aaron2874

I just started building a Lanier giant scale Stinger. It's going to be powered by a Zenoah G62, have a smoke system, and onboard wireless video. For the video, I want to cut a hole where you would normally put a pilot figure and install a standard servo. I'm want to mount the camera on the servo for the "panning cam" action from the pilots' perspective. Now here is the big question: Where will I need to locate the tx antenna? I would like to know now so I can have this in mind when I get to building the fuse. And, what would be the best way to orient the antenna? I was thinking I should probably drill a hole in the fuse floor and orient the antenna to the rear. However, I have not actually used a wireless system, so I don't know what would be best as far as reception goes. BTW I'm talking about one of those thick antennas that you can adjust the angle on (they look adjustable anyway).

Thanks in advance,
Aaron

Fubar-One

My Feedback: (1)

From what I have learned:
You want the antenna pointing down if posssible since the plane is usually above the rx. We hope.
You are also better off if you are able to NOT bend that antenna at the pivot point. By bending it, you are screwing up the radiation pattern. It will work, but not as well.
You dont want the antenna near any aluminum landing gear type stuff. Metal is not a friend of the antenna.
Me, I am heading over to BlackwidowAV and ordering that 200mw 5v system he sells.

yb2normal

What fubar said

The main problem with orienting the transmitter antenna horizontal is that the polarization changes as the plane turns. This will still happen even with a vertical antenna, but to a lesser extent.

Fubar also brings up another good point. The case of these transmitters is at ground, and will interact with the antenna. The angle of the antenna in relationship to the transmitter can affect your results, so consider this as you are tweaking your installation for best results.

I thought I read somewhere where a guy lined the bottom of his plane with tinfoil or mylar and mounted his antenna through the foil. The idea was that it made a nice clean groundplane. I've never tried this myself, but it sounds plausible.

Bill

IA-Flyer

Aaron,
The Giant stinger is a great flying plane from what I've seen, wow that should make a great video platform!
Think you'll have enough power?

I noticed you were talking about the spylinker 800mW system in a different thread. I'm not going to recommend against it, but since Bill from BlackWidowAV.com (yb2normal) didn’t mention his stuff I will. Remember the 800mW is an ebay rating not to be confused with actual output.

I was using a small video sender last year (tested it to 1.5 miles LOS) and just received one of Bills 600mW systems. Although I haven’t flown the system yet I did a quick test with the transmitter on my kitchen table, I drove around town with the RX in my car.
Wow this thing looks like it is going to have some range! I was even receiving video through several brick buildings 2 blocks away! My old system wouldn’t come close to that.

A few benefits of Bills 2.4 GHz systems are, more frequency separation from your 72MHz RC transmitter, smaller antennas, 5v power, standard SMA connectors for the TX / RX antennas and they are PLL (no knob to tune). Almost forgot, HAM legal frequencies.

Looking around for a new antenna for the plane I'm building for next year I came across this 2.4GHz antenna.

[link=http://www.wifi-plus.shoppingcartsplus.com/catalog/item/509770/219794.htm]Bullet Antenna[/link]

They claim 360x360 pattern (no dead spots)! I asked a few questions in a post and they asked me to call them Monday because they have several of their systems in aircraft. I’ll let you know if they have any good recommendations.

Jim

Fubar-One

My Feedback: (1)

Well, I ordered the 2.4ghz 5v system from BlackwidowAV. One reason being the 5v power aspect, one being the 200mw actual output and the third being that, for some reason, I am not getting the results lately with the Spylinker system that I was originally. Kind of got the idea that the rx we used this last time is crummy. Never used that one before and the results this time were MUCH poorer then they ever were. Oh well, havent given up on it quite yet but looking forward to trying the 2.4ghz setup.
Bill, I noticed on the Blackwidow site that you sell a patch antenna for the 2.4ghz system. How well does it perform compared to the GPP build it yourself antenna? Gonna build one for the 1.2ghz stuff I have but if the factory built one works as well as the do it yourself one does...

PlaneKrazee

My Feedback: (14)

Jim,

I am interested in the operation of that little antennna as well. I wonder if it is a QHA antenna.

Skycam41

Just one thought that comes to mind and it is not antenna related. If you are pointing your camara through a cheap plastic canopy you will loose image quality. Try some test footage shooting through your canopy before deciding on its final location...just a thought.

Mike

Spanky1

Hi aaron2874

If you can swing the extra money, buy the 1500mW. It appears that any configuration won't lose the signal.

When you are not a video guru (like me) you do the only responsible thing; OVERSIZE IT. I've not been disappointed in the least. Loops, barrel rolls, loooong distances don't effect the signal. Antenna placement front, back, topside, or underneath doesn't effect it. This includes climbing into the stratosphere. This current mount is anchored to an arrow shaft extending back looking down over the LE and motor.

This system is off ebay from a no namer. I think all systems come from Elcom.

Good luck. Should be pretty cool.

Spanky

aaron2874

Fubar
You make a good point. Note to self: Keep antennas straight and change aluminum gear to non-metal gear. I didn't think of that. Definately need my plane to be my antennas friend. Can you tell me why the 5 volt system is beneficial?

Flyer
I am going to get my ham license in the next month or two so I will definately be looking for a system that I can use it with. What your talking about sounds good. I'm going to need a system that can hang with some serious aerobatics and not drop the signal constantly. I plan wringing this plane out! That little bullet antenna looks good. I could put that anywhere. About the engine choice... SUPER SIZE IT!! I want this plane to do more than I can so I'm splurging. I plan on glassing and pinning the firewall.

Skycam
I will just have to try the cam in the cockpit and see how it looks. If it's bad, then I can always cover the hole with a pilot figure. Maybe I could get a cam dome and belly mount it. I should still be able to use a servo for adjusting cam angles. We'll see what we see... That's a good thought though. Something else I need to keep in mind.

I think I'll surf on over to the Blackwidow site and check his stuff out. I plan on using this coming tax return for my video equipment so I'll probable spend some serious cash on whatever I do eventually buy.

IA-Flyer

I think your engine choice is perfect, underpowered airplanes aren’t much fun. I saw Bubba fly one with a 62 in it and it flew like a feather being drug around by a rocket!

Don’t over study for the ham test, it's easy. QRZ site for the PDF and practice tests for a night or two and go for it!
One thing you could consider is using a small DV or Micro-MV camcorder for the video system, and connect the video feed to the video TX so you can monitor and control the view from the ground. Your stinger shouldn’t notice the extra 12 ounces of weight, and you wouldn’t have to worry about any dropouts in the final 500-line video recorded at the source.

Skypilot_one
From my understanding it's not, but I'll ask them when I call.
We should start an antenna thread to see what everyone has found and is using.
I'm looking for something that can fly a mile to the side and a mile above (or two) without signal loss, using the same TX antenna.

Fubar-One
The RX for my 1.2GHz (all in one) system died, at first it just drifted while flying now it has bars across the screen. [] I’m tempted to put the new black widow system in my kougar for a test hop, real tempted…

Fubar-One

My Feedback: (1)

Well, for me the 5v system is beneficial since not only can one power source operate both the camera I already have (CX-161 CCD) and the BlackwidowAV system I just ordered, but 5v means more options. Standard rx pack will power the system. 2 cell Li-Poly pack with a 5v regulator will power the system and weigh very little.
I can stick the one system on various planes from slope glider, 2 meter glider, park flyer and even on something wild like my Uproar.
The 200mw system I just bought is also very tiny and I have great hopes for it. I am also dying to see how the 2.4ghz stuff works with either the GPP antenna or possibly the factory patch antenna he sells. If I can do a snap roll and hold the signal, I will be In Like Flint.

Fubar-One

My Feedback: (1)

Are the bars vertical like prison bars? You might just need a new battery. That is one of the symtoms of a low battery. One of my first video tests I flew till the sucker died and the bars increased till the entire picture was black. Still had a good signal tho!

IA-Flyer

Unfortunately no, they are horizontal and the picture scrolls, I opened it and checked for loose wires with no luck.
I know it’s in the receiver because it has bars even when the video transmitter is off.
It's a downer, I wanted to throw it on my slow stick. []

yb2normal

I can't compare the two unfortunately. I've heard that the GPP is linear polarized, so that would be one difference from my patch (circular polarized). My feeling is that a circular polarized antenna is a better match for our mobile application since the tx antenna is constantly changing orientation.

It has worked well for me so far!

Bill

aaron2874

"I saw Bubba fly one with a 62 in it and it flew like a feather being drug around by a rocket!"

LOL That's a good one!

I've read from many that the 62 is a real powerhouse and good for this plane. I can't wait to see what an inverted flat spin looks like from up there. I just finished one of the main wings (fully sheeted). It's massive! This sucker should definately have some payload capacity.

Here is another wireless noob question: Would there be any benefit to having two antennas? Like say two of those little nubby ones. One on top of the plane and one on bottom.

yb2normal

The problem with multiple antennas is twofold.

First, you have to figure out how to split the signal to both antennas while at the same time maintaining the proper impedance.

Second, it is hard to predict how the signal from the two antennas will interact with each other. At it's worst, the two antenna will cancel each other out.

Your best bet is to stick with a single antenna. Mount it, fly it, tweak it, repeat. Stop when you achieve perfection

IA-Flyer

"Your best bet is to stick with a single antenna. Mount it, fly it, tweak it, repeat. Stop when you achieve perfection "

What he said.


Cyber-Flyer made a diversity system using 2 video transmitters (on different channels) and a receiver that monitored and switched to the best signal. Sweet setup, but its unlikely well ever see one for sale.

Even if we could find a perfect RC antenna that had a pattern like a ball, the engine or something will get in the way at times, but with a high gain circular or multiple polarity receiver antenna, a good antenna on the plane and lots of video TX power it may work well enough.

Fubar-One

My Feedback: (1)

Guess I need to send another $40 your way!
I need a cheaper hobby!

IA-Flyer

I contacted WiFi-Plus today and they sent me a pattern for the bullet.
The said the technology is different than the QHA antenna.
The person I talked to said there is a chance they could make one for me with a SMA male connector, (fingers crossed!).
The weight is stated at 5oz in their add, and seems heavy for such a small antenna, I hope it's shipping weight. I guess I’ll have to weigh one when I get it, but I asked them to see if they could get the actual weight for me.
Aaron, with your big plane weight shouldn’t be a problem and it would be easy to make a SMA male to N Male adaptor.

Yep, I’m excited about this! Who knows what problems I could find with it but its multi polarity, small and looks like the best pattern I’ve seen yet.
Down side is the weight, and 3dBi isn’t much of a boost over a stock dipole antenna. But the pattern looks great!

Can anyone think of any problems I should ask them about, or should I go ahead and order?

I’ve included a tracing of the Bullet plot (asking for permission to post the original) and a plot from a standard dipole omni antenna. It’s easy to see the difference and where the dead spots are.

aaron2874

Could someone define antenna polarization for me? So much to learn... so little time...

IA-Flyer

Hope I wrote this so it makes some since! I did a google and came up blank.

The radio “wave” is much like a wave in a pond.
A water wave is vertical, so is a normal dipole omni with the antenna facing down and plane is flying level. If you turn the antenna on its side the wave it produces will be horizontal (vertical climb, roll or dive).
For best reception the polarization of the TX and RX antennas should match, if they don’t signal strength will reduce.
A MP (multi polarity) antenna has both vertical and horizontal elements. A circular polarized antenna has an element shaped like a spiral, and comes either in right hand or left hand spirals and the spiral should be matched for best reception. They can also be used with a single polarity antenna on one end, but at about a 3dBi decrease in overall antenna gain (from my understanding).

Most all antennas are designed to produce a pattern to send the signal just to the area needed. The dish shape of a satellite dish creates a very narrow focused beam. A rubber duck omni antenna like on a video transmitter or a portable phone makes a doughnut pattern for good reception all around the antenna. But the key is “all around” for 99.9% of the population sending the signal above and below is wasted energy, so that signal is focused to the sides at the expense of top and bottom coverage.

The only reason an antenna like the bullet exists is because people like to save money. They have more than one floor in their house or business with a computer, and want to use a single wireless access point for the network transmission instead of one on every floor.
That’s why I like 2.4GHz, there is a lot of development done on the computer side and we use the same frequency range.

Corrections welcome!

mithrandir

My Feedback: (2)

Hi guys.. Well.. I got the FCC license so I could go the 1.5 watt, 426.25 ATV route. Here is a link, seems to be sensable info on it, and it is where I got most of my equipment... http://www.hamtv.com . I have not yet got this system up and functional yet, but another HAM told me of this place. Here is a link with some insight on antennas... http://www.hamtv.com/pdf.files/R-C.pdf they are suggesting a dipole antenna for airborne.. I will keep yuh'all posted regarding my success/failure with this system!!

mds

aaron2874

Very interesting. By the time I'm ready to buy a system, all you guys will have me well informed. That's good cuz I don't like to waste my money on junk.

PlaneKrazee

My Feedback: (14)

The bullet antenna looks like it could be a winner with guys on 2.4ghz. To boost the power of equipment it is possible to add amps in series with the receiver, transmitter or both. This way you can use an omni antenna and still have good reception. One unit set up for the GPS band is located here http://www.ien.it/~brida/LNAGPS.htm

If anyone is interested in this type of info let me know. I have been collecting it for some time and have found QHA calculators on the web.

Justin-Ca.

Let me/us know how the WiFi-PLUS MP-BULLET antenna works...It looks like it might well be a winner for us here.