Securitex Electronic Systems Engineering

As we realize many of our customer may be confuse over wireless system application we have compile some FAQ for your reading. Hope you will find this information useful.


Q1: What do you mean "line of sight" and the range I can expect?

A1: "Line of sight" in wireless equipment simply mean the transmitter and receiver is install on a 100%  flat plane with zero obstacle  and zero interference (Electrical, Radio, Electromagnetic and even Atmospheric interference). Both antennas must be at the same height (at least 5 ft. and preferably MUCH higher due to the nature of radio transmission) and situated identically along the same horizontal or vertical plane. The "approximated range", whether realistic or exaggerated- as found on many websites- is always measure based on maximum line of sight conditions. When using wireless system customer must expect some degree of interference and realized that they are not 100% even our million dollars mobile network sometime do affect by interference. No doubt wireless system is easy to install and the quality is quite good   they cannot match the quality of wired system. Most wireless sold by us has been   hand selected and tested by us for practical use and the quality is of the best you can obtain in the market, however you must not expect wireless equipment to penetrate multiple wall, partition, metallic screen. Structural beam etc. As such invest in the very best and most powerful equipment money can buy of course IDA and government approval is very important so as not to break the law. You can be assured that when we sell wireless we sell the best equipment and the cost is also very reasonable. If you search other site you can come across our system selling at much higher price.

Q2: Can I use 433/ 434 / 900 MHz in Singapore. What about  2.4 GHz units?

A2: 900 MHz wireless system MUST not be use as they are not approve for use in Singapore. Some 433 / 434 MHz and 2.4GHz can be used in Singapore but the safest is to invest one that is IDA approved (look out for IDA approval logo on the set) The above   frequencies are part of the radio spectrum. As far as 2.4 ghz (or 2,400 megahertz) signals in motion- it's a little hard to explain. When both points are stationary, you'll generally have a crystal clear signal (depending, of course- on interference and barriers). As one or both of the points are in motion, there will be digital interference. Unlike "snow" received from lower frequency units, you get momentary pops in between clear signals. Higher frequency signals are more directional by nature. By using the two receivers (one with built in omni directional antenna & the other with a high gain directional antenna), some normal interference will be stabilized. Essentially, 900 megahertz is better for those applications where motion exists in one or both links (i.e. body worn or mobile applications). 2.4 gig systems penetrate walls 10-20% more efficiently than 900 systems. The quality is otherwise identical. The TX-5 and TX-5A (434 MHz UHF) are both excellent transmitters- but 434 MHz can be a little tricky in the "real world". The receiver/ antenna combinations used will make all the difference in terms of the signal quality and range. Performance will range from marginal or even poor to excellent, depending on the quality/ sensitivity of the tuner and the dB gain of the antenna within the UHF band. A lot of consumer video equipment is known for having relatively weak built-in UHF tuners. For that reason, most would-be users of UHF 434 are ideally recommended to use either 900 MHz or 2.4 ghz transmitter and matched receiver. Again, however, lower frequency (900) units will provide a MUCH more stable signal than microwave links for transmitters and/ or receivers in motion. For stationary links, 2.4 giga hertz is usually ideal due to it's slightly higher penetration ability- but all will have similar excellent performance.

Q3: Are SecureCiti wireless transmitters more powerful or better than others I've seen advertised?

A3: Well, right off the bat- there are several considerations to make regarding this topic. When it comes to most transmitters we've seen out there on the net-profit over performance value seems to be the primary consideration of most sellers. Not to be confused with most toys with their low power output and often heavily exaggerated claims of range / distance ability, our A/V systems have the latest built in surface mount technology. Our 2.4Ghz systems use FM synthesized signals, featuring more stability and higher resolution capabilities than the typically found AM modulated units. Crystal IC controlled transmitters with phase loop lock receiver for drift-free signal performance. Patented signal reception technology and exclusive internal omni directional antennas in our 2.4 Ghz equipment make our units head and shoulders above inferior and highly directional units which feature adjustable flat plate antennas requiring both antennas to be directly pointed at each other.

Q4: What interference sources and barriers are the best & worst?

A4: When it comes to wireless, there really is no such thing as a 'good' barrier or interference source- but there are definitely some that are much worse than others. If you are using a 900 megahertz cordless phone around 900 MHz wireless video, you may experience interference. Likewise, 2.4 GHz video and telephone equipment competing for the same bandwidth may cause undesired interference as well when using 2.4 ghz equipment. If you use channel one of the 900mhz transmitter, interference may result. However, if you use channels 2/ 3/ 4, cordless phones will not interfere. *NOTE: when you operate this transmitter on channels 2, 3, or 4- an amateur radio license is required to use legally. SecureCiti International and Securitex Electronic Systems Engineering assumes no liability for unlawful use of these items.

Q5: What is a "high gain antenna" and how effective are they?

A5: A high gain antenna is a specially engineered antenna which is 'tuned' to a particular frequency range within a given bandwidth of the RF (radio frequency) spectrum. They are extremely effective when used properly and will greatly increase the reception range of any of our products. Securitex and SecureCiti only carries two types of high gain antennas- flat panel 'polarized patch' models for 2.4 gigahertz and "yagi" for 900 megahertz. We do not carry high gain tuners or antennas for 434 MHz equipment as amplified/ powered UHF antennas are more commonly found as "consumer-end" electronics at stores like Radio Shack, etc..

Q6: How many wireless transmitters/ cameras can I operate at one time?

A6: Theoretically, with our equipment, you could operate 9 transmitters at the same time- 4 in 2.4ghz, 4 in 900mhz and one in 434 mhz. However, use of our 900 MHz transmitters on any other channel than one may require licensing and/or may not be able to be used. We strongly urge you to check into the legalities before use. So, for practical purposes- 2.4 ghz with 4 simultaneous signals + 1 for 900 MHz + 1 434 MHz= 6 signals with which you shouldn't have to worry about potential licensing issues.

For more answers about multiple camera systems, please refer to the FAQ answer page.

Q7: If I use more than one transmitter, will I need more than one receiver?

A7: It depends. For multiple channel transmitters operating at the same time (and for the same frequency), you may choose to use a single receiver and manually switch between channels to view and/or record activity. Should you wish to monitor all signals at once- you will require a receiver for each transmitter.

Q8: Can you guarantee that your equipment will work in my desired situation?

A8: No- not at all. Due to the reasons mentioned at the top of this page- there are too many variable factors which may impede what you'll call "desired performance". Therefore, it is recommended that you do your homework & purchase the best equipment you can attain. For larger projects, start small and see for yourself with real field testing to decide whether or not more wireless links will be beneficial to your goals. It's not going to provide an ideal solution for everyone's situation and that's just as realistic as it gets. That's not meant to scare away potential customers who may be wary after having seen some of the JUNK floating around out there.

To return to main page CLICK here. To download the FAQ in PDF format Click here.

To purchase the above equipment please call or e-mail to or contact Securitex Electronic System Engineering. Our sales personnel will get back to you.


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