Antennas on Backrack instead of roof holes on Crew Cab GM HD

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W1HVN
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Antennas on Backrack instead of roof holes on Crew Cab GM HD

Post by W1HVN »

So I've promised myself on the new crew cab Chevy HD I'm not drilling holes. As such, I'm purchasing a Backrack and looking to mount two or three antennas on the rack. They make a 3.5"x3.5" plate with a 7/8" hole in the center (closer to 3/4 in reality) which secures to the top of the rack post. I've got two of them, one for each post. I'm thinking for 800 and UHF (450) this will serve as an immediate ground plane and the nmo will also have electrical connection to the body for additional help. For VHF I'm going 5/8 wv cowl (front driver fender) mount. The VHF won't have an adequate ground plane for a 1/4 wv. Stico flexi I was running in roof if I try and put it on the rack.

Suggestions, comments, am I going down a path of wasted time and effort?

Thanks.
tvsjr
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by tvsjr »

How long are you planning to keep the truck? If it's more than a year or two, drill the holes and be done with it.
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Bill_G
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by Bill_G »

There's a 82 Jeep battle wagon down at the Joe's Used Cars with your name on it. Perfect. $250 cash. That will leave plenty of room in the new truck because besides no holes for antennas, you weren't really going to mount stuff in the new cab, were you?
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Tom in D.C.
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by Tom in D.C. »

Chris,

Drill the holes and put the antennas on the roof. Mobile analog FM is crappy enough without making it worse by using what will in all likelihood be a serious mismatch between the transmitters and the antennas. You might get away with a short radial groundplane on UHF but you won't on VHF. For UHF you can put a Comtelco A2584 puck on an NMO mount and paint it to match the truck's color and nobody will notice it. For VHF you can use a quarter wave whip on an NMO which is almost as invisible when it sits 'way up on top of the crew cab. A local ham here had two dualband short antennas mounted in the two front corners of the bed of his crew cab right behind the cab and the results were terrible. He finally got tired of us yelling at him about his crummy mobile signal and he moved the antennas to the roof. Now we can hear him.

The Comtelco antenna is their A2543 in either white or black, for about $35, and it has 3db gain.

Regards,
Tom in D.C.
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SteveC0625
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by SteveC0625 »

I have been told repeatedly over the years that car dealers don't care about a couple of antenna holes in the roof of a vehicle. They get plugged with a nice neat little plastic plug that is barely visible any way.

Mounting the VHF spike on the fender cowl can result in at least 2.4 db loss compared to drilling the hole and mounting it in the center of the roof.
KG4LHQ
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by KG4LHQ »

How about in the back towards the 3rd light brake light?
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W1HVN
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by W1HVN »

Sold.

The Stico Flexi VHF and UHF 1/4 waves are going back on the roof. probably going to put the 800 on the rack still with the 4x4 plate, that should be fine.

The flexis btw work awesome for putting the truck in the garage. They came off a suburban and they perform very well if cut right (use a good analyzer and sweep it). They cost significantly more than your garden variety 1/4 wave, but they flex and return to total vertical over and over, with zero affect on the garage.

Didn't take much to convince me... Thanks guys, and yes this vehicle is a keeper.

There will be no holes visible in the cab. High power decks under the back seats, holes there for the drawers yes, and a simple Havis console for the remote heads, again no holes.

Feel free to keep sending the opinions.

Thanks all.

And Tom you know me well enough, running good equipment, and no sense in killing their abilities.
mmckenna
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by mmckenna »

I think you will be happier in the long run. I've tried the set up with the back rack, and while I could technically make it work, it didn't work well. I've tried the cowl mount and the very back edge of the cab, yeah, they work, but again, not well. I bought a new crew cab back in July and did it right. 1/4 wave VHF right smack in the center of the roof. I'm glad I did it. It works well, and I feel better knowing I've done it correctly all the way around, no corners cut. This is my 5th personal truck, 7 if you count my work trucks. I wish I"d done it this way before.
"The nice thing about standards is that there are so many to choose from."
KG4LHQ
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by KG4LHQ »

W1HVN wrote:Sold.

The Stico Flexi VHF and UHF 1/4 waves are going back on the roof. probably going to put the 800 on the rack still with the 4x4 plate, that should be fine.

The flexis btw work awesome for putting the truck in the garage. They came off a suburban and they perform very well if cut right (use a good analyzer and sweep it). They cost significantly more than your garden variety 1/4 wave, but they flex and return to total vertical over and over, with zero affect on the garage.

Didn't take much to convince me... Thanks guys, and yes this vehicle is a keeper.

There will be no holes visible in the cab. High power decks under the back seats, holes there for the drawers yes, and a simple Havis console for the remote heads, again no holes.

Feel free to keep sending the opinions.

Thanks all.

And Tom you know me well enough, running good equipment, and no sense in killing their abilities.
You got anymore of those Flexi-Whips and I've heard they don't do to well in cold winter weather. I'm interested in going to a flexi-whip.
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W1HVN
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by W1HVN »

Going to do a VHF Stico I ran on my Suburban, right in the middle.

Also running 800 and UHF. Considering putting the 800 where the Onstar would go. I have a work truck package without Onstar, so if I do the 3/8" there, I someday can throw a on star shrk fin in it's place.

Opinions on the Antennex Phantom Elite fins for UHF vs 1/4 wave standard whips?

Any info on the 3/8" NMOs vs. The standard 3/4"? Any disadvantage. If not I will do these, just cuts down on the hole size and makes a little less conspicuous if removed.

Thanks again all...
Jim202
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by Jim202 »

W1HVN wrote:Going to do a VHF Stico I ran on my Suburban, right in the middle.

Also running 800 and UHF. Considering putting the 800 where the Onstar would go. I have a work truck package without Onstar, so if I do the 3/8" there, I someday can throw a on star shrk fin in it's place.

Opinions on the Antennex Phantom Elite fins for UHF vs 1/4 wave standard whips?

Any info on the 3/8" NMOs vs. The standard 3/4"? Any disadvantage. If not I will do these, just cuts down on the hole size and makes a little less conspicuous if removed.

Thanks again all...


You can get the rubber hole plugs to fill the hole if you remove the mount. Most dealerships don't care about antenna mounts today when you trade in a vehicle unless it is on a lease. The lease people very so much, that you need to ask.

Jim
motorola_otaku
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by motorola_otaku »

W1HVN wrote:Any info on the 3/8" NMOs vs. The standard 3/4"? Any disadvantage. If not I will do these, just cuts down on the hole size and makes a little less conspicuous if removed.
Use the "dual" 3/8-3/4'' mount; they "grab" a significantly larger surface area beneath the mounting surface. The only downside is the need for unobstructed access to the area beneath the mounting surface; i.e. you can't pop a hole in the roof and slip one in from the outside.
jpeted
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Re: Antennas on Backrack instead of roof holes on Crew Cab G

Post by jpeted »

As for flexi-whips in cold weather, if you are driving in fog with below freezing temps they will lay over on the cab until you knock the ice off.
jpeted
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