| Author |
Message |
    
Jimmy396
| | Posted on Sunday, January 18, 2004 - 9:04 am: | 
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Can you ? or How can you Co-phase 2 A99's together and if so need to know how its done Please.Also would a IMax 2000 with ground plane be just as compatible
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Forummaster
| | Posted on Sunday, January 18, 2004 - 12:14 pm: |
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We carry a weather proof cophasing harness for use with the A99. However you would get more gain from a 3 element beam. We had a lot of customers ask about cophasing the A99's so we started stocking a heavy duty weather proof harness.
Cophasing Harness. |
ryan
| | Posted on Sunday, January 18, 2004 - 12:22 pm: |
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before you go out and buy two antrons, take this into account:
while talking groundwave to a friend about 20 miles out, he gave me an S3 with the a-99 about 30' up. he switched over to a homemade wire dipole about 15' up and hit me with an s-5. if you want to cophase, my suggestion would be to stack two dipoles if you have the tower/mast space for it. the gain from stacking two vertical dipoles is pretty good. if you want cross polarisation, turn the bottom dipole sideways. this will give you about -1db gain, but will reduce fading due to atmospheric changes in the directions broadside to the horizontal antenna. |
Dx431
| | Posted on Sunday, January 18, 2004 - 1:43 pm: |
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Forum Master is correct.
You would be better off with a 3 element beam. I tried the co-phasing a99 thing, and was very dissappointed with the results. I guess it would work if you used a rotor, but then again, a 3 element beam would be much better.
JMO
431 |
Bruce
| | Posted on Sunday, January 18, 2004 - 2:56 pm: |
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check your email for a large file from me |
ryan
| | Posted on Monday, January 19, 2004 - 1:53 am: |
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note: to stack dipoles on a tower, i recommend making them of 102" whips or copper pipe witha white pvc radome |
Bullet
| | Posted on Monday, January 19, 2004 - 9:39 am: |
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first question i have is,
is what your wanting to do meant to be directional or omni directional?
if your going for a directional array id take another path (a beam) unless your just experimenting.
i have had very good results using verticals antennas stacked as a omni directional array.
these are known as colinear arrays and are very effective.
all kinds of info can be found in arrl handbooks on these antennas and how to construct and feed them.
good luck
bullet |
Ozzie
| | Posted on Monday, January 19, 2004 - 11:20 am: |
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Ryan Out of curiosity what antenna were you using at the time?? |
ryan
| | Posted on Monday, January 19, 2004 - 2:47 pm: |
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i myself was using the slohbby a-99 with the bottom of it about 25' up.
i wasnt the only one on the channel at the time that noticed the difference. its amazing what two pieces of wire can do. im suprised more people dont use the tried and true dipole on the cb bands |
