San Antonio HamsSan Antonio Area Hams Operator

 

Serving the Amateur Radio Community
in San Antonio and South Central Texas
since 2003


Antenna Tips and Hints

This page will be expanding tremendously with lots of coverage about antennas, from mobiles to base station to portable / emergency operations. We'll be calling upon, and depending upon, the combined expertise of our San Antonio Hams, plus anyone else we can coax (pun intended) into helping out.

It may take us awhile to build this section, so check back frequently to see what new info we have collected and posted for your viewing pleasure.

Warning: Some Deed Restrictions May Apply

Before we get started, there may be restrictions that apply to external antennas on a residential lot, depending upon what city you live in, or if your neighborhood has deed restrictions. It is the opinion of the webmaster that if you get involved (in a positive manner) with your neighborhood association (if you have one), you are likely to get less hassle from your neighbors no matter what the restrictions say. And never take the HOA's word for it on the restrictions, go down to the county clerk's office and request a copy of the version filed with that office. There may be a fee for this copy, but it might be worth it. One HOA in San Antonio, where the webmaster and his wife reside, claimed we couldn't have an antenna higher than 5 feet above the roof of our house, but when we checked the officially filed version, we found out that our subdivision didn't even mention the word "antenna" at all, thus there were no restrictions.

The City of San Antonio is supposed to have some ordinances that cover towers in your residential yard, but push-up poles are apparently exempt. Rumor has it that engineering studies are required even for ham radio installations, same as commercial towers. We'll try to track down facts on this issue via our City Council Representative, and invite anyone else who has facts to email them to the webmaster. Common sense, clean operating equipment that doesn't bleed over your neighbors' TV, Stereo or Phone, and some tact when dealing with such neighbors, goes a long way toward avoiding problems.



Lubbock Ham Tower Video
/ Soldering Tips / Outdoor Antenna Warning
W2IK Home-Built Antennas / W2IK J-pole / W2IK NVIS Portable / W2IK Emergency NVIS
Mobile Radio Installation Tips / Where To Install / Routing Feedline / Antenna Choices
Prefer To Let someone Help? / Eliminating Alternator White / Anderson Power Pole Installation


Coax

Lubbock Ham Gets to Keep His Tower Despite Protests

Lubbock Ham Antenna ControversyWe recently found a video uploaded to www.youtube.com about a hamoperator up in Lubbock, Texas who put up a tower that could be cranked up from a low 21' to nearly 50' tall. The neighbors were quoted on the local TV news channel (this is the video of the news program) objecting to the presence of this antenna (HF Beam Array), but the news anchors say that there is nothing that can be done because the owner is a Federally licensed Ham Radio Operator. If only it was truly that easy to bypass such hassles in San Antonio, but it's not. Click here to view the audio/video clip after turning up your speakers. Length is 2 minutes 38 seconds.

Coax

Soldering Coax Connectors

Soldering Coax ConnectorsWe've added a new section dealing with soldering coax connectors by Greg Ordy, W8WWV, of Ohio. Greg shares with us his tips on how to make trouble free connectors, and explains the difference between the different common types of connectors and adapters used by most hams. Click Here to learn how Greg prepares his coax connectors for trouble free use.

Click Here to learn how


Outdoor Antenna Installation WarningsDanger!

We have provided you with some general recommendations to help insure your safety during the installation of an outdoor antenna. The following should be considered as a supplement to the specific directions supplied by the manufacturer of the antenna and you use this at your own risk.

The following general recommendations are made to insure your safety during the installation of an outdoor antenna. The following material should be considered as a supplement to the specific directions supplied by the manufacturer of the antenna.

If you are installing or dismantling your antenna for the first time, seek professional assistance. If you are unsure of your competency regarding the installation, it is best to seek the help of a qualified professional antenna or tower installer.

Read the manufacturer's directions and this advisory in full before proceeding.

The installation or dismantling of any antenna near power lines is dangerous. Each year hundreds of people are killed or injured while attempting to install or dismantle an antenna. In many cases, the victim was well aware of the dangers, but did not take adequate steps to avoid the hazards. For your safety and proper antenna installation, read and follow all safety precautions.

Choose an installation site for safety as well as performance. All electric power lines, cable lines and telephone lines look alike. To be safe, assume ANY overhead line can kill you.

Do not place an antenna where it could potentially fall on to, or blow into a power line. To determine the SAFE DISTANCE follow these steps:

(A). Determine the proposed height of your antenna.
(B). Add the antenna length and the length of your tower mast.
(C). Double the figure.

Utility Co MarkingYour answer will be the minimum safe distance from the nearest power line that you should install your antenna.

Call the Power Company. Let them review your site and mark any underground wiring in your yard before you dig holes to install towers, push-up poles or other structures. This might seem like an inconvenience, but a few hours with the Electric Company may help avoid a fatal accident. Play it safe. Never dig without contacting the utility companies. [Photo on the right shows marking on grass near the house where various utilities enter the house from underground. Click on photo for larger view. Orange is power, yellow was gas]

Never use a utility pole as a support for an antenna or guy wire. Never climb a utility pole.

Outdoor antennas should be grounded with an approved lighting arresting device. Local codes may apply. The radio should also be grounded to an earth ground to help protect both the radio and its user. Do not use hot water pipes or gas lines as a ground source.

Height or other restrictions on antennas may apply to your installation depending on your proximity to an airport, or local ordinances.

Take the time to plan your installation procedure. Each person should have assigned tasks. A foreman or "boss" should be chosen to call out instructions and watch for signs of trouble.

Dress properly with rubber soled shoes, rubber gloves, and long sleeve shirt. Use an approved safety belt.

Do NOT work on a wet or windy day or if a thunderstorm is approaching.

Do NOT use a metal ladder.

If the assembly starts to drop . . . get away from it and let it fall. Remember that the antenna mast, cable, and guy wires are all excellent conductors of electrical current.

If any part of the antenna should come in contact with a power line . . . DON'T TOUCH IT OR TRY TO REMOVE IT YOURSELF. Call your local power company immediately. They will remove it.

Should an electrical accident occur . . . DON'T TOUCH THE PERSON IN CONTACT WITH THE POWER LINE, or you too can become electrocuted. Instead, use a DRY board, stick, or rope to push or pull the victim away from the power lines and antenna. Once clear, check the victim. If he has stopped breathing, immediately administer cardiopulmonary resuscitation (CPR) and stay with it. Have someone else call for medical help.

Remember that guyed towers are NOT self-supporting at any height. If your antenna installation includes towering, read the additional advisory on towers.

Install wire antennas high enough that they will not be "walked into" by people.

Do not install wire antennas over or under utility lines.


Want to Build Your Own Antenna?

Interested in building your own antenna? We'll be collecting stories, ideas, and links to other web sites with "how-to" information you can use to build antennas with.

Bob Heil, W2IK, hard at work during a local 2003 Field Day Event.

In March 2004, Bob took a trip to a clear area in Shertz Texas to setup his new IK-STIC 2 antenna mount. It was made by shortening a child's small metal bedframe for the stand and adding a PVC mast (painted green) so all he has to do is screw in a PVC-to-metal shaft and slide the antenna on it. The model shown here is the newer version of his IK-STIC2 and with a tuner covers 160-10 meters. It stands only about a foot taller than the standard version (without the mount, 5 ft with the mount making the total height 30 ft ), but has a longer bottom coil with many more turns. The adaptation procedure was posted at the end of the IK-STIC 2 web page in February 2004.

On 160 meters, during the 160 DX contest the end of February 2004, I made several contacts with it. The furthest being Ohio after I came home from the ROOST ham shack that first night of the contest. Again, it takes less than 5 minutes to set up. - Bob W2IK.

At the right you see a photo of W2IK holding his antenna following his quick 5 minute installation process. The antenna is fed at the point above the coil you see several feet above where Bob is holding on. Bob recommends using nylon rope as guywires if you are expecting heavier than moderate winds, but this mount works great in an area where you can't normally run guy wires for some reason. Total height is about 30 feet above the ground.

At the left you see a close up of the mounting base he built using a child's bed frame. Bob found the bedframe sitting on the curb during a time of brush pickup in San Antonio, thus proving the old adage that "one man's trash is another man's treasure". Thanks Bob for saving space in the landfill and sharing such a nifty idea with the rest of us!

The "How To" Page

We'll be adding to this section as ideas occur to us, such as how to build your own portable antennas for less than $50 - $100

Coax

Tip #1 - 2 meter J-Pole Antenna - deployable

W2IK Antenna KitThe featured photo above shows the W2IK emergency deployable 2 meter J-Pole antenna that also works on 440 quite well. When slipped inside the tube (that also serves as the base) the total size is less than 48" long. Easily shipped with a weight less than 5 pounds (excluding weight of coax). We'll be posting links here to let you build your own antenna for about $30 using parts from your local hardware store (excluding the radio coax connector and coax that you can't get there).

This is an emergency deployable VHF and UHF antenna that is stored in a pvc sewer tube (which also acts as it's lower base) is under 48 inches yet expands to a whopping 16 feet plus. It is UPS and USPS shippable. It is so effective that I've built 15 units but kept only 4 to loan out. Great for EMCOMM deployment. NO TOOLS NEEDED TO ASSEMBLE IN THE FIELD. For instructions on how to build this antenna, visit this web site.

Coax

 

Tip #2 - HF Antenna - NVIS type - 2006 Design

NVIS Antenna KitAs shown in the picture to the left, I made a few minor changes to the original design of this NVIS antenna kit. I replaced the hammer-in support rope stakes with a screw-in variety. At first I thought that they wouldn't be able to withstand the torque or pullout stress. A few tests showed me I was wrong. They are easy to use and easier to remove from either soft or hard soil while still supplying enough strength so that they won't pull out like a conventional stake might.

The picture also shows the kit without the coax cable and ground reflector system that were a part of my other pictures. I did this to give you a better view of the antenna, itself. The ground reflector system is very important in creating the RF waveform needed for NVIS signals and I have designed a reflector system which is easy to deploy yet suits the ground conductivity of our area. It took many field strength experiments to come up with the ideal reflector design.

There are three antenna supports, all of which are 5 feet tall when assembled. This height, after field testing, I feel is not only RF adequate to create the "half grapefruit" lobe needed for communications within a 400 mile circular range but it also makes the antenna easier to handle and construct. With this height above ground, it also means that it lessens the reception of both static crashes AND European broadcasters on 40 meters making it very valuable during emergency communications in south Texas. If every emergency communications operation in south Texas, that used HF, were wise enough to also use the same type of antenna system it would make a very reliable communications web between all counties. I have also designed a NVIS antenna system which will create the same radiation pattern when it is installed on the roof of a building, such as at an emergency operations center. The reflector system is completely different to compensate for "pooling" and nearby metal structures.

Visit http://hometown.aol.com/alonestaryank/NVISKIT.html for more details, construction instructions and full parts list for building your own portable Texas NVIS Antenna. 73 de Bob W2IK

Coax

 

Tip #3 - HF Antenna - ENVIS type - 2007 Design

ENVIS W2IK AntennaW2IK's latest Emergency Near Vertical Incident System Antenna Design. The total weight, including the container is 12 pounds. This is the third such antenna I've sent to ARES units for beta-testing. To see how this antenna was constructed, just go to http://hometown.aol.com/alonestaryank/ENVISANT.html for a parts list and step by step construction details.

Most NVIS antenna systems consist of dipole antenna positioned at a low height so that it's radiated waveform covers a limited area, usually under 500 miles or so. This method also inhibits the reception of unwanted signals such as international broadcasters on 40 meters. By being able to change the height you can change the transmission and reception pattern to maintain emergency communcations in an area while avoiding unwanted signals and noise such as "static crashes" caused by distant lightening. Usually you have to use a tuner to match the antenna and transceiver when operating NVIS as one antenna might be used on frequencies from 3.6 - 7.3 MHZ.

This is my newly designed NVIS antenna system which can be quickly deployed to supply regional communications during an emergency. It's height above ground level can be easily adjusted to limit or extend signal range by simply twisting the three support poles to loosen, change the height of each and then twist in the other direction to lock in place. There are less parts than my first NVIS antenna kit so you don't have to be an engineer to assemble it. This is a temporary field antenna setup and should not be thought of as a lasting installation.


Mobile Radio Installation Tips

One immediate hint we would like to toss out there for new hams, is on the topic of mobile installation. Here are three considerations you might want to make before embarking upon the chore of putting a mobile radio into your vehicle.

Power source

  • To avoid power problems, run that powerline through the firewall to the battery, both positive and negative leads, using heavy gauge wire (such as 8-12 gauge, no thinner than 12). Frequently you can find this on spools in the red/black color combinations for affordable pricing at the area ham fests.

We've also found this web site to have competive pricing on power wire and coax plus cost effective shipping rates.

At the right is a drawing from the Icom radio manual. There are two reasons you want to do this.

    • Avoiding/reducing chance of interferrence by your alternator or other engine noise by connecting directly to the battery.

    • Depending upon the amperage draw by your radio, you could exceed the rating of your cigarette lighter plug if you tried running high power with a mobile rig.

  • When you run this wire through the firewall of your vehicle, be sure to use a rubber grommet where it passes through the metal, or run the wire through an existing insulated opening to avoid letting the metal wall slowly cut into the insulation of the power lead.
  • Install fuses on both leads at the battery and inside your vehicle before attaching to your radio or radio console. This way if something shorts out the wire, such as where it passed under the dash and through the firewall, it won't set your vehicle on fire!

  • To avoid interferance with your vehicle's inboard computer (as has happened to some newer cars) , you might want to consult your owners manual so that you can route your power leads away from that point under your hood or dash.

  • If you still have electronic / engine noise, you might consider placing some ferrite chokes or beads on the power lead.

    Here is what a local experienced ham, Bob (W2IK), had to say on the subject:

    "An important detail is that when you deal with any wires, power or coax, that they be as far away from the car's computer as possible to avoid stray RF from entering your car's computer and creating havoc during driving or even causing permanent damage to the computer. There have been many cases where the car would either stall or "buck" when the driver keyed his mic.

    There have also been cases where the vehicle's computer was damaged and a costly repair bill ensued. It's also a good idea to add RF chokes, or at the very least a few RFI beads, to each side of the power cables to your radio, and a few windings of your coax antenna feed around a core wouldn't hurt. In either case, use a core or bead made for vhf use, such as one made of # 31, 44 or 43 material."


Where Do You Put the Darn Radio?

Where are you going to put that darn thing? The answer to this question varies from vehicle to vehicle depending upon the space you have to mount it. The days of having that big dash with all that empty space under it has gone bye, so you have to get a bit more creative. Some radios allow the use of a "remote head mounting kit" which lets you detach the front control head from the radio and mount that up on the dash where you can easily view it while driving. If you do this, you can mount the rest of the radio under your seat or even in your trunk, and connect it to the control head with a connecting cable. Above is a photo of the Kenwood TM-D700A mobile, a dual band Amateur rig. This is the radio that is used by most, if not all, of the area hospitals for disaster communications utilizing Amateur Radio operators. It can be installed remotely like the photo shows, or reattached to the body of the radio and installed normally.

When you install your mobile rig in your vehicle, be aware that they don't like heat, so keep them out of direct sunlight when possible. Also, the rule of "out of sight, out of mind" applies very well to avoid attracting attention of those interested in "collecting" radios from "involuntary donors". Keep the radio mounted where you can easily see the display while driving.

And no matter where you decide to mount it in the end, please remember that if you have to make changes to the frequency that involved more than turning the knob or punching the up/down button on your microphone, be sure to stop moving before doing that or you might have a reason to use that radio and call for help from another ham!



Routing the Coax Feedline in your Vehicle

When you route your feedline through an opening on the outside of your vehicle, such as an open window, car door, trunk lid or back hatch...

  • You need to be sure that you are not pinching your cable between the metal of the body of your vehicle.

  • You also need to route it in such a way that it is not in a high traffic area of your vehicle (like the driver's side door) and doesn't let the rain get in when it is wet outside. For example, if you seldom open the rear passenger door on the car, use that door to run the cable through (if using a roof mounted magnetic mount antenna).

  • Examine your coax periodically to be sure it hasn't been pinched and, while the outside rubber covering appears okay, the interior conductor might be broken.

  • Check your SWR (Standing Wave Ratio) of your antenna using the appropriate meter on a regular basis to be sure nothing has changed to put your radio at risk of damge. The K-Comm Ham Store will do this for you, for a small fee, or ask around during a ham club meeting for help and someone will volunteer.

Magnetic Mount vs Permanent Mount Antenna

When considering what type of antenna to get, you will find there is a wide selection of types, sizes and brands to fit your needs. This is an area where you don't want to simply grab the first antenna you find and slap it on your vehicle, connect it to your radio and hit that transmit key.

  • There is an old saying "You aren't a real ham until you've drilled a hole in the roof of your truck for an antenna to mount." Not sure everybody buys into that saying, but there is a definite advantage to each method of mounting.

  • If you run the larger antennas, you need stronger mounts. The taller the antenna, the bigger the magnet mount you need should you choose that method. If it is too large, you have no choice but to mount it permanently somewhere, somehow, especially if you start talking about HF types of antennas.

Don't want to install it yourself?

There are places you can take your vehicle and pay to have them do the work for you. Obviously the local ham store would be one starting point to compare with, but you might not think about checking with your local auto alarm installer. These companies go through that firewall installing accessories and alarms all day long. What might take their tech a mere 30 minutes or less to perform, might take you all weekend unless you are a contortionist able to bend your body into strange positions so that you can get under your dash to make sure you aren't drilling through a valuable part of your vehicle.

  • One ham told us he took his wife's Toyota Camry to his auto alarm company and they only charged him around $20 to run the cable (he supplied it) between the battery, through the firewall and under the front seat where he planned to remote mount the radio. They also insulated the wire in the engine area using that black tubing to protect it better.
  • A few months later, a new van later, he took his van to the local ham store for some holes in the roof. (No, it wasn't after the hail storm!) They professionally drilled two holes in his roof, installed quality NMO style mounts (sometimes referred to as "Motorola style"), ran the coax under the roof liner, down the passenger side front column between the front windshield and the front door, down into the front carpet area of the van. They installed connectors on both coaxes, labeled them appropriately, ran the new power line from the battery through the firewall to the same area, all for a little more than $100. The ham later routed the coax himself under the door jamb and behind the passenger seat in a secure manner that reduced the chance of accidental snagging.

Coax

Curing Alternator Whine By Jim KB1MVX

Whine FilterI recently installed a new transceiver in my truck.  On the first day of using the new radio I got reports that I was transmitting very noticeable alternator whine.  I could also hear it on receive and when the radio was quiet.  I checked the diodes in the alternator, verified I had good grounds, and I even ran the truck with the alternator removed to be sure that the whine was indeed from the alternator. I tried an off the shelf filter from Advance Auto. It did very little so I decided to build a filter. The first filter I built worked VERY well. The problem is that not everyone has the tools required to build that filter so I decided to figure out a filter design that could be built in less than an hour by anyone with basic tools, have a cost under $20, and handle a current draw of at least 20 Amps.

Click here for full story and instructions on how to build your own filter

Coax

Anderson Powerpoles - Removing the Mystery

Whine FilterThe local ARES group recently asked all of their members to become "Anderson Powerpole Compliant" in their vehicles. This was so that they would be able to install and use city provided emergency radios if deployed with such, and to encourage the use of these more reliable connectors.

Either the 15-ampere, 30-ampere or 45-ampere sizes may be used, and both sizes mate with each other. The plastic parts are the same for both sizes. In fact, there is even a 75-ampere size available for a much higher cost per pair of connectors, that will handle 6, 8 or 10-12 gauge wire. Usually the 30-ampere size is used for most installations, but if you need to feed a group of radios from one wire, we recommend use of the 45-ampere or 75-ampere rated connections with the higher gauge wire. (Note: the cost of 75-ampere connectors is triple the expense of 45-ampere connectors. Most common size is the 30-ampere connectors.)

Click here for full story and instructions on how to order and use these connectors

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