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MOBILE BEAM FOR A SURBURBAN

This section is dedicated to Keydown Competition rigs and high-performance competition base setups. If you have questions or information on how to maximize a competition setup, this is the perfect place to share and discuss!
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5pills
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MOBILE BEAM FOR A SURBURBAN

#253456

Post by 5pills »

I'm using the M105 element spacings and a 2''x2'' square aluminum boom. I want to know which is better........having my reflector out behind the suburban off the surface ground plane (which will be grounded to the receiver hitch) or should I build it with the reflector over the surface ground plane and move my hot antenna foward then my directors and so on.. Which will achieve more gain and be more efficent. I want all the gain and direction I can get out of this plan. The boom will be grounded so do I insulate all the directors. PLZ HELP??????????
I'm doing this for competitions, mudducks, keying on base stations, and talking skip. I have a junky 78 surburban with 16 pills and 2-300 amp leese's....so drilling holes is no issue....again...PLZ HELP?

I noticed in pics at the keydowns the suburbans where using PVC pipe off the front bumper extending outwards with directors that are longer than the hot or reflector that is mounted at the top of the burb........all my elements on my 78 burb are going to mount on my boom in a straight line. but i do need to know does the refector need to start over the top of my suburban or will it be o.k. to mount it behind the vehicle not over the surface ground plane?
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5PILLS in ALABAMA is reedin' on tha MAIL!!!
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Tattoo-
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#253951

Post by Tattoo- »

I've done quite a bit of experimenting on mobile beams, and ill show you what has worked best for me. I mount my antenna as far back on the vehicle as i can get it, then I support a boom off the back of the vehicle at least 9 feet long and I space my reflector exactly 9 feet away from my hot. The reflector is grounded to the vehicle body. As for the director, I mounted it four feet 2 inches in front of the hot and it has to be isolated from ground. I only used one director, any more than that and you start running into swr issues. And when I got the SWR issues fixed, I saw no more gain. As far as the people running a PVC boom in front of the vehicle, I see no more gain from a three element mounted to the way I described. On my truck I only have enough room to go 16 feet in front of my vehicle, I mounted directors all the way down, got the swr low, and saw no more gain than the three elements. So I took it off.
I hope this information helps you.
I'll see if I can take any detailed pictures of my mobile antenna system.
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Mr508
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Real Name: Boss Casper

#305633

Post by Mr508 »

Tattoo- wrote:I've done quite a bit of experimenting on mobile beams, and ill show you what has worked best for me. I mount my antenna as far back on the vehicle as i can get it, then I support a boom off the back of the vehicle at least 9 feet long and I space my reflector exactly 9 feet away from my hot. The reflector is grounded to the vehicle body. As for the director, I mounted it four feet 2 inches in front of the hot and it has to be isolated from ground. I only used one director, any more than that and you start running into swr issues. And when I got the SWR issues fixed, I saw no more gain. As far as the people running a PVC boom in front of the vehicle, I see no more gain from a three element mounted to the way I described. On my truck I only have enough room to go 16 feet in front of my vehicle, I mounted directors all the way down, got the swr low, and saw no more gain than the three elements. So I took it off.
I hope this information helps you.
I'll see if I can take any detailed pictures of my mobile antenna system.

For a ride around beam which has greatest gain and direction one hot with a director, one hot with a reflector, or two hots (135 degrees out of phase)
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5 pills
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#317349

Post by 5 pills »

wow...i need to retrieve my old account info.....go 5-pills
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420Snowman

#320448

Post by 420Snowman »

So what did you end up doing? Got any pics?

Snowman
Sent from my Grim Reaper powered HTC.
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