groundplane question

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snakecharmer

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I recently got a new truck and am in the process of transferring the equipment I had mounted in my old Jeep. My main issue at this point is antenna mounting. One the jeep, I had a lip mount scanner antenna mounted to the lip of the hood and I had a 1/4 wave mag mount for the Ham in the middle of the roof. I don't claim to know much about antennas but I have always heard the CB and Ham antennas need to be surrounded by metal which is why I had mine in the middle of the roof. But I had not put much thought into the ground plane for the scanner antenna because I guess I was under the impression it was only important for radios that transmit. So am I way off here?

So anyway....deal is that on the new truck, any drilling of holes is not an option and antennas mounted on the hood area is not acceptable. For the scanner, I modified my lip mount to clamp to a vertical lip on the inside top of my bed about a foot back from the cab. Im not real keen on putting the mag mount on my roof and there is no other way to get an antenna up there. So for the Ham, I was thinking of buying or building another mount to clamp to the lip on the opposite side of the bad that the scanner antenna is on and using an NMO mount with it. So I guess that I don't really have a ground plane with the antennas mounted at the top of the bed like that? And if it makes a difference, the bed is rhino lined and has a plastic bed liner on top of that. So will I be giving up performance with my antennas mounted this way, and if so, to what extent? The scanner antenna seems to be working but of course I have no way to know what I am missing.

Also, what effect is there to having the antennas below the roof line of the cab?
 
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af5rn

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Why is the hood area not an option? That's really usually the best "no-hole" option for a pick-up truck. It would be my first choice.

Yes, ground plane is important for any radio, transmitting or not. But if you're not transmitting, at least you won't kill your radio by not having it. You will, however, probably kill your reception, lol.

There are all sorts of brackets made for mounting antennae in or around the stake holes in your bed walls.

Similarly, there are mirror mount antennae, like the truckers use.

If you have a bed mounted metal tool box, a roll bar, or a headache rack, those are great for mounting antennae on.

Depending upon what bands you monitor, and at what distances, glass mount antennae can work just fine for you, and are underrated.

Never really understood the belief that you can't drill into a new vehicle. New or old, you're still decreasing value either way. But on a pick-up -- unless it's a low-rider mini truck -- nobody can see the roof anyhow. A colour coordinated plug is not going to be noticed, much less decrease your trade-in or resale value. And, as you know, it is always going to be your best performer. Chances are, by the time you're ready to get rid of the truck, it's got much bigger problems than a little barely noticeable bump on the roof that nobody can see, lol. :lol:
 
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snakecharmer

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Well lets just say that keeping the wife OK with what I do to my truck is just as important as radio performance. Now don't get me wrong, I ain't whipped or anything like that. Its just that I promised I wouldn't drill any holes in this one because I have a tendency to get out of hand and once there is one hole there would be a dozen. Every hole I have ever drilled in a vehicle, I have almost always regreted later for one reason or another. I also like to keep things fairly easy to undo because I have a tendency to be driving by a dealership, see something I like and trade up on the spot. I'm kind of an impulse shopper when it comes to vehicles so the easier it is to remove stuff and put it back stock, the better.

So to address the other mounting options....My bed has no stake pockets, just plastic caps on the bed rails and my mirrors are plastic as well. I have no rack, roll bar or toolbox although I am wanting a toolbox. Unfortunately, I don't see on in my near future but if I had one, that where the antennas would be.

What i have is a mirror mount with an NMO base in it. That is what I was planning on using to mount the Ham antenna except it would be on the bed lip instead of a mirror. Now this is what confuses me...with a mirror mount, what makes the ground plane any better than on the bed rail? I see alot of city vehicles with that style mount which is where I got mine actually so I assume they work but I just don't understand where they get the ground plane.

I snapped a couple pictures my scanner antenna so you can see exactly what I have going on here.



 

jon_k

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With the self-imposed limitations here I don't see very good performance. It may work but it will never work great, and it won't be ideal. This is fine if you're willing to sacrifice to keep the wife happy. The way I see it, an awful lotta good ground plane is going to waste that it's almost a crime. On my truck I'm utilizing my toolbox for a ground plane, then will move to the roof and hood. I'm weary about the hood at this point because of engine interference, I may set up a test antenna connection on the hood to see how bad it is.

Good luck though! Remember a ground plane is an IMPORTANT factor to some antennas. Antennas will /WORK/ but they won't work ideally. One reason HT antennas are so poor is because they are missing a ground plane. To do the same thing to a vehicle or home base installation when a ground plane is readily available will only result in poor reception and transmission.

You are correct in ground planes being essential for transmission. Your xmit distance could be doubled with a sufficient ground plane. For scanning, I would prioritize less importance for the ground plane, you will still hear -- but maybe not from as far, or as clear in instances. Don't die if you can't get a ground plane for scanning -- but if one can be incorporated, use it if not, forget it. However, I would not settle without a ground plane for the transmitting antenna -- you might as well string up half a dipole antenna -- it would work but that would be almost beyond a generous comment.
\ I see alot of city vehicles with that style mount which is where I got mine actually so I assume they work but I just don't understand where they get the ground plane.
A ground plane is a sheet of metal 90 degrees to the vertical whip, that surrounds the antenna 360 degrees as long as the antennas wavelength. The less you represent the ideal image I described, the less of a ground plane you have. Antennas mounted to the mirror do not represent that ideal image very well. It may get a bit of a ground plane from the hood of the car depending on how close it is mounted. If the dash was made of metal, that would constitute a ground plane as well (how good? Who knows.)

The reason truckers and C.B.ers mount there is unknown to me, but then again it's that crowd who thinks that pushing 1500 watts with a 2:1 SWR on their antenna is the way to really "get out." This shows how credible this crowd is regarding antenna design, placement, and use.

Never really understood the belief that you can't drill into a new vehicle. New or old, you're still decreasing value either way.
You will decrease the value of a car new or old MUCH more by daily abuse. Adding 1500 miles to the odometer will hurt your trade in value more than an antenna mount ever will. Unless you're clocking less than 200 miles a year, you're going to hurt the value big time by driving it. Adding an antenna in the roof is about equal to 300 miles of devaluation I'd say, a drop in the bucket compared to what other things you're devalulating it with (milage.)

Now with 165,000 miles on my truck I don't see much harm in doing anything to it anymore. It's has the stock tranny and engine, not much I can get for that in trade-in value. I'm drilling a hole once I find someone in the area who has done it before to help. I toured a lot in Glen Rose that was using a vehicle with a NMO mount as a selling point. Said it's already ready for C.B.!

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af5rn

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Yeah, you don't have a great "ground plane" with that arrangement, but you do have a good ground (assuming that is sheet metal you are mounted to), which is a start. Your range is going to be much more limited than other arrangements, but probably quite acceptable.

That location will give you a pretty funky, unpredictable radiation pattern. It'd be interesting to check field strength readings to see exactly what it is. But typically, you can expect attenuated performance to the front of the vehicle, with the cab acting as a reflector. That's what we see with tool box mounts.

Again, why is a hood groove mount not an option for you?
 

snakecharmer

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Ya, I'm good about self imposed limitations. I'm just very anal about my vehicles along with a little OCD mixed in and talking a drill to my new truck really goes against the grain. I will probably never get past that so I just need to work around it.

The lip that the antenna mount is attached to is metal behind the plastic but I dont know how good a ground it has from the 2 little set screws. And the hood mount was kind of annoying flapping in the wind right there in my line of sight and it also scratched the paint. Not a big deal on the Jeep but I don't want that on the truck. But if I did do that, would it be any better than where it is now? I mean since its still below the roof line?
 

Einstein22

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Don't you have a luggage/bike rack, or something on back on the outside that holds a spare tire. You could attach a ground wire to that..
 

jon_k

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Ya, I'm good about self imposed limitations. I'm just very anal about my vehicles along with a little OCD mixed in and talking a drill to my new truck really goes against the grain. I will probably never get past that so I just need to work around it.

The lip that the antenna mount is attached to is metal behind the plastic but I dont know how good a ground it has from the 2 little set screws.

[quote. But if I did do that, would it be any better than where it is now? I mean since its still below the roof line?

If you have any doubt about what a ground plane does or how it works, please read this!
This should clear up any questions about how they work, what they do, etc. If it's not enough, Google can take you to sites with more detail.

First lets be very clear up front. a Ground Plane does not need to be electrically grounded to anything. It simply needs to be a plane of metal.

Pictured Above: A nice ground plane. Don't you wish you had one as perfect as this?

Lets answer your questions specifically.

PICKUP BED RAILS:
Electrically grounded or not, you do not have a ground plane back here (unless the antenna is mounted IN THE BOTTOM OF YOUR BED) You've got it mounted on a bedrail which makes up about 0.5% of a full ground plane. I'm not even sure what shape the emitted field would look like from transmitting here. Wouldn't be a donut field thats for sure.

VEHICLE HOOD
If it is on the hood lip, you now start getting closer to an almost perfect ground plane. You can see that your hood starts representing the picture above more closely.

BELOW THE ROOF LINE? Good or bad?
Yes it creates signal problems.

E.G. Signals coming from behind your truck will be attenuated if the antenna is on the hood. The reverse will apply with the antenna in your bed. Otherwise the reception will be excellent on the hood because of ground plane. Mediocre at best for the bed rails with no ground plane.

How do I achieve the perfect plane?
In a perfect world you would mount the antenna in the CENTER of your roof. It would be highest and it would have a large ground plane. Failing this, you would mount it in the center of your hood. This would give you the best ground plane. We all know mounting an antenna in the center of your hood would look really strange and nobody would want to do this. Thats why the world is not perfect.

Why in the center? Since the antenna is omni-directional and the antenna field is shaped like a donut -- you want a ground plane that surrounds the antenna from each direction equally. This is ESPECIALLY important when transmitting, or the field you emit may not be a perfect donut shape (in the areas lacking ground plane the field is subject to distortion.) The more of a ground plane you supply, the more uniform a transmitting signal field becomes. For the receiving end, the more signals are directed into the antenna with a ground plane

Examples of ground planes in the wild.
  • The metal top of a refrigerator is a ground plane.
  • A filing cabinet is a good ground plane.
  • A tin roof is a ground plane.
  • The top of a barn with galvanized roof flashing is a ground plane.
  • A vehicle hood or vehicle roof is a ground plane.
  • Mama's cookie sheet is a ground plane.
  • A metal computer case flipped on its side is a ground plane.

Some people don't care about a ground plane. Others build a steel plate over their house and stick the 20 meters antenna in the center for the ultimate ground plane. It is your decision on which extreme you want to go. I usually try to keep a centrist view of things and supply the best ground plane possible conditions permitting around my house and vehicle.
 
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af5rn

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ROFL@groundplanes in the wild :lol:

Nice job, Jon!

Anyhow, looks like you've found the solution that is probably best for you. Stick one on the other side too and you get a balanced look out of it.
 

snakecharmer

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Thanks allot Jon_k. You actually helped me out quite a bit but also opened up an entire new set of questions.

I have been considering the possibility of punching a SINGLE hole in my roof. Problem is that I have 2 scanners and the 2 meter so I would still need an extra couple of mounting locations. If I did do a hole in the roof, it wouldn't be in the center however. It would be maybe a foot from the rear of the cab. Mainly because I have some form of access to the rear of the panel there by removing the 3rd brake light.

I have also decided to be OK with an antenna on my hood lip. I have seen a couple of nice adjustable mounts with rubber in the clamps so I think I could live with that. Having a hard time finding one however.

Now given those 2 mounting locations and knowing that I am needing to mount a 2 meter and a scanner antenna primarily to receive 800MHZ stuff, which would you put where and why. And antenna recommendations for those locations are welcome as well.

Now on to the 3rd antenna. It will run to my second scanner which I use to monitor a few frequencies that are still conventional 150 and 450ish frequencies. I would like to use the antenna I have there in the bed for this but I still have to address the lack of ground plane. Ground planes in the wild and particularly Mama's cookie sheet got me to thinking. What if I were to somehow attach a ground plane to the antenna mount? Something like a half circle of sheet metal with say a 12" radius. Would something like that be considered an acceptable ground plane? I also tried to research ground planes but most of what I found related to building base style ground plane antennas rather than addressing ground planes in a mobile environment...but it did give me an idea. What about attaching a pair elements at a 45* to the base of the antenna. It would be down in the bed where it wouldn't be visible but that would also limit to being able to only use a pair rather than four like most I have seen. Does that even make sense?

Or would a better option be to stick with just the 2 antennas and run both scanners off the same one? What effect would that have?
 
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jon_k

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Thanks allot Jon_k. You actually helped me out quite a bit but also opened up an entire new set of questions.
Glad to help.


I have been considering the possibility of punching a SINGLE hole in my roof. Problem is that I have 2 scanners and the 2 meter so I would still need an extra couple of mounting locations. If I did do a hole in the roof, it wouldn't be in the center however. It would be maybe a foot from the rear of the cab. Mainly because I have some form of access to the rear of the panel there by removing the 3rd brake light.
Understandable for one hole. I am considering 1 hole in my roof as well. I'd put it in the center horizontal, but vertically it would be further near my brake light as well.

I have also decided to be OK with an antenna on my hood lip. I have seen a couple of nice adjustable mounts with rubber in the clamps so I think I could live with that. Having a hard time finding one however.
I have also seen hood mounts that are made for specific trucks. You may see if you can find one made for your truck specifically.

Now given those 2 mounting locations and knowing that I am needing to mount a 2 meter and a scanner antenna primarily to receive 800MHZ stuff, which would you put where and why.
We may have differing priorities and interest in the radio hobby which may conflict with each other.All I can share is what I would do with your truck, and why:
ROOF: The hood is the #1 best spot, and in my mind thats for the transmitter. Mainly because transmitted signals go out further with a proper ground plane. After all, don't you want to be able to reach those distant repeaters on the other side of town? (My biggest pet peeve is to be able to hear a repeater, but not be able to Tx to it. I try to do anything (height/groundplane) to increase my chances.) I also like to at least listen to repeaters as distant as possible.

To add to my reasoning, amateur radio repeaters (and your transmitter) run on very low power output when you compare it to the hundreds of watts your commercial Police/Fire repeaters are pushing. So you earn more with a ground plane here in my opinion. You might pick up Police with a twist-tie made into antenna buried 6 feet under concrete with rebar. Unfortunately the amateur systems aren't as powerful with their output, and your 2 meter rig probably does 50watts max. Give it the height and ground plane advantage.

HOOD / BED
The next best option with the best ground plane area will be your hood. The antenna will be likely in the top left corner of your hood by the drivers area. Not the best ground plane, but OK.

I can't tell you what to put here.

  • Do you value performance on 150/440mhz?
  • Do you value performance on 800mhz?
Pick one that has higher value and put it on the hood. It will gain the benefit of the ground plane. It just depends on which priority you want for which antenna.

Pro TIP: For all your antenna mounts, purchase the same type of antenna mount types. That way you can move antennas among the mounts. The antennas and each mount will be interchangeable this way. If your priorities change, you can just unscrew an antenna and move it to another mount. I've made this decision on my vehicle and have standardized in NMO. I'm happy with the standardization.

Pro TIP 2: Use the same coax connector on the end for your radios. Standardize on all BNC end connectors, or all PL-259. That way any antenna wire can be used with any radios. (I'd do all BNC since it's a small connector. For the HAM radio you can get BNC to PL-259 to connect to your radio. Your preference. This is so you can interchangeably change antennas on your radios.) This will just simplify interchangeability and makes things simple for new equipment addition in the future.

And antenna recommendations for those locations are welcome as well.
I use an Austin Spectra for my scanning needs. I use an Comet SBB-7 2 meter/70cm antenna for amateur use. I'm happy with both.

These are my first mobile antennas. I've not been around long enough to start making recommendation's for other peoples rigs. However, 3 of my HAM friends purchased the Comet SBB-7 the same day after I purchased mine at the Hamcom here (and one of the operators who purchased has been an operator for 7 years, general.)


Now on to the 3rd antenna. [SNIP] I would like to use the antenna I have there in the bed for this but I still have to address the lack of ground plane. Ground planes in the wild and particularly Mama's cookie sheet got me to thinking. What if I were to somehow attach a ground plane to the antenna mount? Something like a half circle of sheet metal with say a 12" radius. Would something like that be considered an acceptable ground plane? I also tried to research ground planes but most of what I found related to building base style ground plane antennas rather than addressing ground planes in a mobile environment...but it did give me an idea.
Building a ground plane with sheet metal is acceptable. Aluminum is an excellent conductor. When you get /really/ specific the ground plane will need to be a specific length out from the center of the antenna base. You will need to find a site with a list or the equations to calculate proper length of your ground plane for the frequency your running. (In the perfect world they say an infinite ground plane is the best. This is never possible though unless you have property rights to a place like Earth made out of pure copper. I'm also sure you appreciate some space in the bed.

What about attaching a pair elements at a 45* to the base of the antenna. It would be down in the bed where it wouldn't be visible but that would also limit to being able to only use a pair rather than four like most I have seen. Does that even make sense?
Well an proper ground plane would be a solid circular sheet of metal with a length calculated base on the center frequency of the antenna tuning (90 degress from the whip). Of course, those guys with a huge HF antenna towers usually bury steel rods of the calculated length (as many as they can muster) under the ground in their back yard. You can do the same thing with metal rods. You would add as many as you can (or ideally a flat circular peice of sheet metal) around the base of the antenna. Again you will need to calculate how far out the metal reaches for the center frequency your antenna is tuned for.

Again, for the bed you may not even bother adding a ground plane. It's just something to do for added performance if you happen to have one in a suitable location for antenna placement. Myself, I don't think I'd fabricate a ground plane if I didn't have one readily available.

Or would a better option be to stick with just the 2 antennas and run both scanners off the same one? What effect would that have?
Having a dedicated 800mhz isn't a bad thing. But running two scanners off one antenna is fine.

Running both scanners off the same antenna has been done before plenty of times. Some people just get a T connector and do it that way. Other people get isolator devices to isolate the two scanners.

The scanners shouldn't interfere with each other in my opinion. You may get a birdie or two from internal interference from the VFO's but this should be rare and there's only about 4-5 birdie frequencies in the whole scanner. The birdies won't damage anything.

As long as you aren't transmitting no interference should be caused. (If you do transmit, the scanner connected will be destroyed from the power obviously.) I'm not an expert at running multiple devices off one antenna. This should be fine though.
 
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N1BHH

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It's a truck, what's the problem with drilling holes? The best place for any antenna is on the roof, it's high and clear of obstructions. The hood in my opinion is one of the worst places for any antenna, too close to the engine compartment, where most of your noise comes from in any vehicle. And mag mounts are NOT bad. A magnetic mount antenna inductively couples with the body of the vehicle it is attached to, to create a ground plane situation. If there is a garage clearance problem , a mag mount can be removed.
 

snakecharmer

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It's a truck, what's the problem with drilling holes?
Well to rednecks like me, it's a Cadillac. If it was an old work truck, I wouldn't give it a second thought. But I have come to grips with the idea of a single hole. I just need to find someone with the appropriate punch to do it write. I don't plan to go at it with a drill. And quite honestly, the main reason I decided on a hole is that I don't like having the cable laying across the roof like with a mag mount.

I think I did decide against a hood mount though. I had decided it would be OK before but now I don't think so. I don't care so much for how it looks and the style mount I would have wanted to use, doesn't look like it would work with the lip on my hood upon further inspection. I did get a toolbox in my bed yesterday but its aluminum so I cant stick mag mounts on it. I did consider mounting antennas on the side of it but I'm not sure that would be all that great. What I am considering right now is possibly mounting the scanner antennas onto lip mounts that attach to the tops of my rear doors. As long as I can find mounts that will not scratch my paint, I think I would be OK with that setup aesthetically. Basically, I would have the 2meter antenna (considering a 5/8 wave) on a permanent NMO in the center rear of the roof and a scanner antenna on either side close to inline with the 2 meter antenna mounted mounted to the top lip of the rear doors. In the picture above, the area I am talking about would be that open area behind the vent visors.

Any thoughts on this setup? Would the antennas be far enough apart from each other and would the tops of the doors allow the roof to act as an adequate ground plane?
 

jon_k

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I did consider mounting antennas on the side of it but I'm not sure that would be all that great.
Well lets throw in some information for this.

In my opinion it works GREAT. Aluminum /is/ conductive, it was used in homes prior to 1950 for electrical wiring.

Here's some facts. I've got a scanner antenna on the left side of my bed toolbox, and a 2 meter / 70cm amateur antenna (Comet SBB7) on the center of the toolbox.

Over in Dallas (32 miles away) my friend has horrible reception and has to push 50 watts to even make the repeater. Today I was down the street coming to work and my friend called me in our work parking lot, and was unreadable. I just recognized his voice. I told him to boost power, and he was at 50 watts before I could get him clear. I keyed up at 5 watts output on this antenna a block away from him and he said I was full quieting. The repeater again was about 30 miles away (Granted the repeater antenna it is on a 150 foot tower.)

He always told me RF is horrible in Dallas and he's a veteran operator so I thought Dallas was off limits to try amateur operation. I'm finding out now that it's more than adequate with my toolbox setup. If transmit has performance works this well on an aluminum toolbox, scanning should be more than adequate. The way the antennas are mounted are via bolts and an L bracket with NMO mount.

Any thoughts on this setup? Would the antennas be far enough apart from each other and would the tops of the doors allow the roof to act as an adequate ground plane?
You'll get half a ground plane, as with my toolbox I get half a ground plane, since the antennas are mounted on the edge. I can still transmit to a repeater 30 miles away without issue. Transmit performance is always about 100x more dependent on a ground plane than receiving ever will be.

The distance between the two will be fine, unless one is transmitting (which will desensitize the receiver of the other.) For two scanners, more than adequate as the antennas are both passive.
 
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RADIOGUY2002

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You look into

You look into glass mounts? For your more not as activate hobbies of listening. I'm bias, I tried almost all of it for mobile instalations. I've done the mag mount on a truck, quite impressive with out a hole mount. Make sure you get the right mag mount makes a hole heck of a difference if you go this way. I have three hole mounts on a buick century which suppily a connection to 1. uhf radio, 2. vhf radio, 3. scanner done professionaly for a reasonable price (shop around), one guy quote me 600.00, needless to say I did not pay that and was offer a lower bid which works just fine. Know in addition to that my other fleet vehcile I guess you could say has a truk lid mount which works very well. That particular can not have hole mounts, so that was my option. I've tried quterwave and 5/8 wave antennas, really depends on the area and what your intending to tx/rx on. Realsitically the quterwave is just easier all the way around.

Consider the glass mount if youur always upgrading (easy to swap out), their are mix reviews out their on performance. I wish I could provide more feedback on this arena, but I have not had the oppurtunity to test one yet. Sometime hopefully this year on a truck as I to can not put holes on it, not to mention gas prices are not practical to drive this vehicle daily. And compainies that sell them at half off the listed price, shop around. Dont be a sucker, quterwaves do not cost 10.00 either if you now where to get them at. What a market

Now only if I could get a could get a good repeater antenna for a reasonable price I be set. I'm not paying 900.00 dollars for an antenna that only going to be in the air at max 60 ft.
 

snakecharmer

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Well lets throw in some information for this.

In my opinion it works GREAT. Aluminum /is/ conductive, it was used in homes prior to 1950 for electrical wiring.

Here's some facts. I've got a scanner antenna on the left side of my bed toolbox, and a 2 meter / 70cm amateur antenna (Comet SBB7) on the center of the toolbox.

Over in Dallas (32 miles away) my friend has horrible reception and has to push 50 watts to even make the repeater. Today I was down the street coming to work and my friend called me in our work parking lot, and was unreadable. I just recognized his voice. I told him to boost power, and he was at 50 watts before I could get him clear. I keyed up at 5 watts output on this antenna a block away from him and he said I was full quieting. The repeater again was about 30 miles away (Granted the repeater antenna it is on a 150 foot tower.)

He always told me RF is horrible in Dallas and he's a veteran operator so I thought Dallas was off limits to try amateur operation. I'm finding out now that it's more than adequate with my toolbox setup. If transmit has performance works this well on an aluminum toolbox, scanning should be more than adequate. The way the antennas are mounted are via bolts and an L bracket with NMO mount.



You'll get half a ground plane, as with my toolbox I get half a ground plane, since the antennas are mounted on the edge. I can still transmit to a repeater 30 miles away without issue. Transmit performance is always about 100x more dependent on a ground plane than receiving ever will be.

The distance between the two will be fine, unless one is transmitting (which will desensitize the receiver of the other.) For two scanners, more than adequate as the antennas are both passive.
Well what I might do then is mount one scanner antenna on each end of the box. I already have one NMO mirror mount that can be very easily modified to bolt to the box. Would definitely be cheaper than the lip mounts I was looking at. How important is it that the "ground plane" be at the same level as the base of the antenna? I would probably want to bolt the mounts to the under side of the box where it sits over the bed rails rather than drilling through the diamond plate box sides. That would put the base of the antenna probably 4" below the lid of the box. Even if I bolted the mounts right to the side, it would still be an inch or two lower than the lid.

The glass mount isnt really an option because I wouldn't want to stick anything to my tint.
 

af5rn

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The glass mount isnt really an option because I wouldn't want to stick anything to my tint.
Good, because you're not supposed to, lol. :lol:

You have to stick the antenna to the outside of the glass, then go inside and cut out a square of the tint over where the inside coupler goes, so that there is no tint in-between the antenna and the coupler. Otherwise, your signal fails.

Why wouldn't you want to do that? Not that I am promoting glass mounts or anything, but geeze... it's not like anyone can see the tint (or lack of it) underneath the antenna anyhow.

What kind of tool box is it? It used to be easy back when everyone got those tool boxes that opened on the ends. That gave you three separate ground planes for three separate antennae, which was great! Now everyone is getting those coffin-style, single lid boxes with the diamond plate that aren't good for even one antenna.
 

andrewccm

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For the record, if I drilled holes in my vehicle for a scanner/radio antenna, my wife would buy me the Ultimate HeeHaw DVD set and force me to eat vittles and such while watching for the rest of my life. LOL

And I ain't whipped either... You should have seen the look I got when I told her I was going to stealthly put a scantenna between our house and the neighbors (away from HOA). I did get away with (for now) running a wire antenna out my upstairs window and through my backyard trees for SW. The Yagi and ST2 went into the attic unfortunately.

I guess you could say she doesn't dig the "look" of antennas.

hehehe.
 

jon_k

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Well what I might do then is mount one scanner antenna on each end of the box. I already have one NMO mirror mount that can be very easily modified to bolt to the box.
This is ___exactly__ my setup. It works wonderfuly. See attached images for reference on my setup for my scanner antenna.

The amatuer antenna is more on the center though, for more ground plane. Scanner antenna gets about 1/4 a total ground plane, and the amateur antenna being near the middle gets more of 1/2 a ground plane area. I figure that's better for transmitting.

How important is it that the "ground plane" be at the same level as the base of the antenna?
Can hear Dallas police from home with the scanning antenna 30 miles away. The height is pictured from images below. (The amateur antenna is mounted the same height, and has similar performance.)

I would probably want to bolt the mounts to the under side of the box where it sits over the bed rails rather than drilling through the diamond plate box sides.
The toolbox in my opinion is easier to drill into vs the bed rails.

This was taken before the amateur antenna was added, pictured is the Austin Spectra scanning antenna.. First picture is a far-away view of the system. Second that is embedded in post is closeup of assembly.Note the spacers to get clearance with the lip of the toolbox lid Now days the coax runs between the bed and the toolbox, and isn't ghetto rigged like pictured. (I was on a time budget!)


Click link for OVERALL picture of the mount on the truck. http://i27.tinypic.com/jfgn6r.jpg

Emedded on the right: Closup of assembly


af5rn said:
Now everyone is getting those coffin-style, single lid boxes with the diamond plate that aren't good for even one antenna.
Perhaps not ideal, but in my opinion this is second best compared to the roof of the vehicle. I'm definitely pleased by my performance. Sure, I can't work Waco from Dallas even in best sporadic E... but this setup on my vehicle outlives any expectations for monitoring and communication within DFW. I think this will suit all but the most distant monitoring preferences.

andrewccm said:
For the record, if I drilled holes in my vehicle for a scanner/radio antenna, my wife would buy me the Ultimate HeeHaw DVD set and force me to eat vittles and such while watching for the rest of my life. LOL
[......]
I guess you could say she doesn't dig the "look" of antennas.
You haven't even ventured into amateur radio yet! Get a license, come back to me in 6 months and if you still have no vehicular antennas, I'll be impressed. No, I mean really impressed.:) If your trend in radio continues to grow, your wife will be embarrassed to ride with you -- and sooner than you think. :D:D For better or for worse they say!

Some would say you haven't degraded (upgraded as I'd say) to that level of geekdom yet.:lol:
 
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RADIOGUY2002

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I not supporting the glass mount antena 100% either just considered as an option. I would remove the tint if need be in that square section. Personally I go with the metal box install like shown above if I had a metal box, just bescause of the ground plane factor. What a difference it can make, see that in radio test decribe above with portables and mag mount attached to them. Kills the fact that their portable thow, kinda defeats the purpose. Done more as a study then anything else.
 
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