Antenna Placement / Location

[Glider]

So, going to bite the bullet and do my own antenna install and figured I might as well do a permanent install of BOTH my GMRS NMO roof mount and CB Roof Mount antennas and get rid of the magnet mounts.

 

I have a 2018 Ram 2500 Power Wagon Crew Cab truck. I do not have a sunroof so have basically the entire roof for antenna install.

 

For the CB I plan to use BOTH a 66” whip and/or a 36” short load whip (depending on traveling cross country vs 4x4ing etc., etc.

 

For the GMRS I plan to use both a 5/8 over 5/8 wave at 33” and a ¼ wave at 6”, again dependent on where I am driving.

 

Most the time, daily routine driving will use the 36” CB antenna and the 6” ¼ wave GMRS antenna.

 

So, what would be the best placement for these antenna’s?

 

I am thinking down the middle rather than side by side.

 

Should the CB antenna be centered on the roof left to right and front to back and then the GMRS centered left to right but closer to the rear? How far from the other antenna or the rear etc., etc.? Hopefully you get what I am asking.

 

The truck is only a year old, so I really don’t want to mess this up and want to do it for the best possible performance results.

 

Looking on line I see antenna’s being mounted all different way – sometimes do to sun/moon roofs which I DO NOT have so am fortunate there.

 

Look forward to hearing from all of you and saving myself from the heartache of doing it wrong. Have no problems saying I don’t KNOW what to do and need some help.

 

Thanks,
Tim

[coryb27]

I ran mine down the center without issue. The UHF and CB will not cause any issues.

 

Corey

[marcspaz]

Unless you only need to consistently talk a mile or two, you're wasting your time installing a CB antenna that is not a 114" whip. 

 

I have tested every single possible configuration on everything from motorcycles to a new 2019 Cascadia tractor.  Even with the most well placed antenna and the best performing equipment, bottom loaded, center loaded and fiberglass wound antennas are all poor performers.

 

The absolute best talking CB antenna that I found (aside from a 114" whip) is a 4' Firestick (5/8 wave) mounted on a 12" solid steel extension acting as part of the antenna (like a top-loaded antenna).  That talked 11 miles as the crow flies, on AM, when mounted on the top of a tractor, 8 feet above the ground with 4 watts RMS.  Same vehicle and radio with a 114" whip talked 42 miles as the crow flies on AM, using only 2.5 watts RMS.  I don't know how far it could on low or high power, because we got tired of driving and gave up.

 

The next two best antennas I tested are the Wilson 5000 and Wilson 1000.  The only benefits to using those over the Firestick is you can also use them with a 600 watt PEP amp or 200 watt PEP amp (respectively) on 10 meters... assuming you're also a ham and are trying to keep your antenna count down.

 

EDIT:  To help improve your chances of getting good performance on the CB, be sure to buy a very high quality 18 foot transmission line with 259 connectors on both ends, and use a HD stud with a 259 input.  The impedance balances out perfectly for a half wave.  The half wave cable and the quarter wave ground-plain antenna give you a perfect full wave length from the output of the radio to the tip of the antenna.

[Glider]

My last trip cross country reinforced that CB is not anywhere near as popular as in the 70's and 80's. We still use them routinely while  4x4ing along with GMRS. I have had good luck and am very pleased with the Stryker SR-A 10 antenna which is a base loaded antenna. Outperformed the Wilson 5000 in my case. I can get 10 miles pretty easily with a legal CB, maybe because it is so dead around here. Around town here though the whip on the SR-A 10 which is the same as the Wilson 1000 & 5000 in length hit every drive through and tree hanging over the roads in my neighborhood and why I use the 36" short load whip. Although CB is not as busy as before I still find it useful while traveling cross country which we do every summer.

 

Still trying to figure out the order and thinking I will center the CB antenna and then put the GMRS antenna halfway between the CB antenna and the rear of the cab of the truck.

 

Think this will work out OK? Any reasons why I shouldn't?

[Elkhunter521]

Im using a headache rack to mount antennas on my ford Superduty. The GMRS antenna is mounted on the top center of the rack. It is a unity gain (6") nmo mount on a 6"x6"x1/16 plate. Also on the headache rack are co-phase 4' firestick 5/8 wave antennas. They are 5'6" apart and mounted on plates 4 inches behind the rack. Both antennas are completely exposed to each other. The rack is bonded to the bed with 4 8ga stranded coper wires. The rack is also bonded to cab with 4 8ga stranded copper.

 

I am also running a 30 mHz low filter on the system before it splits to co-phase. This brought swr down to 1.1.

[marcspaz]

My last trip cross country reinforced that CB is not anywhere near as popular as in the 70's and 80's. We still use them routinely while  4x4ing along with GMRS. I have had good luck and am very pleased with the Stryker SR-A 10 antenna which is a base loaded antenna. Outperformed the Wilson 5000 in my case. I can get 10 miles pretty easily with a legal CB, maybe because it is so dead around here. Around town here though the whip on the SR-A 10 which is the same as the Wilson 1000 & 5000 in length hit every drive through and tree hanging over the roads in my neighborhood and why I use the 36" short load whip. Although CB is not as busy as before I still find it useful while traveling cross country which we do every summer.

 

Still trying to figure out the order and thinking I will center the CB antenna and then put the GMRS antenna halfway between the CB antenna and the rear of the cab of the truck.

 

Think this will work out OK? Any reasons why I shouldn't?

 

 

Glad to hear you are having luck with the Stryker.  Environmental conditions will play heavily into how well your radio can receive a weak signal.  If you have a received signal that is only 1 S unit, but you have 3 S units of stray noise around you, you will never hear the 1 S unit signal.  If you drive out of the high noise area, even if you get further away, the reduction is RF noise will allow you to have a conversation with that station, even at 1 S unit, and be able to have a 100% copy.

 

As far as placement goes, as long as they are spaced in a way that one doesn't fall within a physical harmonic, you should be fine.  It's damn near impossible to do on purpose.  It's very unlikely that you will do it by mistake.

 

I have noticed that when I key my GMRS while in high power, the noise level on my HF gear goes up. Nothing unreasonable, but when the squelch is open, I can notice it.  That's all.  When the squelch is closed, there is no impact.  I have a 120 watt RMS amp on my 10m radio.  Whenever I use the amp, I turn the GMRS gear off.  Though, I have never actually experienced any of my HF gear causing issues with my VHF or UHF gear.

 

 

Im using a headache rack to mount antennas on my ford Superduty. The GMRS antenna is mounted on the top center of the rack. It is a unity gain (6") nmo mount on a 6"x6"x1/16 plate. Also on the headache rack are co-phase 4' firestick 5/8 wave antennas. They are 5'6" apart and mounted on plates 4 inches behind the rack. Both antennas are completely exposed to each other. The rack is bonded to the bed with 4 8ga stranded coper wires. The rack is also bonded to cab with 4 8ga stranded copper.

 

I am also running a 30 mHz low filter on the system before it splits to co-phase. This brought swr down to 1.1.

 

That sounds like an awesome setup!

[taco6513]

Service truck has a AnyTone 5555N opened up export mode.12 watts. 108" whip. Hits the low bridges. Does ok. Not near the traffic there was 25 years ago. GMRS is a Motorola M1225 with a 6db gain Midland on a nmo mount. First time I have used nmo mounts. They look clean inside and out. Have not noticed any interference from each other.

[gortex2]

I run a Larsen NMO27 on my work truck. If done properly it will outperform most antenna's. I have a 4' fiberglass on my personal vehicle and the Larsen is night and day. Its an NMO mount and done properly will last for years. 

[Jones]

I also have a Larsen NMO27B on my work van for CB.  About 2 feet in front of it is a 48" Hustler VHF antenna, and a foot-and-a-half in front of that is a Browning 5/8 over 5/8 UHF mag-mount antenna.  No problems with them interfering with each other.