Drilling Holes
Alan Applegate (K0BG)
on
May 14, 2003
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Drilling Holes
After many years of mobiling I still find it fascinating, almost irresistibly, and even mysterious. The ease of making international contacts with a minimum of radiated power remains a conundrum when compared with the typical non-mobiler’s maze of amplifiers and high strung aluminum as any QRP operator can attest to.
I do not use the reference to QRP lightly, as the average mobile is more akin to QRP than the aforementioned QRO setup. This is because most mobile stations radiate only a fraction of their input power. There are many factors to this equation, and anyone who has read my previous installments here on eHam.net know most of them. One of the most important is proper mounting of your mobile antenna. Many amateurs shortcut this part of their mobile installation for all of the wrong reasons. And I want to address these reasons one by one.
Let me say from the outset that most of the following is slanted toward HF mobile operation, but the basics can be applied to VHF and UHF as well.
And I’m not going to be drawn into an argument about radiation angles, HAAT measurements, and other esoteric technical data. This is, after all, a discussion about drilling holes with a bent on getting the most out of your mobile. In other words, efficiency.
The average short, 80 through 15 meter HF mobile antenna (8 to 11 feet in length) exhibits a capacitive reactance of between 20 and 45 pf, some amount of radiation resistance, and other losses. Some form of coil cancels the reactive component and resonates the antenna on the frequency of choice. Below is a schematic of the average mobile antenna.
The nomenclature is as follows: -XA is the capacitive reactance of the antenna; +XL the inductive reactance which cancels -XA and brings the antenna into resonance; RL which is the resistive losses in the coil; RG which is the ground losses; RR the radiation loss; and CS which is the capacitive shunt losses. It is this latter loss we’re most concerned with here because it bypasses the radiation loss component of the antenna as can be easily seen by looking at the schematic above.
Contrary to popular convention, radiation resistance is a loss albeit desired. And it is the ratio of this loss with respect to the other losses which determine antenna efficiency.
We can control RL by using higher Q factor coils; we can control RG to some extend by selecting an advantageous mounting location; and we can control CS if we pay close attention not only to mounting position, but how we mount as well.
Below is a pictorial of a short mobile antenna showing the capacitive coupling which occurs. Less obvious is the shunt capacitance of the mount itself. Some recent authors suggest this loss equals 2 or 3 pf, but it can be much larger in value. While we’re on the subject, think about this: An 8 foot mobile antenna at 7.2 Mhz has a capacitance of Å28 pf. If by poor mounting location and position we were to introduce 10 pf of stray (shunt) capacitance, our antenna efficiency would be cut by 35%. This is not rocket science, it is Ohm’s law!
It may not be clear to all, but the most advantageous mounting position is in the middle of the top of the vehicle. The shunt capacitance to ground and to the body are at their lowest value, and if we use a good-quality, low loss ball mount, we’d have the ideal setup. There is a problem here at least in some localities because of overall antenna height. Out in the desert southwest where I live, overall heights up to 16 feet are mostly okay. On the eastern seaboard, even 11 feet can get you into trouble. It’s obvious then why lots of amateurs mount their antennas similar to the pictorial above. The problem is, however, this is the least efficient position in terms of RG and CS. "Well", they say, "this was the only way I could mount it without drilling holes in my lease vehicle." (We’re getting closer to the truth of the title of this treatise.) Some amateurs bypass this (or so they think) by using a large magmount attached to the truck and maybe even the top of the vehicle. Aaaah, but magmounts add a large measure of CS unless they are well RF grounded which isn’t always an easy task without drilling holes (we’re getting closer!).
So just what am I suggesting? First, select a position on your vehicle where the antenna (mast and especially the coil) is as clear of the vehicle’s body as possible, where the overall height of the antenna is consistent with the environment where your principle driving is conducted, and mounted in such a way as to minimize stray capacitance. And keep in mind, a short antenna mounted on the roof just might be superior to a longer one mounted on the bumper, all else being equal. For those folks driving vans or pickups with camper shells, your best bet may be to mount the antenna at the front of the vehicle.
Now, I’m not naive and I do realize the complexities of mounting a 10 pound screwdriver antenna on the side of a vehicle made out of 16 or 18 gauge steel of questionable quality. Not all of us have this problem, but still choose to mount smaller antennas with all manner of truck lip mounts, and even CB-style license plate mounts. And all because we just won’t drill holes (We’re here at the gist of it!)
I suspect I should have written a list of excuses and come up with a smartalic, terse, or inane answers. I chose not. But I have done my research and the following is a synopsis. I have purposely left out the actual names and locations for obvious reasons (advise of council), but after reading this information, you can check with your dealer for details with respect to leasing, trade in or other provisions or lack of them.
The most prevalent excuse is; It is a lease car and I’m forbidden to attach any permanently mounted antennas or drill any holes.
I have to date spoken with one owner, three sales managers, two lease managers, one used car sales manager, and one nonaffiliated appraiser. They’ve encompassed one Mercury dealer, two Ford dealers, two Toyota dealers, one Chrysler dealer, and an independent insurance adjusting firm. I’ve read four different lease agreements. (One dealer wouldn’t let me read a lease agreement unless I was going to lease a vehicle. I’m told this is against the law so beware of the dealer if this happens to you!)
Much to my surprise only Toyota has a lease provision which prohibits certain after-market devices from being installed in or on the vehicle. Antennas and radios were not specifically mentioned. The sales manager of the dealer in question is oddly enough, an amateur radio operator. He gave me a few statistics about his dealership’s lease program which may or may not correspond to your dealer. Some 76% of his lease cars are purchased by the lessee at the term of the lease, so drilling holes in this case is moot. Nearly all of the extra charges applied to turned in lease cars are due to excess mileage and excess interior wear. He couldn’t remember if he ever added charges due to antenna holes. We looked at three recently turned in lease cars and one of them had a plug right in the middle of the trunk lid! His comment? "I didn’t even see it until you mentioned it."
The owner of the Mercury dealer is a personal friend of mine whom I’ve known since high school. Their lease mentions over all appearance in specific terms, but he echoed the over mileage charges expressed by the Toyota sales manger. He did say he’d almost bet every vehicle he’s ever taken back had at least a cell phone antenna on it.
One of the Ford dealer’s salesmen asked me a question as I approached the front door. "How do you keep that thing (my antenna) from pulling a hole in your fender?" I told him I don’t worry about such things as I know they have a good body shop. His unsolicited reply (honest to john), "Yeah, we fix lots of antenna holes especially on trucks and vans." His lease manager seemed unconcerned about antenna holes and more about the amount of manure they had to clean out of them (this is after all ranch country).
The most direct answer I got was from the Chrysler dealer’s lease manager. "I don’t give a damn about holes, antenna or otherwise. How it looks, how it was serviced, and how many miles are on it is what I look for."
Thus the answer here is, check with your dealer and reread your lease agreement. It just might not make any difference whether there is a hole or not.
The second most prevalent excuse is; My wife won’t let me drill holes in her car.
Well, if it is truly "her car", and she’s making the payments, I guess you have a valid excuse. Then my question is, why are you putting the rig in her car instead of yours? In my personal case, my wife married me knowing I was an amateur radio operator, and nowadays she’ll just have to put up with the clutter, holes, rigs, noise, dangling mic cords, etc. And if your wife is like mine, I have to swallow some of her idiosyncrasies, so turnabout is fair play. In all honesty, if it is a family vehicle and she says no, then you haven’t presented your case correctly. And if she threatens divorce if you do so, then you’re destined for divorce anyway and you might as well get it over with.
The third most prevalent excuse is; It’ll reduce the trade in value.
Nowadays, a smoker’s vehicle will reduce the trade value in much further than any antenna hole ever could. If you’re a smoker, you’re already down the tubes, so trade in value is moot.
The average trade in mileage of one owner vehicles (not including lease vehicles) is 68,000 for cars, and 107,000 for trucks. With this much mileage, they’re going to the auto auction and not to the dealer’s lot. Thus, this is not a valid excuse.
The fourth most prevalent excuse is: I just can’t bear to drill a hole in my new car.
The answer is, bring it to me!
Alan Applegate, KØBG
Roswell, NM
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Drilling Holes
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by WA2TTP on May 14, 2003
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Alan,
I agree with you 100%. I drive a Nissan pickup truck that was only 1 day old when I drilled a 3/4 hole in the roof for a dual band 2m/70cm antenna. If your going to keep your vehicles a fair amount of time a hole in the roof won't make any difference in it's value. My old truck had 4 holes in the roof and some 1/4 " holes in the bumper. The guy that bought it was only concerned with how it ran and the overall condition.
As far as HF antenna'a go I have a HS 1500 screwdriver antenna on a custom built motorized tilt over mount attached to pickup box on the inner area where the tailgate closes. The mount to the truck consists of a 12" x 6" x 1/8" alum plate that is attached with SS hardware in the tailgate hinge area, had to remove the tail light assembly to tighten the nuts but ended up the very strong mount. When I remove it someday the holes won't show with the tail gate up. I would just put the same nuts and bolts back in the holes after the mount was removed.
I've seen more damage done to vehicle paint from mag mounts and clamp on mounts that most permanent mounts would cause.
73,
Steve
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RE: Drilling Holes
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by N6AJR on May 14, 2003
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I Like to reccommend the use of a steel or aluminum plate mounted (bolt or weld) to the underside of the driverside rear of the vehicle at the 45 degree angle. Just stick it out a couple inches and mount most anything there and usually you can slip a brace in behind the tail lite housing.
This way you can make a tall platform for even a two meter antenna. When you sell, unbolt it or cut it off. On those with no frame you can make a sandwich with a plate on the inside and outside of the spare tire well for a mounting place.
This may not be the best place to mount, but it will keep the top out of the overpasses (not too tall) is away from little fingers walking down the side walk, and the trees are taller in the center of the road. Not the best, b ut you can do this on a vette ( run a ground strap to the motor)or a camero.
73 and nice article tom N6AJR
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RE: Drilling Holes
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by VE6XX on May 14, 2003
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Greetings All: Thank you Allan for yet another illuminating article. Your description of the sources & effects of "shunt C (Cs)" are no doubt a revelation to some, & are virtually absent from the amateur literature. SGC, the antenna coupler folks have an admonishment in their propaganda about NOT using co-ax to couple from the output of their random wire tuners to the antenna, because of the dire effects of the Cs.
For your readers, a practical example. Years ago I was running a side scan sonar survey in the south china sea , using a tug boat to pull the "fish". We had an HF radio aboard & the antenna was a twenty odd ft whip mounted on the wheelhouse. I was sending & receiving traffic during a force eight gale (bloody windy!!) with the vessel rolling heavily in the high seas. I was compelled to "ride" the tank tuning knobs as the boat rolled, because the change in Cs as the antenna changed position with respect to the water, detuned the tank!
There are some egregiously bad installs around. Many times I have seen vans with a steel whip (8 or 9 ft) mounted to the side on a ball mount, with the high current portion of the antenna shunted by the sheet metal of the van. Allan mentioned "high quality" ball mounts. I doubt they exist. Motorola & GE mobile radio divisions both sold a VERY good ball mount, but they were discontinued years ago according to my info.
I make my own ball mounts, using a commercial trailer towing ball(the biggest diameter available(2 5/8 ?) & drilling & tapping the ball to take a 3/8 bolt, then band sawing it at a 30 to 45 deg angle as the commercial mounts do. I make the base from 3/16 steel, hole sawing the centre(1 1/8) & drilling three 1/4 or 5/16 holes 120 deg apart for the mounting bolts. I usually make these bases 6 inches in diameter & the base insulator is made from 1/2 in HDPE(high density polyethylene) or Teflon(r). HDPE is MUCH cheaper & works just fine. I have NEVER had one of these crack or arc over. The "pot metal" ball mounts (CB style) available today with that gray plastic or black "cycolac" insulators are to be avoided as the plague!
The insulators mechanically crack, & electrically the damned things arc internally, even with 100 watts!
Watch at hamfests for the Motorola or GE mounts, & throw away the spring. Springs are the source of more ills than I care to mention. Electrical NOISE is the big one! Corrosion, resulting in high series "R" etc .
Give the springs to someone you hate! If you feed the antenna base via co-ax, keep the pigtail on the ballmount as short as possible....long pigtails have Cs! If you feed via an SGC style tuner keep the feedwire SHORT, SHORT, SHORT! I use RG213 with the jacket & braid removed, from the tuner to the antenna base. Remember...this is with a "random wire" tuner. If there is no option but to run a foot or so of feedwire from the randdom wire tuner to the antenna base, keep it away from conducting surfaces. If it MUST come through a conducting surface, make a hole at LEAST twice the diameter of the feedwire & run it through a HDPE, Teflon(r) or other EXCELLENT RF insulator. Rubber grommets often have high "carbon" content & arc over almost immediately. Anytime an open feedwire or the radiating portion of an antenna are in proximity to a conducting surface Cs is present. Electrically short antennas suffer more from Cs effects thasn longer antennas for the obvious reason. Thanks again Allan, & please forgive me adding my bit here...but I see so many TERRIBLE installs, I thought a remark or ten would not be untoward! CHEERS! Brian, VE6XX
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Drilling Holes
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by AC7YC on May 14, 2003
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Alan, I agree with the points made in your article. I recently took the plunge and drilled a hole for a ball mount on the rear corner of my Dodge Dakota. I am currently running Hustler resonators and use either their 22" mast for mobile operation or the 54" mast when I am stationary (to get the radiating portion of the antenna further from the body). I won't list all the DX I have worked from the drivers' seat, but I will say that everyone comments on how good a signal they are hearing from my mobile. Thank you for another great article.
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RE: Drilling Holes
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by KJ9A on May 14, 2003
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Well...You may like drilling holes in a motorhome or pickup truck. No thanks, I'd rather trunk lip mount my Tarheel to my Saab and work the world. Why drill holes in my car when I don't need to...
73's
Jim
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Drilling Holes
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Anonymous post on May 14, 2003
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More nonsense from Mr. Alan. Cs is a loss capacitance????? Capacitors don't have loss, resistive elements have "loss" resistance. Alan, as usual, you have no idea what you are talking about. You copy simplistic explainations from handbooks and magazine articles and then add your stupidity like "loss capacitance".
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RE: Drilling Holes
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by NO8D on May 14, 2003
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Allan mentioned "high quality" ball mounts. I doubt they exist. “
DX Engineering sells Stainless Steel 2-inch diameter Ball mounts. P/N HUS-SSM-2.
RE: Drilling holes in the roof for an antenna mount
If you have an SUV, which more and more people do, just mount an aluminum plate to the underside of the luggage carrier rails and drill all the holes that you want. At trade in time, remove the plate.
73,
Paul
NO8D
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Drilling Holes
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by K4DGW on May 14, 2003
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I do not have any problem with drilling holes in my vehicle's roof. Them main problem I am concerned about is the headliner. I have not found anyone who can reliably deal with keeping the headliner up, once it has been taken down. It always seems to be a matter of time, and exposure to heat, before it falls down again.
Dave
-=K4DGW=-
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by KS4XN on May 14, 2003
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Hi Jim. I installed a Little Tarheel with a k400 mount to my Nissan Pathfinder's liftgate. Couldn't get it as high as I would have liked, but it still seems to work very well with good sig reports.
Still...I might experiment with a ball mount on the rear side to see if more height will make any difference. I'll show u a pic of mine if you want and I always like seeing pics of others' installation.
73 de John, ks4xn
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RE: Drilling Holes
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by K0BG on May 14, 2003
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Apparently, Richard (WA8KJP), you can't read schematics, nor do you understand Ohm's law. The Cs is SHUNT capacitance to ground and is in parallel with the antenna's capacitance Ca, and bypasses the radiation resistance, Rr. And it is a much larger loss than most amateurs believe it is. Perhaps you should read VE^XX's response.
Alan, KØBG
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Drilling Holes
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by K4IA on May 14, 2003
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"And keep in mind, a short antenna mounted on the roof just might be superior to a longer one mounted on the bumper, all else being equal."
This is exactly my dilemma. I have a short Yaesu ATAS 100 mounted at roof level using a trunk lip mount attached to the top of the door. The base of the antenna is about 6 feet high. It gets out but so does the proverbial wet noodle.
If a mount a longer more substantial screwdriver antenna to the rear bumper it will only be 2 feet off the ground and the lower section will only be inches from about two feet of body before it gets in the clear.
So, has anyone got scientific prooof of the short/high vs. long/low antenna quandry? This is beyond my ability to model with EZNEC but maybe someone out there understands it better. I am not interested in antecdotal stories about DX worked - we've all had our share.
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by KT8K on May 14, 2003
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Thanks Alan. You are giving me courage to do this. My mag mounts have always been poor performers (2m-440) and my new $22 dual band duckie (1/4 wave on 2) performs nearly as well inside the car as my mfj dual band mag mt does on the roof ... Now I understand why. VE6XX advice is excellent also.
Thanks, gentlemen, and best dx to you.
73 de kt8k - Tim
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by K5LXP on May 14, 2003
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Rats! Alan beat me to it. I'm in the middle of writing my "Mobile Antenna Manifesto", subtitled, "Just Shut Up and Drill the Hole". It never ceases to amaze me the antics and efforts some hams put into *not* drilling a hole in their car. I did 2-way installations professionally for a number of years and drilled holes in untold number of vehicles, some worth many times my annual income. The only time drilling an antenna hole in a car is bad is when it's done badly. A hole cut with the proper tool, in the proper place, with the antenna securely mounted and dressed feedline, will last the life of the vehicle. In my case, I drilled my first (of many) antenna holes in my pickup back in 1986, and that same mount is still in use. HF mobile gets trickier due to the mass and wind load of some antennas like screwdrivers, but where there's a will there's a way. I'm not proposing getting out hammer drills and pry tools and going at your car, but a thoughtful and careful evaluation of the installation, procurement of tools and installation supplies, and a deliberate work procedure to get it done. My truck's mobile install took me 4 months to complete and involved removing most of the dashboard. Not everyone may want to go this far but I would say most don't want to go far enough. It's not adequate to just plug a radio into a cigarette lighter, you need to run a wire to the battery. Yes, this may mean drilling a hole in the firewall- so what? Just be careful about it. There are dozens there already, one more isn't going to hurt. Mag mounts, trunk lip mounts and other temporary antenna fixtures aren't permanent. They are a compromise and typically cause more damage then they were intended to prevent. Radio brackets need to fastened to metal, not velcro strips or bungee cords. Air bags need to be taken into account. A proper install is possible in *any* vehicle, if the proper steps are taken. Like Alan said, if you're squeamish bring it over to me, I can perforate with the best of them.
K4IA wrote:
> ... mount a longer more substantial screwdriver antenna to
> the rear bumper it will only be 2 feet off the ground
I solved this problem, and the associated "Cs" issue by "extending" the mount above the level of the trunk lid. My ATAS100 mount resides within the metal frame of the car's plastic bumper, and gets extended via a copper pipe extension that I built. It was a good compromise between performance and mechanical considerations. There are photos of it, and my pickup truck, in the mobile section of my website:
http://www.qsl.net/k5lxp/mobile/mobilemain.html
http://www.qsl.net/k5lxp/projects/ATAS100/ATASControl.html
Mark K5LXP
Albuquerque, NM
k5lxp@arrl.net
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Drilling Holes
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Anonymous post on May 14, 2003
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Mr. Alan, you need to go back to school and learn how matching networks at the base of an antenna work. Specifically, you need to learn about parallel to series, and series to parallel transformations, along with how the match is made using an L network to 50 ohm coax. If a correct match is made there will be no loss from current flow though a stray capacitance. Give it up and learn something.
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by W9JCM on May 14, 2003
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"I am concerned about is the headliner. I have not found anyone who can reliably deal with keeping the headliner up, once it has been taken down. It always seems to be a matter of time, and exposure to heat, before it falls down again. "
Ok I have drilled holes in many roofs with cellular antennas. Have never had a problem with headliners coming back down. Allot of these car where high end, IE Audi,towncars,caddilacs, bmws. No problems. The biggest problem is getting it centered and making sure you dont go through the headliner with the drill hi hi.
I would never drill any holes in my car or truck. There are enough mounts out there that will work. It takes away from resale value and looks like crap. Thats why they make ground strap.
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RE: Drilling Holes
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by CASPER669 on May 14, 2003
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Allen;
I currently have an FT-100D mounted way inside my trunk, with an ATAS-100 mounted on a trunk-lip mount (Diamond K400c) on the drivers side part of the back quarter-panel. I originally had the antenna on a Wilson 1000 Magnet Mount on the middle of the roof, but this proved to be a very bad idea. Any speed over 55 would push the mount. When I purchased the K400c kit, I was concerned with where I can 'safely' install this antenna. After much Internet research on the subject, I decided on its current location. After the installation came the testing. Radiation in every part of the cabin was at a more than acceptable level. One last test was on the air, although I knew that 2 meter and 70 cm was already working fine. I attempted some DX'ing and found that I was able to go further out than when I had it on the mag mount. I hit Havanah, Cuba in an area where I was surrounded by apartment buildings. I hit Jamaica (not Jamaica, Queens - the island) while I was on the highway. Both reported 59 signals. That fact alone proves part of your explanation. The fold-back circuit in the rig has never decreased the power. SWR readings have never been a problem. The one thing that you barely touched on (and I felt it needed to be added) is the 'type' of car. This 'seems' to make a difference as well. I drive a large 1994 Oldsmobile 98 Regency, which has plenty of shielding and is well grounded. It is comparable in size to a Lincoln Town Car. I'm no expert on the theories of electronics or automobiles, but at the risk of sounding ambiguous, size (or, perhaps design) may matter. With a short copper wire attached between the rig - and the antenna itself (no, they aren't chained) - and the chassis of the vehicle, I feel I've accomplished a well rounded antenna installation. I think it is important to add to your post that different vehicles, rigs and antennas - although we should use the same fixes for the various problems we may encounter - will display different results. Although I personally don't like to drill holes on the outside of my vehicle, it is the best way to install an antenna. There is no way I could debate that. I just felt that the points I'm bringing out may help others in similar scenarios. As for the equations you use, well it's all greek to me so I don't know if it's right or wrong. But the post was definately informative and should give everyone interested some food for though. Take care and 73!
Chris KC2KFW
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by K2GW on May 14, 2003
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Although I currently operate only VHF/UHF while mobile, I've found that a roof mount here is still important for increasing the range of the signal. On an SUV, it is possible to mount an antenna on the roof without drilling holes and still be able to pull into the garage at night
I use a Diamond trunk lip mount attached to the top of the rear passenger door immediately behind the driver. This mount has a thumbscrew that I can then reach through the driver's window to flip the antenna parrallel to ground when needed. To be really fancy, there is also a motorized version of this mount that flips the antenna down remotely. Such mounts are available to attach to the roof rack as well.
Admitedly a center location gives a bit more uniform pattern, but the advantage of being able to pull into the garage at night outweighs that for me. BTW, the antenna does work somewhat in the horizontal postiion if needed when driving off road through wooded terrain.
73
Gary, K2GW
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RE: Drilling Holes
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by K5DVW on May 14, 2003
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Let me see if I can argue this correctly. If Cs exists, it can be tuned out, right? If it's tuned out, all the reactances cancel. Assuming that Cs doesnt have an associated Rs, then adding Cs will not cause an "Ohms law" or voltage divider kind of loss.
If the antenna is resonant or tuned to be resonant at the antenna, then the antenna network reduces to radiation resistance, matching network resistance, ground loss and antenna loss resistance. No reactance terms exsist. Rs may exist, but it's likely very large in practical terms compared to Rr and not likely to give you appreciable loss.
But I still think you are right to want to reduce Cs because...
..the most detrimental effects of Cs that I can see are that you require more L in the tuning network to tune it out. Additional L is always potential additional loss (RL) in the antenna system.
I believe that SGC recommends not using a piece of coax with their random wire tuners because of mismatch losses on the coax, potential arc over from high voltage, and the additional required L to tune it out. In that case the additional coax looks like a lossy capacitor, so you do have appreciable Rs. Infact, the SGC tuners have a high Q discreet Cs right at the input as part of the tuning network!
Please correct me if I'm wrong.
K5DVW
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RE: Drilling Holes
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by N2YPH on May 14, 2003
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I think the problem is that Alan oversimplified a bit with that schematic. Yes, a true shunt capacitance can be tuned out.
The problem is that this "shunt capacitance" is inherent to the way the antenna operates in such a manner that even if it is tuned out impedance-matchwise, it will STILL affect performance of the antenna.
At least in the case of trunklip mounting - think of it this way: What metal objects are in the antenna's radiation pattern, and how close? All the tuning in the world isn't going to cure problems with the antenna's pattern.
Antennas aren't simple passives, they're complex beasts. For impedance matching purposes, you can model them as simple Rs, Ls, and Cs, but if you actually want performance, you have to deal with a large number of other issues.
It is possible with proper choice of antenna to get good performance without good grounding or any drilling of holes - Look at the J-pole antenna. But for the majority of HF antennas, the design is such that proper grounding is vastly important, nearly as important as keeping metal out of the antenna's radiation pattern.
On an unrelated note - Does anyone know of any good resources for mobile operation from a convertible? (Roofmount is not an option, although the "roof" will interfere far less with the pattern than in a normal car.) I'll be starting with VHF/UHF operation, but may go to mobile HF later.
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by W0FM on May 14, 2003
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K4DGW wrote: "I do not have any problem with drilling holes in my vehicle's roof. Them main problem I am concerned about is the headliner. I have not found anyone who can reliably deal with keeping the headliner up, once it has been taken down. It always seems to be a matter of time, and exposure to heat, before it falls down again."
If you think you have to drop the headliner to put a hole in your roof for an antenna, you are already worrying about something unnecessarily. If you're not comfortable with drilling the hole, I'd suggest that you let a professional two-way radio installer do that part of the install for you.
Our installers haven't pulled a headliner out of a vehicle for an antenna installation in many years. By using a special antenna hole saw (it has a built-in stop to keep it from going through the headliner) and a simple fish tape, NMO-type antenna mounts install easily from the OUTSIDE of the vehicle with little or no disruption to the headliner.
I'll bet your local two-way shop wouldn't charge much at all just to drill the hole and snake the coax over to the door trim. You could take it from there.
Good luck!
Terry, WØFM
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Drilling Holes
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by N7QF on May 14, 2003
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I appreciate you taking the time to write that great article Alan ! Very informative and helpful. I just bought a nice used F-150 and plan to drill just where ever I want to. It's not the family car ! :-)
Timely article for me Alan. 73, John N7QF Utah
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RE: Drilling Holes
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by K0BG on May 14, 2003
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Thanks John (N7QF). Long time no talk to with 17 meters dead in the water.
And again, I'd like to answer Richard (WA8KJP). The shunt capacitance is BEFORE any matching network, including the loading coil (resonator if you please). No matter what if any kind of matching network you use, the shunt capacitance is in parallel to the antenna capacitance. As such, they share what ever power flows in the antenna. What isn't lost as radiation resistance, or as resistive losses in the coil and metal of the antenna itself, is shunted to ground!
Considering the other posts I have from you, and those you've answered on other articles leads me to believe your self-assigned roll in life is to berate anyone you don't agree with regardless of the validity of the data present.
Mark (K5LXP), I'm sending you an e-mail with respect to your article.
Alan, KØBG
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RE: Drilling Holes
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by KG4IHJ on May 14, 2003
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Who cares about the theories and formulas. Alan has got a good point whether you understand any of it: If you want the best performance from your antenna and it's in/on the vehicle, GET THE DRILL OUT!! Trunk mounts rust, mag mounts are OK at best, and license plate mounts?????
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RE: Drilling Holes
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by K0XU on May 14, 2003
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The XYL here has been resistant but not totally against holes in the roof. When we bought a new car last year I told her I was going to mount an antenna through the roof. Until I got around to it I put a little mag mount up there and ran that way for a month or 2. Then 1 day I stopped at the 2-way shop & they drilled the hole for me with the special bit & we fished the coax out over the headliner & I routed it under/through/around to under the dash where the rig was being mounted (took out the ashtray). Never did tell her I did it. Now 6 months later it comes up in another dicussion and she tells my daughter that I am going to drill a hole in the roof, and of course my daughter says "He did that months ago!".
She had never noticed. As long as the wires are out of the way there should be no reason to worry about it.
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Drilling Holes
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by W4CNG on May 14, 2003
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I've been drilling holes in cars and trucks for years. Having the 3/4 inch drill that W0FM talked about makes the chore easy. Back in the 70's and early 80's it was easy to hear the Mag Mounts and other forms of temporary 2 meter antennas on the air, those were the signals that had noise on them into the repeaters, that could not dial the autopatch. Today the big challenge is HF mobile and antenna efficiency. I run an ATAS-120 that I modified within 4 hours of purchase. I extended the whip length from the shorty 30 inches to 60 inches by using one of my spare HamStick whips, and drilling out the hole for the whip. Improved measured Field Strength by 25%. BTW I do not have any matching coils on my HamSticks as all are tuned resonant in the band. Yes, I caved in to a less efficient antenna in the ATAS-120, compared to others, but when the bands are coming and going as fast as they are today, it is much easier to have an autotuning antenna than making lots of stops on the interstate to change whips.
Good Article
Steve W4CNG
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Drilling Holes
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by AD7DB on May 14, 2003
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Thanks Alan for another well written article. Yeah, drilling a hole in the roof of your new car only hurts if you watch them do it. I was just cringing while they did it. But, I have a nice installation and I can really enjoy my mobile radio. Now I'm going to rip a hole in the side for an HF mobile antenna!
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Drilling Holes
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by KE2IV on May 14, 2003
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There are two responses here that are of interest because they deal with "how" to make the hole and run the feedline rather than "why" to do so.
I would really like to know how the pros install antennas through vehicle bodies.
What kind of tools do you guys use? How do you seal the opening after installation to prevent rust and corrosion etc.
That's the real dope I'd like to know -- not Alan's flawed treatise on antenna feedline losses and auto manufacturer/dealer return policies!
C'mon you installers - tell us in real simple and easy to understand terms - how do you install a vehicle roof (or whatever) antenna - including snaking the coax around the headliner?
Now...THAT'S practical advice!!!
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RE: Drilling Holes
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by AA4PB on May 14, 2003
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I've put a number of holes in the roof without removing the headliner. In every case, I was able to open one side and get my arm between the roof and the headliner without much problem. I use a greenlee chassis punch. First drill through a piece of wood to act as a spacer to prevent the pilot bit from going thru the headliner. Use a piece of cardboard over the roof to prevent scratching the paint. Reach under the headliner and place the cutting edge of the punch under the pilot hole. The headliner will usually hold it in place so that it can be a one person operation. Put the punch on top of the cardboard and through the pilot hole into the punch. Tighten it with a wrench and bingo - nice hole in the roof.
On most new vehicles it is most important that you locate any roof structual members so that you can position your hole to clear them.
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Drilling Holes CAN BE DANGEROUS!
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by LNXAUTHOR on May 14, 2003
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- just an fyi:
- drilling holes through any part of the upper structure on certain vehicles can be extremely dangerous... for example, on Volvo vehicles there are compressed gas canisters embedded near the roofline and in supporting structures for airbag deployment...
- i use a simple 2M radio and magmount with a nice monoband - works just fine... i understand the issues get more complex w/HF and multi-band arrangements, but i would caution anyone not to "just get out the drill" and to research mounting first, consult a local auto radio shop (to at least drill, install the mount, and route the coax), or talk to the dealer...
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RE: Drilling Holes
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by KZ9G on May 14, 2003
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I agree with Terry, W0FM. Holes saws are great for 3/4 in. NMO mounts. In a pinch, a Unibit can also be used quite successfully in producing a hole of the proper size.
Yep, headliners shouldn't have to come down at all. A fish tape or even a 50+ inch, stainless steel, antenna whip can be used to route coax while the headliner stays in-place. Just remember to "fish" the the headliner with the ball-end of the whip... 73.
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RE: Drilling Holes
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by VE3IVM on May 15, 2003
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When it comes to experience, mine tells there is absolutely no need to make holes or erect towers in order to work DX. Just put up a moderate size vertical (mine is just 6 feet long), use a nice looking mount solid enough for the vertical, and put it wherever you feel comfortable. What a sexy setup- always can be brought down in a few seconds, no problems with garage, and no crazy looks from other people around not speaking of any damage to your car.
First mobile QSO after I put everything together in Toronto was with Brazil, 8000 km away. Then Bolivia, Argentina, France, Spain, Germany. Same day worked 2 guys from Spain, one was running 100w into 3el Yagi, the second one worked QRP 5W. The thing is I heard them equally well, and got similar reports from both. You can imagine difference in money those two put in their setups to achieve same result.
Most of my QSOs I made at lunchtime, right from parking lot, behind a building located in a heavy industrial area. I never specifically look for hills or savanna like places before hitting PTT button, just enjoy amateur radio working from a nicely looking car right where I am.
I think there was at least one more line missed here in list of excuses 'why': 'cause I do not see any need to.
If you think your life is about to end because you do not want holes, think twice. With all my respect to theory and purity, it does not worth extra S unit (if there is any extra at all). I do not care if Europe gives me 57 or 56. Do you?
Regards,
Ivan
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Drilling Holes
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by N8VQJ on May 15, 2003
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MAG MOUNTS WORK! I will never drill holes in my vehicles when I don't have to. I have used Mag Mounts in a mobile situation for many years. So have several club members. When you get A GOOD magmount (not a hacked up CB one sold by radio shack, but one by Valor or anyone else), they can last many years. Only "problem" I have ever had is them wearing out. If you start to get noise on your signal, time for a new mag mount. It's usually cheaper to just get a new mag mount then trying to clean up your old one. Besides, you should also replace the coax too. Most coax on mag mounts get abused by opening and closing the door. IN my old 1980 cutlass, I managed to find a hole in the firewall for sneaking the power in. I actually found it in the door well....poked a hole in the plastic cap and removed the trim around the door frame, ran the power through that trim and snuck it under the dash to the mount point. Did the same with the magmount antenna cable. It ran fine for years until I traded it in. Only had to replace the mount once. The MOUNT in most mobile stations is what does go bad. The metal where the coax makes contact usually rusts first. You can probably clean it up once, but even then the little ring that the coax is hooked to was also shot. Since finding that new is next to impossible, I just go buy a new mount. Now the dash....it's usually my first victim in a mounting situation. Bungee cords to the seats work if you have an older car, but most newer cars have that center console thing. If your worried about resale value, then go to the dealer and order a replacement piece and stow it in the garage. You may even be able to find a whole new dash for cheap in a junkyard. Your usually only talking about a panel anyway. Of course if you have a dual din head unit hole and a single din car radio, there is usually a cup there(1992 thru 2001 Saturns had this). Put your mount there. Velcro will work if it's strong enough. What you can do is mount the removeable face on a 706 or other rig to a block of wood and put that velcro on the block of wood and the opposite piece on the cup. For looking at GOOD mobile installs that do not damage the car, check out the GM display at Dayton. The installs they do in thier cars are all designed to be installed and taken out without damage as they are usually just borrowing the car for the weekend. They usually drive them direct from the factory to the show with complete HF thru UHF setups (usually IC-706MKIIG's). Another excellent rig for mobile stations is the Kenwood TS-B2000 with the remote control head (this looks like the head off of the D700). You can mount the radio in the trunk or under a seat and the control head up in the drivers area. When your not driving, you can run a laptop and use the software interface. This way you could run packet as well. Drilling holes is not needed! It's definitely a superior way, but remember, your jsut talking about getting on the air! Your ideal situation is not a mobile one!
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RE: Drilling Holes
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by WA4DOU on May 15, 2003
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It is interesting that no matter what is written, by whomever, the other camp refutes it. This basically comes down to this: There are two camps as regards holes in vehicles. One cuts holes, the other goes to great lengths to avoid holes like the plague, willingly accepts whatever performance they get and often doesn't know the difference.
I marry vehicles so I'm not considering the resale value of a vehicle since I'm planning to drive it for the duration. I am aware of a study years ago , I think by Motorola, where they polled NADA to determine if the resale value of a vehicle was adversely affected by having an antenna hole drilled in it. The outcome was that there was little if any affect on the vehicle value. If we could prove this beyond any shadow of doubt, there would be some who would refute it. Do what you must. I am not squeamish about drilling a hole in the roof of my vehicle. I have installed possibly hundreds of antennas on vehicles, many of them in holes I've drilled. There used to be (and may still be) a hole saw in 3/4" available from Larsen, perfect for the Motorola NMO mount, and similiar antennas. It has a shoulder on it which prevents its passing thru the hole and adversely affecting the headliner. I've never seen a case where it was inadaquate. I've also never had an antenna mount to leak. A small amount of silicon grease on the "O" ring keeps it sliding smoothly as the mount is tightened down so as not to squish out of its groove. That is therefore not a concern.
I wouldn't hesitate to cut a larger hole in the side of a vehicle for a more substantial antenna for HF use, for instance. However, I wouldn't do it indiscriminately without knowing what was behind where I was going to do it at. For instance, in pickup trucks and probably some SUV's, I'd avoid corner pillars where there could be L shaped reforcing inside the pillar for strength in rollovers. It would be a shame to drill a hole and have to plug it after discovery of this. Speaking of plugs, Motorola has the very best 3/4" rubber plugs that are made and they seal holes very well, after the antenna is removed.
For those who cringe at the thought of drilling holes, there are better options than magnetic mounts. Magnetic mounts will ultimately mar the vehicle paint. And most magnetic mounts are incapable of providing an effective ground at 6 meters much less below that freq. Trunk lip mounts will mar a vehicles finish even worse. However, an "L" shaped bracket mounted in the vehicle trunk groove(or sometimes hood groove) with screws might be found to be an acceptable mount since it does make a solid electrical and mechanical connection to the vehicle body. An antenna thus mounted will not have a perfect omni radiation pattern and it is very advisable to ensure adaquate weatherproofing of the underside of the mount and cable juncture since any cables thus used are exposed to weather. Antenna Specialists makes a very good mount called the K-49 which works nicely in this application. This is the mount in the ASPS-177 ,144-174 mhz. half wave antenna which covers 2 meters. If you use a "L" bracket, get the stainless steel one, not chrome plated.
Probably the best springs and mounts suitable for HF use on vehicles ,outside of finding an older Motorola or GE mount, would be those available from Antenna Specialists.
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RE: Drilling Holes
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by W0FM on May 15, 2003
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I think that the underlying message that Alan truly attempts to convey in this article is that, in order to OPTIMIZE mobile radio performance, an antenna mounted in a hole in the center of the roof is the best option. Is it everyone's option? No. Is it an option for ALL types of antennas? Of course not. Mag mounts work. Trunk lip mounts work. Bumper mounts work.
You'll hit the repeaters and work your share of DX with any of those options. But OPTIMUM performance is attained by installing the antenna in a hole in the center of the roof.
Hey, if you don't WANT to drill a hole, for whatever reason, no one says you won't have fun with your radio. However, I have seen concerns covered in these posts that are not truly valid ("my wife won't let me drill a hole" IS a valid concern for many of us).
But, if your concerns lie with re-sale value, water leakage or headliner damage, then you are concerned over nothing (assuming that the antenna is a quality antenna with a quality mount and installed with the proper tools).
When I worked for Motorola's Cellular Group in 1984, we installed thousands of cell phones (trunked mounted transceivers with front mounted control heads) in luxury cars of all types (and prices) including August Busch's (the beer guy) Porsche, a hotel developer's Rolls Royce Silver Cloud and Barbara Streisand's Bently. EVERY VEHICLE got a hole drilled in the center of the roof or center of the trunk lid for the antenna. If you didn't want the hole, you didn't get the cell phone. Right or wrong, that was the stance that Motorola took and it was strictly to optimize the transceiver's performance. Cellular infrastructure build-out was in its infancy and you had to squeeze all the performance you could out of the mobile unit to make up for the lack of infrastructure or customers would be unhappy. Of course that has all changed.
But, no customer ever walked away without his phone. Not one vehicle suffered from low re-sale, leaks or headliner damage stemming from the antenna installations.
(However, there was that one black Mercedes that got an errant sheet metal screw through the gas tank.....Ye-ow!)
Drill if it suits you. Don't drill if it doesn't suit you.
Just have fun with your radio!
Terry, WØFM
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RE: Drilling Holes
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by VE6XX on May 15, 2003
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Greetings Again: WA4DOU has succinctly observed and stated the trueism: "There's them as drills holes, & there's them as don't". Anyone serious about mobile operation has drilled holes for antenna mounts or anchors of some type. As the ads for the "Texas Bug Catcher" antenna says " for serious HF mobile". Those of us who are long time mobile operators, or serious(as opposed to casual) operators, & work 160, 80, or 40 metres run big ugly antennas, add brackets or stiff arms for support or whatever is necessary. I can appreciate that there are those who view amateur mobile operation as a diversion while driving, hang a hamstick on a magnetic mount, & have a Hell of a time with the setup. I am a casual operator at home, & I have a 135ft dipole fed with ladder line with the apex about 60 ft . I use an antenna coupler & work all bands.
I am not a contester nor a DXer, so my HF set-up at home does all I require. I have zero interest in huge yagis & rotators & all the crap necessary to make the top 5 on the honor roll. I personally do not use, nor will I ever use a magmount. I wish they had never been invented. A lot of the problems of commercial radio are those damned mounts! Having radios "lashed to the seat" or some other jury rigged arrangement is also not for me. The casual guys are not interested in investing time in making a permanent install & I understand completely. I have 14 permanently mounted antennas on my truck, ALL of which have a function. I realise there are those who find that ONE antenna disturbs the aesthetics of the vehicle, & they find it intolerable. Different strokes for different folks.
On a parallel note, I was listening to a group discussing a particular antenna, & why they thought it was a waste of time, money, & energy to erect it.
Another Canadian ham known to the group broke in & said that he wished the hams he knew would GET ON THE AIR regardless of WHAT antenna they used! Point taken!
It's great to hear the number of mobiles on the air that I do, & hear them working DX as well. I suspect that most are using a "lash-up" of some description, & would not be active if they were required to have a professional level install. It is, after all, a HOBBY.
W0FM Sir: Your comments and observations were also poignant, & I strongly agree with your position.
CHEERS! It has been an interesting & informative thread, & with the exception of one ham, positively oriented.
Brian, VE6XX
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Drilling Holes - A Commercial Solution
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by AE4FB on May 16, 2003
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Hell, it’s about time somebody brought the terrible affliction of Mobilecom Holophobia (MH) into the open. This affliction surely debilitates ham radio operators more than any other part of the population. The most notable symptoms are an embarrassing dB deficiency combined with hearing loss for the mobile operator. In addition there is the negative psychological impact on a suffer of this dread disease when he encounters a “Real Hams Do It With Holes” or a “Pussy Whipped Hams Use Mag Mounts”, bumper sticker. Mr. Applegate is to be commended for bringing this curable condition into the light of day.
The cure is of course really nothing. And it is nothing from which holes are made. After all if there were something there, it wouldn’t be a hole, would it? Holes in ham radio are probably one of the few special cases in engineering where we are able to get something for nothing. From a hole in our vehicle we get dBs of gain on transmit and receive, better signal to noise ratio, neater installation and the feeling that we haven’t compromised the Zen perfection of our radiated mobile signal. All from nothing.
The inspiration for my company, Gain Hole Signal Solutions Ltd., was based on some of the thoughts above. For over ten years we at GHSS have been able to offer mil-spec holes with a no holes barred unconditional guarantee of from 3 to 9 dB Gain over a mag mount (depending on frequency) without ever having a single hole returned under the guarantee.... that we know of.
All our holes cost only $5.95, Shipping Included! No matter what size! What a bargain! Take our Model NMO-1 Hole Mount for example. It's made from pure mil-spec hole material and the average gain of our NMO hole on 2 Meters is 4dB over a mag mount or 7dB over an on glass mount. As far as bang for the buck is concerned it’s impossible to beat this average of around a dollar a dB with any other mobile accessory, bar none!
We are able to offer these exceptional values because our material cost are virtually nothing since our proprietary hole design requires no material and minimal tooling to produce. Our warehousing and storage cost are also low because of the two dimensional nature of our hole design. We can stack a hundred in the same height we can stack one. Furthermore our shipping costs are also minimal because holes weigh virtually nothing and along with the 2 dimensional aspect this allows us to ship large quantities of holes in a regular # 10 envelope. You pay no extra shipping no matter how many holes you order. You the buyer are the one who benefits most from these aspects while we manage to turn a tidy profit and have the satisfaction of helping many hams to overcome the too little know affliction of MH (Mobilecom Holophobia).
To order any one of our high gain holes simply send $5.95 per hole to:
GHSS Ltd.
attn AE4FB
2711 Belaire Cr.
Doraville, Ga. 30340
Include your return address and the number and size of the holes you would like to order.
Note: Holes are so easily lost that we are unable to offer insurance, so be careful when you open your envelope not to spill any your holes since they are nearly impossible to find until installed in your vehicle. However we will replace any lost holes for only half price if you send a copy of your original receipt to the attn. of our customer service department. We do offer hole installation tools at additional cost if you don’t already have your own.
We are currently offering $0.95 discount per hole to all new slow code Extra Class Hams as our special welcome to the upper echelons of Hamdom. If you’re new and slow don’t miss this opportunity.
Ever So Sincerely,]
Mike Adams
de AE4FB
CEO
GHSS Ltd.
GAIN HOLE SIGNAL SOLUTIONS Ltd.
“The Home of the High Gain Hole!”
Dealerships Available to Qualified Individuals*
*To qualify you must have more money than sense.
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Drilling Holes
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by K4CMD on May 16, 2003
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I've owned a 3/4-inch hole saw (indispensible when you use Larsen NMO antenna mounts) since the mid-80s and have drilled holes in the trunk lids of all seven vehicles I've owned.
All six have been traded in at various car dealerships (the seventh is the one I currently own, duh), and I've always left the Larsen NMO mount on the vehicle at trade-in (hey, it's only $15 to replace it with a new one, and I figure a fairly flush antenna mount beats a 3/4-inch hole).
To date, in not one of those cases has anyone even asked about it. I guess they figure it's a cell phone antenna mount.
And to the gentleman who recommended mag mounts, no way Jose. Been there, done that, got the crimped cable, interior hassles and paint scratches to prove it! (Not to mention a REAL ground makes all the difference in the world!)
Meade K4CMD
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RE: Drilling Holes
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by K0BG on May 16, 2003
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Mike Adams, AE4FB, you made me laugh out loud and I woke my wife in the process with a "what's so funny" query from the nearby master bedroom. She failed to see the humor, but then again she's not an amateur.
What will be even funnier is when someone actually sends you a check for 4 or 5 holes!
Thanks again for the chuckle. It made the effort worth the trouble.
Alan, KØBG
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RE: Drilling Holes - A Commercial Solution
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by AD7DB on May 16, 2003
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To AE4FB, Mike, do your holes come in special colors? I know some guys over at Cal-Tech and at other centers of science that would like to get some black holes for study.
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RE: Drilling Holes
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by VE6XX on May 16, 2003
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Greetings: Alan: WHADDYA MEAN "WHEN SOMEONE ACTUALLY
SENDS YOU A CHECK??" I got my order off already & have applied for a dealership! You have missed the boat on a good thing again Alan....The last time I got in on a deal like this was when I got a dealership for " Mother Fletcher's NO-CAL roach powder" !! WOW! Did you see the GAIN figures for those holes? The only people in the world who can beat those figures is CushCraft!
CHEERS! Brian, VE6XX
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RE: Drilling Holes - A Commercial Solution
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by AD7DB on May 16, 2003
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Thanks Mike for your quick response to my inquiry about becoming a dealer, and supplying me so quickly. My orders just came pouring in, from the likes of Jerry Pournelle, Larry Niven, Kip Thorne, Bob Forward, Stephen Hawking, and many others.
That first delivery went OK. I'd loaded all of the black holes into the back of my truck and was enroute to Pasadena to deliver the ones that Cal-Tech ordered. Everybody I passed swerved as if they were drunk. I heard one guy yell out, "Hey man, your vehicle sucks!"
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Recommended SO-239 mounts for a hole
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by N3EO on May 16, 2003
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So what through hole SO-239 would you all recommend? I'm thinking of taking the plunge.
73,
Patrick N3EO
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RE: Drilling Holes - A Commercial Solution
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by N8VQJ on May 17, 2003
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While you do have a humours post, I disagree with your claims about lower signal quality and the like. I have worked on all types of antennas, mobile and base, verticals and Yagis. I have never heard a tremendous difference in either on 2 m and 70 cm. The only difference I have ever heard was the difference between a 1/4 wave and a 5/8 wave hustler whip. The difference was I was able to hold a repeater longer with the 5/8's then with the 1/4 wave. Mag mount are much maligned because people slap it up there and forget about it. Years down the road, they start blaming the mount and not themselves for not taking care of it. Most mag's are made out of stainless steel, but even stainless rusts. Take it apart every once in a while and scrub the mating surfaces clear of rust. Check the oring connector and see if it's corroded. After a few years, you need to replace magmounts. NMO's are good and do last longer then a mag mount, but I would rather be on the air with a mag mount (and a semi happy XYL) then not be on the air (no antenna cuz my wife won't let me drill a hole).
Mag mounts work in alot of situations. I had a buddy use one with a base setup. He mated the magnets to a wire in basket, and attached a wire to the hole. He tied some wet noodles(styrofoam ones) to the rack, floated it out on the pond at our field day site and was able to get the antenna to load on 10-160.
Most hame antenna "problems" come from lack of maintenence.
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RE: Drilling Holes - A Commercial Solution
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by K0BG on May 17, 2003
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Joel, you should go to Radiall-Larsen's web site and request a free catalog of their mobile antennas (http://www.radialllarsen.com/). Pay particlular attention to the gain specs between the same antenna mounted with the various mounts; i.e.: Mag, NMO, etc. You just might be surprised at what you see.
Alan, KØBG
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RE: Drilling Holes - A Commercial Solution
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by KE4ENX on May 17, 2003
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Senior Engineer Mikey Adams and the other good folks at Gain Holes Signal Solutions are GENIOUSES! I have purchased several Ham Holes from these guys and dolls and have found them to be of the highest quality non-material and workmanship. And now I get out like gangbusters...and I don't even know any morse code!! Remember friends, there's no substitute for the real thing....NEVER EVER buy any holes from Radio Shack!!! They're flimsy, cheap and by golly I just learned that they're made in France...so you don't want one. Only a quality hole can assist you in radiating a quality signal. My new friends at Gain Hole Signal Solutions are the best damn hammy friends that $5.95 can buy.
Yours Truly,
Formerly Holeless in NE Ga.
KE4ENX
NoCode International 4140
nocode.org
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RE: Drilling Holes
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by KD7ZD on May 17, 2003
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>I'll bet your local two-way shop wouldn't charge much >at all just to drill the hole and snake the coax over >to the door trim. You could take it from there.
We'd do it on a normal vehicle for $30 plus any parts.
Phil
KD7ZD
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RE: Drilling Holes - A Commercial Solution
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by N3ZKP on May 17, 2003
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<< (no antenna cuz my wife won't let me drill a hole). >>
When my wife makes the car payments and pays the insurance she can dictate what I can and can't do to the car. Until then it's ...
Honey, pass me the drill!
Lon
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RE: Drilling Holes - A Commercial Solution
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by VE6XX on May 18, 2003
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Greetings: N3ZKP, Lon, Sir: Permit me to congratulate you for being a member of the "its my vehicle & I do as I see fit" group. I was fortunate enough to have been married for twenty years to a woman who didn't give a hoot what I mounted on my vehicle or hers. When we were first married I asked if she would be upset about my mounting a couple of antennas on HER car. Her position was that as long as the car started and ran normally, the brakes & steering, heater & air conditioning worked, she was unconcerned about what I installed in her car. I erected antennas on the house, in the yard etc. & she could care less. I did not presume to tell her what color to paint the house,
offer sage advice regarding interior furnishings, or attempt to dictate the location of various items in the kitchen cupboards! My shop was mine & my shack was mine....not her problem. I had a two metre base station in the living room, & she had a scanner..the world was a better place!
When we went our separate ways I left a dual band radio installed in her car because she liked to keep track of my friends. Her mom & dad were both licensed hams, as is our boy & youngest girl. She evidenced no interest in becoming licensed herself...dunno.
I had a fiance many many many years ago who, when I came home with my brand new Oldsmobile & commenced measuring the roof to find centre, said" You are NOT going to drill a hole in the roof!" I said " Just watch me!" Her calling off the engagement probably saved me untold grief! I simply cannot imagine anyone being told that they were not allowed to mount an antenna on a vehicle that they bought & paid for! If they would tolerate that level of interference in their life, they deserve what they get. A wife who contributes financially to the purchase of a vehicle has an interest in it & is entitled to bitch. One would think that antenna mounts would be discussed previous to the purchase! Anyway Lon, I am with you.
The guy (or gal) who pays for the vehicle gets to make the rules. I saw the term "PW" used here & I think it valid! I talked on the air recently with a guy in California on 17 metres. He was bubbly about the band, & went on to explain that he lived on 10 acres & that he was on the air because his wife was getting her hair done. He wanted to put up an antenna for 17 metres, but his wife had to "approve" any antennas, & she thought he already had too many. He said he had to get off the air & go upstairs, because if his wife returned & found him on the radio she would be angry!
How the Hell any man lives like that is beyond me. I would tell her to take a hike & either she would go or I would! Who knows, maybe she owned the house & property. In any case ,at his age nothing was going to change! I personally never cared what my wife did with the house, furnishings, or whatever. If it suited her, it suited me. If she asked me which unit, color, thing or whatever I liked better, I told her. That was no guarantee that she would pay any heed to my preference, but I really didn't care. If mom was happy, everyone was happy! Appliances, the lawnmower, snowblower, vehicles etc were my problem & the house was hers. A good deal for both of us. Can't drill a hole ! BAH! HUMBUG!
73, Brian, VE6XX
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RE: Drilling Holes - A Commercial Solution
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by N3ZKP on May 18, 2003
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Bryan,
You are a man after my own heart!
You are correct, I am very fortunate. My wife of 36 years and I have no disagreement on my radio hobby. She is used to my vehicle looking like a porcupine, whether the antennas and radios are ham, land mobile or law enforcement. She says it makes the vehicle easier to find in the parking lot! It's even easier now with the HS 1800 on the rear corner instead of a HamStick.
Conversely, I don't give her instructions on the inside of the house, either - wouldn't do any good. :) I also don't rag her about scrapbooking, sewing, crafts or any other of her interests. The only thing we fuss about is I usually pass around new photos of the grandchildren before she does.
Personally, I think many of these wimps are simply afraid to put their feet down and insist that that there are TWO opinions that matter in the house. As one ham wrote a few months ago, when his girlfriend asked whether she really had to put up with the radios in the car he said NO, and opened the door for her. <g>
Lon
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Drilling Holes
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by TDA1963 on May 18, 2003
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I am not a real ham but I have installed a couple hundred radios of many types for the municipality that I work for. The author is Escentally correct! Police cars that use 2 hocky puck antennas are a good example for me as almost all have 2 antennas. 1 for the radio, and one for a wireless modem, the systems are at 800-900 mhz and encrypted. The com radio is usally on the roof, and the modem is usually on the trunk. We work very hard to center the antenna on the vehical to maximize output. I will not into the details on the testing but i can say the one instrument cost well over $20,000.00 and is calibrated 4 times a year. about Drilling the hole its self. You can do allot of damage fast to a headliner!!!! Been there done that. a 3/4 or 1 inch hole saw can chew up a head liner fast once you punch through the top. I NEVER COMPLETLY REMOVE A HEAD LINER, It can get messy fast.I use a special 1/4 deep hole saw that works well for 100 installations but the blade alone is $65.00 With a regular 1" deep holesaw make a Blacktape stop 1/8" from the end of the cutters/theth of the saw. Dont hurry the cut and take time at the end of the cut. I usually spend more time fishing wire and wraping loom than drilling holes. Remember to use wire loom every place the antenna wire contacts the steel body of the car/truck Vibration is an evil genius. remember the same on your high current Wires.
A good 2 meter mobile Ground plane for a tempory antenna can be made with an old 36" Dia Aluminium railroad crossing sign attached to a cartop carrier the city of Saginaw MI Sells the signs for $2.00 each. I use an Allan telecom, ASPS 177 rooftop mount Mobil 1/2 wave gain antenna. on the RRxing Temp mount and have very good results. I always attribute it to the ground plane.
My two cents, 73s, Tracy, The reckless one.
http://www.albert-cordova.com
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RE: Drilling Holes - A Commercial Solution
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by AB4EJ on May 21, 2003
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Enjoyable article; last week my wife told me I had "ruined" my Mercedes by drilling into it to install a ball-mount. Ham buddies told me I had increased its value by $10K.
At least the wife does recognize that it is my car. Well actually, it's the bank's car.
I thought about the roof-mount idea, but there's this motorized sunroof that wants to move through that area. Results have been pretty good with the fender mount.
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Drilling Holes
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by W7USR on May 21, 2003
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Alan, my experience tells me that your technical discussion is right to the point. I have had alot of antennas, mounts towers etc. Possibly the best operating position I have ever enjoyed is a Jeep Grand Cherokee (Leased) with a Ham Stick or Hustler with Mast mounted to the Roof Rack. Directly under the CB mirror mount ( adding longer bolts to go around the rack) I drilled a hole in the roof and inserted a 1/4" Sheet Metal screw to attach a #8 copper wire which was then connected to the mount. I ran RG-8 shield from the mount to the frame and grounded everything, radio, gel cell battery,and 400 watt amp to the frame at the rear of the vehicle with #4 stranded copper. I did the same with my Jeep Liberty using a 3 legged mag mount instead of the roof rack.
Great operating! Nice and quiet. The place I would set up was probably a help. A 20 acre site of a former copper smelter, now devoid of any buildings covered with 5" of asphalt and flat as a die.
Who ever looked for a 1/4" hole in the top of an SUV?
73
Tom
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RE: Drilling Holes
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by KC0JBJ on May 27, 2003
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Well, the Brits are always on top of any new technology it seems. I heard this on the Broadcast Band the other day:
"I read the news today oh, boy.
Four thousand holes in Blackburn, Lancashire.
And though the holes were rather small,
They had to count them all.
Now they know how many holes it takes to fill the Albert Hall. I'd love to turn you on."
Obviously, an English mining firm has discovered a new source of natural holes and is exploiting this resource. That should make the American-made synthetic holes a bit pricey. But, perhaps competition will force US hole manufacturers to lower their price as well. However, the main effect is probably that there will be an increase in the number (and signal strength) of mobile HF operators in England, and in fact all of the UK, if not all of Europe, since Britain will be free to export their holes duty free to the entire Common Market.
Are we up to this challenge? I say we should lobby Congress to fund new Hole Research, perhaps require Detroit automakers to equip all new vehicles with at least one US-made hole by 2005. Of course, that will raise the cost of new vehicles by around 3.14159%. It should be as easy as pi.
Write your Congressman today! If they respond that they will get a round tuit very soon, please explain that is no subsititue for a genuine hole.
I am sure the Japanese are already at work on this. I would not be surprised if they had a knock-off of the new British hole ready to roll-out at the beginning of the next model year. My greatest fear is that we will see a flood of inferior quality holes from China being passed off as top-quality natural Blackburnian holes. Maybe we will need to set up a new governmental unit to regulate hole production and importation, the Federal Hole Commission. Any commercial holes which do not meet Federal Standards must be immediately removed from service. Of course, amateurs with home-brew holes will be exempt, but they will only be allowed to construct one hole per year.
If you are with me on this, then the best way to show your support is to join the national organization for superior holes, the American Superiority Society -Holes. I think you can figure out what their acronym is! Then just "Google" it to find their website.
Or should we just forget the hole thing?
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Drilling Holes
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by KE7DLG on April 18, 2005
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I realize this is probably considered a stale post by many (almost 2 years old) but I just wanted to let everybody who contributed to the content know that I found it to be very informative.
This post and the facts, advice and opinions from both sides of the topic, to drill or not to drill, helped me do what I previously thought to be the unthinkable. This morning the holesaw from Antenex came in and i commenced to measuring and drilling the roof of my brand new truck.
The end result is the first NMO mount I have ever installed and the cleanest install of an antenna I have ever done.
The advice I found to be of the most help were things such as removing the domelight to gain access without dropping the headliner and the mention of the Antenex holesaw. Of course the kicker was a couple of people who stated "If you don't want to do it yourself bring it to me and I'll do it". While it would be tempting to have somebody else do it I find it to be so much more rewarding when I do it myself so I just bit the bullet and went to work.
While I did have to dismount various mounting hardware such as sunvisor brackets and pull handles to allow flex in the pre-shaped headliner for ease of running the cable I did not have to remove it and everything went very smoothly.
Dropping the domelight was one of the best ideas as it allowed access to survey roof supports and gave me a good staging are to pull the cable in from the outside and then to fish it through to the front of the cab to take a down turn inside of the plastic trim over the door post.
Thank you Alan for heading the original post and to everyone who contributed to the thread. You have all helped to make my first amateur antenna install a very pleasing experience.
I just hope at least some of you still monitor this old thread so you will know the appreciation I have for your input.
Ron
KE7DLG
Cheyenne, Wyoming
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RE: Drilling Holes
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by KS4XN on May 1, 2005
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Moving from drilling holes in cars to drilling holes in your house. Any special precautions? How big? no grommets but maybe pvc plastic? Any commercial solutions? Closest I can find to a commercial solution is to mimic installing a dryer vent, just into your shack.
73 de John, ks4xn
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RE: Drilling Holes
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by KE7DLG on May 2, 2005
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Being far from an expert of anykind and just relating a thought or two I had on the subject.
If just one cable it's no big deal. Just drill a hole making sure you are clear of such things as electrical wiring and plumbing. Hitting a water pipe would be messy but hitting gas pipe could ruin the whole plan in a hurry. There are feed thru bussings widely available will help protect the cable from sharp edges around the hole, help to seal out weather and of course give that all important finished look. I am still very partial to using a rain loop when bringing wire into the house. The local cable company either doesn't know what one is or thinks their budget can't afford the extra 10" or so of cable to do this.
If running a number of cables a more organized approach would be in order. When entering the house I have often thought it would be a good idea to use a conduit with a 90 degree elbow if coming horizontally through the wall and if coming vertically through the roof to use a 180 degree elbow. Not sure if the 180 degree is still considered an elbow as it is more of a "U" shape but you should get my drift.
This is similar to what you find with overhead electrical installs coming in and should help to keep water out. You would still want to seal around the cables coming into the elbow to avoid other moisture such as condensation.
As I said, I am no expert on this subject but have giving the matter a bit of thought over the years as I have planned my wish list of how I would like to do things.
73
Ron
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