New Bearcat 989 SSB installation high SWR across the spectrum.

[tandlbrewer]

I installed all new equipment. I have a duel 4ft antenna system with the antennas mounted to the fenders on my pickup. 96 f250. Ok so step by step. I mounted the stud to the mount. Checked for continuity between the mounts and the studs and there was none. Got good continuity through the studs. I mounted the antennas and got the same results all good. Mounted the mounts to the fender and retested between the mount and the battery ground, good continuity. None between the neg on the battery and the antenna stud. Checked the coax, pos to pos, good continuity in both wires. Inside pos to outside neg on both wires isolated no continuity. Attached the wires to the base of the studs rechecked continuity between pos in wire and antenna pos, good continuity. Pos on wire to stud, no continuity al good. Plugged the wire into the back of the CB, now all of a sudden I have continuity between mount and stud on the antennas. Disconnected everything and tested the coax plug on the back of the CB, I have continuity between the positive pin and the neg outside threads... Help please. Not sure what to do. My SWR is about 9 on channel 1 and 40

 

[prcguy]

There can be continuity between center and ground on some radios, don’t worry about that. Tell us more about what the antenna mounts are on, how much metal, etc. Are you using a factory co-phasing harness with two 75ohm cables about 18ft long each from the radio to antennas?

Do you have a single piece of 50 ohm coax you can run to just one antenna for a sanity check?

 

[redbeard]

Try running a coax to only one antenna. You can run duals for the look but they are too close on a pickup to be effective and could be part of the issue.

Also RF ground is not electrical ground and your battery plays no part in your antenna system. Neither does the vehicle frame in case you are thinking of wiring it in for no reason.

And do not test the radio antenna plug for continuity unless you are trying to damage internal components.

 

[tandlbrewer]

There can be continuity between center and ground on some radios, don’t worry about that. Tell us more about what the antenna mounts are on, how much metal, etc. Are you using a factory co-phasing harness with two 75ohm cables about 18ft long each from the radio to antennas?

Do you have a single piece of 50 ohm coax you can run to just one antenna for a sanity check?

I don't have a single piece of coax.. would I get the same result by just disconnecting one antenna? It's all factory stuff. Trying to figure out how to post pictures of the antenna. The cable I have is 8ft.

 

[tandlbrewer]

Here are some images

 

[tandlbrewer]

Here is the radio side

 

[prcguy]

I don't have a single piece of coax.. would I get the same result by just disconnecting one antenna? It's all factory stuff. Trying to figure out how to post pictures of the antenna. The cable I have is 8ft.

If you disconnect one antenna you still have the unterminated cable from that antenna connected to the radio, not a legitimate test. The dual antenna phasing harness is usually about 18ft long. Did you buy it new being 8ft long or did you cut it?

The pictures look ok, not real pretty but no reason it should not work and tune up.

 

[niceguy71]

The pictures look ok, not real pretty but no reason it should not work and tune up.

I had always thought the duel antenna's have to be 9 feet apart from each other... great for a Semi Truck... but they don't work on a pick-up truck? or is that just for optimum performance?

I just looked it up.. I don't think he has the absolute minimum between antenna's to allow it to work

The Dual CB Antenna Guide

Dual CB antennas sure look impressive. But are they a good choice for your truck or vehicle? We cover everything you need to know.

www.rightchannelradios.com

 

[redbeard]

Also what meter are you using to check SWR? Most built-in meters on radios are notoriously wrong. External always.

 

[tandlbrewer]

Just tried a friends mag mount antenna, SWR dropped to normal range

 

[WSAC829]

Agree to the above. Running duals is a PITA to get working properly. As suggested, I'd only hook up 1 of the antennas with a single piece of coax. The other can be left unhooked for “looks”, or sell it and recover some money. Passenger vehicles aren't wide enough to properly space dual cb antennas apart.

I have a similar setup on my F150, but I only run 1 cb antenna. The other fender has an antenna mounted for my dual band uhf/vhf radio. Not sure if it helped at all, but I also ran a small ground wire from the mount to another ground screw in the fender well. Tested with both the internal and external swr meters and I'm pretty much 1:1 across all 40 using a 3’ Diesel whip.

 

[slowmover]

Welcome!

Good to have come to a place where advice can be sought, and some research done.

Best location for an antenna mount (highest performance) is atop the center of metal mass. Pickup truck roof, in this case.

Cophase antennas are a crutch we use on big trucks to deal with that huge trailer behind us.

Yes, you can make it work.

Here’s the ideal:





This is the man I’ll talk with the farthest while on the road. He will sound best, too, assuming the rest of the installation is top-drawer, and the gear carefully chosen.

Start with a guide:

Learning Center

www.rightchannelradios.com

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[prcguy]

Agree to the above. Running duals is a PITA to get working properly. As suggested, I'd only hook up 1 of the antennas with a single piece of coax. The other can be left unhooked for “looks”, or sell it and recover some money. Passenger vehicles aren't wide enough to properly space dual cb antennas apart.

I have a similar setup on my F150, but I only run 1 cb antenna. The other fender has an antenna mounted for my dual band uhf/vhf radio. Not sure if it helped at all, but I also ran a small ground wire from the mount to another ground screw in the fender well. Tested with both the internal and external swr meters and I'm pretty much 1:1 across all 40 using a 3’ Diesel whip.

I’ve probably installed at least a hundred sets of dual antennas on pickup trucks and big rigs and they all tuned and worked fine, that was my job a long time ago. Pickups are easier with more ground plane to work with compared to just a mirror on a fiberglass big rig cab. A single antenna on the roof of a pickup will work better than duals but some don’t want to drill the hole. One antenna on the cowl or upper side bed wall behind the cab can also work well.

 

[niceguy71]

I’ve probably installed at least a hundred sets of dual antennas on pickup trucks and big rigs and they all tuned and worked fine, that was my job a long time ago. Pickups are easier with more ground plane to work with compared to just a mirror on a fiberglass big rig cab. A single antenna on the roof of a pickup will work better than duals but some don’t want to drill the hole. One antenna on the cowl or upper side bed wall behind the cab can also work well.

I learn something new everyday here.... Today I learned dual antennas will work on a pickup

 

[slowmover]

“One antenna on the cowl or upper side bed wall behind the cab can also work well”.

Easiest.

 

[prcguy]

“One antenna on the cowl or upper side bed wall behind the cab can also work well”.

Easiest.

I prefer the side bed wall mainly to keep the ignition noise down. Sometimes a cowl or hood mounted CB antenna can pick up more spark plug noise.

 

[slowmover]

I prefer the side bed wall mainly to keep the ignition noise down. Sometimes a cowl or hood mounted CB antenna can pick up more spark plug noise.

And I’m happy to hear the voice of experience to relay better advice.

IIRC, a foot back from cab and an inch down interior bed wall tunes better than atop bed rail?

It seems pretty easy to mount if given that good result (and not as likely to be hit as with rail-top or to bed exterior).

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[prcguy]

And I’m happy to hear the voice of experience to relay better advice.

IIRC, a foot back from cab and an inch down interior bed wall tunes better than atop bed rail?

It seems pretty easy to mount if given that good result (and not as likely to be hit as with rail-top or to bed exterior).

.

I‘ve had problems tuning antennas on the top bed rail but down on the inside or outside 6” or a foot seems to work great. Might have something to do with how the antenna sees the ground plane like a thin metal strip on top vs seeing the entire inner walls with bed or entire outer wall, fender, etc.

 

[slowmover]

I‘ve had problems tuning antennas on the top bed rail but down on the inside or outside 6” or a foot seems to work great. Might have something to do with how the antenna sees the ground plane like a thin metal strip on top vs seeing the entire inner walls with bed or entire outer wall, fender, etc.

Thanks. I wanted that as a clear picture. It makes sense to me that bed walls trump top rails.

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