Mobile Radio Installation Guidelines

Salam semua... aku pun baru keluar dari busut yang dah beranai2.... hehheh yg ni just as a guideline jee.... Jika berlaku sebarang kecurangan kami pihak 1 Malaysia tidak bertanggung jawap (Malu tanya lapar la sesat jalan la dan macam2 lagi)... p/s: tak lama lagi proton pun akan keluarkan guideline gak.... so tunggu!!!! Radio Telephone / Mobile Radio Installation Guidelines Certain radio telephones or land mobile radios or the way in which they are installed may adversely affect vehicle operations such as the performance of the engine and driver information, entertainment and electrical charging systems. Expenses incurred to protect the vehicle systems from any adverse effect of any such installation are not the responsibility of General Motors Corporation. The following are general guidelines for installing a radio telephone or land mobile radio in General Motors vehicles. These guidelines are intended to supplement, but not to be used in place of, detailed instructions for such installations which are the sole responsibility of the manufacturer of the involved radio telephone or land mobile radio. INSTALLATION GUIDELINE (refer to enclosed figures during installation) 1. Transceiver Location A. Locate transceiver for remote radios on driver's side of trunk as near to the vehicle body side as possible. B. One piece transceivers should be mounted under dash or on transmission hump where they will not interfere with vehicle controls or passenger movement. C. Great care should be taken not to mount any transceivers, microphones, speakers or any other item in the deployment path of a Supplemental Inflatable Restraint or "Air Bag". 2. Antenna Installation A. Each vehicle model and body style reacts to radio frequency energy differently. When dealing with an unfamiliar vehicle, it is suggested that a magnetic-mount antenna be used to check the proposed antenna location for unwanted effects on the vehicle. Antenna location is a major factor in these effects. B. The antenna should be a permanent-mount type located in the center of the roof or center of the rear deck lid. Glass mounted antennas should be kept as high as possible in the center of the rear window or windshield. If a magnet-mount antenna is used, care should be taken to mount the antenna in the same location as a permanent-mount type. If a disguise-mount antenna is used, great care should be taken to shield any tuning network from vehicle electronics and wiring, or to mount the tuning network in an area completely clear of vehicle electronics and wiring. C. Standard metal mount antennas may be mounted on a vehicle with nonmetallic body panels by two methods. Most nonmetallic skinned vehicles have metal frames underneath. Mounting the antenna near a metal frame section and bonding the antenna mount to the frame with a short metal strap will provide the groundplane connection. Some antenna manufacturers offer "groundplane kits" that consist of self adhesive metal foil that may be attached to the body panel to provide the groundplane for the antenna. D. Some vehicles use glass that contains a thin metallic layer for defrosting or to control solar gain. Glass mount antennas will NOT function when mounted on this type of glass. Consult your GM dealer or owner's manual to determine if this glass is installed on your vehicle. E. If RF related interactions occur when using a hitch or bumper mount HF antenna on a vehicle that has body on frame construction (ie Pickup, SUV) connect a ground strap from the vehicle frame to the bottom rear of the vehicle body (for station wagon type vehicles), or from the vehicle frame to the bottom rear of the cab (pickup style vehicles). 3. Antenna Cable Routing A. Always use a high quality coax (at least 95% shield coverage) located away from the Engine Control Module and other electronic modules. B. Care should be taken to maintain as great a distance as possible between any vehicle wiring and the feedline. 4. Antenna Tuning A. It is important that the antenna be tuned properly and reflected power be kept to less than 10% (VSWR less than 2:1). 5. Radio Wiring and Connection Locations A. Connecting radio power on General Motors vehicles is model dependent. The installer must decide which one of the following four methods will be appropriate. 1.) Connect the positive and negative leads directly to the battery terminals (illustrated in this guideline). 2.) Connect the positive lead to the auxiliary power terminal (located at the underhood fuse center or identified by a red plastic cover in the underhood area) and connect the negative lead directly to the negative battery terminal. 3.) Connect the positive lead to the auxiliary power terminal and connect the negative lead to the battery body connection point (identified by a short #10 AWG or larger wire running from the negative battery terminal to the body of the vehicle). 4.) Connect the positive and negative leads to the Special Equipment Option (SEO) wiring provided for this purpose. B. If connections are made directly to the battery terminals, the GM approved methods of connecting auxiliary wiring include the adapter package illustrated in Figure 2, NAPA-Belden replacement battery bolts (part # 728198), or drilling and tapping the hex end of the original battery bolts 10-32 X 3/8" deep. NOTE: It is recommended that a fuse be placed in the transceiver negative lead to prevent possible transceiver damage in the event the battery to engine-block ground lead is inadvertently disconnected. C. For ONE-PIECE TRANSCEIVERS where ignition switch control is desired and no SEO wiring exists, a 12 Volt power contactor must be installed in the transceiver positive lead. The contactor should be located near a proper 12 Volt feed. The coil of the contactor should be connected through an appropriate in-line fuse to an available accessory circuit or ignition circuit not powered during cranking. The contactor coil must return to a proper negative point. Detail "A" illustrates direct connection to the vehicle battery. D. Any negative lead from a handset or control unit must return to a proper negative connection point. It is preferable that the positive lead for a handset or control unit be connected directly to a proper positive feed. If ignition switch control is desired, the handset or control unit positive lead may be connected through an appropriate in-line fuse to an available accessory circuit or ignition circuit not powered during cranking. It is recommended that the handset or control unit positive and negative leads be appropriately fused separately from the transceiver positive and negative leads. E. If multiple transceivers or receivers are to be installed in the vehicle, power leads to the trunk or under dash should be connected to covered, insulated terminal strips. All transceivers or receivers may then have their power leads connected to the strips. This makes a neater installation and reduces the number of wires running to the vehicle underhood area. 6. Radio Wire Routing A. The power leads should be brought through a grommeted hole in the front bulkhead that must be provided by the installer. For trunk-mounted transceivers, the cables should continue on along the driver's side door sills, under the rear seat, and into the trunk through the rear bulkhead. All attempts should be made to maintain as great a distance as possible between radio power leads and vehicle electronic modules and wiring. B. If the battery is located on the passenger side, radio power leads should cross the vehicle in front of the engine. 7. Troubleshooting A. Should vehicle-radio interaction develop following installation, the source of the problem should be determined prior to further operation of the vehicle. Most interaction problems can be eliminated by following the installation guideline. B. If any vehicle-radio interaction problems exist after following this guideline, the vehicle should be returned to a GM dealer for examination and resolution of the problem. ^ Instructions ^ ^ Instructions ^

The Worry and Apprehension of VHF Antenna Polarization

........ hasil cedukkan"plagiatism" oleh kerana malas

ENJOYYYY READING

The Worry and Apprehension of VHF Antenna Polarization
By John Wendt, WA6BFH

While this article will primarily address the bands of 10 and 6 Meters, I will add some thoughts on other VHF and UHF wavelengths as we get into the meat of the issue.

Probably the first wavelength band that I need to address is in reference to my mention of 10 Meters! You see 6 Meters is often referred to as the “Magic Wavelength Band”; and this is because it often works like an HF wavelength band, when it is in fact a VHF band. Well 10 Meters, an HF band, often works like a VHF band in terms of its signal propagation. So I guess some of that magical pixie dust has just sprinkled on down frequency almost one octave!

Now with this next band, 6 Meters, I have lots of experience, about 38 years worth! It is a truly magic band, although I feel the same way about several bands above it! Anyway, 6 Meters will avail itself of all of these below listed forms of distant (DX) communication:

F-layer skip every 11 years at or near the Solar peak-- along with the HF spectrum.

E-layer skip, regularly at the Spring of every year, and other times; also seen on 10 Meters

Meteor Scatter (skip) several times each and every year (at regularly noted meteor showers.

Auroral Skip, at times when major solar events ionize the D-layer of the ionosphere.

Tropospheric Ducting, at weather plus maybe E, or F layer events.

Knife Edge Refraction over mountain tops, not too great for distance, but fun!

These are the physical elements that make the Magic! You see when you have bands of frequencies that can be propagated by ducts of differential air temperature, that’s pretty magic. When you can have bands of frequencies where signal propagation can be facilitated by the exhaust gasses of jet aircraft, that’s Magic, and of course I don’t mean that in a literal sense. My point is that it is fun and interesting to exploit these methods of signal propagation, and learn about them.

The counterpoint of this is when we run into people who will tell us that this is not important, fun, or that there are only certain ways that WE MUST PROCEED in these endeavors. Noted fables that I have heard through the years are:

1) You must use horizontally polarized antennas!

2) Cubical Quads don’t work on VHF!

3) Vertical omni-directional antennas will not work on 6 Meters for DX!

4) “J” or J-pole antennas are less efficient than Ground Plane antennas!

I think that part of the fun is to de-bunk such ideas! It is also fun to learn the perspective of any amount or shred of truth that might be contained in such broad statements! Let’s take a look at each one of these; and see what might have been meant by any negative aspersion, and lets see if we can benefit from the contrasting truths.

Why must you use a horizontal antenna? This is often done so as to improve “Signal to Noise Ratio”. It is true that much, or maybe even most, electrical noise has a vertical component. This is “pulse noise” generated by ignition sparkplugs, or other arc bursts of energy. Remember though that pulse noise is the easiest sort of electrical noise to effectively cancel!

In any case, while this noise is most notable, in larger cities, where overhead power lines are prevalent, horizontal noise will be the most obvious! It will be so predominant that it will virtually make a blanket of noise at relatively high signal levels. When this S3, S4, S5 or higher noise level exists, many radio signals or VHF band openings may get lost in the noise.

I know of many practical instances over the years when I with either a vertical quarter wavelength Ground Plane, or a home-made copper “J” antenna -- both of which don’t work on 6 Meters -- was able to work either E-layer openings, Meteor Scatter, Auroral, or F-layer skip, before many ‘big gun’ horizontal Ham’s could hear the DX signals. Why was this?

A vertical antenna has a lower angle of radiation than does a horizontal antenna. That is in fact why horizontal Yagi’s etc must be raised to appropriate height to provide an optimum launch angle. Most 6 Meter Ham’s who are serious about working DX will have an antenna tower of some 60 feet or better, and one or more Yagi beam antennas of at least 1.5 wavelength booms. Or, perhaps better to say, they will try to at least provide a good 10 dBd of antenna gain. A 25-foot boom Yagi will do that, as will two 4 element Yagi’s on 12-foot booms.

So if a simple unity gain, or less than unity gain (the Ground Plane) antenna will work quite nicely for 6 Meter DX, after all, I worked 50 states and several countries with such verticals, what would be the best beam antenna configuration.

You can stack multiple beams on a tower and improve radiation angle. If you want to keep things simpler though, put two Yagi’s up vertically polarized. Two 4 element Yagi’s as I mentioned before will yield 11.2 dBd of gain. Subtract about 1 dB for transmission line loss, and you still have better than 10 dB’s at a very nice low angle of radiation. This also works with even shorter tower heights. A short tower will kill horizontal antenna performance but not when they are vertical!

How about that statement that Cubical Quads don’t work on VHF! This was said in all seriousness once at a VHF/UHF conference in the California town of Santa Maria. This conference even sponsored “an Antenna Gain Contest” on Sunday near the close of the conference. After the statement had been made, Saturday, a hasty visit to the local hardware store garnered some 12-gauge wire, some wooden furring strips, and an S-239 coax connector was obtained from somewhere.

After a few fevered hours of sawing, drilling, assembling and testing, the 4 element Quad was produced that you will see in the web posted article below. The winning entrant is that antenna that has the greatest gain, for the shortest boom length. That is the advantage of quads, they produce much higher gain, over relatively short boom lengths. They do unfortunately develop “I squared R” losses pretty quickly as well, such that after the 5th or 6th element, further gain is minimal. Yagi’s by contrast can be as long as is mechanically practical, and they will just keep developing gain!

This quad did won the contest by the way! The next best antenna a “KLM Band-pass Log Fed Yagi” produce 13 dB’s of gain but it was more than twice as long!

I have already touched on vertical Omni’s but, I thought that comment about “J” or J-pole antennas being less efficient really tossed me for a loop. A “J” antenna is simply an end-fed dipole, with a Q-line matching device. There is no more efficient matching method other than the Q-line transformer! Take a nice vertical half-wave antenna, match it to any desired impedance -- with practically no loss -- how can that be bad!

What about the other bands? I’m not so certain, as I have not had nearly as much or as broad experiences on 2 Meters, 135, 70, 33, or 23 centimeters. Experience and self-learning is key! It would be nice to find out and test these concepts however. I guess most Ham’s don’t do this because they don’t want to take a chance. I’m getting to be a little long in the tooth, with gray chin whiskers, and legs that don’t climb antenna towers as easily as I used to. I know one Ham on 135 centimeters that tries things just to find out! Now to me, that’s what Ham radio is all about!