Question The CCTV/Surveillance Expert

The capabilities of 900 MHz network video solutions


Sifting Through the New Products
Q:
Our company has just received the latest update on 900 MHz Network Video Solutions products, as well as information on a new, affordable, point-to-point wireless Ethernet bridge from a well-known supplier. This new bridge provides 1.5 Mbps throughput to support network camera installations where cabling is difficult or cost prohibitive. Are you familiar with this type of technology and can you give a bit more understanding of the quality picture our client may expect? There is nothing worse than making promises to clients that you can't keep.

Of course, all my IT clients are interested in this type of technology and it seems like new product is entering the market every day.

This particular client, in the past, has been very fussy about the quality picture and quality playback. This customer is in the jewelry business and has had many cases where the video we have provided has led to arrests. The arrests have been of professional thieves, as well as internal thieves working for the chain of stores with remote management.

A: I am familiar with this technology. For lower bandwidth applications, it is probably a good solution.

But, there are a few things to keep in mind:

  • This type of system is operating in the 900 MHz bands, which may be more susceptible to interference. A product like this operates on the data radios in the 900MHz band because data requires a much lower bandwidth for successful transmission. Many readers have, more than likely, had applications that have not worked due to interference in the 900 MHz band, even with the lower bandwidth requirements.
  • The 1.54 Mbps throughput you mention is probably the high-end rate and may fall significantly if interference is present. Full frame rate, high-resolution video can require up to 5 Mbps.

It is true that many digital cameras, encoders, DVRs, etc., will transmit video at much lower frame rates, but frame rate and resolution will be sacrificed. I cannot say with certainty that 1.54 Mbps is enough for high quality full frame rate images. This determination is obviously up to you and your end user customer. Every application is different.

As a reference, a benchmark is 5 Mbps for full frame rate, high-resolution video.

  • 900 MHz signals will penetrate certain barriers better due to the longer wavelength of the signal as compared to 2.4 GHz and 5.8 GHz. With high gain antennas, in effect, the signal is being blasted out, which helps with penetration. It is probable that signals can be transmitted through leafy trees and walls made of plywood, sheetrock, etc. However, it is doubtful that even a 900MHz system with high gain antennas would be able to penetrate concrete, steel or a dense forest or timber area.

As always, I recommend that the system be tested in the application it is intended to be used in to ensure success. At the end of the day, if the system is priced right and will do the job, go for it. It is your responsibility to deliver what your customer wants and needs but unfortunately, it is buyer beware-on your part.

John W. Colley is president of Integrated Security Systems, Ltd. Colley has been in the security industry for 25 years, beginning his experience in the CCTV segment of security and gaining knowledge through field experience, manufacturer training and designing systems to meet customer needs. Colley started his security integration firm 16 years ago, providing design, engineering, installation and service to commercial accounts using integrated systems. Send your CCTV/Surveillance questions to john.colley@secdealer.com.