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Description
Sharing information on Topband Homebrew Antennas, Base, Mobile & Receive.
I wanted a Topband antenna that would fit in less than 65' of my garden. I came across a design that a few people in my local area of East Yorkshire had tried previously.
The Topband Homebrew Helical in the picture is the second one I have tried. To build this antenna you need a former, a hot glue gun & a quarter wavelength of wire for the frequency you want to operate on. I use the formula 234 divided by the frequency in mhz. So for the DX window 234 divided by 1.830 = about 128'. Allow 2 feet of wire extra for adjustment.
I found 1.5mm pvc covered wire ideal. My second antenna is the one in the picture. This is on a 2" thick walled former, that is less than four feet long. It only required 100 turns to space wind the 65' of wire.
This antenna is designed to be fed with coax. The center of the coax is joined to the wire at the base of the coil, either by a choc block, direct solder, or pl259/so239. Check the PHOTOS out for ideas on feeding the Helical. Also read some of the messages I have posted with other information. The coax braid needs to be returned to a groundspike & will benefit from a counterpoise(s) attached to the groundspike. The better your earth, the better this antenna will work.
I use an elaborate earth system with four 4' groundspikes, a 3' copper tank, buried 4' in the ground & two 125' counterpoise wires, attached to my groundspikes.
Good luck if you intend homebrewing a Topband Helical. This is a compromise antenna, but I have worked USA & Canada with one.
Regards,
Phil. M0VEY
Latest Antenna:
This is a Homebrew mobile antenna. Nearly 10 foot tall on 1.972. Check the photos for pics & more info on this antenna I have had much success with. LATEST NEWS, FILE UPLOADED, HOW I MADE THE 160m MOBILE ANTENNA.
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Posted - Wed Jul 1, 2009 10:29 pm
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Phil
m0vey
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Re: ON4UN book online
... Hi Will, thanks for the info. Johns book ( ON4UN ) is certainly worth a read. It is essential reading if you are a "Low Band DXer" . I've had a copy for
Posted - Wed Jul 1, 2009 10:03 pm
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Phil
m0vey
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Inverted L antenna
Hi folks, I have had a go with the helical - I'm not sure if it's my particular qth, or how I had it mounted (in the trees), I had trouble trying to get it to
Posted - Tue Jun 30, 2009 9:07 pm
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manxmat
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ON4UN book online
This is the web link for the ON4UN lowband DX book. All chapters are there for browsing.
Posted - Tue Jun 30, 2009 8:40 pm
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william_northcote1970
william_nort...
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Re: Helically Wound Mobile Add On.
... HI from Ken, G4KIR, I was monitoring 1933 last evening when Simon made his call into the group, and here in LOFTUS (Nr Saltburn-by-the Sea)his signal
Posted - Mon Jun 29, 2009 5:25 am
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Ken Chattenton
k.chattenton...
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