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 Yaesu FT-897D Tri-band Aerial Question
 M0SPN   Quote Post
Posted: Nov 9 2009, 01:37 PM Post #4057 
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I'm considering one of these dual-band beams for my new house:- http://www.radioworld.co.uk/~radio/catalog...agi-p-1979.html

I know it's only 3 element and relatively low gain, but I'm thinking even a 3 ele horizontal beam will make a huge difference compared to a omni vertical. It's lightweight and hence a cheap 'TV' rotator should be adequate.

I just wonder how long a cheap rotator will last, and how long it'll take to start pointing in the wrong direction compared to the controller indicator. However, a rotator with proper feedback costs crazy money blink.gif


Steve
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 radioFAB   Quote Post
Posted: Nov 9 2009, 01:55 PM Post #4058 
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QUOTE (M0SPN @ Nov 9 2009, 01:37 PM)
I'm considering one of these dual-band beams for my new house:-  http://www.radioworld.co.uk/~radio/catalog...agi-p-1979.html

I know it's only 3 element and relatively low gain, but I'm thinking even a 3 ele horizontal beam will make a huge difference compared to a omni vertical.  It's lightweight and hence a cheap 'TV' rotator should be adequate.

I just wonder how long a cheap rotator will last, and how long it'll take to start pointing in the wrong direction compared to the controller indicator.  However, a rotator with proper feedback costs crazy money blink.gif


Steve

Hi Steve, thatís the sort of thing I'm after brilliant well done, itís a shame itís not centre balanced but that looks just the ticket, I'm sure I should get away with local FM with it I am also looking at the cheap rotators as well.
I recently brought a ladder and braved it, and managed to put my Sky/Freesat Dish under the eaves, a little shaky to start with but once I got engrossed in the aliment I was OK.
Itís not so bad if you can get up to the aerial and sort problems out.
These are only fed with one coaxial lead I take it?
Peter

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 M0SPN   Quote Post
Posted: Nov 9 2009, 02:48 PM Post #4059 
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I've never owned a rotator but I believe you have DC and control wires - exact number depending on the model. The fancy ones feedback exact heading so require more wires. It's all low current though so basic cheap multi-core wire from maplin would probably be sufficient.

I'm sure someone with experience of rotators will confirm smile.gif


Steve
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 radioFAB   Quote Post
Posted: Nov 9 2009, 02:59 PM Post #4060 
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I have used one before it was a 3 wire type and was reasonable accurate, and yes it is definitely low voltage
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 gw8asd   Quote Post
Posted: Nov 9 2009, 10:43 PM Post #4061 
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Obviously using horizontal polarisation for FM will give you similar loss problems as using vertical polarisation for SSB.
Over the years I've used the cheap TV type rotators for experiments.
None of them lasted very long before failing in one way or another.
The "proper" rotators I have, Prosistel and Yaesu, are still going strong after years.
You are correct that the lightweight ones are generally 3 wire where the others are 5/6 or, sometimes, more.
Rotators are low voltage but the current depends on the model and the load.

With regards to antennas, there are plenty of sites with info for building your own.
Just a couple are :-
http://www.yu7ef.com/
http://www.g0ksc.co.uk/
It might be better to save money on the antenna and put it towards a better rotator, which will still be OK if you put up larger antennas.

Cheers

Tony
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 Riverside   Quote Post
Posted: Nov 10 2009, 11:53 PM Post #4062 
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I used a cheap Stolle rotator for many years with a light 9 ele Tonna 2m and 19ele Tonna 70cm antenna. It did seize up after being left unused for several months one winter. All the internals were steel, no nylon gears, so it was easilly freed and regreased. Sadly I dont think they are in business any more. I've seen them come up for sale s/h. They used a four core lead to an induction motor like in an old record player.
I would try to get a horizontal beam, even if only 5 elements. Plenty of good easy to make ones on the net. Dont forget a beam as well as having gain also has the ability to reduce interference from stations on or near the same frequency. On many occaisions I have been able to work stations better "off beam" by being able to steer the beam to reduce signal from a stronger local to such a degree than the wanted station could be heard and worked.
Cheers, Bill, G6BCC
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73 n gud dx
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 gw8asd   Quote Post
Posted: Nov 12 2009, 12:31 AM Post #4063 
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QUOTE (Riverside @ Nov 10 2009, 11:53 PM)
Dont forget a beam as well as having gain also has the ability to reduce interference from stations on or near the same frequency. On many occaisions I have been able to work stations better "off beam" by being able to steer the beam to reduce signal from a stronger local to such a degree than the wanted station could be heard and worked.
Cheers, Bill, G6BCC

This is something often overlooked completely.
Many time I've been told there is no need for a long Yagi on 4M or 6M and that a dipole, or even a vertical, is good enough.
The argument being that when the bands are open with ES the signals will be very strong.
Often very true.
You cannot work the stations you want to because of strong signals from another direction. sad.gif

A good beam saves the day.

In addition, if you live in a noisy location, at least the yagi reduces the signals from the unwanted directions.

Now tropo is different again.
Then you really do need as many elements as possible. biggrin.gif

Cheers

Tony
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