possible antenna switch

[mfd2727]

I currently have a 5' fiberglass K40 antenna on the bed rail of my F150. I have it mounted about 2 feet behind the edge of the cab and more than half of the antenna is sticking up above the cab.

I have been thinking of getting a magnet mount antenna base load antenna to put on top of the cab instead (K40 or Wilson probably, not sure which yet).

Here is the reason why: In order for the antenna to tune, I had to run a ground from the mount to the frame. I did this in 2 short sections. One from the mount to the tie down point in the bed, then from there to the frame. I am getting alot of noise from the fuel pump.

I wasn't sure if going to a magnet mount on the roof would help any of that noise, plus wasn't sure if mounting it higher like that would help my tx/rx any, if at all.

Thanks

 

[Robb]

Welcome to the forum.

Putting the Wilson antenna on the top of the vehicle will be well worth the effort and expense. Both receive and transmit will be better and noticable; best wy to go. If it was me - I wouldn't bother with the K40; they are just so-so antennas. Whereas the Wilson will 'blow the K40 in the weeds'. You will wonder how you ever got along w/o it. I had a K40 until I got the Wilson; I never looked back. Except to give the K40 away to someone who had no antenna and needed one...

 

[mfd2727]

thanks for the reply. I've been getting out pretty good with what I have. my main thought was wondering if switching to a magnet mount that is using the cab as a ground plane would have any less RFI than a bed mount that is grounded to the frame. didn't know if anyone had tried that with any luck or not.

I have had Wilson's in the past, just couldn't find any in a fiberglass whip locally when I put this one together.

 

[biz]

im no expert but i think putting a noise filter in line on your power wires will cut down fuel pump and alternator noise.

They are pretty cheap too.... some are only 10-25 bucks i think.

 

[mfd2727]

already tried that. the noise is coming through the antenna wire. in order to even get the antenna to match I had to ground the mount to the frame. I am just wondering if using a magnet mount on the cab would help out any.

 

[biz]

maybe this will help...

http://www.worldwidedx.com/installation-station-setup/30136-fuel-pump-noise.html

 

[Moleculo]

my main thought was wondering if switching to a magnet mount that is using the cab as a ground plane would have any less RFI than a bed mount that is grounded to the frame.

Ideally you should be using the entire vehicle as a groundplane. Often you need to accomplish that by bonding things to gether with ground strap. For example, you might need to bond both the cab and the bed to the frame. You'll just have to inspect the vehicle to see how it's currently set up.

If the noise is coming in through the antenna, you can try relocating the antenna. Changing to the mag-mount may help; it may not. If relocating isn't practical or doesn't solve the problem, then you have to try to eliminate the source of the noise. Eliminating fuel pump noise is fairly easy if you can get at the fuel pump. Usually a couple of bypass ceramic disc capacitors across the power leads and snap on ferrite beads on the power line will get rid of it. If it's impossible to get at the source, you can try filtering it out by using a DSP speaker of some type. They really work pretty good for filtering fuel line and alternator noise.

 

[Robb]

Lotsa things can make noise in a vehicle. The fuel pump, alternator, and even the spark plug wires - if they are old. I run a Wilson 1000 mag mount on a new Honda CR-V and have no noise whatsoever. Don't blame either antenna - and neither will either antenna cancel out noise better than the other.

You might have to get down 'n dirty with your ride and sort it out. I would eliminate the alternator noise and fuel pump noise by using what 'biz' suggested. Then I would consider changing out the spark plug wires if the inline power filter didn't take care of the problem...

 

[mfd2727]

I like some of the ideas on the link that was sent such as ground strap from cab to frame and grounding the exhaust. I don't have traditional spark plug wires because my truck has the coil on plug ignition. have wondered about doing something with the pump wiring. may have to wait until it gets warmer to tackle that one. ground straps can be done fairly quickly outside.

So I take it I would want to look at something like an electrolytic capacitor and put it between the wires going to the fuel pump as close to the pump as I can? Something like a 50volt 2200 microfarad?

After getting that taken care of: would a magnet mount on the roof get out and receive any better than my 5' fiberglass on the bed rail?

Thanks for all the help guys

 

[W5LZ]

mfd2727,
Nothing wrong with any of those suggestions/ideas. None of them may be an instant 'cure', but they also will very, very seldom cause any harm.
Would there be any difference between the antenna you are using now on the bed-rail and a mag-mount on the roof? Sure, there will be some difference, but not much, and that difference can be in either direction, good/bad. The only good reason for using a mag-mount antenna is that you can't drill a hole, it's only for convenience. There are no electrical benefits. They do have electrical limits because of how they work. And if you think you are 'saving' the market value of your vehicle by not drilling that hole, you are mistaken.
- 'Doc

 

[mfd2727]

not afraid to drill holes, have done that already with my mount. current antenna is a 5' fiberglass antenna that is about 24" back from the cab, and 60% of the antenna is above the cab.

would a base mount magnetic on top of the cab with a 52"whip like a Wilson 500 or 1000 get out any better than what is on there because it sticks up higher?

 

[Robb]

not afraid to drill holes, have done that already with my mount. current antenna is a 5' fiberglass antenna that is about 24" back from the cab, and 60% of the antenna is above the cab.

would a base mount magnetic on top of the cab with a 52"whip like a Wilson 500 or 1000 get out any better than what is on there because it sticks up higher?

Having all of the antenna above the cab is going to have a better transmit pattern than an antenna that is partially below the cab. That will be a gain right there - as well as having it put up higher. As usual, I think the Wilson 1000 is the best of the bunch. It handles a decent amount of power if you are going that way with it - and the receive is better than most antennas on the market. That's been my experience - it's a winner.