April, 2009
A Low Cost BACKUP System
Is mobile data (EVDO) already a part of your remote news gathering operation? Here is a discussion of how you can use that resource as a low cost backup system for your IFB system.
IFB for EVDO requires only three components:
- A PC with at least two USB-2 ports
- An EVDO USB “stick” with activated service (caution: both the service and the stick must be REV. A)
- A Voice Over Internet Protocol (VOIP) USB module
Just connect everything together and call into your news room cell home interface. If it works, you have just created a very low cost backup system.
Why should EVDO only be used as a backup system?
- The viability of IFB over EVDO is highly dependent on how heavily loaded the EVDO network is. Operation in the suburbs may be acceptable, but use in an urban business area in mid or late afternoon will likely include a disastrous combination of long latency, drop outs and choppy audio.
- In addition to long latency (up to seconds), expect a loaded EVDO system to have large ssecond to second variations in latency. This highly distracting artifact is engineered out of cell phone service - latency typically only changes when cell sites hand off. EVDO, designed for data, has no such protection.
- IFB via EVDO only remains a bargain if 5 GB (approx. 10 hours of IFB) of data per month is not exceeded. Depending on your carrier, the cost can skyrocket to as much as $1.50 per minute thereafter.
- The rates and terms of service of EVDO are not regulated, and are subject to changes at the discretion of the carrier.
- Like cell phones, EVDO depends on an external infrastructure NOT under the control of your station. EVDO relies on the same cell towers and hardware that cell phones do, and depends on limited emergency power, including the same interconnect into either the internet or the public switched telephone network (PSTN).
- Use of EVDEO when airborn (helicopter use) will undoubtedly face the same fate as use of a cell phone when in the air - nearly immediate shutdown. This is not a matter of FCC or FAA rules, but self preservation on the part of the cellular carriers. The cellular control software swiftly recognizes when too many cell sites are lit up and immediately sends the offending transmitter a signal to shutdown.
At this time EVDO is not subject to Priority Access Service (PAS) preemption by emeregency workers, which makes it a valuable backup to cell phone usage.
If mobile data is already a part of your remote news gathering operation, then why not create this low cost BACKUP system?
Posted in EVDO, IFB | No Comments »
April, 2009
Recently mobile data has been suggested as a method for delivering IFB to ENG talent.
Many broadcasters are familiar with mobile data (formally known as EV-DO Rev A). It is the email and internet link for BlackBerry and iPhone. I’ve used EVDO for years to provide connectivity for my laptop. It works most everywhere cell phones do. Mobile data is especially useful in avoiding the often $15 a night hotel charge for internet access sometimes demanded. Significantly, an informal survey of our ENG customers revealed that most have EVDO in their live-trucks. It provides inexpensive internet and email access for the crew.
As proponents of IFB via transport stream (a digital version of “pro channel”) the possibility of using EVDO for IFB was intriguing; so a trial seemed in order. Putting together an EVDO IFB system was simple and inexpensive. Only three items were needed; an EVDO stick, a laptop computer and a voice over internet (VoIP) module.
The preliminary test produced a “mixed bag.” On the plus side, EVDO shows value as a backup to other ways to get IFB into the field – you can never have too many backups, especially ones as inexpensive as EVDO IFB.
However, as a primary means of delivering IFB to live trucks, EVDO seems a poor choice. It is a weak alternative even to cell phones. And cell phones remain an unwise choice for IFB with their frequent drop outs and difficulty in getting a connection at major incident scenes.
Mainly, EVDO is unreliable. In areas of even moderate EVDO usage it develops problems that will drive an on-air reporter crazy. The delay (latency) can grow to more than half a second, and even worse, it varies widely from second to second. Another issue is “holes.” Because EVDO is intended for data, the carriers make no special effort to insure steady, uninterrupted transmission. A pause of a second or two in the flow of data is hardly noticeable. The same hole in IFB during a live segment could be devastating to a reporter. Finally, because EVDO is part of the cell phone infrastructure, sharing the same towers, antennas, interconnects and power, it can never be more reliable than the cellular network.
While the hardware costs for IFB EVDO are insignificant and the monthly basic charges very modest, use for more than five to ten hours a month for IFB can generate BIG overtime bills. Most EVDO contracts (Verizon and Sprint) provide 5 GB per month of data. For web surfing that is a lot of data, but for IFB audio it is less than ten hours. News operations people say that it takes one to two hours of IFB per live segment. If the 5 GB limit is exceeded, the charge can be as much as twenty-five cents per additional MB (an MB is one-thousandth of a GB or about 25 cents per 10 seconds of IFB).
There are more test results and other issues in evaluating EVDO for IFB. Modulation Sciences is preparing some more papers with those details as well as instructions on how set up your own system for doing IFB EVDO inexpensively. Check back here in a week or so for the next installment.
Tags: DTV, ENG, EVDO, IFB
Posted in DTV, ENG, EVDO, Modulation Sciences | No Comments »