NGP? (1 Viewer)

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ntsqd

ntsqd

technerd
Joined
Apr 26, 2007
Threads
90
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6,857
Location
Upper So. CA
No Ground Plane?

I've been looking for a better 2M antenna solution for my tow rig with a pop-top camper. Something that can handle mild western trails w/o fear of ripping it off. To that I've decided that the top of the camper is off limits. Which reduces my ground plane options to nearly non-existent since the camper covers 85-90% of the cab roof and I'm not keen on it being in the middle of the hood. Front bumper is stock, no ARB mount tab option although I've been pondering a serious tube bumper built to fit over the OE bumper like one of the "light bars." Saw one built like this for a Ford and rather liked the concept. I've thought every aftermarket front bumper that I've seen for my truck was ugly. They all give it a decided "chin" that it doesn't need or look like a wannaB pre-runner which the truck isn't. So a front bumper mount may possible.

Not that it should matter, but use will be almost entirely simplex. The more gain the better, but I'm coming to understand that NGP and gain aren't mutually inclusive.

So, I'm looking for suggestions for an undecided mounting location. :D
What I can get will likely decide where and how it will be mounted. In the past I've only used NMO antennas and bases, but for this antenna I'm not going to limit my options to just those.
 
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86 views and no suggestions? So far searching the topic here hasn't been much help.

I've been considering one of the marine VHF antennas since they're designed for fiberglass boat hulls. Just don't know if I could tune one to work in the slightly lower freqs.
 
What is your tow rig? I'd stay away, far away, from NGP antenna solutions. I do a lot of installs on Tacoma trucks and have a lot of issues with the damn plastoc beds! I ended up going with amount that attaches on the bed adjacent to the tailgate. As far as antenna mounts go, Comet makes a ton of solutions. I have my 2M mounted on a comet deck lid mount on the back door and it woks great.
 
'96 CTD Club/Long w/ Phoenix pop-top camper:
http://i168.photobucket.com/albums/u196/ntsqd/95 CTD/IMG_0433.jpg

Almost no bed mount options unless I string ~12' of coax under the truck to get to the tailgate. And then not much ground plane would be available.

Maybe I have too finite of an idea of "ground plane", but to me that means either perpendicular surface or perpendicular radials of a certain distance or length around the base of the antenna. Anything less is a performance loss. In 2M what I'm finding is 19" radially. There isn't an area that big available except for the hood and the camper roof - both of which I'd rather avoid for various reasons.

What sort of issues are you running into with the NGP antennas?
If I thought for sure that I could tune it to work2M instead of ~165-175 MHz I'd be tempted to bolt one of these 5/8 wave to the front bumper:
4' Shakespear Marine VHF @ West Marine
12008215.jpg
 
For no ground plane, what you want is a 1/2-wave antenna. Larsen makes a good one, so do others. I use the Larsen NMO150 1/2-wave on the spare tire carrier of my 40 and it works well for me.
 
1911 said:
For no ground plane, what you want is a 1/2-wave antenna. Larsen makes a good one, so do others. I use the Larsen NMO150 1/2-wave on the spare tire carrier of my 40 and it works well for me.
Click to expand...

1911... u on the Blue board too? :D

What is your SWR readings on the NGP? With the Tacoma's that I have tried them on, I could never get an SWR below 2:1 (hardly ever). That just is not efficient. BUT, if you have found one that works better, then I'd love to see the SWR numbers because I'd love to offer them to my own customers.
 
ntsqd said:
'96 CTD Club/Long w/ Phoenix pop-top camper:

Almost no bed mount options unless I string ~12' of coax under the truck to get to the tailgate. And then not much ground plane would be available.

Maybe I have too finite of an idea of "ground plane", but to me that means either perpendicular surface or perpendicular radials of a certain distance or length around the base of the antenna. Anything less is a performance loss. In 2M what I'm finding is 19" radially. There isn't an area that big available except for the hood and the camper roof - both of which I'd rather avoid for various reasons.


12008215.jpg
Click to expand...

Nice idea for a bumper mount!

Looking at your rig, "If" this were mine to fix, what I would do would be to replace the AM/FM antenna with the 2M antenna. Like this one:
2m15s.gif


OR/and add the FM or 2M to the other side. It would take a little fabrication, but honestly I would do that in a heart beat. Makes for a good ground plane and a nice look as well.

I do something like that for people that want to use the same antenna for their CB radio:
8222800544_0b60151030_c.jpg
 
Poking around the Firestick page I found that they offer a mount plate for either the typical 3/8-24 cb antenna thread or for an NMO that bolts on under the top-rear most fender bolt. I need to look at the truck in the daylight to see if I can figure out where the antenna would come up at. I'm sold if it is near the base of the windshield and behind the hood. Just have to decide on which mount and antenna type.

As best as I can figure you have to remove the whole fender to get to the backside of the stock AM/FM antenna. Mine won't stay tight enough to not wiggle and wear thru the paint.
 
ntsqd said:
Poking around the Firestick page I found that they offer a mount plate for either the typical 3/8-24 cb antenna thread or for an NMO that bolts on under the top-rear most fender bolt. I need to look at the truck in the daylight to see if I can figure out where the antenna would come up at. I'm sold if it is near the base of the windshield and behind the hood. Just have to decide on which mount and antenna type.

As best as I can figure you have to remove the whole fender to get to the backside of the stock AM/FM antenna. Mine won't stay tight enough to not wiggle and wear thru the paint.
Click to expand...

From what I remember, you have to pull the wheel well liner to get to that. It has been 20+ years since I have worked on a Dodge truck. Let me know which firestick mount you are looking at. (I am a Firestick retailer as well as about 100 other CB radio and antenna manufacturers.)
 
VegasNick said:
1911... u on the Blue board too? :D
Click to expand...

Used to be... :eek:


VegasNick said:
What is your SWR readings on the NGP? With the Tacoma's that I have tried them on, I could never get an SWR below 2:1 (hardly ever). That just is not efficient. BUT, if you have found one that works better, then I'd love to see the SWR numbers because I'd love to offer them to my own customers.
Click to expand...

I don't remember exactly what it was for my Larsen 1/2-wave, but I know it is less than 2:1. Had to trim the whip a bit to get there.

SWR on the same antenna will vary with the installation though; many other factors which affect it. In general, 1/2-wave antennas are much less demanding of ground plane than 5/8 or 1/4-wave. If your ground plane is dodgy or suspect then a 1/2-wave is the best place to start in my experience.
 
I have a couple of NMO mount antennae in 2m/440. One is longer (1/2 or 3/8, I forgot) and the other one is a real shortie that is also flexible. I use them with a magnetic mount on a bar over the roof. The little flex guy is used in tree country, the other one in the desert. Had the bigger guy get kicked down a couple of times by unexpected trees but no damage done (has a spring base too IIRC), the mag mount just shifts a bit.
 
Local shop had the Firestik parts (I was surprised at his having the 2M antenna!). Figured to give them a try. I have just gotten them installed, but not yet thru the firewall with the coax. That's one of tomorrow night's jobs. Figure if I don't like how they perform I can always open up the bracket's hole for an NMO base or something. SWR meter came from amazon, so I should have an idea in a couple of days.
 
ntsqd said:
Local shop had the Firestik parts (I was surprised at his having the 2M antenna!). Figured to give them a try. I have just gotten them installed, but not yet thru the firewall with the coax. That's one of tomorrow night's jobs. Figure if I don't like how they perform I can always open up the bracket's hole for an NMO base or something. SWR meter came from amazon, so I should have an idea in a couple of days.
Click to expand...

Damn, should have PM'd me. I could have saved you a few dollars on the Firestik parts. :frown:
 
Local guy has solved cb problems for myself and many friends. Keeping him in business is more important to me than a few dollars.
 
FWIW I've been using the Larsen 1/2W antennas on my FJ40 with NGP and with a hatch mount on my UZJ100. They work great and are very robust.
 
ntsqd said:
Local shop had the Firestik parts (I was surprised at his having the 2M antenna!). Figured to give them a try. I have just gotten them installed, but not yet thru the firewall with the coax. That's one of tomorrow night's jobs. Figure if I don't like how they perform I can always open up the bracket's hole for an NMO base or something. SWR meter came from amazon, so I should have an idea in a couple of days.
Click to expand...

Firestik was a better way to go than the Shakespeare for sure. They don't hold up well in a marine environment, let alone a jarring 4x4 application :).

Post up results with the new stick?? I just bought a diamond dual band to mount on the rear of my cruiser since I didn't want to roof mount (similar reasons as yours). If you like the results, I may put a firestik on the tundra for when I swap the radio on work trips. The mag mount I use on it is bubbling the paint underneath :(.
 
I have the parts installed. Right up to, but not including poking the coax thru the firewall, making the termination, and tuning the SWR. Hoping to get some time for that today, but first need to prep Patch for SWMBO's off-road driving class next weekend, and then I need to prep the CTD for a weekend in AZ helping my Sis deal with a burst water line at their vacation house.

The location is nice in that the antenna is almost entirely hidden by the A post. Only ever see it if I shift out of my normal driving position.
 
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