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Mobile anybody on here run a high power (5kw+) suburban? i need some advice

Slowmover said:
“As back as I could” . . . meaning cab roof (I take it).

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Yes. Centered from left to right and as far back back on the roof as possible. Take the headliner down first see where all the supports and wires are hiding. Take the size of the backing plate into consideration. My puck is on a 2002 Dodge 2500 with extended cab.

A friend put a puck and same antenna dead center on an extended cab f150. He couldn't get it to tune. He centered it because removing the dome light was easy access and he didn't want to pull the headliner. I warned him but he was lazy. That's the guy that put the 102" whip on the bumper.
 
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543_Dallas said:
Yes. Centered from left to right and as far back back on the roof as possible. Take the headliner down first see where all the supports and wires are hiding. Take the size of the backing plate into consideration. My puck is on a 2002 Dodge 2500 with extended cab.

A friend put a puck and same antenna dead center on an extended cab f150. He couldn't get it to tune. He centered it because removing the dome light was easy access and he didn't want to pull the headliner. I warned him but he was lazy. That's the guy that put the 102" whip on the bumper.
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As mines a 2004 Dodge 2500 XT Cab (3rd Gen vs your 2nd Gen) that advice sounds good given this experience related.

I’d recalled your saying the same in another thread and wondered about it.

I may not ever have much of an amp aboard, but the Omni-directivity (?) can’t be hurt (measured) “enough” to matter, or so I gather. Sounds like a plan.

Thx!

.
 
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Slowmover said:
As mines a 2004 Dodge 2500 XT Cab (3rd Gen vs your 2nd Gen) that advice sounds good given this experience related.

I’d recalled your saying the same in another thread and wondered about it.

I may not ever have much of an amp aboard, but the Omni-directivity (?) can’t be hurt (measured) “enough” to matter, or so I gather. Sounds like a plan.

Thx!

.
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I never noticed it being directional. I don't have anything substantial in that truck anymore. The extra batteries went bad and I only drive the truck about once a month. I downgraded to a Sryker 447 hpc2 and an old 4 pill xforce. Old as in circa 2004.

A hard mounted antenna on the roof is worth doing. My 16 pill didn't even bleed on the stereo unless I put a hacked up radio inline. I also put a few snap on ferrite cores around the coax before I put the headliner back up.
 
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That’s what I was thinking per directionality. It’s a short distance in changed location. I think it might actually be more appealing aesthetically.

I already “know” from being on the road that the permanent mount out-talks everyone around. In a good way. How you want your radio to sound.

Few big trucks ever do well. A 1T pickup is a Corvette In more than one way
 
Captain Kilowatt said:
Many of us know a lot more than a lot of others here. That is not the issue. The issue is in how things are presented. In that department you could learn a few things. That's all I'm saying.
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I’m about halfway down the block in that line. Before it turns the corner. Tell ‘em we could use some cold ones here he goes past. Buy two for himself. On us.

.
 
M0GVZ said:
Don't know it all, just a whole lot more than you do.
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That attitude is exactly what I'm talking about. I'm not ashamed to admit when I don't know something. There's a lot I don't know.

You come across as a bitter man that likes to insult people. Maybe you aren't as respected as you'd like to be in your professional or personal life. Insulting a bunch of cbers may make you feel better but it's not dealing with whatever problems you have.

When you say it's not possible to run 5kw (on 27 mhz) in a mobile without issues and then start talking broadcast stations I know you are not speaking from experience.

When you start talking about SSB and ALC in a thread about a cobra 29 I can't take you seriously. You're obviously not familiar with the rig. That's ok if CB is not your thing but don't BS people.
 
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543_Dallas said:
That attitude is exactly what I'm talking about. I'm not ashamed to admit when I don't know something. There's a lot I don't know.

You come across as a bitter man that likes to insult people. Maybe you aren't as respected as you'd like to be in your professional or personal life. Insulting a bunch of cbers may make you feel better but it's not dealing with whatever problems you have.

When you say it's not possible to run 5kw (on 27 mhz) in a mobile without issues and then start talking broadcast stations I know you are not speaking from experience.

When you start talking about SSB and ALC in a thread about a cobra 29 I can't take you seriously. You're obviously not familiar with the rig. That's ok if CB is not your thing but don't BS people.
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I think you got the right attitude. Too many ducks and super hams..Start small, ask questions. Your not reinventing the wheel. I can't tell you ham many "experts" said it wasn't possible to key north of 20kw in a mobile back in the '90's.
 
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DoctorAudio said:
If your front antenna is the hot it's mounted to close to the center of the roof. On a Suburban roof the hot needs to be 2 feet or less (preferably less) from the windshield or the back. There is too much flat ground plane around the antenna.
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DoctorAudio said:
A quarter wave antenna that is direct fed needs to see at least some sloping ground plane close to the base to match correctly. With too much flat ground plane around the base of the antenna you have to add inductance to the feedpoint to get it up to 50 ohms.
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Doctor Audio, I don't think I've ever read any of your posts, but I agree with both of your comments above.

I only have modeling evidence with your idea noted above. That is probably why Buickid never did respond to my suggestion about his friend's large van with a big flat roof...he wasn't interested in a model.

I never posted my follow up model with a smaller roof that positioned the vertical wires closer to the antenna feed point...similar to slanted down radials on the old Starduster GP. This reduction in the size of the roof line also improved the match, just as you've noted. These slanted down wires, close to the feed point, did allow me to maintain resonance and get a 50 ohm resistance, but I did have to make the radiator longer as I reduced the ground plan for the antenna. I have no idea if this is the way this will work in the real world, that would have to be compared and tested. This also increased the gain by 54%, at a 3* degree increase to the angle at the horizon.

Below is a link to my post back then with my version of his buddies large van using a very simplified mobile object instead of including the mobile look of his van.

102" whip tunes great, but other antennas won't

I have the models and I will post them if there is any interest. Here are two antenna pattern overlays of these two models in the PDF file below. This is only an effort to try and compare a larger flat mobile roof line vs. a smaller roof line.
 

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  • Large Van model with a large flat roof vs. small roof..pdf
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Marconi said:
Note for my post above.

I forgot to add the link to the thread where Buickid was helping a buddy with his big van antenna installation and I posted a model of a big van model I made for him.

102" whip tunes great, but other antennas won't
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Marconi, I appreciate your help and your efforts in modeling the van. Just been a bit busy with the new job and such, haven't had much time to play radio. I do have a bit of an update, though maybe not what we all want to hear. I will post it in the thread!
 
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There are alot of ideas here ad none of them good. Alot of bad information from people who are poking their chests out acting smart.

A single antenna that is not loaded with a shunt to ground especially in the middle of a roof will always tune to about 1.6-1.3:1 usually around 37 ohms.
Move the antenna to the back and 1.3-1.2:1 is achieveable .

A bounce back is easy to tune once you learn how and will almost always net 1.0:1 50ohms match.

As far as 5kw not being achievable in a mobile? Come on dude, where HAVE you been?
Most of problems i find is people not grounding correctly, or using a weird multiple of coax to the hot antenna etc. K.I.S.S.
Run an electrical half wave to the hot. Grind paint to get to bare metal.
 
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