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Old Mar 05, 2012, 01:32 PM
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Nice tip costi_n, thanks for sharing!

Martin
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Old Mar 05, 2012, 01:35 PM
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Quote:
Originally Posted by costi_n View Post
Hello guys. I wanna show you a simple method to tune your helix if you already have a SWR-meter or a professional VNA. For me that method works. I tuned the helix for a 1:1.2 SWR which is very good for a DIY antenna .
After building the antenna from mictronics thread on FPVlab

http://fpvlab.com/forums/showthread....Y-5.8GHz-Helix

I found that is very difficult to move the wave trap to the first turn to find the best match. I tried for several times, I found the best place for wave trap, but after secured the solder, the match was gone so...I cut a little piece of FR4 board, about 3X4mm, put down on the reflector under first turn and move slowly forward and backward to find the best match. Pay attention not to touch the turn with FR4 board piece. If you are still not able to find the best match try to move the feed point higher or lower. For me that method worked.
That's a really good idea! I never thought of moving the base plate. I always moved the first 1/4 turn. I need your name because this matching technique deserves your name on it.

-Alex
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Old Mar 05, 2012, 01:57 PM
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Originally Posted by IBCrazy View Post
That's a really good idea! I never thought of moving the base plate. I always moved the first 1/4 turn. I need your name because this matching technique deserves your name on it.

-Alex
Tnx Alex. My name is Costin

It would be really nice if someone with an professional VNA will try this tuning method and post some screen of analyzer.
I don't have a VNA, it costs more than my car with my wife inside.
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Old Mar 05, 2012, 03:05 PM
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Markus123456 has a spectrum analyzer and I sure when he has time he will try it out.

I am really interested in the board. I have a few modules myself and i would love to put them on my smaller planes. 15grams plus a light weight camera and all up I would add very little weight. I hope for under 30 grams with an e-osd. I would put a rp-sma because I have so much damn rp cable Sounds like a great dyi project and if you need someone to test your board (I'll use my modules etc) just let me know.

thanks for the tip on tuning too. I am going to try that with a few helicals I have!
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Old Mar 05, 2012, 06:54 PM
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Where are you guys buying the 200mW module?
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Old Mar 06, 2012, 01:15 AM
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They are all the same, the source is not important, fortunatelly the unique mfr of these modules make the final user job easier.
But beware to not get Airwave modules instead, those are indeed other story.
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Old Mar 06, 2012, 02:15 AM
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@ papa_lazerous

http://www.foxtechfpv.com/fpv-equipm...t-c-70_76.html

Don't bother with the 500mW version though


Nigel.
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Old Mar 06, 2012, 03:26 AM
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Quote:
Originally Posted by RENATOA View Post
They are all the same, the source is not important, fortunatelly the unique mfr of these modules make the final user job easier.
But beware to not get Airwave modules instead, those are indeed other story.
They are not all the same.

Two main things to consider. a) Band strapping. Most modules sold are strapped to band "e", but i.e. RangeVideo sells modules (and matching RC305 receivers) strapped to band "a". The modules can be opened. I posted a way to modify them some months ago.

b) voltage regulation. There are variants of this module around with an aditional internal 3.3v linear regulator. Most modules don't have that.

The one refered to is band "e" without voltage regulator. That's the most frequently seen incarnation of this module.

Markus
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Old Mar 06, 2012, 03:35 AM
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You know very well what I meant
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Old Mar 06, 2012, 03:50 AM
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All the modules are identical, the band is a PLL selection feature, not a hardware change. The fpvhobby version internal LDO also could be external as well, not worth the 100% price increase anyway
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Old Mar 06, 2012, 04:59 AM
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On a related subject , has anyone tried writing SPI PLL rather than using set frequencies?
To use the rx module with higher power airwave tx modules?
I have the data sheets for both tx and rx, but have never changed frequencies with these modules. It doesn't look too bad for someone who could code pic/avr/arduino even. They are very kind and even give you default settings for 5.8ghz...! any takers...
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Old Mar 06, 2012, 05:00 AM
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I also disagree that all the modules are the same. OK, very broadly they are the same, but there are differences and that small difference is a huge one !!

The PLL is changed by a hardware link (0402 SMD pull down resistor) and the module does need opening up to make the band change.

I did add some description in this thread and also made a 'how to' in the FPVUK forum, here
http://www.fpvuk.org/forum/index.php?topic=4163.0

Nigel.
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Last edited by Devonboy; Mar 06, 2012 at 05:13 AM. Reason: typo
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Old Mar 06, 2012, 05:24 AM
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Quote:
Originally Posted by costi_n View Post
All the modules are identical, the band is a PLL selection feature, not a hardware change. The fpvhobby version internal LDO also could be external as well, not worth the 100% price increase anyway
Errr, the band is selected using internall straping resistors as you know, the internal LDO is also a component that is stuffed or not inside the modules housing. I do consider this to be different, at least for the average RC-Groups user. Depending on where you buy them, the price does not matter. I formyself also use the standard Band E modules, but stating here they are all the same could lead some beginner to try to combine i.e. a Band A module from RangeVideo with a standard Band E Rc305 leading to a tuff time for said beginner IMHO. It's all about not posting inadequate information. Not every reader here is electronics savey.

Markus
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Old Mar 06, 2012, 06:03 AM
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Quote:
Originally Posted by markus123456 View Post
Errr, the band is selected using internall straping resistors as you know, the internal LDO is also a component that is stuffed or not inside the modules housing. I do consider this to be different, at least for the average RC-Groups user. Depending on where you buy them, the price does not matter. I formyself also use the standard Band E modules, but stating here they are all the same could lead some beginner to try to combine i.e. a Band A module from RangeVideo with a standard Band E Rc305 leading to a tuff time for said beginner IMHO. It's all about not posting inadequate information. Not every reader here is electronics savey.

Markus
Yes, from this perspective you're right. I stated they are identical from another point of view.

cheers
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Old Mar 06, 2012, 06:29 AM
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Quote:
Originally Posted by RENATOA View Post
They are all the same, the source is not important, fortunatelly the unique mfr of these modules make the final user job easier.
But beware to not get Airwave modules instead, those are indeed other story.
What you mean with the airwaves modules? Not good?
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