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[Articles Home]  [Add Article]  

Capacitive Grounding Mobile Antennas

from Richard Fusinski K8NDS on March 30, 2009
View comments about this article!

Capacitive RF Grounding
Technique for Trunk Lip Antenna Mounts

Installation shown for Diamond

CR9800A - Quad Band Antenna

Non- Intrusive Mount (no paint intrusion)

  • 1/32” copper shim between set screws and paint for non-intrusive mount.

  • There is NO DC Ground connection from mount to trunk.

  • Notice split shrink tubing between paint and mount channels for non scratch.

  • 1 inch copper strap solders to 1/32” shim for RF ground and good skin effect.

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RF Coupling presents low Xc to vehicle body

with no actual DC contact, no paint removal.

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  • 1 inch copper strip soldered to 2 inch adhesive strip.

  • Diamond foam strip covered set screws and coaxial cable for better trunk seal.

Capacitive RF Grounding (Low Xc)

  • 2 inch Copper Foil Tape runs across entire underside of trunk lid.

  • Capacitance of 8000 pf was measured from mount to car body.

  • 8000pf is equal to approximately 1 ohm Capacitive Reactance @ 18 Mhz

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VSWR Measurements

< 1.2 to 1 on 2 Mtrs & 70 Cm

No ground plane is necessary on VHF/UHF

< 1.2 to 1 at resonance on 10 Mtrs

< 1.5 to 1 at resonance on 6 mtrs

Finished Mount

  • Finished Mount seals nicely against trunk seal.

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My particular Installation

Convertible Top Cable Track

  • Convertible top opens in both directions.

  • Supplied Diamond Coaxial Cable is tie rapped to existing scissor track.

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Trunk in Convertible Position

  • Trunk can open in both directions.

  • Coaxial cable follows scissor hinge

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Finished Mount

  • Diamond Mount presents a finished look.

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Cup Holder Mount

  • Cup holder mount presents an easy non-intrusive installation.

  • No holes necessary, easily removable.

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Rear View

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Side View

  • Constructed from one can of automotive bondo, mixed

and molder in a plastic cup with wood wedge epoxied

on top. Heavy material stays in place.

Cup Holder and Control head

  • Swivels easily for proper viewing angle

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The end of installation and the Beginning of some fun operating………………..

  • General Motors and Diamond!

  • A Great Automobile with a fine Antenna System…..

CQ CQ de K8NDS

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By: Richard Fusinski

K8NDS Cottonwood, Arizona

Member Comments:
This article has expired. No more comments may be added.
 
Capacitive Grounding Mobile Antennas  
by W9PMZ on March 30, 2009 Mail this to a friend!
There is NO DC Ground connection from mount to trunk."

But the coax shield on the antenna goes back to the radio and I assume that the radio's case is at the same potential as the chasis???

Isn't this kind of asking the shield to the antenna to radiate and be part to the total antenna?

But if it works, what the heck! Nice article and pictures.

73,

Carl - W9PMZ
 
RE: Capacitive Grounding Mobile Antennas  
by N4CQR on March 30, 2009 Mail this to a friend!
Nice artice and expecially nice photos.

Now let's see usuals tell us how this can't possibly work.
 
Capacitive Grounding Mobile Antennas  
by K4IA on March 30, 2009 Mail this to a friend!
Neat install. Yes, many trunk lids are isolated from the body because the hinges have nylon bearings and there is no metal to metal contact.

But I am curious. Why attach the antenna ground to a piece of copper tape? Why not directly to the body?
 
Capacitive Grounding Mobile Antennas  
by WX7G on March 30, 2009 Mail this to a friend!
Most excellent!

Calculations confirm your 8000 pF measurement. Copper adhesive tape is expensive. If some of the ham outlets would stock this in small quanities...

Hobby stores stock copper foil that can be used with an adhesive.

Remember the formula from the ARRL Handbook:

C = 0.2249KA/D, capacitance of parallel plates

K is the relative dielectric constant
A is area in sq inches
D is spacing in inces
C is pF

For your installation:
K = 2, A = 100 sq in, D = 0.005 inches, C = 9000 pF
 
Capacitive Grounding Mobile Antennas  
by WA7NCL on March 30, 2009 Mail this to a friend!
I think the formula for capacitance given by one poster does not account for the dielectric constant of the paint. It would be higher than air.

In the case of the other poster concerning "DC" ground. How can you use the word "DC" and radiate in the same sentence? Why would a connection for DC be significant for an AC phenominon?

By making the coupling high enough the author reduces the common mode problem. Even if there were to be a common mode problem, it could easily be circumvented by adding a ferrite common mode choke and or more copper tape for coupling.

The approach presented by the author is much superior to the usual long chunks of braid etc to DC ground to bolts and screws with boasts of how low the ohmmeter reading of the result were.
 
Capacitive Grounding Mobile Antennas  
by KC0RBX on March 30, 2009 Mail this to a friend!
Bad ham! Bad HAM! You didn't drill a hole in your car like a "good ham" would do! Hi Hi. Nice article, great pics. Gave us some things to think about. Good creativity.
 
RE: Capacitive Grounding Mobile Antennas  
by WB2WIK on March 30, 2009 Mail this to a friend!
Nice article.

What's described appears to have been quite a lot of work. I just punch a hole and make the direct DC connection (NMO mount), and be done with it: Takes maybe 60 seconds start to finish, and then I have more time for other stuff. Plus, the through-hole mounts are very inexpensive, so with the money saved, I take the family to dinner. ;-)

I've found "paint" is not the intended dielectric material for an RF capacitor. An 8000pF air capacitor is great, a vacuum is better; NPO cermic is good; X7R is less good; Z5U/Y5V types are much less good; Teflon's not bad; mica is good; polystyrene is terrible (at RF), and mylar, PVC and other plastics are lossy dielectrics at even 10 MHz, let alone VHF.

Since paint probably varies by mix, color, thickness, batch and other things, I won't even try to characterize it -- too much like a big project. But I'd expect it's not as good as dielectrics already characterized as low loss for radio frequency work.

I'll stick with punching holes -- less work!

Nice job, though.

WB2WIK/6

 
RE: Capacitive Grounding Mobile Antennas  
by K8QV on March 30, 2009 Mail this to a friend!

"Now let's see usuals tell us how this can't possibly work."




Yep, I'm waiting too!

Nice looking install. Thanks for posting it.
 
Capacitive Grounding Mobile Antennas  
by KB2DHG on March 30, 2009 Mail this to a friend!
Very nice article...
I see that you are an inovator and that my friend is what this hobby is all about...
Nice work and good pictures.
 
RE: Capacitive Grounding Mobile Antennas  
by K5END on March 30, 2009 Mail this to a friend!
FYI

Copper tape in rolls with a *conductive* adhesive is available in various widths at stewart macdonald.

It's sold there for quieting electric guitars, but it works well for applications similar to that depicted in the article.
 
RE: Capacitive Grounding Mobile Antennas  
by K0BG on March 30, 2009 Mail this to a friend!
Ground plane losses dominate the efficiency equation of any mobile antenna installation. Even a one ohm reduction can be significant. Calculations aside, any improvements made in the ground loss could be easily measured with an antenna analyzer.

While the author has gone to a lot of work, I suspect you couldn't measure the difference in ground losses, even with a laboratory-grade analyzer. After all, there is a vast difference between an RF ground, and a ground plane; a very common misunderstanding.

Even if the ground plane losses could be reduced to zero, the efficiency of this particular antenna wouldn't improve, as the resistive losses are rather large (low Q, short length).

Alan, KBG
www.k0bg.com
 
RE: Capacitive Grounding Mobile Antennas  
by K5END on March 30, 2009 Mail this to a friend!
PS. they also sell conductive paint. Didn't think to mention that.

Priced around $60 per pint.
 
Capacitive Grounding Mobile Antennas  
by WI7B on March 30, 2009 Mail this to a friend!

Richard Fusinski K8NDS,

Fantastic article on a misunderstood aspect of mobile radio installation. The key, as you point out, is an efficient RF ground, not bonding every nitch and cranny or drilling holes everywhere in an effort to make a perfect DC ground.

73,

---* Ken
 
Capacitive Grounding Mobile Antennas  
by WD9ICU on March 30, 2009 Mail this to a friend!
I like the cup holder idea for the remote head. Nice job!
 
Capacitive Grounding Mobile Antennas  
by N8QBY on March 30, 2009 Mail this to a friend!
That didn't take long.
 
Capacitive Grounding Mobile Antennas  
by N8QBY on March 30, 2009 Mail this to a friend!
Excellent article, and great pic's. Thanks!!
 
RE: Capacitive Grounding Mobile Antennas  
by K0BG on March 30, 2009 Mail this to a friend!
<The key, as you point out, is an efficient RF ground....>

No it's not! The key to efficiency is an adequate GROUND PLANE! While the two may be coincident, they are in fact, not the same thing.

Ground planes do not have to be RF or DC grounded in order to be effective. As I said before, this is a very common misunderstanding.

It is true that the coax shield should be connected to the ground plane, but is sure doesn't have to be "grounded" otherwise.



Alan, KBG
www.k0bg.com
 
RE: Capacitive Grounding Mobile Antennas  
by WB2WIK on March 30, 2009 Mail this to a friend!
As a sidebar, what is the advantage of "no paint intrusion?"

To me, it just looks like a lot of added work.

Is there some reason to avoid "paint intrusion?"
 
RE: Capacitive Grounding Mobile Antennas  
by K5END on March 30, 2009 Mail this to a friend!
quote, "Is there some reason to avoid 'paint intrusion?'"

It's like a religion to some car owners.



My pet peeve is door dings.

I'll drill any number of holes for a new antenna on a brand new car, on the cowl, fender, trunk, bed rail, etc...

...but let me catch you dinging my door just once in a parking lot with your grocery basket and we'll both be on the 6:00 news. :-)

 
RE: Capacitive Grounding Mobile Antennas  
by WB2WIK on March 30, 2009 Mail this to a friend!
>RE: Capacitive Grounding Mobile Antennas Reply
by K5END on March 30, 2009 Mail this to a friend!
quote, "Is there some reason to avoid 'paint intrusion?'"

It's like a religion to some car owners.<

::Yeah, I always wondered about that. I punch antenna mount holes in my cars usually the same day I bring each one home from the dealer's lot. Makes me feel better. I do this even with leased cars, and have turned in many, many leased cars with antenna mounts installed -- nobody ever even mentions it.



>My pet peeve is door dings.

I'll drill any number of holes for a new antenna on a brand new car, on the cowl, fender, trunk, bed rail, etc...

...but let me catch you dinging my door just once in a parking lot with your grocery basket and we'll both be on the 6:00 news. :-)<

::I'll be the one running fast, pushing the grocery cart...

:-)

WB2WIK/6
 
RE: Capacitive Grounding Mobile Antennas  
by W8JI on March 30, 2009 Mail this to a friend!
I know a few people will take this technical comment personally (because they don't understand the difference between personal and technical discussion), but there is an important technical fact we should remember.

The low frequency impedance or capacitance has little or nothing to do with the high frequency capacitance or impedance of a system like this.

If for example we have a one inch wide strip that happens, counting the velocity factor of the dielectric (paint), to be 1/2 wave long on a certain frequency (say two meters) then it will be a virtual open circuit at the far end. It becomes a half-wave strip transmission line.

Another factor is the shunt impedance of the coax going back to the rig. It can parallel tune a reactance shunting the line to ground.

What we generally have with long leads is a series of ripples or gyrations in impedance as frequency is changed. This is why RF capacitors use compact multiple layers with very short lead lengths. Stick a 1000 pF cap on the connector of a MFJ-259B and sweep it from 1.8 to 1000 MHz while watching the impedance.

8000 pF in a meter that measures at 1000 Hz might easily be 1000 ohms impedance on some higher radio frequency. This is how RF systems and RF components work.

73 Tom



 
Capacitive Grounding Mobile Antennas  
by KC2CBA on March 30, 2009 Mail this to a friend!
I echo the praise of the cup holder mount -simple yet elgant at the same time.I'll be mixing my bondo this weekend.
 
Capacitive Grounding Mobile Antennas  
by WI7B on March 30, 2009 Mail this to a friend!

"<The key, as you point out, is an efficient RF ground....>

No it's not! The key to efficiency is an adequate GROUND PLANE! While the two may be coincident, they are in fact, not the same thing."

When is an RF ground NOT a ground plane?

Let's go L.B. Cebik who is so freely quoted by some:

"In fact, the so-called ground plane is never a GROUND plane, but always a hat-plane. Hence, the so-called antenna-completing ground is not a ground at all--even though we sometimes use the ground to do the work of the plane. This is not the first time we have misnamed something in radio. It took a long time to weed out the term "condenser." It will likely take even longer to drop the term "ground" from ground plane.

"But do we not always connect the braid of the coax to the plane and the center to the monopole? Most of us do, but it is not required if we separate our DC and RF grounds from the antenna end of the transmission line. We can feed a monopole through an inductively coupled balanced ATU and then connect either side of the line to either antenna terminal. Once again, we collect a number of functions into a single configuration, like connecting the case to the coax braid and the braid to the monopole ground rod as our station ground: then we forget to sort out the functions, and the configuration makes it hard to separate them. Nonetheless, the antenna, as an antenna alone, does not need a ground for its ground plane. (But add one anyway for lightning, static discharge, RF, and DC grounding.)

By sorting out our grounds--and further sorting real grounds from planes we only call grounds--we can achieve a better understanding of a. how monopoles work and b. why some vertically polarized antennas do not need a ground plane. But I doubt if the term "hat-plane" will ever gain currency." - L.B. Cebik

=> http://www.kandka.com/mirrors/www.cebik.com/gp/gp1.html

73 Alan,

---* Ken


 
RE: Capacitive Grounding Mobile Antennas  
by K0BG on March 30, 2009 Mail this to a friend!
If you want to use a cup holder as a mount, then just remove the rubber protector in the bottom. Screw the mount down to the plastic. When you sell the car, just replace the protector, and no one will be the wiser. Just remember, that heavy chunk of bondo will become a missile in a crash.

Alan, KBG
www.k0bg.com
 
RE: Capacitive Grounding Mobile Antennas  
by K0BG on March 30, 2009 Mail this to a friend!
Well, Ken, then call it an image plane. The fact remains, it does not need to be earthed. On the same token, an earthed ground rod does not constitute an image plane or a ground plane.

The real unfortunate part is, far too many folks don't know the difference.

Alan, KBG
www.k0bg.com
 
RE: Capacitive Grounding Mobile Antennas  
by N6EY on March 30, 2009 Mail this to a friend!
Echoing Alan's last, many think that because their power supply has a grounded cord, then they claim to have an efficient RF ground, which really is the "image plane."

Even many rf technicians make this mistake!

Still, the install looks clean. It may not be the most efficient, but if the author is happy with it, congrats.

As for peer review...better saved for serious journals.

 
Capacitive Grounding Mobile Antennas  
by WI7B on March 30, 2009 Mail this to a friend!

Well Alan, you KNOW we are in agreement.

The image plane is key. And there is more than one way to achieve it. RF capacitive couple is one way, without a bunch of holes or massive bonding. An ATU is one way to achieve this with RF capacitive coupling.

We're all not "screw-heads" Hi HI!

73,

---* Ken
 
RE: Capacitive Grounding Mobile Antennas  
by W8JI on March 30, 2009 Mail this to a friend!
Well, Ken, then call it an image plane. >>

An image plane is formed by the reflections throughout the Fresnel region. It is not formed by wires or counterpoises under a vertical. It is a "phantom" antenna that represents the radiation that reflects off the earth or other media to form the pattern. In a vertical the image is formed in an area extending several wavelengths out.

We are much better off to call it what everyone knows it is. A ground. A ground does not have to be an earth connection, and we all know or should know that. The textbook definition of a ground is a common reference point for multiple circuits or systems that may or may not actually be connected to earth.

73 Tom
 
RE: Capacitive Grounding Mobile Antennas  
by KE3HO on March 30, 2009 Mail this to a friend!
W8JI said: "An image plane is formed by the reflections throughout the Fresnel region. It is not formed by wires or counterpoises under a vertical. It is a "phantom" antenna that represents the radiation that reflects off the earth or other media to form the pattern. In a vertical the image is formed in an area extending several wavelengths out."

Exactly. Regardless of what you do with your ground connection at the mobile antenna, good or bad, you will never create a "ground plane" or anything remotely like one in a mobile installation on HF. There just isn't enough car body there. Even if you had a full size van and put a 10M antenna in the center of the roof it would not come close to being a "ground plane".

The simple truth is, you have current flowing on both halves of the coax, and both halves need some place for that current to flow. If your impedance on the ground (shield) side is high, you will have high losses, high common mode current, and reduced current flow in the antenna resulting in poor efficiency.

You can chase every last ohm if you want to, but let's face it: if you are using a 5 foot antenna on 40M, efficiency is NOT your top priority. In an ideal world, every ham would have a 13 foot (or bigger) antenna on his/her car and would seek out and eliminate every milliohm of impedance on the ground side. In the real world, most guys are happy to just be on the air with an antenna that presents something close to 50 ohms to their rig. Don't believe me? Read the product reviews for hamsticks and see all of the glowing reviews.

73 - Jim
 
Clean Install  
by N6BOB on March 30, 2009 Mail this to a friend!
Thanks for taking the time to post such a clean mobile installation. The photos are large and clear... I can imagine all the strange positions you had to be in to shoot some of them from the trunk looking up. They are well illuminated too. I'm always looking for new ways to do something and I learned about the capacitive grounding method. I have never seen that before.
Thanks for all nice write up. 73 N6BOB
 
Capacitive Grounding Mobile Antennas  
by KD5SFK on March 31, 2009 Mail this to a friend!
Out of curiosity, why not center the lip mount in the middle of the trunk instead of off to one side?

Also, what's the button antenna that is already mounted through a hole in the trunk? Satellite radio/On-Star that GM puts on everything these days? Looks like a nice pre-existing hole for a future antenna mount when the On-Star and Sat-radio free subscriptions expire!
 
Capacitive Grounding Mobile Antennas  
by K1CJS on March 31, 2009 Mail this to a friend!
Nice article, but it seems like the author did a lot of work for little gain. A trunklip mount can be easily used with a bit of touchup paint around the binding screws to prevent rusting. As a matter of fact, I've seen trunk lip mounts that have been on for years--and the place where the screws dig into the paint haven't rusted AT ALL. If and when removed, a bit to touch up paint on the screw indentations and you would never know the mount was there--unless you examine the underside of the trunklid closely.

Anyway, I'm going to agree with WB2WIK--just drill a hole and be done with it. Better mounting system--it won't slip off, and better position--right in the center of a ground plane.

I'm also going to comment on the cup holder idea--the heavier you make it, the more likely it is to go flying in the event of a sudden stop. At the very least, put a piece of double stick tape on the bottom of it--so you have to work to get it out of the cupholder well. On the inside of a car, well attached is better than loosely attached--especially if you get into an accident!
 
Capacitive Grounding Mobile Antennas  
by K1CJS on March 31, 2009 Mail this to a friend!
Wow, the page formatting on this article is way off!
 
Capacitive Grounding Mobile Antennas  
by WW5AA on March 31, 2009 Mail this to a friend!
Even Diamond gets it wrong!

"The CR8900A is pretuned to give best bandwidth and VSWR over the FM portions of 10m, 6m, 2m, and 70cm ham bands when mounted on the side of the vehicle".

Side of the vehicle?

73 de Lindy


 
RE: Capacitive Grounding Mobile Antennas  
by WX7G on March 31, 2009 Mail this to a friend!
W8JI:
Tom, you make a good point. I did a quick t-line analysis before my post. Here's the math.

The copper strip is 2" wide and 48" long (as long as the trunk according to the author. The effective dielectric constant is 2. That makes the length of this transmission line 6 ns, which is 90 degrees at 40 MHz.

The Z0 of this line is 3/4 ohm. At 20 MHz, where the line is 45 degrees the input Z = -j0.75 ohm. AT 40 MHz, where it is an open 90 deg input Z = 0 ohms.

It looks like a good ground connection up thru the 6 meter band. Just


Handy formulas: C = td / Z0
L = td x Z0

td = propagation time
Z0 = line characteristic impedance
td = 85 ps/inch in vacuum (air)
 
RE: Capacitive Grounding Mobile Antennas  
by RFSOAKED on April 1, 2009 Mail this to a friend!
Looks nice but i see no reason for the copper adhesive backed tape. That's just forming a capacitor not a solid ground, your still using the coax braid back to the radio as your ground. I prefer a solid direct ground at the mount, or a short lead from the mount to the body. You can usually find plenty of nearby fasteners to put a ring terminal under without drilling any new holes. But even then a small 1/8" screw hole in an area that doesn't see a lot of direct exposure isn't going to cause major problems. If your worried about that use some dielectric grease on the screw and over top of it, or seal it up with a bit of RTV sealant or caulk, but make sure its pure silicone.

The copper strap is nice but not flexible enough for my installs. I use some tinned braid between two pieces of copper flashing cut to the size of the original shim that comes with the mount, solder it together to make a nice sandwich and then put it under the screws of the mount. This way the braid is between two pieces and soldered together making not only a soldered bond but a mechanical bond once the mounts screws are tightened down on it. Run the braid over to the body and install a screw, i prefer the shorter self tapping stainless screws they make for marine use, not the self drilling ones, you have to drill the correct size pilot hole and then the screw cuts its own threads. Install a ring terminal on the body end of the braid and solder it, tighten screw and your done. If you want to tidy it up further get some of the woven wire covering like you see being used on factory harnesses, doesn't cost much and its cheap at most auto stores, regular split loom tubing is too bulky for this. Or you can even take the braid and paint the exposed section between the body and door with some flat black and it blends right in.

None of my grounds pass through the weatherstripping so i don't have that problem either, the antenna mount goes on the edge of the rear hatch or door of the family minivan and car and its at a point outside of the weatherstripping. The ground braid goes from there to a body point between the door and body, or to one of the hinge bolts if cleaned up for a good connection.

I think after seeing the pictures of this car, nice car by the way, i would have skipped the copper tape and bonded directly to the deck using an existing fastener or put in a small screw. Then make sure the deck is grounded to the rest of the body through it's hinges, if not just add a braid from the point the mount is bonded to the deck down to the body following the coax route down. I don't like relying on the coax shield for the ground.

 
RE: Capacitive Grounding Mobile Antennas  
by RFDANNY on April 1, 2009 Mail this to a friend!
Ahhh, K1CJS back at it.

Learn about K1CJS stealing money from his ham club, and all sorts of other interesting facts at:

http://webpages.charter.net/n1joy/K1CJS_Facts.htm

Danny
 
Capacitive Grounding Mobile Antennas  
by KD8DEY on April 1, 2009 Mail this to a friend!
Nice Article.

I have no problems with drilling holes or filing paint away from screw mounting locations etc.

Got an Astrovan with a BALL mount in the center of the roof. The headliner was falling down so why not :) ...A cavalier that I am planning on adding a lip mount to.....

I don't trade a vehicle in every few years, By the time I'm finished with a vehicle it's bound for the scrapper :)

No Worries, Be Happy
 
RE: Capacitive Grounding Mobile Antennas  
by K1CJS on April 2, 2009 Mail this to a friend!
You know, Danny, you should know the specifics of a story before you go and make suppositions. The whole story--not just the printed antics of a person carrying a grudge. It has been said that the person putting that rubbish up on that site has also been accused of the same exact thing at another club.

In any event, he can go on forever as far as I'm concerned. It doesn't bother me.
 
RE: Capacitive Grounding Mobile Antennas  
by K5MO on April 4, 2009 Mail this to a friend!
"i see no reason for the copper adhesive backed tape. That's just forming a capacitor not a solid ground,"

You might re-open the license study manual to refresh yourself of what a capacitor looks like at RF.

John K5MO
 
RE: Capacitive Grounding Mobile Antennas  
by K8NDS on April 5, 2009 Mail this to a friend!
I have really had some laughs reading some of the comments made here. It becomes very obvious who is versed on the subject and who is just trying to show their knowledge or lack of. First of all this system has been proven by me on more then one install. I had a mobile install 5 years ago that used nothing but capacitive grounding to the vehicle roof. The method used on the vehicle was 6(qty), 5 inch magnets on a whole made mount. The 6 magnets offered a low enough Xc to complete the RF ground. The antenna was a Hi-Q screw driver; model that covered from 6 to 40 mtrs. I used this system on the 17 mtr band for several years with more then outstanding results. I worked mobile to mobile on 17 mtrs from USA to Europe several times during so-so conditions. I made hundreds of contacts and had consistently been told that I had one of the strongest mobile signals that was heard on the 17 mtr band. I was well known for my mobile signal on that band. The antenna preformed just as well from 40 thru 6 mtrs. As stated by some on this blog I guess that I don't understand what I am doing?????
By the way I have a US patent concerning a similar concept for Microwave antennas, this patent has been used in production with thousands of units and performed very well in the field. So the person that said to go back and read the license manual needs to read much more info then the license manual. The license manual is only for people to skim by, by the skin of their teeth. As one commenter stated, this is what Ham Radio id all about, innovation. My new installation shows me a close to perfect match with the antenna analyzer; try to read a perfect match on that antenna with out a good RF ground....Good luck!
Oh yes! I forgot to comment on the fact that this is not meant to be a world class signal generator, I have had several of those on my SUV's; this was meant to be a decent installation on a fancy vehicle that I didn't want to damage in any fashion. There are many Hams in this situation that may employ this on their comparable vehicles with out scarping paint or having set screws come loose and cause issues. This was not meant to be "The Perfect World Class Signal", just a technically sound alternative to the known antenna art. The several commenters that stated it looks like allot of work; it only took me 2 hours to completely mount the antenna and check it with the analyzer.
 
RE: Capacitive Grounding Mobile Antennas  
by G6NJR on April 5, 2009 Mail this to a friend!
Punching holes is all very well if you CAN but some of us have to go to Extreme lengths to avoid holes at all costs unless we are feeling rich and if that was the case we would not have to worry about holes cus we would OWN the vehicle instead of it being a lease vehicle .

Pete Disabled UK Motability customer hence the no holes bit
 
Capacitive Grounding Mobile Antennas  
by KG4CLD on April 5, 2009 Mail this to a friend!
A nice article on a nice installation. Wonderful pictures too.

It opens the creative thought process to similar installations on various other types of vehicles. Good job Rich!

73's, Dave-KG4CLD
 
RE: Capacitive Grounding Mobile Antennas  
by K8AI on April 6, 2009 Mail this to a friend!
What's the big deal with drilling holes, "paint intrusion", etc. It's not a like it's a Bentley or something... gee whiz :)
 
RE: Capacitive Grounding Mobile Antennas  
by K8NDS on April 6, 2009 Mail this to a friend!
In Reply to Curtis, K8AI..... It amazes me that some hams are sooooo short sighted that they cannot understand that everyone in the world does not think the same or have the same values. Just because you think it is ok to drill holes, it doesnt mean it is ok for all others! In case you didnt bother reading other replies, many here liked the idea. You just sound like one of those crotchety old men who have to find fault with everything that you read; I sure hope that I never get that way. Many people take pride in caring for their vehicles, in which it also maintains the resale value.
Some people don't keep a vehicle long and some wear them to the ground, there is a large population of hams which feel the same as me; this was meant for them. If you feel the need to drill a hole, more power to you. I have also drilled holes in vehicles that I didn't car about but this is an alternative for people who don't want to. If you didn't like the article, soooooo what! :-)

 
RE: Capacitive Grounding Mobile Antennas  
by K8AI on April 6, 2009 Mail this to a friend!
C'mon man, I was just kidding around (hence the "smiley"). Lighten up dude.
 
RE: Capacitive Grounding Mobile Antennas  
by K8NDS on April 6, 2009 Mail this to a friend!
April fools.....There was a smiliy at the end of mine too!
 
RE: Capacitive Grounding Mobile Antennas  
by K8AI on April 6, 2009 Mail this to a friend!
You got me!
 
RE: Capacitive Grounding Mobile Antennas  
by G6NJR on April 8, 2009 Mail this to a friend!
>K8AI said What's the big deal with drilling holes, >"paint intrusion", etc. It's not a like it's a Bentley >or something... gee whiz :)

Tell you what it's simple i drill holes in a panel i and i mean me personally not the insurance pays to have the panel replaced painted ect ect ect ect rather simple in reality

 
RE: Capacitive Grounding Mobile Antennas  
by RFSOAKED on April 17, 2009 Mail this to a friend!
"""Punching holes is all very well if you CAN but some of us have to go to Extreme lengths to avoid holes at all costs unless we are feeling rich and if that was the case we would not have to worry about holes cus we would OWN the vehicle instead of it being a lease vehicle ."""

Actually its the other way around, those worried about holes are the ones that can actually afford to! Hey, your the guy buying a BRAND NEW car every few years, i'm lucky if i can afford to buy a newer vehicle every 5-10 years once the one i have is worn out.

Not to mention i won't even get into how you people are getting raped on a lease, what stupid crap. I pay $155 a month for my current auto loan, a neighbor went out and leased a new vehicle and pays around $225, and what does he get in the end?? It's like renting a house instead of buying one, i rented the house i now own for eight years, why did i buy it instead of continuing to lease/rent it? Because the money goes to owning it!

Must be nice to have all that money to piss away on leasing a brand new car every 2-3 years. No wonder the auto makers got overinflated heads and egos...
 
RE: Capacitive Grounding Mobile Antennas  
by K8NDS on April 17, 2009 Mail this to a friend!
To RFsoaked:
You know what they say about Asumming?
It is quite the opposite, I own this vehicle outright and I like to keep my vehicle like new with no holes.
Some people like their radios, I like my cars.
 
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