiation components ? You are however correct when you state that the Tx antenna is held at random angles by whoever holds the Tx. What is the basic radiation pattern of a simple whip ? What happens to that radiation pattern when the antenna is lowered from the vertical? What effect does height above ground have ?
If your statement was correct... we only need Tx antennas because the FCC insists on a certain polarisation of the transmitted signal... Then those holding the Tx at a slight angle to the ground would actually be using the optimum method to ensure best contact between Tx and Rx ! You seem to have the impression that the ruling is to ensure that the TX antenna is held vertically.... now why would you think that ?
I lost control of a large glider while using a Futaba Tx with the aerial accidentally left retracted. Control was lost within some 30 yards. By this I mean... the glider went straight in BUT it had not been responding properly before it got anywhere near that distance.
I was flying part way down a sloping hillside which is at an angle of about 50 degrees and is a very high hill. I was some 1/3 of the way below the summit. The surface vegetation is mixed - rough grass and heather. The soil covering is thin and overlays limestone and slate.
Now why is my description of the site relevant ? Why does it show you are spouting rubbish ?
Note.... I was using a Futaba Tx which as you correctly state still has a certain length of antenna even when it is in the retracted state.
The importance of polarisation in RC is another myth. By arbitrary convention it's the direction of the electric vector, but that changes all the time in an RC environment. The transmitter is all over the place, as indeed is the model, and then there's a number of mechanisms that confound polarity.
If there is indeed an FCC reg that transmitters shall be vertical pol, then it's one of their most breached regs, and 99.9999% of RC modellers should be prosecuted.
Even in a carefully constructed (and expensive) Outside Area Test Site (OATS) it's not always easy to tightly control polarity. A typical RC site has zero chance.
Agreed, there is no special reason to chance it, but it can and does happen for a variety of reasons. The RC manufacturers have a duty of care to anticipate it. I believe they all do these days, but that was not always the case.
I have never found any good documentation that suggests such a failure mode exists, including the superb "RF Transistors, Principles and Applications" by Dye and Granberg of Motorola. However, while such a failure mode COULD exist, it's many orders of magnitudes below the other things that modelers do, and have personal control, and a responsibility, over, like:
Lack of care with batteries. Ditto for black wire corrosion Proper freq control Ditto for RC system care and routine checks Ignorance of structural considerations Ditto for aerodynamic loads Stupid things like leaving the servo arm screw out. Flying a model beyond their capability. Airworthy repairs
and there's many more
A silly strawman argument, not capable of withstanding any rational analysis.
A number of transmitters disable the RF stage when the DSC is connected to the sim. That would be the sensible way to go.
Agreed, and I don't accept anybody would ever go flying like that, except for two cases.
a. Forgetfulness (let the person who has not suffered this at some stage put their hand up now) b. A carefully staged trial to explore margins
However it's interesting to note that of the RC fatalities I'm aware of over the years, the authorities have not prosecuted anybody, even although a couple of the accidents were caused by negligence. And yes, I'm well aware the Hungarian Police locked up Stefan Wurm after the double fatality there in May 2006, but it was a knee-jerk reaction, and he was released with an apology from the public prosecutor's office.
My experience exactly. About 30 -60 yards with a retracted antenna. I use it as a range check all the time. If I get 15 yards I will fly, but only to arioud 300 yards out. If I get 30, I can fly to around 600 yards and if I get 60 yards I am safe to over a kilometer.
Thats on a Futaba set with the antenna as retraced as it will go.
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