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Author Topic: Dual band (2/440) antenna ideas for top of the front cap?  (Read 3785 times)

John Canfield

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Dual band (2/440) antenna ideas for top of the front cap?
« on: June 27, 2013, 01:20:38 PM »
I pulled the Yaesu FTM-10R from the Jeep finding it completely obtuse to operate while bouncing around the trails.  Being completely menu-driven I never could remember even how to turn the dumb thing on most of the times since I used it so infrequently.  Replaced it with a Kenwood TM-V71A which I found to be very intuitive and easy to program and operate.

Anyway I was thinking about installing the Yaesu in the coach instead of trying to sell it, it would be fun to have 2m/440 with us on the road and I could spend more time learning the Yaesu in a kinder environment.  What have others done for a dual band antenna (no counterpoise required) with a whip length of the 30" or less range?  What about the mount?  I installed a Diamond on the Jeep that would work well for the coach but the mount is an SO-239 and I don't know how I could make that work on the front cap.

73 de wb5tht
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
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gwcowgill

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #1 on: June 27, 2013, 07:38:28 PM »
John, have you thought about cutting a piece of aluminum to put under the antenna mount with a chassis ground wire hooked up to the aluminum. This may act as a good enough ground plane. Test it before you drill holes in the cap but I believe it will work. Right now, I don't have any of my 2m440 radios mounted.
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

Jim Godward

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #2 on: June 27, 2013, 09:47:53 PM »
John,

Since most conversations on 2/440 are through repeaters, I used a 12" Comet dual band antenna.  If I remember correctly, it is a so239 mounted directly through the roof on my MH, i.e., luan/TPO.  I used the existing mount for the old single band cell phone.  Works well and I have been using it for about 8 years now.  Wife bent it a little this last trip but I didn't notice any change in performance.  Bend is only about 15 above the coil about 1/2 way up.
Jim
Jim & Pat Godward
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Hillsboro, Oregon

John Canfield

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #3 on: June 27, 2013, 10:32:08 PM »
John, have you thought about cutting a piece of aluminum to put under the antenna mount with a chassis ground wire hooked up to the aluminum. This may act as a good enough ground plane. Test it before you drill holes in the cap but I believe it will work. Right now, I don't have any of my 2m440 radios mounted.
The counterpoise really isn't a big problem, the Diamond antenna I have on the back of the Jeep doesn't need one and it was almost 1.0:1 when I checked it.

John,

Since most conversations on 2/440 are through repeaters, I used a 12" Comet dual band antenna.  If I remember correctly, it is a so239 mounted directly through the roof on my MH, i.e., luan/TPO.  I used the existing mount for the old single band cell phone.  Works well and I have been using it for about 8 years now.  Wife bent it a little this last trip but I didn't notice any change in performance.  Bend is only about 15 above the coil about 1/2 way up.
Jim, yeah, a 12-18" one would be okay, I was more concerned about the actual mount.  Now that I think about it, I probably could use a double SO-239 through the roof.  Thanks guys.
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
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Jim Godward

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #4 on: June 27, 2013, 11:40:35 PM »
Mount it on the drivers side as there is less chance of trees there, well slightly anyway.   :)
Jim
Jim & Pat Godward
AC7PO & KD7ZDM
Hillsboro, Oregon

Lou Schneider

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #5 on: June 28, 2013, 01:10:47 AM »
An 18"  1/4 wave 2 meter whip cut a little short is also 5/8 wavelength at 440 MHz and can be made to work well on both bands.   It's about as simple as you can get without having to worry about loading coils, etc.

Just take a stock 2 meter whip antenna and trim a little at a time off the length of the whip until you reach minimum VSWR on 440 MHz.  The VSWR null on 2 meters is more broad and should still be acceptable, around 1.5:1 or less.

I built one of these out of a Radio Shack mag mount CB antenna after bypassing the base loading coil and used it for several years.  No reason it shouldn't work with a so239 or NMO base and an 18" or longer ground plane (3 or more wires radiating out from the connector).
« Last Edit: June 28, 2013, 01:23:32 AM by Lou Schneider »

John Canfield

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #6 on: June 28, 2013, 08:08:44 AM »
Jim - yeah, I was thinking driver's side for the antenna and transceiver since that's where I have good 12V access.  The FTM-10R already has the detachable faceplate with quite a long cable so I can mount there where convenient.

Lou - I used to home brew quite a few of my antennas, it would be a little trickier on the road.  I think I'll buy the same antenna I have on the Jeep - it doesn't need a counterpoise and I had very low vswr when I checked it.
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
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gwcowgill

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #7 on: June 28, 2013, 08:29:59 AM »
John, now you have me thinking...I have several radios just sitting so I may try to set one up in the MH. My coach came without wiring for a CB or for that matter anything else so I will have to start from scratch. Sounds like I may need several pounds of motivation.
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

John Canfield

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #8 on: June 28, 2013, 08:37:14 AM »
There ya' go - let's get radio active!  ;)
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
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gwcowgill

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #9 on: June 28, 2013, 11:28:17 AM »
Wow, do we glow in the dark? :) :) :)
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

Lowell

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #10 on: June 28, 2013, 12:25:51 PM »
I'm still a newbie Ham.  My son got me into it. It has been great use in our last two camping trips as there is no cell phone coverage at our preferred campgrounds.  Using the AZ Rimlink repeaters, we were able to stay in touch over 250 miles distance.  A nice feature when my son is driving a 50 year old International Scout.  (I always wonder if he has made it there and back) And it was also nice using the hand helds to check with each other when one was fishing on the lake.
Lowell

2005 Cherokee28A TT
pulled by 2009 Dodge 1500 Crew Cab 4X4
KF7YET

Tempe, Arizona

Lou Schneider

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #11 on: June 28, 2013, 12:28:28 PM »
Quote
Wow, do we glow in the dark?

I used to, but now everything I deal with is solid state.

gwcowgill

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #12 on: June 28, 2013, 07:12:38 PM »
Lou, we used to have all those glow in the dark labels on our radar and control tower consoles in the old days. Now when I go into an ATC facility I am amazed at the improvements in equipment more especially the solid state radios.
2009 Bounder 36B, 2014 Honda CR-V, various grandchildren when school is out. KG4LHS
2014 Honda CRV Toad,
2014 Jeep Grand Cherokee Toad

John Canfield

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Re: Dual band (2/440) antenna ideas for top of the front cap?
« Reply #13 on: June 29, 2013, 08:55:07 AM »
I'm still a newbie Ham.  My son got me into it. It has been great use in our last two camping trips as there is no cell phone coverage ...
Welcome to a fun and practical hobby!  I wanted a vhf/uhf radio in the Jeep because we are frequently in remote areas with no cell coverage like your situation.
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
Our Horizon projects
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