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Message |
    
Airplane1
Intermediate Member
Username: Airplane1
Post Number: 251
Registered: 5-2004
| | Posted on Thursday, January 06, 2005 - 8:46 am: | 
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I have a PDL-2 that I`m mounting, I want to know if the rotor can be mounted in the path of the vertical elements or does it have to be mounted below the elements?
Please help, the instructions dot say a word about this.
Roger |
That ELCO Guy (Unregistered Guest)
Unregistered guest
| | Posted on Thursday, January 06, 2005 - 5:28 pm: |
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If you have to I guess it would be OK but if at all possible use a longer pipe--like the chain link fence pipes they sell at the home improvement stores--and raise the antenna above the rotor.
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Road_warrior
Intermediate Member
Username: Road_warrior
Post Number: 243
Registered: 7-2004
| | Posted on Friday, January 07, 2005 - 10:53 pm: |
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I would also like to know if it matters./As i have seen others that have rotors mounted high and in the path of elements and quad wires./
Does it matter???
JIM/CENTRAL PA/CEF 375 |
Cm4257
Junior Member
Username: Cm4257
Post Number: 11
Registered: 12-2003
| | Posted on Friday, January 07, 2005 - 11:59 pm: |
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I had my Maco Comet mounted on a 1' piece of pipe above my rotor and had great SWR's and nothing noticeable to me. Now its on 35'foot tower with a 10' mast above the thrust bering and it has the same performance as it did when the rotor was chillin in the area of the elements. |
The ELCO guy (Unregistered Guest)
Unregistered guest
| | Posted on Saturday, January 08, 2005 - 8:44 am: |
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SWRs do not tell the whole story.
Did the rotor, a mass of metal, in the immediate fild of antenna radiation, alter the design radiation pattern, the angle of elevation of the signal? Did the rotor change the manufacturers specs on Forward Gain, or front to back ratio?
The reason I ask the above is that a big lump of metal in the signal field of the antenna MIGHT, just might, change the design specs of the antenna. Commercial Beams are not designed to have big lumps of metal near them. Todays antennas are designed via computer as if they were in 'Free Space'. So placing a big lump of metal very close to the beam might, just might, change the design specs of the antenna and its performance.
The best course of action if there is question of altering design factors is to simply call the company that made the antenna. Ask them what are their recommendations as to how to mount the antenna for best performance. If they as the designers recommend a specific method of installation then I would take them at their word and follow their recommendations.
The reasons for this is simple. If after following their recommendations down to the last dotted "i" and the antenna has performance problems then the company cannot say "BUT YOU SHOULD HAVE" and dismiss my complaint.
Later guys...
That ol ELCO Guy
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Pig040
Advanced Member
Username: Pig040
Post Number: 628
Registered: 7-2003
| | Posted on Saturday, January 08, 2005 - 11:21 am: |
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Airplane, I think EG is right as usual, I had my pdl II mounted first with the rotor right by the antenna, then with it below the antenna, and it seemed to me like my rejection was better with it below the antenna. Since rejection is a main reason for beams, it seems like keeping the rotor outside the radial would be better.
Rich |
Airplane1
Intermediate Member
Username: Airplane1
Post Number: 255
Registered: 5-2004
| | Posted on Saturday, January 08, 2005 - 11:34 am: |
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Thanks for the info, it makes perfect sence to have the rotor below the signal field. That means the boom will be about 7-8 ft above the thrust bearing.
Now for one more question about mounting the quad,
How much space is good to have between the rotor and the thrust bearing for best support? 2ft, 5ft or does it matter?
Thanks |
Tech833
Moderator
Username: Tech833
Post Number: 941
Registered: 8-2002
| | Posted on Sunday, January 09, 2005 - 12:07 pm: |
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On a true quad (like the PDL 2, not a Moonraker) having the rotor in between the elements makes no difference at all. |
