Hello Before I reinvent the wheel I want to run this project by you. My current satellite antenna system is on a 15 foot tripod using a G5400 az/el rotors. Consists of 14 el cp 2M yagi, 40 el cp 70 cm yagi, 3 foot dish for S band 16 turn helix for L band. I want to change the tripod to a 30 foot tower and add a 5 el 6 M beam. Question- put the satellite antennas just above the top of tower and the 6M beam above the satellite ants. high enough as not to interfere with the sat. antennas when rotated in elevation. Then if possible have the whole thing being able to tip over. Has anyone come close to doing something like this? Or any ideas. 73 Bob W7LRD CN87
-- "if this were easy, everyone would be doing it"
I did something similar when I lived in Los Angeles. I mounted a 5-element 10-meter beam under the satellite antennas on the tower in the attached photo. This required increasing the length and wall thickess of the mast and changing the azimuth rotator to a more powerful version. Note that the tower is the heavy-duty model and has an extension to accomodate a thrust bearing. The tower was not fully extended in that configuration so that the top of the new mast didn't exceed the original height of 45 feet.
However, I reread a mechanical engineering textbook from college and did the necessary calculations to prove that it wouldn't blow over before trying it. The wind load has to be kept close to the tower. CP yagis have a much lower wind load than a 3 foot dish so this my not work in your case.
The 6 m beam or the 3 foot dish could be mounted separately as I did in the photo.
73,
John KD6OZH
----- Original Message ----- From: [email protected] To: "AMSAT-BB" [email protected] Cc: "NW VHF" [email protected] Sent: Tuesday, January 20, 2009 08:42 UTC Subject: [amsat-bb] springtime project
Hello Before I reinvent the wheel I want to run this project by you. My current satellite antenna system is on a 15 foot tripod using a G5400 az/el rotors. Consists of 14 el cp 2M yagi, 40 el cp 70 cm yagi, 3 foot dish for S band 16 turn helix for L band. I want to change the tripod to a 30 foot tower and add a 5 el 6 M beam. Question- put the satellite antennas just above the top of tower and the 6M beam above the satellite ants. high enough as not to interfere with the sat. antennas when rotated in elevation. Then if possible have the whole thing being able to tip over. Has anyone come close to doing something like this? Or any ideas. 73 Bob W7LRD CN87
-- "if this were easy, everyone would be doing it" _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Bob, did you mean to say to place the 6 meter beam BELOW the satellite antennas? Why would you want to elevate the 6 meter beam? I personally would not add that additional strain to the elevation rotor of the G5400.
73 de W4AS Sebastian
On Jan 20, 2009, at 3:42 AM, [email protected] wrote:
Hello Before I reinvent the wheel I want to run this project by you. My current satellite antenna system is on a 15 foot tripod using a G5400 az/el rotors. Consists of 14 el cp 2M yagi, 40 el cp 70 cm yagi, 3 foot dish for S band 16 turn helix for L band. I want to change the tripod to a 30 foot tower and add a 5 el 6 M beam. Question- put the satellite antennas just above the top of tower and the 6M beam above the satellite ants. high enough as not to interfere with the sat. antennas when rotated in elevation. Then if possible have the whole thing being able to tip over. Has anyone come close to doing something like this? Or any ideas. 73 Bob W7LRD CN87
Putting words in Bob's mouth (correct me if I misunderstand):
I believe he intends to mount the G5400 with the azimuth part of the rotor holding a mast that the 6m antenna is attached to the top, and atrtach the elevation part of the rotor just above the tower to support his satellite antennas. The separation being sufficient so that when the satellite antennas are elevated they clear below the 6m antenna. BTW my satellite array on a B5400 is essentially the same as Bob's and it survived 5-6 years in the wind about 12-foot above the roof (~25 feet above ground). I have yet to re-install them at our new house on a ten-foot tower. http://www.kl7uw.com/sat.htm
My concerns would be two: 1. Is the azimuth part of the B5400 strong enough to support approximately 12-feet of mast with a 6m beam on top (a solution would be to mount the rotor below the tower top and use a thrust bearing (my Tower #2, raised this last Thanksgiving, is constructed this way using a Ham-IV rotor ten-foot below the tower top having a TB3 thrust bearing and ten more feet extending above the tower. On this I have a 3-elem Triband HF beam, two stacked 3-elem 6m beams, a 432 and two 222 eleven element beams. The mast is twenty feet of 1-1/2 inch ID sched-80 steel (very heavy). 2. Will the 6m beam interfere with the beam pattern of the satellite antennas when they are elevated?
Note that my two 6m beams are stacked with one 5-foot above the HF beam and the other 5-foot below the HF beam, so one could ask whether the HF beam will interfere with the 6m antennas? I'll have to let you know as one is not yet connected to coax. http://www.kl7uw.com/6m.htm
73, Ed - KL7UW
At 09:02 AM 1/20/2009, Sebastian wrote:
Bob, did you mean to say to place the 6 meter beam BELOW the satellite antennas? Why would you want to elevate the 6 meter beam? I personally would not add that additional strain to the elevation rotor of the G5400.
73 de W4AS Sebastian
On Jan 20, 2009, at 3:42 AM, [email protected] wrote:
Hello Before I reinvent the wheel I want to run this project by you. My current satellite antenna system is on a 15 foot tripod using a G5400 az/el rotors. Consists of 14 el cp 2M yagi, 40 el cp 70 cm yagi, 3 foot dish for S band 16 turn helix for L band. I want to change the tripod to a 30 foot tower and add a 5 el 6 M beam. Question- put the satellite antennas just above the top of tower and the 6M beam above the satellite ants. high enough as not to interfere with the sat. antennas when rotated in elevation. Then if possible have the whole thing being able to tip over. Has anyone come close to doing something like this? Or any ideas. 73 Bob W7LRD CN87
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
----- Original Message ----- From: [email protected] To: "AMSAT-BB" [email protected] Cc: "NW VHF" [email protected] Sent: Tuesday, January 20, 2009 2:42 AM Subject: [amsat-bb] springtime project
Hello Before I reinvent the wheel I want to run this project by you. My current satellite antenna system is on a 15 foot tripod using a G5400 az/el rotors. Consists of 14 el cp 2M yagi, 40 el cp 70 cm yagi, 3 foot dish for S band 16 turn helix for L band. I want to change the tripod to a 30 foot tower and add a 5 el 6 M beam. Question- put the satellite antennas just above the top of tower and the 6M beam above the satellite ants. high enough as not to interfere with the sat. antennas when rotated in elevation. Then if possible have the whole thing being able to tip over. Has anyone come close to doing something like this? Or any ideas. 73 Bob W7LRD CN87
How would you mount the 6M beam ABOVE the elevation rotor?
There is no mast clamp on top of, and a vertical mast does not pass thru, the elevation rotor....
George, KA3HSW
participants (5)
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Edward Cole -
George Henry -
John B. Stephensen -
Sebastian -
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