Montee

I have never, personally, experienced a problem on 2.4Ghz, but I am curious about the effect that a poor antenna installation would have on the RF link.
My question is not specific to Spektrum as I have seen poor installations with many different makes of RC equipment.

AndyKunz

Oh good, I thought it had turned to "how can we flame each other" instead.

First, the coax portion can be permanently damaged by bending it too tightly, or by kinking it. Doing so will dramatically affect performance. So it's not just the tip that's important.

Folding the tip over or bending it will reduce range as well. As for a number, I can't give you that because it depends very much on the geometry and orientation if you do that.

Personally, I have always used either a McDonald's coffee stirrer as an antenna tube (on longer antennas) or used a toothpick and heat shrink over short ones.

I know what you mean! Yes, those are all "worst practices" and it's not brand specific - the laws of physics apply to everybody. Just ask the Futaba pilot who planted his jet at Joe Nall by installing the antennas inside a fancy radio box that worked as a half-decent RF shield! I know, a JET pilot - somebody who should know better due to thousands of hours of flight time and experience. And with non-Spektrum equipment!! How ever could that possibly be?!?!

Andy

wcmorrison

My Feedback: (2)

I am not the only person that had problems with early Spektrum equipment. And I had basically bad service from Horizon Hobby in supporting that equipment. So I do not use it. I was even reluctant to give away my stuff as I thought it was decidedly flawed. Now that is not to say, Spektrum has done wonders to make better gear, they had to or go out of business. I moved on, used several different systems and stumbled on to Hitec. I have not had a problem with Hitec and I am very happy with that equipment. But as you can imagine, I will never use Spektrum again. That others do use it is okay by me. I do not comment to them about my experiences. Why do that, they already have the gear. That is just sour grapes. Like I said, I have moved on to what I think is better equipment.

init4fun

Hound , buddy , I am truly not in denial about my 1000s of glitch free flights , and the only denial I'll admit to is the denial to believe there is some great big secret "Spektrum Conspiracy" whereby they are hiding some flaw that only crashes a fractional percentage of models flown on the Spektrum system ! Far too many thousands of your fellow hobbyists have among them hundreds of thousands (maybe even millions) of glitch free flights flown for there to be an inherent flaw as you and a few others claim . Now , if you aren't comfortable with using this brand radio , I'd say it's entirely your choice to go with what you think works best for you . Just don't expect me or the countless others who get good service from their Spektrum systems to jump on your bandwagon . At least 5 posters now have agreed with my theory of the radio being fine and the stall killing the plane , but again you go on and believe what ya will . And I will continue setting up my planes my way , and getting great service from my radio , no matter which manufacturer's product I happen to be flying that day .........

HoundDog

My Feedback: (49)

I've seen many Spectrym receivers with a very short antenna coming out of each side (Whiskers).
I've always been under the impression that when a Receiver has two antennae, that it is more efficient when they are placed at Right angles to each other. Is this a good or poor practice. Or Doesn't it really matter, with these receivers, that the antennae are in the same Plain?

Montee

No Andy, not from me. That would be pointless.

We are all modelers and should be helping each other to better understand and enjoy our hobby to the fullest.

All brands had, have and will have some problems at some stage. Once these problems have been ironed out, lets close the door behind us and move forward.

AndyKunz

When you look at one of our receivers (or remote receiver) with two short wires sticking out from the sides in a line, that is actually ONE antenna. It should be straight end to end.

When you look at one that has the coming out at right angles (AR6115, for example) then those should be kept at right angles. They are actually TWO antennas, and they're oriented at 90 degrees for diversity. The ones that come out the same end are TWO antennas also (AR6260, for instance).

When you see a receiver where there is a long and a short lead (AR400, AR610) then those are TWO antennas. When the long one has a bump in it, that's an amplified antenna.

Andy

BarracudaHockey

My Feedback: (11)

Robart air tubing is perfect for keeping those antennas straight and safe

AndyKunz

Yes! I also use small (1/2A size) fuel tubing, or small fish tank air tubing.

The McD's tubes are the cheapest though.

In the photo below you can see the TM1000 antenna tube as a short white line near the LE of the left fin, sticking straight up from the fuselage. On the second photo you can see how that same tube angles out of the fuselage.

Hope that helps a bit.

Andy

Montee

I use some small silicone tubing, more or less the same size as the Robart tubing.
It slips just over the antenna nipple that protrudes out of the Rx casing.

drac1

My Feedback: (4)

I use cable tie off cuts and clear heat shrink.

Rob2160

+1 - all my antennas are protected by either heat shrink or stiff tubes (My LHS has dedicated antenna protectors and I cut them to length)

Same experience here. Several Spektrum Transmitters, dozens of receivers in planes / Helis and multicopters with many thousands of flights over 6 years and not a single glitch or failure ever.

I am pedantic about wiring / power set up and careful antenna placement and will always do a full power range test to at least 1500 meters before using any new equipment (TX or RX). On every machine I have you can "see" at least one antenna from any angle.

I always place mine at 90 degrees as per the pics below. If I need to bend the antenna coax I do it carefully and ensure nothing is kinked.

Rob2160

So any Spektrum Satellite should have both antenna totally straight? Even if being used singularly without a main RX? i.e. connected directly to a multicopter Flight controller and there is no advantage to having them at different angles?

init4fun

Hi Rob ,

Well you just taught me something new , I had no idea there is a way to use a satellite RX as a stand alone entity , I was under the (obviously false) impression that a satellite had to be plugged into a "regular" RX to work . This begs the question , does the multicopter flight controller contain an RX that is compatable with the spektrum satellite , or is the satellite the only RX the controller uses to get it's controlling inputs ?

BarracudaHockey

My Feedback: (11)

The satellite is a complete receiver, it just doesn't have servo connections.

Helicopter flybarless controllers, some airplane gyros like the Demon Cortex and Aura 8 all have receptacles to plug in a satellite receiver or two directly into the unit where the satellite performs the receiver function and the flight controller facilitates the servo connections. MR's can use the same setup

Rob2160

Hi Init,

I only learned this recently also and it works well for small and lightweight builds. The satellite is the only thing proving control inputs from the TX to the flight controller.

Its possible with a number of controllers but the one I use is a Naze32 Acro board. The 3 satellite wires connect directly to the board and you put it in bind mode via the configuration software. This also allows you to specify which mode you want to bind, e.g. DSMX, DSM2, 11ms or 22ms.

Mine requires a bit of soldering but there are other flight controllers that you can plug the satellite directly into. (e.g.Pixhawk)

Here is a video that shows the bind process and how the Satellite is connected. Range hasn't been an issue so far.

AndyKunz

Yes, not just each straight, but straight in relation to one another.

Andy

Rob2160

Thanks Andy, learned something new also..

HoundDog

My Feedback: (49)

Originally Posted by Rob2160
So any Spektrum Satellite should have both antenna totally straight? Even if being used singularly without a main RX? i.e. connected directly to a multicopter Flight controller and there is no advantage to having them at different angles?

Then it stands to reason if U are one of the "COOL CROWED" and put the Xmitter antenna horizontally then u should orient your RX antenna with the center line of the plane. Then also if U place the Xmitter Antena "Vertical as is proper" Then it would stand to reason that a RX with a single antenna should be oriented with the Vertical axis of the plane. This of course being for best signal reception. Right Wrong or what?

AndyKunz

Sorry, I'm not getting what you're asking. Can you draw a picture or something? I don't understand how the centerline of the plane comes into play.

My tx has two antennas, 90 degrees from each other. One is always horizontal (the one in the handle) but the other could be horizontal or some angle. Aren't tray users the only ones with their transmitters laying horizontal?

Sorry, but I'm really not getting where you're coming from (or where it's going).

Thanks.

Andy

HoundDog

My Feedback: (49)

I don't understand how the centerline of the plane comes into play.
The when the antenna is aligned to the Center line (Horizontal axis) of the model i.e. level with the ground when sitting on the ground.

Explination:
If a Xmitter Has two antenni then it stands to reason (to me anyway) that one should be oriented Horizontally (The handle) and the other the movable antenna should be oriented 90 degrees to the handle, i.e. vertical. I would not have asked the question if it weren't obvious (to me at least) that most Spectrum users orient their Single Antenna to the right and horizontal to the ground. Why would a tray user orient the antenna anyway but vertical.
I would think A vertical Antenna Emits a signal that seems to the RX that it is stronger because of the signal propagation of a (Stick) antenna. I suppose it is OK to orient an antenna horizontal to the ground if one turns their body and radio toward the model. On the other hand if Like Pattern and Imac fliers they stay facing front and turning their head, when he model is farthest away The Antenna being horizontal and pointing at the model, The RX is seeing the weakest possible signal and while at it furthest distance from the Xmitter. anyways that's how I thing it works. Am I correct?

AndyKunz

Thanks for the better explanation of what you're talking about.

Most (over 50%) Spektrum users are flying radios that do not have adjustable antennas. We haven't been designing new radios with adjustable antennas for about 3 years now. Of those who have adjustable antennas, I don't think there's any "common" way, unless they follow the disinformation on some Internet sites. Our tray radios have an antenna the folds out from below, and when extended it latches into a horizontal attitude with the tray radio in the normal horizontal tray orientation. Other brands might have tray radios with different orientations - I don't follow other brands trays, though.

As for IMAC and Pattern pilots, they are flying so close to the transmitter I doubt if there is much to worry about regarding signal strength from how they hold their DX9's and DX18's. When we hosted IMAC events here, they rarely flew more than 1500' away. Even the jet guys rarely fly more than 2000' away. With guys flying them 2+ mile away for FPV, I really don't think these close-in folks have anything much to worry about.

As for the weakest signal, IF you had a radio with only 1 antenna AND you pointed that antenna directly at the model AND you flew way way way far out, then MAYBE you might have a problem that could be due to orientation of that antenna - simply moving your body a degree or two would fix it. Some people have this silly notion that the toroid is like a donut with a big hole of no-signal in the middle, but that's not accurate.

It sounds like you're trying to find a way to justify pointing your single antenna in one direction or the other. Good luck on that!

Andy

init4fun

Thank You Rob and Andy Barracudahockey for answering my question . As is obvious by my lack of knowledge about them , I have no clue about the helicopters although I do like to watch those that are into them fly them .

And to Andy Kunz , I will say that I have clung steadfastly to my trusty ol DX7 and AR7000 RXs specifically cause they've given me 1000s of trouble free flights . I know DSMX is the replacement for DSM2 and maybe if I ever do see radio related trouble I'll consider making the switch but for now all is well radio wise for me .

So far my formula for success has been simple , No old batteries and cycle the batteries regularly noting performance and trashing any not electrically up to snuff , no matter how "new" they are ! , No underwired 26 gauge switch harnesses carrying all the power to RX and servos , I get the ones with the thicker wire from Electrodynamics , REGULAR range checks , Routine checks of all surfaces and linkage for binding/damage , And lastly but not leastly absolutely NO reuse of "pre crashed" RX !!!! If I plant one hard enough to call it unrepairable then the RX gets retired with the rest of the wreckage , no ifs ands or buts ! Yes I have seen fellow flyers plant one spectacularly and reuse the RX without a second thought . Scary stuff when you see the balsa confetti and the same RX flying a few days later in a different airframe ......

BarracudaHockey

My Feedback: (11)

It's not just helis.

I have an Extra 300 electric with a Demon Aero Cortex that has no receiver, just to satellites plugged straight into the Cortex

init4fun

Thank You Andy . I looked that up and it appears to be a flight stabilization device , is this what's become of what was once called a gyro ? Gotta admit , one of my "never got around to its" was to equip a somewhat powerful plane with a gyro for use as a really windy day flyer (I'll fly in low/moderate winds , but really windy/gusty is too much a chore than fun for me) .