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Old Dec 19, 2009, 07:12 AM
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What's more interesting about that DIY rubber ducky is that you can use a pigtail cable already fitted with a SMA connector. This way you skip a delicate operation, is not an easy thing to solder a high frequency cable on a SMA plug, crimping is much recommended instead.
You can buy such cable from ebay, like item 270496331153
I am planning to use such antenna build to replace the bulky 29 grams rubber stick I get with a 1.3GHz system. The coax cable antenna also will be more flexible, so less strain on the Tx plug at landing. I plan to mount it vertically pointing down, and bend freely at landing, nothing wrong can happen.
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Old Dec 19, 2009, 07:18 AM
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Won't the tuning of the antenna make the soldering not so crucial?
Old Dec 19, 2009, 07:28 AM
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Not sure if a length tunning can compensate for losses in a bad solder
If you overheat the coax cable when soldering, the central wire can migrate from the centered position and even short the external mesh after some flexes.
Also, the flux used for soldering can have unexpected high frequency behaviour.
Old Dec 19, 2009, 07:30 AM
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Ah I see. I will try and see. If the rssi beats the stock antenna on the frequency I like using I'll call it a victory!
Old Dec 20, 2009, 09:26 PM
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RC cam's Dipole is an awesome build. Radio shack already has SMA connector fitted RG-316 cable (but it's incredibly expensive). I'll check around for some other companies that make these adapters and figure out the best way to hack them.
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Old Dec 21, 2009, 08:35 PM
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RSSI Mod


i installed a mini phono jack for easy access to the rssi output.
Old Dec 27, 2009, 07:13 PM
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Will This Work?


Will the coupler interfere with Mr RC Cam's dipole design? Just wanted to ask before I went cutting apart my $30 purchase from "The Shack".
Last edited by pedantik; Apr 12, 2010 at 12:39 PM.
Old Dec 27, 2009, 07:41 PM
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Quote:
Originally Posted by pedantik View Post
Will the coupler interfere with Mr RC Cam's dipole design? Just wanted to ask before I went cutting apart my $30 purchase from "The Shack".
How about 2 antennas worth for $3.29?

http://cgi.ebay.com/Vista-RF-4-RG-31...item439a140817
Old Dec 27, 2009, 07:54 PM
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Too Short?


Wouldn't that be too short for a 900mhz application?
Old Dec 27, 2009, 08:33 PM
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Quarter wavelength is about 3.26 inches so you can get at least one out of it. It's 12in according to the description and picture. Maybe email the seller and confirm (also make sure it isn't an rp sma).
Old Dec 27, 2009, 08:40 PM
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Pedantik, that will work fine. I'll post another way to build the antennas with those components using a circuit bard. it makes a slightly better antenna if you can separate the feed points by 1/8-1/4". I would make the antenna and then just feed it from your coaxial line. You'll have to strip it. RG 316 can be a bit tricky to strip so take your time.
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Old Dec 27, 2009, 09:04 PM
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Quote:
Originally Posted by IBCrazy View Post
Pedantik, that will work fine. I'll post another way to build the antennas with those components using a circuit bard. it makes a slightly better antenna if you can separate the feed points by 1/8-1/4". I would make the antenna and then just feed it from your coaxial line. You'll have to strip it. RG 316 can be a bit tricky to strip so take your time.
What do you think of RG-174?
http://cgi.ebay.com/Vista-RF-12-RG-1...item439a133709
Old Dec 28, 2009, 03:08 PM
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Looking forward to it IBCrazy. The antenna is my last stop in eliminating all excess weight from my airframe. I hope that when it's ready to fly, I'll have reduced the weight by half! Fingers Crossed.
Old Dec 28, 2009, 09:08 PM
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Ok, I have been getting a lot of questions lately on this: The two members of the antenna are not connected in anyway. They are two separate parts. The driven unit (center pin) generates the signal and the grounded unit (outer shield) is a reflection of that signal. The grounded unit is a mirror image of the driven unit.

Hopefully that explains it.

-Alex
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Old Dec 28, 2009, 09:10 PM
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Quote:
Originally Posted by arkcom View Post
I made my Inverted Vee antenna feeding it with RG-174. Check the posts on the first page on how to do it. RG 174 is fairly easy to strip
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