Freightshaker cabover antenna options

[Tricky117]

Hey all, new to dx, only made a few contacts with good skip conditions on Tuesday and Wednesday. Currently running a 4’ fire stick on drivers side mirror and looking to get out better. My stud on the upper mirror arm sits at almost 9’ off the ground and I’m debating a Wilson 2000 with the 5” shaft to get me right to 13’6” which is the max height I’m ok with or should I get a longer antenna like the sirio’s I’ve heard good things about (leaning towards the bull trucker) and put the mount on my lower mirror bracket. I think I could run roughly a 6’6” antenna that way. I mostly haul a livestock trailer that’s 13’4” and was thinking of running a co-phased setup to get around the trailer better. The firestik is tuned as best as I can get it at 1.2 swr

 

[2NC995]

Have you considered adding the longest skipshooter you can run to the lineup?

A 6'er would do well, and a 7' even better.

Just speculation, but I'd be very surprised if both didn't beat a Wilson on a 5" shaft.

 

[Slowmover]

Welcome!

Sirio Performer 5000 3/8 is where I’d start from scratch today. Contributor fourstringburn has a thread on testing that on a Volvo with a bird perch mirror door-mount bolt. A driver knowledgeable both about big truck mobile AND more demanding ham radio installations.

Longest antenna always seems desirable.

I’d rather have mirror mount base brackets than these cab roof factory pieces on assigned 579 Pete.

Cophase worth it to me, but not everyone would agree.



No matter whether a base station antenna or mobile, SIRIO gets a lot of attention around here.

SKIPSHOOTER for big truck mobile: I’d have a spare pair in any big truck in the unlikely event they weren’t the best choice to begin with. Low price & American-manufacture. (“natural” color recommended). A PVC tube capped at one end to store.

Per your question I’d buy both sets.

The mount itself, RF bonding, etc look to this clicky for the mobile install guru:

www.K0BG.com

This is the make-or-break stuff. Fine gear won’t overcome a bad installation.
Bad installation = normal practice in trucker-land.

AM/SSB is the other minimum I’d stress having in a radio. Leaving out 11-Meter Sideband makes no sense given that there may be a day that XL-range is badly wanted.

A Uniden 980 AM/SSB plus an RM Italy KL-203 75W amp will outperform most so-called big radios. Again, a backup I’d carry with me (Harbor Freight Apache 2800 or 3800 transport case). $200 for the pair.

I also highly recommend the

WEST MOUNTAIN RADIO CLEARSPEAKER

as it gives these CBs what ham radio features: digital cleanup of the audio signal. (DSP). Ones radio is better than suspected. While a unit of the same type can be installed in the path to another external speaker, mine has traveled 250k including oilfield work.

Wouldn’t be without it. (Threads to read).



This little box from DX ENGINEERING is how I’ve used Anderson PowerPoles to connect my cables from BATT up to the overhead to run the radio, speaker and baby amp.

The Uniden 980 plus baby amp and the ClrSpkr is better than than $500 worth of truckstop tweaked gear for the same money.

Ever had Squelch closed and RF Gain wide-open. Dead-quiet . . . then had to back it down because of TOO MUCH local conversation? Ha!

A big radio benefits just as much from the ClrSpkr. I’m running a GALAXY 99v2 this trip.

Plan the mobile install according to the K0BG link. Radio & antenna are last.

Ferrites on all coax & power has also been a help (PALOMAR ENGINEERS). See threads on mobile coax chokes.

Finding someone with an antenna analyzer is the near last step. A few install detail changes may be necessary. Then a re-check. SWR checks are a long way from being enough.

It is distinct fun to talk with someone the guys you’re running with can’t hear.

I’ve been doing it for years. The Interstate closed 25-miles ahead and YOU know it ten miles before the others. Etc.

M0GVZ a contributor here from Britain drives big trucks. Great posts.

Other truckers here as well. Digging around this place is a great way to spend some wait time OTR.

(Thumbnail of snap-on ferrite on mic cord)

Take your time on the details and OLD SCHOOL COE will have them shaking fists at you.

Large Car ain’t #%*+

.

 

[Tricky117]

That k0bg site has tons of info thanks for the link, lots of reading to do on there. As for the radio I have a Stryker 955 only opened it up to convert it didn’t touch anything else as I’ve read they’re pretty good out of the box. I’m for sure planning on ferrite in a few different places, and going to look into a clear speaker, I had plans to do an external one never thought to look into a digital cleanup option makes a lot of sense. And I know I have to do a better power feed to the Stryker cause the voltage display dips during transmission which I’m guessing makes the output change and the audio gets garbled. So far leaning towards the sirio 5000 bull trucker in cophase.... might as well go huge with the antennas on the lower mirror brackets. Any input from anybody having the bull trucker vs the performer? I wouldn’t think they’re terribly different coming from the same manufacturer and the bull trucker is 1 foot shorter, don’t want to have to put the antennas at a forward leaning angle like I see a bunch of trucks. Assuming it’s not a perfect donut of radiation but close when you lean them forward aren’t you hurting your range forward? I always thought that was the case and it was people not knowing better doing that.

edit: the performer 5000 is slightly longer but might be the perfect height on the lower mirror mount, only problem with mounting there is the coil would be blocked by the mirror transmitting to directly behind me. Hmm I have to do more measuring

 

[Slowmover]

Lower antenna shaft lengths can be changed. Seen them from 5” to 44”.

 

[Tricky117]

The lower shaft length affects the tune less than the stinger length correct?

 

[Slowmover]

It’s a sort of relation where to change lower means a change to upper. Lower shorter and stinger longer. And reverse.

Maintaining same length.

But it’s not set in concrete.

Where an antenna analyzer comes in.

 

[snippits75]

Always ran Francis co-phased whips on hoods and cabovers. Do remember I ran 4.5 Francis on Freighliner hoods with the metal arm mirrors. Can't remember on the cabover.

You can run a DaveMade five pill on two co-phased 4.5 ft. Francis whips with very good SWR.

 

[Blackcat630]

Run them on the higher mounting point if you can. I would rather have an antenna that's a foot shorter up and in the clear than a longer one mounted low and reflecting off the mirror.

I would also save your money and mount 1 not 2.. co phase requires more space than is actually available to work correctly on a truck.

Run a decent gauge power cable dedicated to your 955. Use quality mounts and coax.. look for a decent swr meter to set it all up.. or an analyzer would be even better.

These are just my opinions.. and you know what they say about those

 

[Tricky117]

An antenna analyzer is on the list as well to get. If you have over 108” between your mounts I thought cophase was ok, I’ll measure the mirror to mirror distance in a bit

 

[Slowmover]

An antenna analyzer is on the list as well to get. If you have over 108” between your mounts I thought cophase was ok, I’ll measure the mirror to mirror distance in a bit

Cophase can work from a shorter width. Done all the time.

Below is sort of a primer for non-drivers:

There are trade offs as with all else. Analyzer SHOULD be used. Access to that tool and working knowledge is the problem (CB shops so equipped almost nil).

With a van behind me, it’s my preference to use cophase. I seem to be able to maintain contact better. If this comes at expense of distance then I don’t find it an impediment.

Ears trumps Voice when mobile and conditions are changing on the road. Whether traffic or weather, having choices miles before coming up on the problem, is the thing.

In a metro — despite modern tools of GPS and sat pics — recent construction or a major wreck, HOW TO get to a shipper or receiver may be dependent on a local giving alternate directions.

Big trucks have problems with turns, height restrictions and route restrictions. Takes another driver to “know” what works. Both are moving and contact may be extremely short.

One can’t just pull over and work the problem, Radio and phone. Too big. Hung-Over Harry hits you while you’re parked and it’s gonna be your fault.

Sometimes a CB is a lifesaver.

CoPhase better 360-degree “capture” is a benefit in this (versus a single mounted off one side or the other).

Roof-mount at center pretty well doesn’t exist except for some tanker outfits. Most of them will mount on back of cab. Favors forward direction, but one loses what’s behind rather quickly.

About the only time one sees center-mount is with two-meter (business radio).

The fact of the trailer, is the real problem. Obstruction.

1). Both men with company-spec tractors and box vans.

2). Both with passenger-mount antennas.

3). Headed into opposite directions same road. A road curve for each where the respective trailers block the signal. At highway speed, the distance is “too far” once each straighten out.

Have had the above happen often enough. Plenty of questions apply when the other guy just came thru that area.

Clearance required overhead is 13’-6”. Pushing an antenna to 14’ can be done (it helps), but it may not last long. Or it may . . . details of the job description apply.

Cophase is worth the trouble, IMO.

Out on the Great Plains — where conditions can be favorable to “local” long-distance (not skip) — a local owner/op with a large car and a short-height grain wagon the distances in TX/RX can be very impressive with typical cophase.



Adequate ground plane will always be the problem despite antenna mount location.

The “other” problem for most drivers is they don’t own the equipment. Restrictions apply.
.

 

[Slowmover]

The OP is inquiring about a COE
(Cab-Over-Engine). Cabover.

Antennas-phased can be seen on this Freightliner. (Tilt can be a problem. 15-degrees, but not more, really).

Despite my earlier, I believe I’d just go with the classic HUSTLER HQD package of (2) HQ27 antennas plus coax & mounts as a kit. (Has the “right look”, ha!).

About $75 at Walcott or WEARECB.

51’ stainless steel antennas (4.5’).

13’-5”

A 5” Wilson shaft plus coupler would put them at near 14’-1”; might work for a cattle hauler. Tuning would change somewhat.

That said, having a box of spare parts — from what didn’t work — never hurt me. (Meaning I’d try it).

See also Mobile Coax Choke thread.

RF bonding of doors across each hinge, and a disconnect-able pair to cab (tilt access) are a minimum. Same for bonds from interior mirror arm bolts to the door hinge bonds. With RF bond: More = Better (to a point). See thread comments this site.

DC ground isn’t same as RF ground. Upgrades of existing DC grounds a good idea, as are MORE of them.

See K0BG on this subject and all others.

www.K0BG.com

The vehicle is, “the other half” of the antenna. Details apply. Bigly.

.

 

[freecell]

"CoPhase better 360-degree “capture” is a benefit in this (versus a single mounted off one side or the other)."

a pair of identical phased antennas matched with a 1/4 wave transformer @ 1/8 - 1/4 wl. spacing do not produce anything close to a 360 degree signal. there's no body metal ground on either side of the cab and the longest run is perpendicular to the plane of the array from the nose to the rear of the trailer, in the directions where maximum directivity is obtained, to the front and the rear, with noticeable rejection of signals arriving from the sides of the truck / trailer and likewise, less transmit signal off of the sides when compared to either the front or the rear.