[Achped]

I just installed my Arizona Rocky Road antenna mount, with a 2ft firestik and some high quality coax.

My SWR is 3.8 on channel 40, and 3.6ish on channel 1. This is using a radioshack SWR meter.

I tried tuning the antenna, doesn't change the SWR much. Looked over everything the best I could. Coax isn't kinked, ground is good.

Also, when the engine is running I hear a humming noise. It doesn't do it when the key's in the ON position but the engine's off.

What should I check first? I mean, 3.8 SWR is alot.

[Bgeddes]

Antenna is too short, based on the SWR it looks like it's just a touch too short. Don't get me wrong, the 2' length isn't the problem, it's the tuning or a faulty loading coil in the antenna.

[newjeeperguy]

Originally Posted by Bgeddes

Antenna is too short, based on the SWR it looks like it's just a touch too short. Don't get me wrong, the 2' length isn't the problem, it's the tuning or a faulty loading coil in the antenna.

Actually his antenna is to long, not to short. Not that it will matter much because he only has a difference of .2 from channel 1 and 40. So adjusting it to be flat (3.7 on 1 and 40) is not going lower his SWR under 3.0, so he can use the radio.

This sounds like a bad ground problem. Is there any way you can take pics of your mount, where the coax connects and how the mount is grounded?

If EVERYTHING is as good as you say (coax, ground, mount) then you either have a bad antenna or bad meter. What Radio are you trying to use with this? Some of the higher end units have a built in SWR feature so you could compare that to the rat shack meter.

[TJ-n-Oregon]

How do you know you have a good ground? An RF ground is different than an electrical ground...and judging by your current SWR's I'd say your ground isn't as good as you think. Run a ground strap from the mount itself to a shiney metal point on the tub and/or chassis. The 2' antenna is going to be extremely narrow banded anyway and likely unforgiving to an insufficient RF ground.

[Achped]

I meant good ground for the radio (i.e. the noise)

But I am double checking now, will get pics.

Edit: Just found the problem : the piece on the coax that actually screws onto the mount was broken off of the coax cable, with the piece fully screwed on and tightened, you could pull the coax right outta the mount.

Off to rat shack for some new (albeit cheap) coax.

[MCanavan]

Take it to an empty parking lot. I know it sounds crazy but I was tuning mine in my driveway and it was about 3-5 SWR and I took it to a parking lot and it dropped to just above 2.

[FmrVette]

Originally Posted by Achped

I just installed my Arizona Rocky Road antenna mount, with a 2ft firestik and some high quality coax.

My SWR is 3.8 on channel 40, and 3.6ish on channel 1. This is using a radioshack SWR meter.

Are you using the FireStik cable? The one with the ring connector? If so, take the ring connector off of the antenna, flip it over, and try tuning your antenna again.

Post back.

[Achped]

Okay, I put the new coax on (not a ring cable, just a standard PL259 connector or whatever.

My SWR is now 1.8 on 40 and 1.6 on 1, again, I'll get 1.7 if I flatten it out. I can "live" with that I guess, but I still don't see why I'm getting about .5 higher than others here with the same setup. I was talking to a guy about ~5 miles away (over a VERY populated area), and he came in clear as day, he said I sounded less than optimal though (understood me ok however).

I'll go to an empty parking lot and see what it says (the rat shack SWR meter and the SWR meter on my radio are almost alike, so I'm just going by the radio SWR meter now)

But I've still got that irritating noise. When the engine is on and the RF gain is above 1/2 way I get that humming noise. I switched the ground to a big thick (sanded down) piece of metal behind the dash, still got the noise.

[Achped]

Here's what it looked like with the old coax.

[newjeeperguy]

How do you have the power and ground running for the CB? The best way I have found to get rid of engine noise was to follow a well written write up on L4J.
Located HERE
It really cut down on the engine noise I was getting. I also used very good coax to run the power with RG-8x (aka Mini 8).

Also have you changed your plug wires? One of the smart mods around here suggested if you have went to a high performance (low resistive) plug wire it will add more noise to your electronics. He is correct, as usual.


As for getting the SWR lower I would try running an extra ground wire from the mount to a good ground spot (like the frame) and see if that helps any.

[Achped]

My SWR, it is under 1.5 from 8 to like 32, but then it just shoots to like 1.8

I changed my plug wires, but with stock.

I hear the plugs shooting, but this noise is different. I believe it's the fuel pump as when I turn the key to on, it makes it for a split second, but shuts off.

[newjeeperguy]

Originally Posted by Achped

My SWR, it is under 1.5 from 8 to like 32, but then it just shoots to like 1.8

I changed my plug wires, but with stock.

I hear the plugs shooting, but this noise is different. I believe it's the fuel pump as when I turn the key to on, it makes it for a split second, but shuts off.

For that noise Stu has some great stuff on his site. Located HERE

Also I have heard doing this with chokes helps ALLOT for fuel pump noise. HERE

As for getting the SWR down lower I would still think it was a grounding issue. Either between the PL259 connector and the mount or the mount and the frame of the Jeep.

[Scrambler82]

Originally Posted by TJ-n-Oregon

How do you know you have a good ground? An RF ground is different than an electrical ground...and judging by your current SWR's I'd say your ground isn't as good as you think. Run a ground strap from the mount itself to a shiney metal point on the tub and/or chassis. The 2' antenna is going to be extremely narrow banded anyway and likely unforgiving to an insufficient RF ground.

As TJ-n has stated run the additional ground braid from the antenna mount (drill a hole if necessary) to a bare metal mounting point on the tub and then to the chassis, same thing bare metal under the lug.

I like to use External Star Lock Washers (heavy duty versions), and some anti-corrision paste in between the lug/frame/and machine screw head.

On the SWR thing... 1.8 is OK but not good, 1.5 or lower should be where you want to go.
Why you ask... because thing of this a 1 to 1 SWR give you almost all of your 4 watts of power at the antenna, a 2 to1 SWR give you approx 2 watts of power at the antenna and so on and so on (don't hold me to teh power levels).
Once you think you have things where you want them, check the SWR on your most used channel, the one you talk on the most; make sure it is as low as possible, all the other channels will work OK.

Ltr,

[smunns]

Not to hi-jack, but I'm having the same problems. I took a standard aluminum mirror antenna mount, drilled a new hole in it, and bolted it to my spare tire carrier. SWR is 3+. I'm thinking I need to ground it better to get my SWR down. Would running a heavy duty ground wire from the mount to the Jeep's frame solve my problems?

[TJ-n-Oregon]

Originally Posted by smunns

Not to hi-jack, but I'm having the same problems. I took a standard aluminum mirror antenna mount, drilled a new hole in it, and bolted it to my spare tire carrier. SWR is 3+. I'm thinking I need to ground it better to get my SWR down. Would running a heavy duty ground wire from the mount to the Jeep's frame solve my problems?

Hard to say...but it most certainly wouldn't hurt anything. No such thing as too much grounding...especially for the antenna system.