Author Topic: New UK 1090MHz co-linear antenna  (Read 4124 times)

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Keith D

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New UK 1090MHz co-linear antenna
« on: March 15, 2013, 10:51:33 AM »


Hi All

Many will have read about the excellent DPD co-linear antenna from the states

it seems Chris Taylor has now got a like antenna for sale on his web site
which can be bought easily within the UK and much cheaper

no mention of how many elements but I guess Chris will tell you if you phone him

http://www.taylormaderf.com/page28/rapidcart-3/store.php

cheers

K/

Anmer

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Re: New UK 1090MHz co-linear antenna
« Reply #1 on: March 15, 2013, 11:03:04 AM »
no mention of how many elements but I guess Chris will tell you if you phone him

And my recent testing (and review) suggests it's a good antenna for the price.

Keith D

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Re: New UK 1090MHz co-linear antenna
« Reply #2 on: March 15, 2013, 06:09:20 PM »
no mention of how many elements but I guess Chris will tell you if you phone him

And my recent testing (and review) suggests it's a good antenna for the price.

ok well maybe you can tell us how many elements this antenna has


K/

Chris-G0WTZ

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Re: New UK 1090MHz co-linear antenna
« Reply #3 on: March 15, 2013, 08:01:58 PM »
Keith can you explain what you mean by elements?

Keith D

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Re: New UK 1090MHz co-linear antenna
« Reply #4 on: March 15, 2013, 09:27:19 PM »
Keith can you explain what you mean by elements?

Sure can

these below hope this huge URL works

http://www.google.co.uk/imgres?imgurl=http://www.sm0vpo.com/antennas/7db-colinear_7-layout.gif&imgrefurl=http://www.sm0vpo.com/antennas/7db-colinear.htm&h=371&w=287&sz=4&tbnid=0kZVGAeZqYkoTM:&tbnh=90&tbnw=70&prev=/search%3Fq%3Dcollinear%2Bantennas%26tbm%3Disch%26tbo%3Du&zoom=1&q=collinear+antennas&usg=__dP2rD7GwYQpZC5iuYun8llxAj0A=&docid=2tRzIkLpYQOLHM&hl=en&sa=X&ei=y5FDUbjSBsGa0AW4hoCwCw&sqi=2&ved=0CFEQ9QEwBw&dur=121

save you reaching for the calculator

1/2 wave for each element at 1090 MHz is 132.100mm according to Microsoft

so full wave is 264.200mm >>I assume

My DPD has 9 of them but as you know it was one of the first imported here in UK some years ago now
they may have made modifications since then

people can build there own if they so wish
"how to do it " pages here including photo based instructions

http://www.nodomainname.co.uk/Omnicolinear/2-4collinear.htm

p.s someone made one for AIS I think a 7 element[ could have been more] and hung it from the edge of the roof of a 2 story house
it just fitted before it hit the ground but apparently it worked very well. he had it inside sections of 4 inch drain pipe !!!

K/
« Last Edit: March 15, 2013, 09:49:26 PM by Keith D »

Chris-G0WTZ

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Re: New UK 1090MHz co-linear antenna
« Reply #5 on: March 15, 2013, 10:09:05 PM »
OK Kieth the diagram you show is a centre fed where as the DPD and the TMRF 1090 are end fed.
I think you will find the one I sell is multiple 5/8 wave over quarter wave stacked (6 stacked and phased so) which helps to give good range and good close in performance.
Normally elements are what we refer to on a beam antenna I just wanted to be sure you did not think my antenna was a beam..
The bottom line is it works well. I looked at many antennas before I chose the one Mike reviewed and I think it is fair to say it works well.
As to a 7 element for AIS I bet a 5/8 th wave Ground pland antenna on the roof would work as well or better. You have to understand that as you increase gain you reduce beamwidth so a 7 element colinear would see in a straight line from its highest point missing boats at ground level

Regards



Keith D

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Re: New UK 1090MHz co-linear antenna
« Reply #6 on: March 15, 2013, 10:17:22 PM »
Well end fed or centre fed they are still called elements regardless in a true co-linear antenna
as in the pictures of the how to make yourself URL
see attached jpeg from those pages that's end fed

I knew it wasn't a beam as its a straight pole

K/
« Last Edit: March 15, 2013, 10:19:08 PM by Keith D »

E:V:A

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Re: New UK 1090MHz co-linear antenna
« Reply #7 on: March 15, 2013, 11:43:17 PM »
...1/2 wave for each element at 1090 MHz is 132.100mm according to Microsoft...
Not sure what you mean with this. This is certainly not correct.
L/2 @ 1090 = 137.5

Keith D

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Re: New UK 1090MHz co-linear antenna
« Reply #8 on: March 16, 2013, 05:22:10 AM »
...1/2 wave for each element at 1090 MHz is 132.100mm according to Microsoft...
Not sure what you mean with this. This is certainly not correct.
L/2 @ 1090 = 137.5


see attached .BMP

K/
« Last Edit: March 16, 2013, 08:03:58 AM by Keith D »

MANOFKENT

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Re: New UK 1090MHz co-linear antenna
« Reply #9 on: March 16, 2013, 07:37:29 AM »
7db-colinear_7-layout.bmp equates to a black hole...or square if space permits lol.

Keith D

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Re: New UK 1090MHz co-linear antenna
« Reply #10 on: March 16, 2013, 07:58:48 AM »
7db-colinear_7-layout.bmp equates to a black hole...or square if space permits lol.

yes roger

weird it saves as a visible image to my desktop but appears as a black square when posted

will try again

what I wanted to show is that the given equation is

144000  divided by 1090MHz = half wave

as can be seen here :-

http://www.google.co.uk/imgres?imgurl=http://www.sm0vpo.com/antennas/7db-colinear_7-layout.gif&imgrefurl=http://www.sm0vpo.com/antennas/7db-colinear.htm&h=371&w=287&sz=4&tbnid=0kZVGAeZqYkoTM:&tbnh=90&tbnw=70&prev=/search%3Fq%3Dcollinear%2Bantennas%26tbm%3Disch%26tbo%3Du&zoom=1&q=collinear+antennas&usg=__dP2rD7GwYQpZC5iuYun8llxAj0A=&docid=2tRzIkLpYQOLHM&hl=en&sa=X&ei=y5FDUbjSBsGa0AW4hoCwCw&sqi=2&ved=0CFEQ9QEwBw&dur=121

144000  divided by 1090 =   132.110

according to the windows Calculator that is


cheers

K/
« Last Edit: March 16, 2013, 08:03:35 AM by Keith D »

Chris-G0WTZ

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Re: New UK 1090MHz co-linear antenna
« Reply #11 on: March 16, 2013, 09:26:25 AM »
This is the calculator I use http://easycalculation.com/physics/electromagnetism/antenna-wavelength.php
However when designing an antenna the velocity factor of the material being used and the diameter of the radiator will affect length
A material will need to be tested to determine actual length.
If I get a commercial sample my test bed is a 25 foot pole in my back garden and I chose the TMRF 1090 as it gives good performance at a good price. It is also good against the elements(Weather elements that is) :-).



E:V:A

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Re: New UK 1090MHz co-linear antenna
« Reply #12 on: March 16, 2013, 03:06:59 PM »
Where's that 144000 come from??

Do not use online calculators! They rarely tell you how the calculation is done, and how they treat significant figures etc. (The one above shows 17 significant digits, but is already wrong after the 4th!)

Lambda = k * c/f = k * 299,792,458/1090,000,000 = k * 0.27504 meters

where  k = velocity factor.

So if you don't know how to do this most basic calculation, I really don't think its a good idea trying to design anything using other peoples "values". But hey, physics was discovered through experiments. So whatever works and make you happy, is fine with me.


 


E:V:A

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Re: New UK 1090MHz co-linear antenna
« Reply #14 on: March 16, 2013, 07:17:32 PM »
...
well for the third time of posting in the same thread  2 of them today
.

Well, there's little point of posting the same link for the 3rd time isn't it? Why don't you just try to explain what the heck he's trying to say with the non-sense 144000/MHz instead!? Heard of units? That picture is complete BS without any half descent explanation... 

I tried to understand what he's doing. This is his original link:
http://www.sm0vpo.com/antennas/7db-colinear.htm
« Last Edit: March 16, 2013, 07:40:04 PM by E:V:A »