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Wilson 5K Magmount on metal table problems

Switch Kit

Well-Known Member
Apr 6, 2005
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Wilson 5K load on a Wilson 1K mag mount (RG58) on a 2 by 3 foot metal table on porch 15 feet off the ground used with a K40 / 58 inch stinger (because it "appeared" to match better then the Wilson's) I'm guessing RF is traveling the outside of the coax because moving wires , radio or coax inside can effect the SWR drastically , left in one place around the cb and free brands "appears to look good" Was using a SWR bridge and it would give me one reading but the radio (AT-6666 at full power) would give me another , just seems like everything is a part of the antenna .
So I just decided to use the radios SWR meter for the mean time . I can stay way below 1.5 not moving anything but it can waver a bit because I think I'm also a part of the antenna . I'm guessing what I'm seeing is a false reading for say ? but it does talk with pretty good radio checks. From what I have read it looks like I have grounding issues ?
I have tried to coil some of the coax next to antenna and that only made it worse and tried a ferrite clip-on and it only did the same thing , problem being there really isn't much to ground it too , the porch is only 10 feet by 6 feet or so , there is a electrical outlet about 8 feet from the mag mount and a tin or aluminum gutter that goes down to the ground to drain water. Condo living doesn't help much with rules and regs as they are. Any suggestions would greatly be appreciated. Thanks 283171582_5372162249481435_3777874351094006042_n.jpg
 

Have you tried to raise or lower the whip to get a good SWR?
Maybe raising the table above the cement ledge so as the coil is above the ledge will help?
Oh yes , that's where the K40 stinger came in . The utility table is on about 4 inch bricks . Like I said , the match "appears" to be good but there's RF apparently all over the place and can change very easily , I really don't know what the "truth" is here ? Maybe false readings and or mismatch because of the RF ? I'm only guessing here but lets for say if I did fix the grounding issue maybe the decent SWR might change as well ?
 
The proximity to the building is not helping. You are getting stray RF all over the place, and if you are sitting on the porch as well ,you are effecting the match.
You would probably be better off trying to run a dipole along to top of the porch horizontally and see how that works for you because you are never going to have a stable match with your current setup.
 
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I don't know about that particular antenna, but I do know that about half of the mag mount antennas I tear open only have the shield connection to the metal cup that holds the magnet, not the foil covering the magnet that is supposed to capacitively couple to the metal surface. From the drastically changing SWR, I assume the latter is the case and the shield is the only counterpoise and the metal table is doing nothing (I could be wrong).

If you can make a ground connection at the base of the antenna, I would turn it into a dipole and (assuming your house is the same design as the neighbors) use that wood post as a support and hang the counterpoise wire straight down.dipole.png
 
As Recon suggested, I would stand the table on its end, making it taller, so that the antenna coil is above the ledge. And would move the table to the left so it is farther from the wall (or chimney) on the right.

In other words, get the base of the antenna in the clear as best you can. Or switch to a top loaded antenna such as a Firestik.
 
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Two options:

1) Get a few 9ft lengths of wire and attach them to the table.

2) Deliberately use the coax as a RF ground. Measure 9ft back from the magmount and put in a coil. Now you can't just do any random coiling up of the coax, it needs to be made to be tuned for the frequency we need it to choke. It needs to be exactly or as close as possible 5 turns of coax with a 4.25"/110mm internal diameter. That will act as a RF choke for 27MHz and stop the common mode RFI you're experiencing.
 
Thank you all very much for the ideas and knowhow . You have all given me something to go on and at least I can give them a try . As I said before Condo living and rules and regulations limit what I can do as is , if it were up to me I would have a good antenna on the roof but that's a no go.
You may be right Triple 9 but at the same time I do have a wavering decent match as is that does transmit fairly well for what it is. Thank you Brandon that is certainly something I can give a shot (thanks for the photos !) FR98 ? Chicken Wire ? Do you mean as if I would be draping that over the top and sides of the table ? and the mag would go on top of that ?
M0GVZ Sounds like you know what your talking about and is certainly worth a try. I do realize that once I get the wires and what not I will more then likely be tuning the antenna again because I'm pretty sure what I have now will rise to the occasion. You guys rock ! Much thanks (Was also wondering if I drilled a hole in that table and used a Wilson type roof mount if that would help as well )
 
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I kind of figured that M0GVZ , I have tried other things suggected and nothing helped my situation but I keep on trying slowly as I go , gonna be running about 60 feet of copper wire hidden behind gutter drain going down to the ground and drilled a hole to get it through my garage to the only water pipe at my washer and dryers , so grateful for all the help guys , Antennas were never my favorite pass time in this hobby , I honestly believe the person that I am just radiates and causes me problems . I doubt it , but it sure seems like it some times. Thanks again (News at a 11)
 
Update over a month later (kind of still working on things as time goes by) The 50ft 10 gage multi-stranded copper wire really helped a lot going down into my garage and to the only water pipe down there .......I just connected the end to where the coax connects on the female 259 inside the magmount casing on the ground side .......I moved my two barbaques along side the table (maybe a little more ground plane ?) I have a 40 channel wave so to speak from channel 15 to 55 (flat in the middle) .......The SSB channels I use 35 to 45 with about 120 talking watts go from flat to about 1.3 ......although being blocked off from the west I'm doing fairly well everywhere else . When DX is in I have blown some minds out there (even my own) Darn H.O.A.'s ! It's hard to be humble when I'm doing the best I can but it's working for now . I got to say though , it's surely been a learning experience . As always , much thanks to everybody that has chimed in. Switch
 
Update over a month later (kind of still working on things as time goes by) The 50ft 10 gage multi-stranded copper wire really helped a lot going down into my garage and to the only water pipe down there .......I just connected the end to where the coax connects on the female 259 inside the magmount casing on the ground side .......I moved my two barbaques along side the table (maybe a little more ground plane ?) I have a 40 channel wave so to speak from channel 15 to 55 (flat in the middle) .......The SSB channels I use 35 to 45 with about 120 talking watts go from flat to about 1.3 ......although being blocked off from the west I'm doing fairly well everywhere else . When DX is in I have blown some minds out there (even my own) Darn H.O.A.'s ! It's hard to be humble when I'm doing the best I can but it's working for now . I got to say though , it's surely been a learning experience . As always , much thanks to everybody that has chimed in. Switch
A solid 5/8" diameter X 8' long copper grounding rod into the ground would be better than attaching the copper wire to a hollow copper or galvanized water pipe inside a building.
 
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A solid 5/8" diameter X 8' long copper grounding rod into the ground would be better than attaching the copper wire to a hollow copper or galvanized water pipe inside a building.
I get that Recon , thanks ! My problem is H.O.A. and I'm being as sneaky as I can under the curcumstances .......it's just the way it goes I'm sorry to say . Just the fact I'm talking and doing fairly well for what it is , I just have to accept my limitations . Switch
 

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