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  #1  
Old 02-15-2009, 02:01 PM
petehowell's Avatar
petehowell petehowell is offline
 
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Default DDRR Antenna

I've had some questions on the DDRR antenna.





Here are the tracks from the Rushford flight today. It seems to do a good job en route and I am impressed with the ground coverage in remote locations. It is more expensive and harder to make than the J-pole, and the performance is nice, but not a great leap.



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Amateur Plane - RV-9A N789PH - 2350+ Hrs
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St. Paul, MN
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  #2  
Old 02-15-2009, 02:40 PM
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Sam Buchanan Sam Buchanan is offline
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Default

Ok...I'll bite.

Where on your plane do you have this critter mounted?

DDRR.......had to look this one up:

http://www.antennex.com/preview/2mddrr.htm

Good work, Pete!
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  #3  
Old 02-15-2009, 03:31 PM
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Default in the wingtip

Sam,

She is in the wingtip! Mounted upside down to ping the ground!

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  #4  
Old 02-15-2009, 03:41 PM
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Sam Buchanan Sam Buchanan is offline
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Quote:
Originally Posted by petehowell View Post
Sam,

She is in the wingtip! Mounted upside down to ping the ground!
I suspected as much.

Hmmm.......wonder if there is room (may not be) for one these puppies inside the cowl firing down at the ground.......the "built-in" ground plane might make it compatible with the Lyco-hunk in there.
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Last edited by Sam Buchanan : 02-15-2009 at 03:45 PM.
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  #5  
Old 02-15-2009, 04:43 PM
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petehowell petehowell is offline
 
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Default Might work!

Quote:
Originally Posted by Sam Buchanan View Post
I suspected as much.

Hmmm.......wonder if there is room (may not be) for one these puppies inside the cowl firing down at the ground.......the "built-in" ground plane might make it compatible with the Lyco-hunk in there.
Sam - Certainly worth a try! I really did not have high hopes for this antenna , but it works pretty well - confirming my lack of understanding of RF - other than it is "goofy"

If you want to make one, let me know and I'll share what I learned.
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Amateur Plane - RV-9A N789PH - 2350+ Hrs
Amateur Radio - KD0CVN
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  #6  
Old 02-15-2009, 06:56 PM
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Sam Buchanan Sam Buchanan is offline
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Quote:
Originally Posted by petehowell View Post
Sam - Certainly worth a try! I really did not have high hopes for this antenna , but it works pretty well - confirming my lack of understanding of RF - other than it is "goofy"

If you want to make one, let me know and I'll share what I learned.
It would be great if you could share with us! I still have a BNC bulkhead connector with a SMA coax pigtail on the firewall of my plane.

So.....knowing what you know now, will the goofy looking one stay in the plane or is the J-pole going back in?
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Last edited by Sam Buchanan : 02-15-2009 at 07:00 PM.
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  #7  
Old 02-15-2009, 08:13 PM
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Default Making the DDRR

Sam,

I pretty much just made this guy's Mark III antenna.

http://www.antennex.com/preview/2mddrr.htm

- PC board material from the local electronic surplus store
- RG58 AU coax
- SMA connector
- 1/2 inch soft copper tubing - Aircraft Aisle at the Despot
- 1/2 inch elbow
- 1/2 inch 3" long nipple

I friction fit a nut in the end of the nipple and soldered it there. Then ran a bolt up thru the bottom of the board to secure it.

I tuned it up using a SWR meter. Move the free end of the ring tube up and down and vary the position of the center coax conductor to achieve best radiation and lowest SWR.

It was a fun little project - I have about .02 aviation money units in it, so even if it failed it would not have been too painful.
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Amateur Radio - KD0CVN
Doggies Delivered - 25+
St. Paul, MN
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