26pdi001
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Re: Home made vertical for 45 metres
what make is it a husler they have coils on the antenna has sevral coils on
my antenna has no coils but reliys on the sevral counter poise elements that it has plus a capasitor for the 80 mtr band and has an huge coax harness in side the antenna as well covers 80 to 10 mtrs at around 1.5.1 and will tune on 160 / 6 / 2 mtrs with the tuner in the pro
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cq dx cq dx
icom 7400 icom 756 pro1 tri bander beam titan dx audio by w2ihy 400 watts helps as well
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22/May/2009, 9:22 pm
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26fb010
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Re: Home made vertical for 45 metres
i have recently turned a gp27 into a 14 wave for 20m by removing the coil and adjusting the length to about 5 metres.
i was thinking of making it a 14 wave on 40m too, by adding a 5 metre wire coil somewhere with the use of crocodile clips so it can be unclipped for 20m again. as anyone else done similar, or can anyone spot any problems with the idea?
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19/Aug/2009, 7:12 am
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crimso
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Re: Home made vertical for 45 metres
If you have the space a quarter wave vertical is preferable to a half wave, in that it's optimum impedance is 36 Ohms at a SWR of 1.4:1 & thus perfect for 50 Ohm coax & modern 50 Ohm radios.
On a qurter wave anything above or below 36 Ohms is loosing performance, so a SWR of 1:1 on a quarter wave vertical means that the achived impedance of 50 ohms has lost you around 30% in radiated watts.
With a base fed half wave vertical you are feeding at a point were the impedance is in the area of 2000 - 5000 Ohms hence why a half wave often uses a "Loading Coil" & states 50 Ohm's impedance!!!!! But in practice a half wave vertical will still work & without a counterpoise & if building one, as long as you do not chase impedance but performance then it can work reasonably well, despite the impedence issue.
The quarter wave vertical will need a counterpoise, but if you work for radiation efficiency & not just blindly chase SWR then a quarter wave can be a very efficient & simple to build antenna, but do your maths & don't just think resonance when it comes to radials.
Think about what is the most efficient way you can achieve that counterpoise resonance in the space you have.
In practice the more & shorter the radials the better the efficiency when it comes to radiated power & then you can drop the SWR below 1.4:1, a little & gain a little more efficiency there too.
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19/Aug/2009, 9:27 am
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madmark1
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Re: Home made vertical for 45 metres
if your after a light weight full size vertical for 40/? then you may want to give this a go, ive got myself a 10mtr roach pole from sandpipers over here in southwales, there 2 inch at the base and tapper to a point. ive epoxy resined a ally tube to the base, its about 2 ft long and fixed a small stand of arm that carries a so239, of the so239 solder your wire and run it up the pole , ground mount it and use a good earth and a counterpoise if needed, a good earth is vital..it works excellent. 163trc20
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2/Nov/2009, 7:51 pm
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