Frequently Asked Questions / Technical Information

We at JDTECK LTD provide you as best a solution as possible with all the testing, (former & continued) customer data and research we have compiled for some time now.

Sadly, many people have allowed the type of antenna they "like" to be the deciding factor on what they should purchase and not the "terrain" of the desired application. This includes hidden, portable, magnetic-mount on your car, glass mount, pole mount etc. The lack of conclusive information or knowledgeable advice on the part of many "cell phone dealers" today, have not made things any easier for the customer who needs to maintain a sure link of communication on a daily basis.

Many have tried several options before finding something that works for them while others are in locations that nothing will help. We have provided this information to help you understand a bit more why getting the "right products for the job" is so important.

3 Watt BOOSTER FAQ'S :

What's the difference between a Booster and a Repeater?

Can the JDTECK Single Band Booster operate on CDMA / TDMA or AMPS cellular networks?

What technology would the JDTECK Dual Band Booster support?

What is the difference between your House/Office Kit and your Vehicle kit?

Can the JDTECK 3 Watt Booster Kit also be used in homes and offices?

How does your Booster Kit connect to my phone?

Will 3 Watt Boosters increase radiation to my head?

What Tech support is there for me, if I buy this Booster?

What warranties do I have?

I already have an antenna mounted on my vehicle; can I use it with the booster?

Antenna FAQ'S :

What's the difference between 0db (unity), 3db, 5db gain?

What dose Omni directional mean?

What is dB gain?

What is the difference between dBd & dBi?

What does dual band mean? (800Mhz/1900Mhz)?

Drill a hole. Not on my vehicle!  What options do you have?

Where should I place my antenna?

I want an antenna that I can hide. What do you recommend?

Can I use a Vehicle Magnetic Mount antenna anywhere else?

What's the difference between CDMA & TDMA?

What's the difference between a "Soft Handoff" and a "Hard Handoff"?

What's the difference between a Booster and a Repeater?

A Booster is designed for hardwired applications, while a repeater is designed to provide wireless coverage to a specified area. Therefore, a repeater is better suited where multiple phones need improved coverage or if a user prefers wireless coverage as oppose to a tethered setup. Our Boosters can also be used to provide wireless coverage inside your home or vehicle, however because the coverage area is not very wide (3-4ft), this is a solution that we do not recommend to our customers.

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Can the JDTECK Single Band Booster operate on CDMA/TDMA or AMPS cellular networks?

Yes! The JDTECK 3 Watt Booster is a linier amplifier that amplifies both transmit and receive signals in the (824-849 / 869-896) frequency band. The actual mode of transportation used (CDMA / TDMA / AMPS) is irrelevant with our amplifier.

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What technology would the JDTECK Dual Band Booster support?

The JDTECK Dual Band Booster is a linier amplifier that amplifies both transmit and receive signals in the (824-849 / 869-896 & 1850-1910 / 1930-1990) frequency band. The actual mode of transportation used (CDMA / TDMA / GSM / GPRS / PCS / AMPS) is irrelevant with our amplifier.

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The JDTECK 3 Watt Vehicle Booster kit is supplied with everything needed for a complete "Plug N Play" setup in your vehicle. The only difference between this kit and the House/Office kit is an AC/DC Power Supply, which has been designed and tested for use with the JDTECK Booster for indoor applications where a 110v power source is available. Investing in a House/Office kit will allow you to use your booster kit both indoors and in your vehicle.

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Can the JDTECK 3 Watt Booster Kit also be used in homes and offices?

Yes! The JDTECK 3 Watt Booster can be used anywhere you can provide it a 12v or 110v power source.

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How does your Booster Kit connect to my phone?

A signal lead is supplied with each booster at no extra cost. One end of this signal lead connects to the "phone end" of the JDTECK Booster, and the other end connects to what is called, a Phone Adapter (Sold Separately). The photos below show several types.

On the phone itself, you will find what is called "an external antenna port" which can be either located at the base of the phone, at the side of the phone or at the back of the phone. The Photos on the right show where these "external antenna ports" can be found.

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Will 3 Watt Boosters increase radiation to my head?

NO!  It uses an external antenna that will keep the signal radiation away from you. Instead of radiation being 1" from your head when using a regular cell phone and ruining the signal pattern, you will now be sending your signal out to where it works best, to external antenna. This also addresses the safety concerns of radiation so close to the head.

Use of our 3 Watt Boosters can greatly increase battery life! Your phone has 7 output power settings. It is instructed by the cell site how much power to put out between approximately 1/20th of a watt to the full power 6/10ths of a watt. If you are using the Mobile Power Booster from JDTECK your phone will power down, because it no longer needs to increase its power settings to keep the signal, thus saving battery life,  which in turn reduces the level of radiation emitted by your phone, which is a by-product of energy.

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What Tech support is there for me, if I buy this Booster?

JDTECK LTD will provide any tech support needed to its customers, whether it is about the Mobile Booster or any other info regarding antenna applications for cellular use. You may contact us at sales@jdteck.com for a prompt response within 24hrs.

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What warranties do I have?

All JDTECK's Products are covered by a twelve-month manufacturers' defect warranty from the date of purchase. If any repairs are required under warranty, they will be undertaken by JDTECK LTD, with proof of purchase.

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I already have an antenna mounted on my vehicle; can I use it with the booster?

YES! However we would like to get details on your antenna to determine whether it would be the best antenna for your specific need. 

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FAQ'S ANTENNAS / NETWORKS:

What's the difference between 0db (unity), 3db, 5db gain?

0-dB gain antennas radiate more energy higher in the vertical plane to reach radio communication sites that are located in higher places. Therefore they are more useful in mountainous and metropolitan areas with tall buildings. A 2dB or 3dB gain antenna is the compromise in suburban and general settings. A 5dB gain antenna radiates more energy toward the horizon compared to the 0, 2 and 3dB antennas to reach radio communication sites that are further apart and less obstructed. Therefore they are best used in deserts, plains, flatlands, and open farm areas.

Omni directional Antennas

What dose Omni directional mean?

This means that (if the antenna is vertical) the signal will be transmitted equally in all directions along the horizon.

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What is dB gain?

Gain is defined as the compressing of the vertical component of the antenna pattern, in effect causing the radiation pattern of the antenna to reach out further toward the horizon. It is not the creation of power, but rather a simple refocusing of energy from all directions to a specific direction. Gain is measured in decibels (dB). Vertical antennas are in fact quite directional, except in the horizontal or azimuth plane.  

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What is the difference between dBd & dBi?

Gain can be expressed in many different ways. The two most common are dBd and dBi. Gain expressed as dBd, is a measure referenced to a half wave dipole. The dBi measure is referenced to a theoretical, dimensionless point source with a completely spherical radiation pattern. Since it has no directivity, any real antenna without excessive loss will provide some amount of gain when compared to the isotropic. JDTECK LTD antennas are all rated in dBd measurements.

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What does dual band mean? (800Mhz/1900Mhz)

Many networks today operate on a dual band system, e.g. (800Mhz & 1900Mhz in the USA) & (900Mhz & 1800Mhz in Europe). Phones on most of these networks however, are what is called, Tri Mode phones. This means they operate in the 800Mhz analog, 800Mhz digital and 1900Mhz digital mode (USA). The 1900Mhz frequency band is predominantly used in the metro areas while the 800Mhz bands are used mostly in suburban areas and rural areas, however this is not a hard and fast rule with all networks.

The network automatically switches between both frequency bands and their three modes, by constantly communicating with the cell phone, which in many cases happens unknown to the user. Due to the fact that so far the 800Mhz cellular band provides a stronger and more stable signal, the networks switch to this frequency band when faced with obstructions between the cell phone and the cell site to keep the signal. It may first switch to the 800Mhz digital mode and if it still isn't sufficient enough, it then switches to the 800Mhz analog mode.

So, you can be pretty sure if you are experiencing poor cellular reception with your mobile phone on a dual band network, your phone would have already switched to the 800Mhz frequency band.

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Drill a hole. Not on my vehicle!  What options do you have?

"On-Glass"  antennas are easy to install and do not diminish a vehicle's value by drilling a hole. Care must be taken during installation to ensure that the antenna is mounted high up on the glass and not over defogger wires or on reflective window tint and this could impede performance.

"Rear-Dash"  is also another option, however performance losses will occur.

"Magnetic-mount"  This step-up, allows the easy placement and removal of your antenna on the rooftop of your vehicle. Very useful for multiple vehicle applications.

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Where should I place my antenna?

In applying all the information provided for the maximum benefit of the radiating pattering of your antenna it would be wise to position the whip as vertically and as high as possible. 

ü      If the antenna is tilted, some of the signal will be wasted because it will be directed up to the sky or into the ground.

ü      If the antenna is much lower than the vehicle's roof, the signal will be blocked and the radiating pattern will be distorted.

JDTECK Ltd customers may direct any further questions to: sales@jdteck.com

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I want an antenna that I can hide. What do you recommend?

Our Mini Patch is used by many of our customers that want to add an antenna but want to make it the least visible.

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Can I use a Vehicle Magnetic Mount antenna anywhere else?

Yes, most magnetic mount cellular antennas are manufactured for use on vehicles, as the roof of the vehicle acts a ground plane for the antenna. However to get the most from your magnetic mount antenna, you should place it on a metal ground surface when using the antenna away from the vehicle. These antennas work great indoors once a sufficient ground plane is provided, such as placing the antenna on a filing cabinet or on a piece of metal (about 8 inches x 8 inches) and placing it outside or near a window.

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What's the difference between CDMA & TDMA? (Courtesy Steve Punter)

Let's begin by learning what these two acronyms stand for. TDMA stands for "Time Division Multiple Access", while CDMA stands for "Code Division Multiple Access". Three of the four words in each acronym are identical, since each technology essentially achieves the same goal, but by using different methods. Each strives to better utilize the radio spectrum by allowing multiple users to share the same physical channel. You heard that right. More than one person can carry on a conversation on the same frequency without causing interference. This is the magic of digital technology.

Where the two competing technologies differ is in the manner in which users share the common resource. TDMA does it by chopping up the channel into sequentially timed slices. Each user of the channel takes turns transmitting and receiving in a round-robin fashion. In reality, only one person is actually using the channel at any given moment, but he only uses it for short bursts. He then gives up the channel momentarily to allow the other users to have their turn. This is very similar to how a computer with just one processor can seem to run multiple applications simultaneously.

CDMA on the hand really does let everyone transmit at the same time. Conventional wisdom would lead you to believe that this is simply not possible. Using conventional modulation techniques, it most certainly is impossible. What makes CDMA work is a special type of digital modulation called "Spread Spectrum". This form of modulation takes the user's stream of bits and splatters them across a very wide channel in a pseudo-random fashion. The "pseudo" part is very important here, since the receiver must be able to undo the randomization in order to collect the bits together in a coherent order.

If you are still having trouble understanding the differences though, perhaps this analogy will help you.

Imagine a room full of people, all trying to carry on one-on-one conversations. In TDMA each couple takes turns talking. They keep their turns short by saying only one sentence at a time. As there is never more than one person speaking in the room at any given moment, no one has to worry about being heard over the background din. In CDMA, each couple talk at the same time, but they all use a different language. Because none of the listeners understand any language other than that of the individual to whom they are listening, the background din doesn't cause any real problems.

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What's the difference between a "Soft Handoff" and a "Hard Handoff"?

Let's begin by defining the term "Handoff" first. In any mobile phone conversation, your call is passed from one cell site to another in order to keep the signal strong. This process of handing the call from one cell site to another is called a handoff (or handover in some countries). It is how this transfer takes place that defines the difference between soft and hard.

In all non-CDMA systems, including analog, IS-136, GSM, and iDEN, the handoff process is an all-or-nothing affair. At some point in time the switch instructs the phone to change from one cell site to another. The phone does this by terminating its connection with the old cell site and then establishing a connection with the new cell site. The term "hard" comes from the sharp-edged nature of this process.

In a CDMA system, all cells sites and all callers operate on the same frequency. Each conversation is distinguished from the next by the encoding sequence used to modulate the bits onto the wide carrier. The receiver in each CDMA phone has the ability to demodulate multiple code sequences at the same time. These receiver elements are likened to the tines of a fork, and the unit is called a Rake Receiver. The CDMA switch chooses multiple cells sites in your general vicinity and it broadcasts a copy of your conversation on each. Your phone assigns each of these sites to one of the tines in its Rake Receiver. The phone may now choose any of these tines, and it may also combine the output of two or more tines to smooth the transition from one cell site to another. Because contact with a cell site is never broken at any time during this process, the handoff is considered "Soft".

CDMA supporters will tell you that this soft approach has three primary advantages over the hard approach. The first is a much lower incidence of dropped calls during the handoff process. However, considering the low number of dropped calls reported by GSM users, and the shockingly high number reported by CDMA users, one has to question if this advantage truly exists in practice.

The second advantage is that soft handoffs do not have a detectable impact on the audio. When you use a phone near a cell boundary, handoffs can rapidly occur between one cell site and the other. This phenomenon is known as "Thrashing". When trashing occurs on a hard handoff system, the call quality can be severely compromised. In practice, this does seem to work.

The third advantage is that soft handoffs allow a phone to combine the signals from two sites simultaneously. Under very weak signal conditions this can translate to more error-free data recovery than either of the two sites could yield on their own. It's hard to say if this actually works in practice or not. If it does, we would tend to think that the number of cases where it might be advantageous to you are very small

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Some Final Observations

CDMA really comes into its element when you are out in the countryside with few sites covering large expanses of land. Under these conditions CDMA provides extremely stable audio with few frame errors to mess things up. This is because Channel Pollution is almost unknown in these situations. Under similar conditions TDMA suffers too readily from interference and it will often blank the audio. Many people who use CDMA systems in sparsely populated areas have given this technology extremely high marks.

TDMA systems also have great difficulties in open regions just outside densely populated areas. In this situation your phone is exposed to signals coming from countless sites in the densely populated areas, but there are no dominant signals from a close-by site. CDMA can suffer under these conditions too (due to channel pollution), but not quite so badly. Valleys don't present a big problem for TDMA, but high ground is a killer.

You can experience choppiness in the audio even when your signal indicator is reading 2 or 3 bars.

So in the end, can we really proclaim a winner in the CDMA vs TDMA war? For the time being we think not. Perhaps in the future when newer technologies built around the W-CDMA standard (wideband CDMA) come into use, the issue will warrant another look.

If you are presently in the market for a new phone, our advise to you is to ignore the hype surrounding the technologies and look at service provider instead. Judge each with an eye to price, phone choice, coverage, and reputation. Technology should play a very small roll in your choice, as the products we carry at JDTECK LTD will more than likely overcome any of those problems. If you follow this advice, you'll probably be much happier with the phone and service you inevitably wind up with.

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