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Old Nov 16, 2011, 05:15 PM
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Originally Posted by idletime View Post
I'll take you up on your offer (PM you later)....but a quick question...how does the tuning affect the individual frequency...for example with this 5.8 Rx,

( CH1:5705 - CH2:5685 - CH3:5665 - CH4:5645 CH5:5885 - CH6:5905 - CH7:5925 - CH8:5945)

are you tuning for one particular channel?? And if so how much is the effect if you have to switch to another channel.

I'm just curious as to how it all works / relates.....thx
Yes, I build for the particular frequency one asks for. If you are on spot with the frequency, range and picture quality will be superior. This gets less efficient the farther away you go from this frequency. The other thing people sometimes forget is the fact that its good to have BOTH antennas on the same frequency. I mean if your tx antenna is 100Mhz below where it should be, but your rx is 100Mhz above (because you can't measure it), they are 200Mhz apart. Especially on the 5.8Ghz band, and more importantly if you use with the sky-rf based tx/rx (foxtech etc.) it's IMHO important not to shoot for the center frequency of 5.8Ghz as with the default band E of those products there is simply no channel near this center. With band E you have four channels going down from 5705Mhz and four going up from 5885Mhz. So the closest you could get to a center tuned antenna would be this channel 5 still being 85Mhz away from where it should be. Again, being off is not the end of the world as those antennas are somewhat wideband, but being on spot is the best you can get.

As I saw your post, I just finished tuning a 5.705G (foxtech channel 1) cloverleaf antenna. Attached you see two sweeps of this very antenna, one with the marker set to the wanted frequency of 5.705G, the other with the marker set to the center frequency of 5.8G. If you would have your antenna tuned to the center but operate it on channel 1, you would thus have about -23dB return loss (which equals an SWR of 1:1.4). Thats truly not bad, but on spot you have a return loss of -50dB which equals an almost ideal SWR of 1:1. So, why not makeing it as good as possible if you can? This IMHO especially holds true for the transmitter antenna as any return loss means this, a loss in transmitted energy.

Markus
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Old Nov 16, 2011, 05:17 PM
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United States, FL, Maitland
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Quote:
Originally Posted by idletime View Post
I'll take you up on your offer (PM you later)....but a quick question...how does the tuning affect the individual frequency...for example with this 5.8 Rx,

( CH1:5705 - CH2:5685 - CH3:5665 - CH4:5645 CH5:5885 - CH6:5905 - CH7:5925 - CH8:5945)

are you tuning for one particular channel?? And if so how much is the effect if you have to switch to another channel.

I'm just curious as to how it all works / relates.....thx
You could tell him what channel you use and then he will tune to that frequency... or you could have him tune it to the middle channel. Or tune it to the average of the difference in frequency. It's your call.

I'm making the 115 antenna now and I'll post back if it works.
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Old Nov 16, 2011, 06:17 PM
Flying low is expensive.
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United States, CO, Boulder
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Originally Posted by chatch15117 View Post

I'm making the 115 antenna now and I'll post back if it works.
Well it will work. But that's not the question. The question is how well it will work. And you really can't tell that accurately without test equipment.
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Old Nov 16, 2011, 06:57 PM
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Well it will work. But that's not the question. The question is how well it will work. And you really can't tell that accurately without test equipment.
I wish someone in my area had test equipment. I'll ask around. I used a combination of sulfuric and hydrochloric acid to remove the insulation. Clean, bare copper ready for soldering!

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Old Nov 16, 2011, 07:27 PM
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I really hope it works well lol... following everything so I can have within 1% tolerance.

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Old Nov 17, 2011, 02:32 AM
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Originally Posted by chatch15117 View Post
I really hope it works well lol... following everything so I can have within 1% tolerance.
No worries, the way you aproach it and on this frequency you will be pleased with the result. Just be carefull with soldering the coax cable so as you don't create a short. Keep the connection to the antenna "tight" in that you don't have a big distance from the ground mesh and the center where they connect to the propper antenna elements.

Markus
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Old Nov 17, 2011, 03:17 AM
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I finished them. I'll post a video tomorrow of my flight. More like in 4 hours haha, it's 4am here
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Old Nov 17, 2011, 03:48 AM
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Originally Posted by chatch15117 View Post
I finished them. I'll post a video tomorrow of my flight. More like in 4 hours haha, it's 4am here
Show us a picture of the finished antenna.

Good luck with the test fligth, and good night. Over here it's 10:48 am, so no nighty night

Markus
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Old Nov 17, 2011, 05:20 PM
Gravity - It's the law
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USA, CO, Denver
Joined Jul 2008
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Hi all,

I have one of Alex's Video Aerial Systems CPCL on my GS and I built one for my plane.

I mounted the antenna on the bottom of the plane and I'm very pleased with the results BUT....

This is about the cleanest video I have ever gotten so I'm really happy and if I can duplicate the lack of breaking and tearing of the video tomorrow I will try going under the hood.

But can Alex or one of you tell me, is the interference at 2:35 multipathing or from external RF or what. I can live with the amount of interference in this video but is this about the best I can expect using my current setup? Or should I try something else before I trust this setup completely?

Thanks for any help,

Yabba

multipathing, or ? (4 min 41 sec)
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Old Nov 17, 2011, 06:02 PM
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Amherst, VA
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Yes that's multipathing. Pretty minimal really. Perfectly flyable. It looks to me like ground reflections. I think you are good to fly. Seriously, that's a solid video link.

-Alex
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Old Nov 17, 2011, 06:07 PM
Gravity - It's the law
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Originally Posted by IBCrazy View Post
Yes that's multipathing. Pretty minimal really. Perfectly flyable. It looks to me like ground reflections. I think you are good to fly. Seriously, that's a solid video link.

-Alex
That's the way I felt but it's good to hear it from someone like you.

I appreciate all you have done for me and for the Community.

Yabba
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Old Nov 17, 2011, 08:33 PM
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Here's the Rx antenna. I need to make a stand for it. Video coming shortly(30% uploaded)
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Old Nov 17, 2011, 09:20 PM
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http://www.youtube.com/watch?v=t3NFRokr8I8
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Old Nov 17, 2011, 10:19 PM
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Yabba, I would be more worried about that serious camera wobble. That would drive me crazy.
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Old Nov 17, 2011, 10:25 PM
Team White Llama!
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Originally Posted by chatch15117 View Post
I really hope it works well lol... following everything so I can have within 1% tolerance.

interesting templates. where did you get them? you make them? want to add them to OP? should help in constructiong this antennas.
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