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Author Topic: mag mount performance  (Read 2544 times)
N1RND
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Posts: 70




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« on: March 15, 2012, 01:37:06 PM »

Is there any difference in performance between a magnetic mount and a permanent mount (meaning screwing into metal) for antenna performance?

I forgot to mention this will be for HF using monoband whips.
« Last Edit: March 15, 2012, 01:42:50 PM by N1RND » Logged
M6GOM
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Posts: 1014




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« Reply #1 on: March 15, 2012, 02:03:30 PM »

Is there any difference in performance between a magnetic mount and a permanent mount (meaning screwing into metal) for antenna performance?

I forgot to mention this will be for HF using monoband whips.

Yes. Massive amounts in respect to common mode issues. Will it receive better? Without doing side by side comparisons you'll not know. However from personal experience I can tell you that magmounts suck. I used a triple magmount with a Little Tarheel II. On the 80m band, using anything more than 50W caused the radio to reboot because of common mode issues. Drilled a hole, put a 3/8 mount in the roof. I could then put 200W through it (all the radio did) and no issues at all.
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N1RND
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« Reply #2 on: March 15, 2012, 02:46:09 PM »

I hate to admit to it, but I thought this might be the answer.
So going by that, how is it that mag mounts make the negative side of the antenna connection?  Is is the negative (ground plane) capacitively coupled?
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W8JX
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Posts: 6682




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« Reply #3 on: March 15, 2012, 02:53:28 PM »

Is there any difference in performance between a magnetic mount and a permanent mount (meaning screwing into metal) for antenna performance?

I forgot to mention this will be for HF using monoband whips.

Yes. Massive amounts in respect to common mode issues. Will it receive better? Without doing side by side comparisons you'll not know. However from personal experience I can tell you that magmounts suck. I used a triple magmount with a Little Tarheel II. On the 80m band, using anything more than 50W caused the radio to reboot because of common mode issues. Drilled a hole, put a 3/8 mount in the roof. I could then put 200W through it (all the radio did) and no issues at all.

Used mag mounts for HF for over 20 years now HF thru UHF and I never had any problems. Used 3 different HF rigs too and none of them even acted strange or rebooted.
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You can embrace new computer/tablet technology and change with it or cling to old fall far behind....
M6GOM
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Posts: 1014




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« Reply #4 on: March 15, 2012, 06:22:14 PM »

I hate to admit to it, but I thought this might be the answer.
So going by that, how is it that mag mounts make the negative side of the antenna connection?  Is is the negative (ground plane) capacitively coupled?

Alan, K0BG, has some good info about mag mounts on his site.
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N6AJR
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Posts: 9927




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« Reply #5 on: March 17, 2012, 07:31:56 PM »

My experience is  that most antenna really want a good solid ground in mobile applications. Also they tend top scratch the paint. they just don't work well as a trunk lip mount, or a through the metal mount , no saying anything about one coming loose at speed. I do have some here in the shack I use on a tin cookie sheet, for testing the odd radio with out having to unhook something else. I also have a LARGE 3 pad and a LARGE 4 pad  heavy duty mount I sometimes use in the bed of the pickup, to try something different out as a temporary mount , but it takes 2 men and a boy to slide them out of the bed and break them loose to put away, and they always leave big scratches, but it is in the bed of a truck, so who cares...   I have no concrete numbers and such to back this up but I got my license in 1978, and have played with many variations, fire sticks, ham sticks, screwdrivers large and small, mag mounts in all sizes, window mounts ( great for rentals and an HT) 3/8 in mounts, mirror mounts, SO 239 mounts and trunk lip mounts.  so I have a bit of trial and error there.  Alan also has some good stuff on his website.
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W8JX
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Posts: 6682




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« Reply #6 on: March 18, 2012, 05:07:34 AM »

I also have a LARGE 3 pad and a LARGE 4 pad  heavy duty mount I sometimes use in the bed of the pickup, to try something different out as a temporary mount , but it takes 2 men and a boy to slide them out of the bed and break them loose to put away, and they always leave big scratches, but it is in the bed of a truck, so who cares... 

I never slide a mag mount loose. By using a combination of side thrush on antenna to match lifting force on one side of mag mount you break one side loose then lift it free.
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You can embrace new computer/tablet technology and change with it or cling to old fall far behind....
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