[50mhz] FW: AA6DD Colinear antenna

[Danny Pease]

A double extended Zepp is a pair of 5/8 radiators that are considered
collinear, on 6 meters it is roughly 25 feet long. A Cushcraft Ringo Ranger
ARX-2 for 2 meters is an example of an end fed DEZ.

NG9R


-----Original Message-----
From: 50mhz-bounces at mailman.qth.net [mailto:50mhz-bounces at mailman.qth.net]
On Behalf Of Chris Boone
Sent: Wednesday, October 19, 2011 6:38 PM
To: 50mhz at mailman.qth.net
Subject: Re: [50mhz] FW: AA6DD Colinear antenna

The design is flawed...the bottom section is NOT a 5/8wave radiator...the
"radials" cannot be counted as PART of the radiator...they are NOT hooked to
the center conductor...they are GROUND....ONLY the electrical length of the
radiating element can be counted..the bottom needs to be as long as the top
element and then a matching network installed to match the antenna to
50ohms....

Otherwise, this design will have the take off angle of radiation looking
upward into the sky, not at the horizon where it should be.
The Hustler G6 is a 5/8 over a 5/8...you'll find the bottom element is the
same length as the top one.

Basic antenna design/RF theory 101 (which I took in college in my EE
studies)

Chris
WB5ITT
Former Capt CAP
Broadcast and Telecom engineer for 35+ years.

> -----Original Message-----
> 
>         The attached .pdf file came from the SoCal Six Meter Club webpage
> but is no longer available online, perhaps I should put it in the files
> section. My version used the 5BVT mount and lower tubing with the top
> section being new 6061 from DX Engineering. Max Gain Systems is another
> source. For the center insulator/coil form I used 1" diameter fiberglass
rod
> from McMaster Carr and the coil wire was reused from the 5BVT coils.
>         Construction and tuning were pretty straight forward with final
> adjustments done at work on our antenna range. My original plan for the
> antenna was to access SoCal repeaters but the antenna with its relatively
> large diameter loads all of six meters at low VSWR. I did not test the
gain
> because the range was needed for real, not hobby, work. Mounted above
> my
> garage/shack/wallow it received 6.5-7 db better than my copper pipe
J-pole.
> That isn't scientific really but will have to do for now.
>      Aluminum based anti-seize conductive grease was used in all slip
> joints, ScotchKote, 3M 2155, and Scotch 33 protect the connections. The
> anti-seize and sealers came from DX Engineering but Home Depot sell
similar
> or the same products. Someplace...I have a file of pictures taken during
> testing but can take others if you like. The antenna is down right now for
a
> move-reconfiguration of the garage roof farm.  Length is right around 23ft
> tall with radials and base then add whatever you use for a mount. I'm very
> happy with the antenna! AA6DD is the Ham involved in developing the
> Quaggi.
>      
> Edward Zeranski KG6UTS

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