Frequently Asked Questions
Yes indeed! We appreciate the opportunity to enter new markets and expand our product line. There are many custom products not listed in our catalog already available. We only ask that you do some preparation before calling. We will need specifications, quantities, delivery deadlines, and target price. A written request is preferred. That information will be forwarded to the appropriate Product Manager for a response.
We are happy to assist with the selection process. We suggest you first determine the reason behind the request. Is it a price, delivery, or performance issue? Because there are few exact equivalents it is important you know which features are most critical before calling us. Unfortunately, a competitor's specification sheet does not give us this insight. We will provide specifications on our similar products. The final choice should be made by the end user's technical staff. They are the only persons aware of site conditions and compatability issues. After a part number has been selected our sales associates can quote price and delivery.
Questions about antennas
Very few people in the land mobile business have heard this term. We include a brief note in our Celwave marine antenna catalog. This is published by our facility in Hillerod, Denmark which manufactures a line of marine antennas. Essentially, 3 dB is added to the actual dBd or dBi numbers to arrive at "marine" gain figure. Why? Legend has it, some marketing person justified putting larger numbers in his catalog by claiming antennas perform better over water. This forced competing manufacturers to comply in order to sell marine antennas to buyers who go by the numbers. It can be very difficult to convince a purchasing department that your 10 dBd antenna achieves the same performance as another's 13 dBd antenna. If the same product is sold in two markets it could have a two specification sheets. The land mobile sheet would list the gain at 10 dBd, while the marine sheet would list the gain at 13 dBd. Our Cel-1 and Cel-3 cellular antennas are an example of this. Perhaps one of our customers has heard a different version of this story. Let us know and we will share it.
Polarization Quality Ratio (PQR) is a measurement that encompasses both orthogonality and cross-polarization discrimination in one measurement. Since poor cross-polarization discrimination and loss of orthogonality both lead to a decrease in diversity quality, it is important to make this a single measurement. This measurement requires two radiation patterns with the source antenna oriented at two orthogonal polarizations, co-polar and cross-polar to the nominal polarization. The same two source polarizations must be used for both antenna ports, and four patterns will result. Over the 3 dB and sector beamwidths, the worst case ratio between the two orthogonal polarizations shall be the figure used. This will be done for both antenna ports. (For example, an antenna under test has two ports - one at +45 degrees slant polarization and one with - 45 degrees slant polarization. For the first port, a measurement of the radiation pattern is made with the source antenna oriented at +45 degrees and then a second measurement is made with the source antenna oriented at -45 degrees. For the beamwidth of interest, the PQR is the worst case ratio between levels of the two orthogonally polarized, radiation patterns. The measurements are then repeated for the -45-degree port. Polarization is defined looking in the direction of propagation.) While this is not a direct measurement of orthogonality, it indicates a deviation from the desired polarization, in conjunction with cross polarization discrimination, and provides a measure of the quality of the polarization of the antenna. It is important to orient the source antenna to within +/- 1-degree of the polarization required, or significant errors can result. Pattern Tracking is defined and the maximum deviation in dB of the patterns of the two orthogonal ports over the 3 dB beamwidth. There will be separate values for azimuth and elevation planes.
Refer to our application note Antenna Painting Instructions.
Refer to our application note Evaluating Antennas.
Electrical and/or mechanical downtilt is normally used to accomplish two objectives. Tilting the vertical pattern downward can either improve close-in coverage or restrict the range to minimize co-channel interference. If you know the antenna's vertical beamwidth, its height, and the desired coverage distance you may find our X-tilt program on the Celtools page useful.
First you should contact the receiver manufacturer to find out how much out-of-band signal it can tolerate. Then you can determine how much attenuation of the transmitted signal is necessary. The distance required for a specific isolation varies with operational frequency and antenna gain. Lower frequencies and higher gains require greater distances. Horizontal spacing distances may exceed practical tower applications. The best orientation is vertical separation when tower space permits it. This places each antenna in the null of the other antenna's pattern. Refer to the Antenna Spacing Chart in the technical section of our catalog for details.
Inverted mounting of antennas is often used to conserve tower space or to provide RF isolation. Some of our antennas are designed for in-field changes between upright and inverted mounting to address these requirements. Some of the others require physical modifications. Of primary concern would be the drain hole. If the particular antenna has one, it must be sealed and then drilled at the opposite end. Unfortunately these alterations will void the product warranty; so first check with our sales department to see if the antenna is available from the factory as an inverted model. This will circumvent two other potential problems because we will also electrically invert the antenna internally. This assures that any downtilt or null fill features remain pointing downward.
We cannot claim the performance of RFS connectors will be equal, exceed or degraded by their use on competitor’s products and vice versa competitors connectors on our cables as we cannot control the design, quality or consistency of non-RFS products. Therefore, no performance warranty is presumed or implied other than a RFS connector installation on RFS cable. Interoperability cannot be assured.
Questions about cables
Q. What is a Rapid Fit Connector?
A. Rapid Fit is the trade name of RFS single piece connector.
Q. Why have you named it Rapid Fit?
A. We have named it Rapid Fit, because it installs quickly and easily - in the field, on top of a tower when the wind is blowing and temperatures are falling, or in the shop. This gives the installer great flexibility, since the job can be done rapidly anywhere.
Q. Why does the Rapid Fit install so quickly and easily in the field?
A. The answer lies in its single piece construction. You simply trim the cable, place the O-ring on the cable, push on the Rapid fit connector, tighten it and you are done!
Q. What is the benefit?
A. The main benefit is that connector installation time is cut down significantly, and that adds up to cost savings on installations. And that's something that our customers like to talk about - saving money!
Q. What about electrical performance?
A. Rapid Fit connectors have excellent electrical performance. Rapid Fit's unique 360 Degree Full Contact Technology, with Snap Finger outer contact design, ensures electrical integrity and delivers lower, more stable and consistent IM performance.
Q. Are these connectors waterproof?
A. Yes. Rapid Fit's rugged, waterproof design ensures extended worry-free service, even in the harshest environments.
Q. Which connector sizes are these initially offered in?
A. Rapid Fit connectors are available in popular cable sizes, that is 1/2", 7/8', and 1-5/8" in both type N and 7-16 DIN interface.
Q. Are trimming tools available?
A. Trimming tools are available for 1/2" and 7/8" connectors. While trimming tools are not an absolute must, it is recommend that these tools are used for fast, easy and more precise installations. Furthermore use of these avoid copper chips from getting into the cables' current path and aid in achieving optimum electrical performance.
Q. Are these the same trimming tools as the standard connectors?
A. No. Since the trimming dimensions are different than the standard connectors, Rapid Fit connectors have different trimming tools. Their trimming method is the same as the standard tools but they have different part numbers. These are going to be red in color. Easy to remember - Red tools for Rapid Fit connectors.
Q. Can these connectors be installed without trimming tools?
A. Yes. 7/8" and 1-5/8" connectors will come with a cutting guide which would provide assistance in producing an even cut. On ½" connectors, since the center conductor has to be exposed, cutting without a tool is not easy. Thus a trimming tool for 1/2" connectors is highly recommended.
Standard and fire retardent jackets (Type J and JFN) are free of halogen gas.
No. Our waveguide products are dimensioned differently and not compatible with Andrew products.