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Old Dec 10, 2014, 03:50 PM
Wallop!
Martin7182's Avatar
Bussum, Netherlands
Joined Oct 2009
805 Posts
That's why I said "perfectly fine". Sorry for the distracting side note.

You can have 4.5 turns or 7.5 turns or 7.75 turns, whatever suits you. Don't go below 3, but that was never your intention I guess.

Martin
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Old Dec 12, 2014, 05:46 AM
Registered User
Joined Nov 2014
22 Posts
Thanks Martin
I asked because the construction of my new antenna perfect fit to 7,5 turns and I did not want cut it if it is not necessary to have 7 turns


Here some photos: ( I am doctor ant that is why the construction is from hypodermic syringe IT PERFECT FIT TO 5,8gHz

Parameters:
* Design frequency 5800MHz
* 7,5 turns
* Internal diameter 19.5mm
* Wire diameter 2,2mm
* Coil spacing 12,4mm
* Reflector54mm
* Wave Trap size 6.4mmx3.2mm
* Wave Trap spacing from feed point 2mm
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Old Dec 12, 2014, 06:32 AM
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Lithuania, Vilnius County, Vilnius
Joined Dec 2006
57 Posts
Nice antenna! Made with "medical precision"
Expecially nice looking carbon reflector backside!
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Old Dec 12, 2014, 07:45 AM
FlyMike
mmilan's Avatar
United States, MI, Holly
Joined Nov 2011
102 Posts
Very nice! How many cc syringe did you use. Can't see the markings in your pictures.
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Old Dec 12, 2014, 10:58 AM
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Joined Nov 2014
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Quote:
Originally Posted by mmilan View Post
Very nice! How many cc syringe did you use. Can't see the markings in your pictures.
10ml for wraping wire and centre of 20ml for wire holder
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Old Dec 13, 2014, 07:49 AM
Fidler & twidler
empeabee's Avatar
Cranfield U.K.
Joined Mar 2004
4,087 Posts
Quote:
Originally Posted by texmur View Post
Thanks Martin
I asked because the construction of my new antenna perfect fit to 7,5 turns and I did not want cut it if it is not necessary to have 7 turns


Here some photos: ( I am doctor ant that is why the construction is from hypodermic syringe IT PERFECT FIT TO 5,8gHz

Parameters:
* Design frequency 5800MHz
* 7,5 turns
* Internal diameter 19.5mm
* Wire diameter 2,2mm
* Coil spacing 12,4mm
* Reflector54mm
* Wave Trap size 6.4mmx3.2mm
* Wave Trap spacing from feed point 2mm
Nice bit of Lateral Thinking
Must go and hassle my GP for freebee's
Mike
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Old Dec 14, 2014, 12:47 AM
Registered User
Australia, NSW, Newcastle
Joined Nov 2012
25 Posts
just finished my 20 turn helix for 1258,
its made with 6mm sq rods and plywood spacers, the antenna element is just zip tied on,
its about 40 ohm, 1.4 swr, it needs a bit of tuning.
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Old Dec 16, 2014, 08:30 PM
Aussie, Aussie, Aussie!
nrg2go's Avatar
Australia, NT, Katherine
Joined Apr 2009
1,193 Posts
Circularly Polarized Helical antenna 7.5 -13 dbi - New: Wave Trap match!

Quote:
Originally Posted by texmur View Post
10ml for wraping wire and centre of 20ml for wire holder

Nice. I went and got one from my local Doc but the manufacturer must be different. The one I got is tapered at the base
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Last edited by nrg2go; Dec 16, 2014 at 11:44 PM.
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Old Dec 17, 2014, 12:52 AM
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Joined Nov 2014
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Quote:
Originally Posted by nrg2go View Post
Nice. I went and got one from my local Doc but the manufacturer must be different. The one I got is tapered at the base
Attachment 7380606
No this is different. My is mark "chirana" from Czech republic
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Old Dec 17, 2014, 01:48 AM
Aussie, Aussie, Aussie!
nrg2go's Avatar
Australia, NT, Katherine
Joined Apr 2009
1,193 Posts
Quote:
Originally Posted by texmur View Post
No this is different. My is mark "chirana" from Czech republic

I can get about a 5 turn before the taper but I was after more turns for an antenna on a tracker.
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Old Dec 20, 2014, 03:16 AM
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Joined Apr 2008
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Quote:
Originally Posted by texmur View Post
Thanks Martin
I asked because the construction of my new antenna perfect fit to 7,5 turns and I did not want cut it if it is not necessary to have 7 turns


Here some photos: ( I am doctor ant that is why the construction is from hypodermic syringe IT PERFECT FIT TO 5,8gHz

Parameters:
* Design frequency 5800MHz
* 7,5 turns
* Internal diameter 19.5mm
* Wire diameter 2,2mm
* Coil spacing 12,4mm
* Reflector54mm
* Wave Trap size 6.4mmx3.2mm
* Wave Trap spacing from feed point 2mm
Nice and cool work you have done there texmur. Realy medical precision!
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Old Yesterday, 03:57 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,577 Posts
Quote:
Originally Posted by texmur View Post
Thanks Martin
I asked because the construction of my new antenna perfect fit to 7,5 turns and I did not want cut it if it is not necessary to have 7 turns


Here some photos: ( I am doctor ant that is why the construction is from hypodermic syringe IT PERFECT FIT TO 5,8gHz

Parameters:
* Design frequency 5800MHz
* 7,5 turns
* Internal diameter 19.5mm
* Wire diameter 2,2mm
* Coil spacing 12,4mm
* Reflector54mm
* Wave Trap size 6.4mmx3.2mm
* Wave Trap spacing from feed point 2mm
Awesome work! I love your innovation!

For those wanting to make one of these, it is a typical dental syringe and can be bought at most medical supply places. I personally use Monoject for glues and adhesive placement on my personal projects.

This is the cheapest unit I could find: http://www.exmed.net/p-1817-covidien...Z1XBoCZxLw_wcB

-Alex
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