roof rack mount options?

[freshlikesushi]

Im actually doing Velcro.

industrial Velcro on the passenger side of the center console will hold. We use it in the aircraft business to secure stuff in the flight deck, so it should work for how light this thing is. It doesn't get hot enough here to melt the glue like it did in Saudi, so I should be alright. ill just remove the mic cord and throw it in the glovebox when im not using it. Id rather have a more perm solution so im not constantly taking it in and out every weekend since the local club requires a CB. Saturday im going, so hence just getting a good magnetic so I can go out and deal with another solution later

 

[4x4junkie]

http://www.amazon.com/gp/product/B000H2W270/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

this is what i got.
http://www.amazon.com/gp/product/B00024DIDK/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Whoops, I thought you were speaking of the original "K40" antenna and the magnet base for it:
http://www.amazon.com/K40-K40A-57-25-Antenna-Stainless/dp/B000FSADEA
http://www.amazon.com/K40-M-40-Black-Magnet-Antenna/dp/B001JT34MW

I suspect a K30 should be fine as long as you don't need top-notch performance. At 35", it wouldn't be my first choice of antenna though.


Another option for mounting your radio (since you mentioned just stowing the mic when you don't need it, assuming you don't need to remove the radio itself) might be 3M Mounting Tape. It's much more permanent than velcro, but you can still remove it with a putty knife or similar if needed (and no amount of heat or cold will melt or cause it to come loose or get brittle, etc.). Doesn't leave any hard-to-remove residue either.

 

[RobRed]

This might work for CB antenna as well

http://forum.tlcfaq.com//viewtopic.php?f=7&t=19&p=971#p971

 

[AlbanyTom]

High strength velcro is a great idea. Is there a brand/version you recommend? Does it hold up long term? This could be the simple solution to mounting my ft-8800 remote head in the truck without having to figure out how to screw it under the plastic dashboard.

 

[freshlikesushi]

Velcro brand industrial strength stuff. The stuff you get from lowes works just fine. Got some 4x2" strips, black to "blend in" with the interior. its not the prettiest thing, but I put a quick disconnect plug on the power cables, and just can unhook the antenna and tuck it up and be done if I wanted to remove it.

doesn't help though that my antenna wire is about 6 inches too short :/

 

[AlbanyTom]

Velcro brand industrial strength stuff. The stuff you get from lowes works just fine. Got some 4x2" strips, black to "blend in" with the interior. its not the prettiest thing, but I put a quick disconnect plug on the power cables, and just can unhook the antenna and tuck it up and be done if I wanted to remove it.

Cool, thanks.

doesn't help though that my antenna wire is about 6 inches too short :/

Just move it 6" toward where the cable goes down. If anyone asks why it's not in the middle, reply with either: a) I had my friend at JPL run a simulation on it, and that's the best spot on this truck for an even radiation pattern. No clue why. Or.. b) That's where you're *supposed* to mount it.

 

[MOguy]

A well made magnetic mount CB antenna such as the K40 or Wilson "Little Wil" actually works quite well in comparison to many setups using the ubiquitous 3' or 4' fiberglass antenna. In my opinion, your K40 will out perform a Firestik "no ground plane" antenna.

If you can't use a trunk/lip/hatch mount, and you don't want to drill any holes in your roof, then your choices are limited to a roof rack mount such as the one pictured.

This/\
I ran a K40 for a while. It is about your best option (or the wilson) unless you go with a perm mount. It will perform FAR better than a no ground plane antenna.

 

[freshlikesushi]

ill most likely get a larger setup that is magnetic as I need a longer antenna cord anyways. this one works decent. swr is a bit high across the range, but meh.

 

[MOguy]

ill most likely get a larger setup that is magnetic as I need a longer antenna cord anyways. this one works decent. swr is a bit high across the range, but meh.

What ever you mount your antenna to becomes the other half of th the antenna. High and center on you vehicle and to bare metal is best. Everything else is a compromise, but life is filled with compromises. Mounting to things that mount to the body, such as a rack, will never deliever top performance. When you mount to things that mount to the body you have layers of paint between the antenna and the body and this will greatly affect your SWR. Your SWR will probably always be higher until you mount or RF ground it to bare metal on the body. If your not looking for optimum performace no big deal.

 

[mpinco]

...... Mounting to things that mount to the body, such as a rack, will never deliever top performance. .......

An aspect that many miss. Mounting to a roof rack adds capacitance to one side of the virtual dipole antenna and impedance to the rf ground. It's like sandwiching a capacitor between the antenna and rf ground. Adding dc grounds to the rack could actually result in even lower performance as the ground straps become little radiators. For HF a bridge probably won't work. For VHF/UHF you can probably be ok.

 

[4x4junkie]

I've mounted antennas to racks of various types and not had problems with them (both for CB and VHF/UHF). The key is to have the rack well-grounded to the roof or body in not just one spot, but in multiple spots (4 spots, one at each corner, is usually ideal). This provides a direct RF path to ground in all directions, and keeps the rack and/or it's grounds from turning into little antennas of their own. The rack itself being all one piece (fully-welded, etc) helps too.

Of course none of this is really relevant if the OP sticks with his decision to use a magnetic-mount antenna directly on the vehicle roof.

 

[MOguy]

I've mounted antennas to racks of various types and not had problems with them (both for CB and VHF/UHF). The key is to have the rack well-grounded to the roof or body in not just one spot, but in multiple spots (4 spots, one at each corner, is usually ideal). This provides a direct RF path to ground in all directions, and keeps the rack and/or it's grounds from turning into little antennas of their own. The rack itself being all one piece (fully-welded, etc) helps too.

Of course none of this is really relevant if the OP sticks with his decision to use a magnetic-mount antenna directly on the vehicle roof.

Did you check you SWR when you did this? It may work but it may not work the best it can.

 

[4x4junkie]

Of course I checked the SWR... Always been under 1.5:1, and very often under 1.3:1.

Again, it's about proper grounding of the rack. If you go and attach a single ground wire to one corner and then run it several feet all the way down to the frame or something, that of course is not going to work well. Each ground wire has to be a direct connection as short as possible from the rack directly to the body (roof). The rack being screwed right onto the roof fulfills this as well, as long as each screw provides a solid metal-to-metal connection at each point (no rubber insulating sleeves, etc).

If the rack is large enough, it can often act as a RF ground (plane) for the antenna by itself without any need for ground wires at all (it being approx 1/4-3/8 wavelength in size or bigger is usually sufficient in my experience).

 

[MOguy]

Of course I checked the SWR... Always been under 1.5:1, and very often under 1.3:1.

Again, it's about proper grounding of the rack. If you go and attach a single ground wire to one corner and then run it several feet all the way down to the frame or something, that of course is not going to work well. Each ground wire has to be a direct connection as short as possible from the rack directly to the body (roof). The rack being screwed right onto the roof fulfills this as well, as long as each screw provides a solid metal-to-metal connection at each point (no rubber insulating sleeves, etc).

If the rack is large enough, it can often act as a RF ground (plane) for the antenna by itself without any need for ground wires at all (it being approx 1/4-3/8 wavelength in size or bigger is usually sufficient in my experience).

If you have a good RF ground you would be fine on a rack, tire carrier or whatever. The OP stated he didn't want to drill holes and was using a magnetic antenna. The post is titled rack mount options. A magnetic antenna will not perform as well as it could stuck on a rack that is not properly grounded.

 

[mpinco]

I would be surprised if today's roof rack mounts provide low impedance/good conductivity between the rack itself and a metal roof. Many roof racks use combinations of channels and swedged in hardware, breaking that electrical path. This is done by manufacturers to address corrosion. That said, not all are the same so a VERY close inspection is required.

And then we have the move to aluminum bodies ...... No more mag mounts.