Co phased coax for big rig set up

[Cody Dixson]

I've been wanting to set up a co phased system in my semi to get a little bit more gain up and down the road. Truck stops do have cb wizards and co phased rg 58 coax which I'm not a huge fan of. My question is what coax can I use, does it matter? Can I use 2 equal lengths of rg8x to a short piece that goes to the radio and still get the 75 ohm that's needed? Any info on this would be awesome im sure there's already been 100000 other threads asking the exact question and if so please push me in the right direction
Thanks
1127 tmb
73

 

[midnight special]

2 pieces of rg 59 is what ya need to use,,, equal lengths,,,most times it is 18 feet rg59 is 75 ohm but when cophased will come out close to 50 ohm,, i used a pl259 coax end with out adapters,,, just prepared the ends to where they soldered up together,,,

 

[BJ radionut]

Antenna Performance : co-phasing - IW5EDI Simone - Ham-Radio

 

[Slowmover]

— BOBS CB for semi-custom harness.

— WILSON “Mini-8” harness if FME ends wanted.

1). What brand & model of truck?

2). What mounts?

3). What antennas? (to 14’ height is worthy goal).

— Look also to antenna feed point isolation (how an MFJ-915 works; other approaches can be smaller or more tidy)

— This may require longer legs if you were wrapping a toroid, for example. Wrap into harness, or wrap with separate piece of coax.

— IOW, do the rest of the planning. As big trucks are noisy I’ve become a believer in treating each end of every cable extant.

1/4” UV-rated split-loom for the coax and same type zip-ties to fasten.
DOW-CORNING #4 at terminations. Scotch 88 over self-fusing tape.

.

 

[jdchet]

I've been wanting to set up a co phased system in my semi to get a little bit more gain up and down the road. Truck stops do have cb wizards and co phased rg 58 coax which I'm not a huge fan of. My question is what coax can I use, does it matter? Can I use 2 equal lengths of rg8x to a short piece that goes to the radio and still get the 75 ohm that's needed? Any info on this would be awesome im sure there's already been 100000 other threads asking the exact question and if so please push me in the right direction
Thanks
1127 tmb
73

I, personally, would stick with one antenna. Getting one antenna right and tight can be quite the task in today's trucks! Adding a second antenna nearly doubles your headaches and I believe will limit your coax choices. My opinion.

JD

 

[Cody Dixson]

Thank you @BJ radionut you always come through! @Slowmover I just switched to the 97 freightshakin fld condo, so mirror mounts and I haven't bought any antennas so far thinking about the hussler whips. Currently just running a single Francis. The radio is a Galaxy dx98vhp but I'm thinking about keeping this at home and getting something like a stryker. @jdchet Roger Roger! That's the current set up I'd just like alittle bit more range up and down the road currently only reaching 5 miles out with a single stick

 

[Slowmover]

Get the antennas above the roof. To 14’. A set of 5’ or 6’ Skipshooter don’t cost much. (Natural color). You can git fancy later. But get em TALL!

K40MMMAX beehive antenna mounts (used to be under Wilson name) are what I had on my last FLD (also a ‘97). Great on west coast mounts. (Prep the surface for best ground). They’ll also polish up nice. (I ran them with Allen screw heads to rear).

You can “hide” the wrapped toroid or whatever you use as feedpoint choke “behind” this sized mount. Keeps it out of airstream like the mount was made for this in mind.

.

 

[hotrod]

i agree with get a skipshooter antenna i run one also.. for ya question ya need rg 59 ,75 ohm coax .. to my best of knowledge this is the only 75 ohm coax.

 

[BJ radionut]

to my best of knowledge this is the only 75 ohm coax.

Many 75 Ohm coax types: RG6 and RG11 are both 75 ohm coax types and will work for a "Phasing" harness.
The length will change "slightly" due to the difference in the Velocity Factor for the various makes and size.

 

[Slowmover]

Been thinking about this thread. This truck.
1997 Freightliner FLD, right?

Don’t see as many as a few years ago and it’s been 17-years since I drove an FLD. I couldn’t remember HOW the mirrors mounted. Door and/or cab?

Whatever the antenna setup, I’d want to loosen the arms and use some woven braid after cleaning corrosion at the body.

Arms to body/door.

Fender mirrors (if so equipped)

Air horns

Jump both door hinges.

Cab/Sleeper to frame at four outer corners.

Sidebox doors.

Sleeper vents.

I’ve looked under the Pete more extensively and realize I can get to the horizontal run of the exhaust and use braid under pipe clamps up to frame.

.

 

[Cody Dixson]

@Slowmover ive been trying to hunting skip shooter antennas down and im finding out it's probably best to order them offline. I've been running alot in Alabama Georgia Tennessee ect. And rays cb shop in West Memphis is the only place I've found that carries them but they're never open when I come through.

I ordered the pl259 to f type adapters and I replaced the pl259 T with an f connector T
Coax is in the mail and on its way and next check I'm gonna get an antenna Analyzers and tune my jumper from the radio to the T connector once I get all this together and up I will definitely post my findings here and @Slowmover you'll be the first to know! If all else fails I'll end up building the harness and getting rid of the adapters and t connector.

 

[jdchet]

This is where I purchased my Skipshooter. Was shipped quickly and packed well in a PVC tube that makes a great holder for a spare, unused antenna.
https://www.ebay.com/itm/NEW-CB-HAM...NA-USA-MADE-/181396122156?hash=item2a3c0d2a2c

JD

 

[ForestRunner98]

I bought my 6’ Skipshooter that I was using before my current Sirio here:

http://www.antennapartsoutlet.com/Pages/Products/SkipShooter.html

 

[Slowmover]

I bought my 6’ Skipshooter that I was using before my current Sirio here:

http://www.antennapartsoutlet.com/Pages/Products/SkipShooter.html

Thx for the link.

Just ordered three (3) more antennas.
A 5’ (to make a pair) and a pair of 6’.
(Already have a 7’ pair).

Can’t go wrong with these as the default choice.
Get something fancy, later.

I recommend as pairs to always have that backup.
Re-test an install with the pristine unused one.

Those 3 were $100 total, shipped. ($33/ea).

,

 

[Beetle]

Many 75 Ohm coax types: RG6 and RG11 are both 75 ohm coax types and will work for a "Phasing" harness.
The length will change "slightly" due to the difference in the Velocity Factor for the various makes and size.

"Cophasing" ... makes me laugh and cringe every time I see it. You're phasing two antennas, not cophasing.