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#1
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I have been advised by some hams that the best way I can hope to do 10-
meters on my jeep is to mount my antenna ON THE WINDSHIELD to get a good ground plane. I read somewhere since then that the primary reason for cophasing CB antennas on trucks is NOT to direct the gain front and back, but to even the ground plane as though the antenna were in the center of the truck. Could I achieve the same effect with my Jeep by cophasing antennas on either side of the jeep by the doors? Even better- could I do this diagonally across from one corner of my jeep to the other? I heard the further apart the antennas are, the better, and I'm not really trying to get front/back gain for DXing. |
#2
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![]() "KE5MBX" wrote in message oups.com... I have been advised by some hams that the best way I can hope to do 10- meters on my jeep is to mount my antenna ON THE WINDSHIELD to get a good ground plane. I read somewhere since then that the primary reason for cophasing CB antennas on trucks is NOT to direct the gain front and back, but to even the ground plane as though the antenna were in the center of the truck. Could I achieve the same effect with my Jeep by cophasing antennas on either side of the jeep by the doors? Even better- could I do this diagonally across from one corner of my jeep to the other? I heard the further apart the antennas are, the better, and I'm not really trying to get front/back gain for DXing. What I did was purchase a 1/2 wave 11 meter whip from Radio shack and trimmed it for 10m. Of course, for 1/2 wave you need not have a ground plane, only a good ground point. I mounted it on the back bumper. It worked very well on my Warngler. |
#3
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On Feb 2, 9:35 pm, "Stefan Wolfe" wrote:
"KE5MBX" wrote in message oups.com... I have been advised by some hams that the best way I can hope to do 10- meters on my jeep is to mount my antenna ON THE WINDSHIELD to get a good ground plane. I read somewhere since then that the primary reason for cophasing CB antennas on trucks is NOT to direct the gain front and back, but to even the ground plane as though the antenna were in the center of the truck. Could I achieve the same effect with my Jeep by cophasing antennas on either side of the jeep by the doors? Even better- could I do this diagonally across from one corner of my jeep to the other? I heard the further apart the antennas are, the better, and I'm not really trying to get front/back gain for DXing. What I did was purchase a 1/2 wave 11 meter whip from Radio shack and trimmed it for 10m. Of course, for 1/2 wave you need not have a ground plane, only a good ground point. I mounted it on the back bumper. It worked very well on my Warngler. Wow, that is some excellent information I didn't know.. that a 1/2 wave antenna doesn't need a ground plane. I looked it up and sure enough, you're right! However, I'm sad to say that I really doubt Radio Shack sells a 1/2 wavelength antenna for either 10 or 11 meters. The classic 102" whip, as I understand, is a 1/4 wavelength. For a second I even considered putting a 2.5-meter (16.4 ft) whip on my jeep, but I finally decided that really isn't practical. So, any opinions on the cophasing of two 1/4 waves? |
#4
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![]() "KE5MBX" wrote in message ups.com... On Feb 2, 9:35 pm, "Stefan Wolfe" wrote: "KE5MBX" wrote in message oups.com... I have been advised by some hams that the best way I can hope to do 10- meters on my jeep is to mount my antenna ON THE WINDSHIELD to get a good ground plane. I read somewhere since then that the primary reason for cophasing CB antennas on trucks is NOT to direct the gain front and back, but to even the ground plane as though the antenna were in the center of the truck. Could I achieve the same effect with my Jeep by cophasing antennas on either side of the jeep by the doors? Even better- could I do this diagonally across from one corner of my jeep to the other? I heard the further apart the antennas are, the better, and I'm not really trying to get front/back gain for DXing. What I did was purchase a 1/2 wave 11 meter whip from Radio shack and trimmed it for 10m. Of course, for 1/2 wave you need not have a ground plane, only a good ground point. I mounted it on the back bumper. It worked very well on my Warngler. Wow, that is some excellent information I didn't know.. that a 1/2 wave antenna doesn't need a ground plane. I looked it up and sure enough, you're right! However, I'm sad to say that I really doubt Radio Shack sells a 1/2 wavelength antenna for either 10 or 11 meters. The classic 102" whip, as I understand, is a 1/4 wavelength. For a second I even considered putting a 2.5-meter (16.4 ft) whip on my jeep, but I finally decided that really isn't practical. So, any opinions on the cophasing of two 1/4 waves? You are right of course...sorry...I didn't caculate the wavelength and was merely making statements comparing the shorter "loaded" whip (forgetting it was loaded), concluding the longer whip was 1/2 wave . However, I knew it was 1/4 wave GP at the time and sometimes I just get afflicted with oldtimers didease, complicated to exposure of high EM fields. :-)) The unloaded 1/4 whip still worked well using the frame as a ground plane. |
#5
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KE5MBX wrote:
Wow, that is some excellent information I didn't know.. that a 1/2 wave antenna doesn't need a ground plane. I looked it up and sure enough, you're right! However, I'm sad to say that I really doubt Radio Shack sells a 1/2 wavelength antenna for either 10 or 11 meters. The classic 102" whip, as I understand, is a 1/4 wavelength. For a second I even considered putting a 2.5-meter (16.4 ft) whip on my jeep, but I finally decided that really isn't practical. So, any opinions on the cophasing of two 1/4 waves? I have a GMC pickup with a three magnet magmount on top of the cab and I use Hamsticks for 20m-10m. There's hardly any noticeable difference when I move that magmount to the hood of the pickup. Why not use a three magnet mag- mount on your Jeep hood with a 10m Hamstick? Do you have a roll bar on the Jeep? Lots of Jeep drivers mount their CB antennas in the middle of the roll bar. -- 73, Cecil http://www.w5dxp.com |
#6
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![]() "Cecil Moore" wrote in message t... KE5MBX wrote: Wow, that is some excellent information I didn't know.. that a 1/2 wave antenna doesn't need a ground plane. I looked it up and sure enough, you're right! However, I'm sad to say that I really doubt Radio Shack sells a 1/2 wavelength antenna for either 10 or 11 meters. The classic 102" whip, as I understand, is a 1/4 wavelength. For a second I even considered putting a 2.5-meter (16.4 ft) whip on my jeep, but I finally decided that really isn't practical. So, any opinions on the cophasing of two 1/4 waves? I have a GMC pickup with a three magnet magmount on top of the cab and I use Hamsticks for 20m-10m. There's hardly any noticeable difference when I move that magmount to the hood of the pickup. Why not use a three magnet mag- mount on your Jeep hood with a 10m Hamstick? Do you have a roll bar on the Jeep? Lots of Jeep drivers mount their CB antennas in the middle of the roll bar. -- 73, Cecil http://www.w5dxp.com When I had my CJ I had a CB antenna mounted on a ball mount back behind the rear wheel well. |
#7
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In article ,
Cecil Moore wrote: Do you have a roll bar on the Jeep? Lots of Jeep drivers mount their CB antennas in the middle of the roll bar. If the roll bar is thick enough, you can drill and tap it to mount the whip directly. Then use a gamma match so you don't have to worry about insulating the mount. Fred K4DII |
#8
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On Sat, 03 Feb 2007 13:02:09 -0500, Fred McKenzie
wrote: If the roll bar is thick enough, you can drill and tap it to mount the whip directly. Then use a gamma match so you don't have to worry about insulating the mount. Hi Fred, Gamma match the roll bar. 73's Richard Clark, KB7QHC |
#9
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Fred McKenzie wrote:
If the roll bar is thick enough, you can drill and tap it to mount the whip directly. Then use a gamma match so you don't have to worry about insulating the mount. Just don't touch the roll bar. :-) -- 73, Cecil http://www.w5dxp.com |
#10
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![]() "KE5MBX" wrote in message ups.com... On Feb 2, 9:35 pm, "Stefan Wolfe" wrote: "KE5MBX" wrote in message oups.com... I have been advised by some hams that the best way I can hope to do 10- meters on my jeep is to mount my antenna ON THE WINDSHIELD to get a good ground plane. I read somewhere since then that the primary reason for cophasing CB antennas on trucks is NOT to direct the gain front and back, but to even the ground plane as though the antenna were in the center of the truck. Could I achieve the same effect with my Jeep by cophasing antennas on either side of the jeep by the doors? Even better- could I do this diagonally across from one corner of my jeep to the other? I heard the further apart the antennas are, the better, and I'm not really trying to get front/back gain for DXing. What I did was purchase a 1/2 wave 11 meter whip from Radio shack and trimmed it for 10m. Of course, for 1/2 wave you need not have a ground plane, only a good ground point. I mounted it on the back bumper. It worked very well on my Warngler. Wow, that is some excellent information I didn't know.. that a 1/2 wave antenna doesn't need a ground plane. I looked it up and sure enough, you're right! However, I'm sad to say that I really doubt Radio Shack sells a 1/2 wavelength antenna for either 10 or 11 meters. The classic 102" whip, as I understand, is a 1/4 wavelength. For a second I even considered putting a 2.5-meter (16.4 ft) whip on my jeep, but I finally decided that really isn't practical. So, any opinions on the cophasing of two 1/4 waves? IF they dont they used to. |
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