My Homebrew Bicone Antenna Project

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n4yek

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I found this project on the web and thought I would give it a try.
Here is the link to the project: http://www.geocities.com/n2uhc/bicone.html
Materials needed:
1) 8 wire clothes hangers
2) 4 feet of Sch40 non-metallic rigid conduit
 

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n4yek

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Cutting, measuring, and hammering element straight, then bending them to desired angles.
 

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n4yek

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Marking and drilling holes for the elements.
 

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n4yek

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Final assembly:
1) Insert elements into the holes, the small bend end.
2) Clamp the other end to mast and position elements.
3) Solder wire around and attach to each element, leaving some left over for attaching SO-239 or direct connection to coax.

Note: in the last pic, the wires sticking out are my feed point wires. I took the photo prior to hooking a coax to it.
I also intended to remove the clamps after I finished, but the elements started to slide down the support due to gravity so I put them back on to tighten it down to the conduit.
 

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n4yek

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I have the elements cut to VHF but it receives well on UHF being that it is wideband. It even picks up an 800 MHz trunk from 40 miles away.

The project would be much easier to build using brazing rods, I just used what I had available and no cost except the time to build which was about 3 hours from start to finish.
 

commscanaus

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Very nice job!

It looks like one of those expensive Weather Satellite antenna's.
I have always found coat hanger steel a real pain to solder so you are right with the brazing rod solution. But coat hangers are free as long as you don't mind your clothes on the floor!

Thanks for sharing those pictures and hope you get some great results with it.

Regards, Commscanaus.
 

rbo

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Homemaid bicone

I maid this bicone antenna with car antennas from a local scrap yard and I don't understand why it does'nt work very good, compared to a discone antenna (factory maid) it yield only poor results.
The elements are 29 inches long.
 

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prcguy

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Nice work on that Bicone and your problem may be these antennas are not 50 ohm, they are usually in the 150-300 ohm range and the element angles have influence on the impedance. It probably has a good match somewhere over a narrow range in the lower VHF band (in the fat dipole mode) by looking at its size.

I've been playing with Bicones for the last few weeks and just put up a modified military OE-354 and a Harris RF-9070 shown in the pictures below.

The OE-254 is originally a 30 to 90MHz antenna and I extended the six 8' 6" elements to 10' and now it covers down to about 25Mhz or so. This thing kicks butt on 10m and 6m!

The Harris RF-9070 covers about 90 to 470MHz with a little gain and each element is 48" long and the whole antenna stands about 6ft tall.

Each of these antennas has a matching network in the hub and the OE-254 has a modified 4:1 balun with a capacitor on the input to lower the impedance range. The Harris matching network is in inside the hub and I haven't looked at that one yet.

I also have a Nevada Double Discone which is a Bicone without any matching network and its about half the size of the Harris even though they claim (or lie) that it covers 25-1300MHz. It doesn't work as well as a RS Discone and the match is terrible except in the 2m ham band.
prcguy

Note:
The first antenna to the right of the big Bicone is the top of a 6dB ish gain 225-400MHz antenna, the next one to the right is a dual band 118-136 and 225-400MHz, the next to the right is a KRECO 100-800MHz Discone the the other Discone is an Astron rated 100-400MHz but it goes much higher.


I maid this bicone antenna with car antennas from a local scrap yard and I don't understand why it does'nt work very good, compared to a discone antenna (factory maid) it yield only poor results.
The elements are 29 inches long.
 

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rbo

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Thanks for the hints Prcguy!
I just build mine out of the blue your post shed light on my understanding...
 

appalachianscanner

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Heres another in the wild, this time for Presidential / UN Protection Purposes, you might be on to something.. :cool:...

pict37.jpg



pict35.jpg
 

ridgescan

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Nice home build:) I was curious-I have the lower element set from an old discone antenna..would it work if I took it and stuck it upside down onto the D130J? (removing the whip element of course)
 
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