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Author Topic: 1/4-wave on trunk vs. higher gain on trunk lip ?  (Read 947 times)
K4DSC
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Posts: 11




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« on: May 17, 2009, 04:08:29 PM »

The trunk lid of my Ford Fusion swings to the vertical position when opened.  If I mount a dual-band (2/440)  NMO-mounted antenna in the trunk lid, the longest antenna length I can use without hitting the top of the roof when the trunk opens is ~ 21 inches (1/4-wave).   However, If I go with a side-mounted trunk lip mount, I could use a Larsen 2/70 or maybe a Diamond SG7500 with more gain.

Anyone care to share your thoughts regarding the relative performance of a 1/4-wave (say a Diamond MR77)  mounted in the center of my Fusion's small trunk lid vs. an a Larsen 2/70 or Diamond SG7500 mounted with a edge/lip mount on the side of the trunk lid ?
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WB2WIK
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Posts: 20542




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« Reply #1 on: May 17, 2009, 06:07:29 PM »

Why not the center of the roof?  That's where whips work the best...
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KI4SDY
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Posts: 1452




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« Reply #2 on: May 17, 2009, 06:54:56 PM »

I would use the MFJ-1729 power gain dual band antenna. That way you will have  a good performing antenna (higly rated on ham net and locally here) for only $39.95, ease of installation and if you leave enough extra cable in the trunk, you can move it back and forth from the trunk to the roof. On the roof for greater range and on the truck for garage clearance.

If you just have to drill a hole in your car, put it on the roof! It will perform better there and if it leaks you will know it. It could leak for months in the truck and you wouldn't know until you smelled it and everything was destroyed. Also, when you get ready to sell the car the rubber hole plug won't show as bad on the roof.

   
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KO1D
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Posts: 383




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« Reply #3 on: May 17, 2009, 09:25:57 PM »

Drill a hole.

Center of roof is where any antenna works best. Larsen NMO 270B will do wonders and then some.

Total price: less than $75 unless you cannot find a friend with the drill bit.
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K8KAS
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Posts: 569




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« Reply #4 on: May 23, 2009, 06:05:38 AM »

A 1/4 wl ON THE ROOF will beat any side/trunk or low mounting position with the so called gain antenna. Save your money and just drill the hole and use a 1/4 wl antenna in the middle of the roof. Look at the AM/FM antenna's mounted on car's, the best system's are mounted on top the roof for a good reason. Performance.. Denny K8KAS
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K8QV
Member

Posts: 50




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« Reply #5 on: May 23, 2009, 04:35:36 PM »

It depends on your needs. Do you want to hit a repeater 40 miles away, or are you in an urban area with easy access to repeaters?

Most people I know around here go way overboard with their mobile 2 meter antenna. I can hit about 8 repeaters with my HT from my house and about 10 more from the mobile with 10 watts and a 1/4 wave mag mount dual band whip on one corner of the roof. I also work a pretty good range using simplex.

If you want to work DX on two meters, then the antenna becomes a consideration. Center mounted roof location is theoretically best, and 5/8 or 3/4 wave has theoretical gain. In practice, it might not matter depending on your circumstances.
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