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Old Mar 27, 2011, 03:23 AM
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Netherlands, NH, Edam
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Sander-style (Ez)UHF antennas

I'm getting a growing number of requests for a how-to on building the simple 433MHz monopole antennas I use for our EzUHF receivers. Alternatively they can also be used on other UHF receivers, so the recipe is somewhat generic. I'd like to illustrate how to build these with a short DIY manual, so here we go:

What you need:

- 2x Right angle male SMA crimp connectors for RG58.
http://cgi.ebay.com/SMA-male-plug-ri...item255b9f93b0

- Two pieces of wire about 20 cm in length, OD should fit within the PVC tubing.
- Two pieces of PVC tubing (servo pushrod sheeting) about 3 mm OD, 17.5 cm long.
- Two pieces of shrinkwrap about 2 cm in length.



Fig 1. All the parts needed to make a pair of EzUHF Sander-style antennas.

How to build the antennas:

Construction is pretty straightforward and starts with stripping one end of the two pieces of wire so the bare copper wire is exposed. Tin the exposed wire and slide it into the right angle SMA male connector and solder it to the slot in the center pin. A fine tipped soldering iron and some small diameter (<0.8mm) solder works best.



Fig 2. Soldering the wire to the center pin of the right angle SMA male connector.

Now we need to cut the wire to length, so it is tuned to 433MHz, this is accomplished by cutting the wire to 153 mm length *exactly*, measured from where the right angle SMA male connector ends. This is illustrated below in Fig 3.



Fig 3. This is where the wire exits the right angle SMA male connector, measure from here.

All that is required now is to glue the PVC tubing to the right angle SMA male connector so it provides support for the wire. A drop of CA (cyano acrylate glue) at the end of the PVC tube will do. Slide it into the right angle SMA male connector whilst slowly rotating it to spread out the glue evenly. Any excess glue can be wiped off with your finger (or a tissue). The end result should look like shown in Fig 5.



Fig 4. The PVC tubing glued into the right angle SMA male connector.

Now we need to insert the plastic cap that goes over the center conductor, this is just placed inside, not glued. Then insert the threaded end cap and screw that in tightly. The right angle SMA male connector should now look like pictured in Fig 5.



Fig 5. The right angle SMA male connector fully fitted with the end cap.

All that is left now is to put a piece of shrinkwrap around the base of the antenna, to give the antenna a more professional looking finish. Fig 6. and Fig 7. illustrate the finished antenna.



Fig 6. The finished EzUHF antenna looked at from the side.



Fig 7. The finished EzUHF antenna looked at from the front of the connector.

That's it! It'll probably take you less than 15 minutes to build a pair of these antennas at minimum cost. They perform better than the Active Robots antennas we recommend in the manual and are thinner/lighter as well, hence have less drag than the Active Robots antennas.

Keep in mind that these *NEED* to go directly on the EzUHF receiver connectors, so don't put them out on an extension cable as their performance will suffer.

Good luck with building these antennas!

Cheers,

Sander.
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Old Mar 27, 2011, 03:45 AM
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Good contribution.

I understand you assume 0.9 as velocity factor and the antenna is quarter wave with ground plane in the servo wiring. Right?

So the best position maybe pointing downwards.
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Old Mar 27, 2011, 09:19 AM
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Nice tutorial ssassen! Any idea how this antenna would perform on DL RX?
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Old Mar 27, 2011, 09:55 AM
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Originally Posted by 3frcg View Post
Good contribution.

I understand you assume 0.9 as velocity factor and the antenna is quarter wave with ground plane in the servo wiring. Right?

So the best position maybe pointing downwards.
Pretty much, they work best pointing up in bunny ears configuration on the EzUHF Rx.

Cheers,

Sander.
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Old Mar 27, 2011, 09:56 AM
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Originally Posted by metalfred View Post
Nice tutorial ssassen! Any idea how this antenna would perform on DL RX?
Pretty good I'd guess

Cheers,

Sander.
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Old Aug 02, 2011, 10:44 AM
making big holes in the sky..
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Great tutorial ...thanx a million..

One question:
Is this the same antenna design as this one?
http://www.bevrc.com/the-stock-anten...dbi-p-235.html
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Old Aug 02, 2011, 12:17 PM
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Can this work on a Chain Link RX? The Chain Link RX antenna has two wires, this only has one?
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Old Feb 06, 2012, 01:41 AM
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Originally Posted by pc_pilot View Post
Can this work on a Chain Link RX? The Chain Link RX antenna has two wires, this only has one?
Yes. it works fine.
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Old Mar 25, 2012, 10:47 PM
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Sander.
Can you show a picture of the best way to mount these on the ezuhf? The unit I have coming is the diversity 8 channel receiver with the dual antenna mounts out the top. So do you recommend laying the receiver horizontal, and then hooking up two of these on the ends so the antenna are pointed up like rabbit ears on an old tv? What about one of these, and a turnstile on the other connector? Best to mount right off the recever or with an extension cable out on the wing?
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Old Mar 26, 2012, 10:34 AM
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Sander won't reply unless he use another account.

I remember seeing trappy's wing with both of those antennas mounted and inclined for a "V" like position. Extensions are always bad. Not sure about your other question.
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Old Mar 26, 2012, 10:50 PM
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I attach my Sander-style antennas directly to the EzUHF receiver. The "V" (rabbit-ears) configuration works great. My RX is at the back of the plane, over 2 feet from the Video TX, so extensions aren't a consideration for my setup.

Mark
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Old Apr 09, 2013, 03:10 AM
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Thank you for the guide but for the life of me i can not find this 3mm OD tubing
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Old Apr 09, 2013, 07:20 AM
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Originally Posted by gitit20 View Post
Thank you for the guide but for the life of me i can not find this 3mm OD tubing
just a thought..
how 'bout a BIC pen..a bit messy cleaning out the ink..
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Old Apr 09, 2013, 07:32 AM
USA: LakeGeorge, New York
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You can also set those two monoPole antennas in a 90 degree configuration....
Sanders said it works great in the config....
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Old Apr 09, 2013, 08:41 AM
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Originally Posted by gitit20 View Post
Thank you for the guide but for the life of me i can not find this 3mm OD tubing
Tubing for the antennas? Go to www.towerhobbies.com and search "Dubro Antenna Tube" -- lots of colors to choose from.
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