antenna distance

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antenna distance

Postby VK4SP » Fri Dec 18, 2009 6:17 am

I would like to put my 6mtr beam above my hf beam what would be the min distance I could go
my rotor sits out side my tower :?:
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Re: antenna distance

Postby VK4TS » Fri Dec 18, 2009 7:11 am

Dave,

Moving the rotator inside the tower is definitely the better option, with a Nally rotator inside the tower I have seen setups with stacked large tribanders....c31xr

For a long time in Tamworth I had an old Fukner 400 on top of a Hills tower with a 4 element 15 and about 6 foot above that a 5 element 10m...before everyone bags the Fukner its still alive....!!

How big a six metre beam and how big a tribander and how big a rotator? check the specs and calculate the wind loading of the antennas and then double it :D :-)

2 metres seems to be a good dx apart but if at all possible rotator inside the tower with some bearings to take the strain both vertically and horizontally..
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Re: antenna distance

Postby VK4TS » Fri Dec 18, 2009 7:19 am

Alternative....but i have never tried it...on the DK7ZB website he has a design for a 10 and 6 M single feed antenna...using what is reffered to as open sleeve elements...

I am building one this weekend...from his theory this should work with a tribander...it involves mounting a six metre yagi interlaced with the tribander and fitting a open sleeve very close to the driven element to make it resonanant on six metres ie it has only one feedline...

http://www.qsl.net/dk7zb/start1.htm the 10 and 6 antenna is accessed by first clicking on
http://www.qsl.net/dk7zb/Duoband/duoband_principles.htm and then clicking on the open sleeve theory and then the 10 and 6 for some reason the other links on his website dont work..

good luck give us a call next week and I can update you on the 10/6
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Re: antenna distance

Postby VK4SP » Fri Dec 18, 2009 8:37 am

VK4TI wrote:Dave,

Moving the rotator inside the tower is definitely the better option, with a Nally rotator inside the tower I have seen setups with stacked large tribanders....c31xr

For a long time in Tamworth I had an old Fukner 400 on top of a Hills tower with a 4 element 15 and about 6 foot above that a 5 element 10m...before everyone bags the Fukner its still alive....!!

How big a six metre beam and how big a tribander and how big a rotator? check the specs and calculate the wind loading of the antennas and then double it :D :-)

2 metres seems to be a good dx apart but if at all possible rotator inside the tower with some bearings to take the strain both vertically and horizontally..

The tower is an old rhon the rotor is a spid, antennas are a3s wind load is 4.36 Ft2 and a505s with a wind load of 2.9Ft2 :|
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Re: antenna distance

Postby VK4TS » Fri Dec 18, 2009 9:06 am

from experience with spids they will handle anything you can throw at them with that combination...

if the tower is a Rohn then get the in tower kit for the spid...

distance apart ? 2 metres should be enough to get rid of any problems....
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Re: antenna distance

Postby VK4ADC » Fri Dec 18, 2009 1:26 pm

Somehow your request for yagi spacing info seemingly got lost in whether to mount the rotator inside or outside the tower - or - co-mounted on the same boom.

General rule of thumb I use is 1/4 wavelength at the lower frequency but this is not always practicable at HF. In which case, use a minimum of 1/4 wavelength at the higher yagi's frequency. The boom lengths don't come into the equation, just the frequencies/bands.

I have my 6el 6m yagi about 1.6 metres above my Wilson HF tribander with negligible effect on either antenna. Each tunes the same as when mounted alone.

I use the same general rule-of-thumb with the spacing of the yagis in my field day antenna setup too and, again, minimal de-tuning effects with the other/s in place. Using this general idea, the 70cm yagi is above the 2 metre yagi & it is mounted above the 6 metre yagi. See http://www.vk4adc.com/fielddayinfo.php & other field day reports on the same site.

Hope this helps :wink:
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Re: antenna distance

Postby VK4TS » Fri Dec 18, 2009 2:53 pm

Antenna spacing can be a bit mute if David was trying to hang an 11 element beam above a Stolle rotator Doug ... :lol:
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Re: antenna distance

Postby VK5APN » Fri Dec 18, 2009 6:06 pm

Have a look at this website. Yes I know it is for VHF and above, but the principle is still the same.

http://www.directivesystems.com/STACKING.htm

Regards

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