I recently got back into the r/c airplanes hobby. I chose to go the electric route and buy all new stuff. I'm running a DX-7 radio in my plane. I skimmed through the manual in the setup, but something keeps catching my eye. I keep watching product review videos @ sites for other airplanes. I can't help but notice whenever someone is flying w/ a 2.4ghz radio they seem to have their antenna folded over to the side.

Am I supposed to have mine this way when I fly? "I've just been leaving it straight up and down", the way it came out of the box?

Dave

Yes, the antenna on a 2.4GHz system transmits from the side.

Keep the antenna bent

The recommendation, as least from Futaba, is that you keep the antenna perpendicular to the receiver (pointing the antenna straight at the antenna is, per Futaba's directions, the worst signal strength). I angle mine so it's vertical when I'm holding the transmitter, but have forgotten a few times without incident.

Both 2.4 and 72 MHz transmit out the side of the antenna. There is very little signal from the tip.

This is true, "for all practical purposes". These antennas, stick antennas, broadcast from the antenna out, but not from the tip... well, not really. There is something there, but it is basically unusable. There are antennas that send out signals in a directional fashion, like a flashlight, but these are dishes, corner reflectors, and so on, but they also consist of a 'stick antenna' that is arranged in such a fashion that all the signal is focused out in one direction with very little going out what are called 'side lobes'.

So, the DX7 or other 2.4 Gig antennas, are measured in what is called wavelengths, or the length of the radio wave in the atmosphere. The lower the frequency, the longer the antenna, as 72 MHz uses about a three foot long antenna, where the 2.4 GHz antenna is much shorter. For practical purposes, these antennas work in fractions of their real wavelength, usuall divisible by two.. ie, half wave, quarter wave, and so on. Most use quarter wave antennas.

Anyway, that's more than you asked for, but I thought it would be helpful to understand what is going on. See the crude diagrams below to sort of describe what's going on with antennas. Note, that the first one is a 2.4 Gig setup with the flex point and the antenna rotated to point up. The other is as if you were looking down from above the antenna at the tip.. where all of the signal goes out in circular form from the center. The first picture does the same, so picture those lines going out all around the vertical antenna such as the second photo showsJeech...

Jeech.. [sm=bananahead.gif]

Wow,

Thanks guys, that really does help out a lot. I'm glad there's a forum for this hobby. I spent some time away from it so I am learning a lot lately. I guess luckily when I flew the plane I wasn't flying too straight. That's good though since I was able to maintain a good signal.

I've posted tech questions on automotive forum sites for help with working on my truck and never got a response. You guys are great.

Thanks again,
Dave

this is correct but if im not mistaken and i may be so someone please clarify if si but i believe it dosent matter with the dx7 since the ar7000 reciever has 2 parts that are supposed to be mounted perpendicular to each other.......thats assuming that you are using the ar7000

It still matters. Keep that antenna bent!

If you point the tip of antenna at the airplane, then the signal is greatly reduced in the direction of the airplane. That means all receivers will see a reduced signal as compared to having the side of the antenna pointed at the airplane.

It is not a question of will it work, but a question of best practice vs worst practice or best signal position vs. worst signal position.

That's absolutely correct. With the redundancy with the AR7000 receiver (dual receivers so dual antennas), the orientation of these two antennas is important. But, if you happen to be flying, say away from you, and you are headed down-wind for a turn around for landing, and if you happen to get to the end of the range by pointing the TX antenna directly toward the aircraft, you could lose control of the aircraft. Then moving the antenna away from pointing directly, will consume some rather important re-acquire time for the RX.

Try to keep the antenna perpendicular to the aircraft path of travel. That's the safe bet.

CGr.

While we're on the subject...

Point your antenna to the right or left, not up.

The reason for this is that very often I see people who tend to drop their hands when holding the Tx.

If the antenna is pointing up, they may just inadvertently point it at the airplane.

Since you mentioned it I am not running it with the AR7000 Rx. I got the microlite system with the AR6100 RX. Either way seems like the bent antenna theory seems to be the key so I will keep it bent from now on.

Dave

The advantage, of course, with the AR7000 is the dual receiver system. But, the same goes because the orientation of the transmitting antenna does become a factor no matter how the receiver, and it's antenna, is oriented.

Some may say it's a bunch of crap, but, it's like a compute virus. You never know that you have one until you do.. you will never know if you are orientating it correctly or if it matters until you are on final on a long approach and lose it. Then you have to play the blame game.. how did THAT happen!!!

CGr.

I`ve been trying to figure out , How That HAPPEN , with my SSE , I was bringing it in front of me about half throttle and it acted like it locked out.
First thing I did before I pick up the busted plane , was check to see if the radio worked , I did have to plug the battery back into the reciever, but it hit pretty hard. Every thing worked , I thought maybe the battery had come loose , It did it right in front of me with the ant. pointed up. Hmmm?

Her is a pic of the carnage

Oh.. No!! When did that happen?

CGr

Sounds like antenna orientation had nothing to do with your crash then.

What is said above is mostly true, a whip antenna radiates more power to the side than toward the end. However, there is still a good portion of the power radiated off the end. To check this out, just do a range check with the antenna pointing at the receiver and find where it goes into fail safe. Now do it again with the antenna broadside to the receiver. You will not notice a great deal of difference. How you hold the transmitter makes a big difference too, the human body makes a poor ground plane, if you had the transmitter well grounded you will have more range. A bare two hand hold gets a lot more RF out than a gloved hand just touching the sticks with the transmitter mounted on a transmitter held by a neckstrap and plastic tray. The old style metal cased transmitters had a big technical advantage over the plastic one of today as they provided a better ground plane.

This is mostly true, but the range check is done in a relatively short distance as compared to the overall range capabilities of a properly oriented antenna. If you take a walk about 200 yards and try this (this is 600 feet.. not being a wiseguy, but 200 yards is a pretty good distance) you will find that it will be marginal even for a properly oriented antenna and probably not functional if pointing towards the plane. Keep in mind that the DX7, for instance, uses the range check button, which reduces the output power when pressed. 72 MHz is done with the antenna collapsed.

Most of the energy is radiated out vertically as shown in the example above. The strength of the signal (field strength as measured in micro-volts per meter) is inversely proportional to the square of the distance.... or some such thing..

Happened about 7 weeks ago . Had 8 flights on it. The first 6 were dead sticks . Installed a GMS .47 and was having a heck of a time dialing in the mid-range. The 7th flight I finally found the sweet spot and spent most of that flight trimming and getting a feel for it.
8th flight did a couple of snaps rolls and was surprised at how violent the SSE snaps . brought it around half throttle and when it got in front of me , it acted like it got locked out. Throttle went W.O and smucked in the plowed feild.
Not sure what really happened, wish it had been dumb thumbs , that way I would know for sure.
Got another SSE kit, waiting for me to get the SlowPoke done.

Oh, so sorry to hear that, Robbie. Tough break on that one for sure.

Did you remember to bind the RX with the throttle at idle? That sets the 'fail safe'.

I flew a member's SSE a few weeks back. He took off with it and was having a terrible time with it. I asked him if he had trimmed it yet, his reply was "Trim.. hell, I can't fly it!!!". A little chuckle but I asked him if he wanted me to take over for him, he answered by sticking the transmitter in my face.. ha..

I smoothed it out, and climbed up to 3 mistakes high altitude. I did a roll and the thing whipped around in about 1 second. Violent was the word. I did a loop.. and it just about did a vertical rotation in it's own length.. again, violent.

I checked to see if it was on high-rates, nope.. it was set up that way. Jeech..

I managed to land it.. the elevator was soooooo sensitive.. but got it down in one piece.

We then proceeded to make several adjustments to linkage, end points, and set up dual rates for him, and added some - expo, and took off.

It made all the difference in the world. He was able to fly it now. Wow.. that first flight scared the hell out of me!! He had been flying for only about 6 months and was definitely not ready for such a capable aircraft.

The SSE is a great plane.. if set up properly and in the right hands.. otherwise.. it can be a real torture trying to get it to calm down in the air. They want to fly, for sure.

CGr.

Yup I did bind the it with the throttle at idle. Set to low rates with 25% expo.

To be honest, I don`t get to upset when I smuck one. But if I get shot down thats another story . Happened to me twice last year. , so I went to the DX7 .

The SSE is a fun plane , but a little small , wish they made it in a .60 size. The SSE ARF was , the best ARF I`ve had yet but at $199.00 for a .40 size it should be. I believe this is one of the few kits , that are cheaper to build than buy in ARF form.