HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 19, 2009, 06:12 AM
Registered User
Romania, Dolj, Craiova
Joined Sep 2007
14,660 Posts
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.
renatoa is online now Find More Posts by renatoa
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 19, 2009, 06:18 AM
Questionable judgement
bracky72's Avatar
Charles Town, WV
Joined Jan 2008
3,072 Posts
Won't the tuning of the antenna make the soldering not so crucial?
bracky72 is offline Find More Posts by bracky72
Reply With Quote
Old Dec 19, 2009, 06:28 AM
Registered User
Romania, Dolj, Craiova
Joined Sep 2007
14,660 Posts
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.
renatoa is online now Find More Posts by renatoa
Reply With Quote
Old Dec 19, 2009, 06:30 AM
Questionable judgement
bracky72's Avatar
Charles Town, WV
Joined Jan 2008
3,072 Posts
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!
bracky72 is offline Find More Posts by bracky72
Reply With Quote
Old Dec 20, 2009, 08:26 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,406 Posts
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.
IBCrazy is offline Find More Posts by IBCrazy
RCG Plus Member
Old Dec 21, 2009, 07:35 PM
five by five
sonicj's Avatar
Panama City Bch, FL
Joined Jan 2009
2,074 Posts
RSSI Mod

i installed a mini phono jack for easy access to the rssi output.
sonicj is offline Find More Posts by sonicj
Reply With Quote
Old Dec 27, 2009, 06:13 PM
Registered User
pedantik's Avatar
Asheville, NC
Joined Jul 2009
51 Posts
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".
pedantik is offline Find More Posts by pedantik
Last edited by pedantik; Apr 12, 2010 at 11:39 AM.
Reply With Quote
Old Dec 27, 2009, 06:41 PM
Registered User
Northwest Arkansas
Joined Sep 2008
617 Posts
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
arkcom is offline Find More Posts by arkcom
Reply With Quote
Old Dec 27, 2009, 06:54 PM
Registered User
pedantik's Avatar
Asheville, NC
Joined Jul 2009
51 Posts
Too Short?

Wouldn't that be too short for a 900mhz application?
pedantik is offline Find More Posts by pedantik
Reply With Quote
Old Dec 27, 2009, 07:33 PM
Registered User
Northwest Arkansas
Joined Sep 2008
617 Posts
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).
arkcom is offline Find More Posts by arkcom
Reply With Quote
Old Dec 27, 2009, 07:40 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,406 Posts
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.
IBCrazy is offline Find More Posts by IBCrazy
RCG Plus Member
Old Dec 27, 2009, 08:04 PM
Registered User
Northwest Arkansas
Joined Sep 2008
617 Posts
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
arkcom is offline Find More Posts by arkcom
Reply With Quote
Old Dec 28, 2009, 02:08 PM
Registered User
pedantik's Avatar
Asheville, NC
Joined Jul 2009
51 Posts
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.
pedantik is offline Find More Posts by pedantik
Reply With Quote
Old Dec 28, 2009, 08:08 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,406 Posts
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
IBCrazy is offline Find More Posts by IBCrazy
RCG Plus Member
Old Dec 28, 2009, 08:10 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,406 Posts
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
IBCrazy is offline Find More Posts by IBCrazy
RCG Plus Member
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion trex 600e build your own fuse. catbalu Large Electric Helis 10 Oct 27, 2009 12:10 AM
Sold Build your own brushless motor sale pending Douglas Cheatwo Aircraft - Electric - Power Systems (FS/W) 1 Oct 07, 2009 11:26 AM
New Product Build your own two channel servo tester for less than $15! W9GFO Product Announcements 0 Sep 29, 2009 07:19 PM
Question Build Your Own Parkzone Mustang Question Blue Jacket Electric Warbirds 8 Sep 13, 2009 08:49 PM