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Re: [Discuss-gnuradio] Daughterboard

From: Kelly Martin
Subject: Re: [Discuss-gnuradio] Daughterboard
Date: Fri, 05 Mar 2010 00:24:15 -0600
User-agent: Thunderbird (X11/20090817)

Brook Lin wrote:
Hi All,

When we use any of the USRP daughterboard to transmit, do we need the
authorization? For example, FRX900 includes the cell phone bands in US. If
we use FRX900 to transmit, do we violate the FCC rule? Or, we could legally use any daughterboard on any band that falls in the frequency range of the

There's four ways you can emit RF and remain within the scope of FCC regulations. First, you can emit RF for the purpose of communication as an FCC licensee, pursuant to the rules of the service in which your license is issued. Second, you can emit RF for the purpose of communication not as an FCC licensee, pursuant to the rules in Part 15 for intentional radiators. Third, you can emit RF not for the purpose of communication pursuant to the rules in Part 15 for incidential radiators or pursuant to the rules in part 18 for ISM equipment. Fourth, you can emit RF for any purpose pursuant to the terms of an FCC-issued Special Temporary Authorization. Any other emission of RF (within the FCC's jurisdiction of 9 kilohertz to 300 gigahertz) is illegal.

In the first case, you must comply with all requirements of the regulations pertaining to the service in which you have a license. The thing is, for most services one of the rules is that you may only use equipment which has been certificated by the FCC for use with that service; using equipment which has not been certificated for use in that service is a violation of the rules and is prohibited. Some services permit uncertificated equipment to be used in certain situations, most notably the amateur radio service. An amateur radio licensee may use just about anything he or she wants to emit RF as long as his or her emissions are consistent with the regulations in Part 97 and with "good engineering and good amateur practice" (ยง97.1). Since the USRP is not certificated for use in any service, it can only be used as an intentional emitter in a licensed service if that service permits the use of uncertificated equipment.

In the second and third cases, you must comply with the relevant requirements of Parts 15 and/or 18 for the class of unlicensed operation that applies to your situation. In many cases relevant to the USRP, neither Part 15 nor Part 18 will require certification. Generally, "kits" and one-off projects require neither certification nor a "declaration of comformity"; those requirements typically only come into play when a device that operates within the scope of these rules is to be offered for sale or distribution in commerce. The frequency, power, spurious emission, and bandwidth limitations applicable to Part 15 and Part 18 devices are complicated, and it's no mean feat to determine whether a given usage is or is not permissible; do your due diligence before you transmit at any measurable power. In the final case, of course, you can do whatever you negotiate for from the FCC. STAs are not that hard to obtain, especially if you already have a relationship with the FCC. If you're trying to develop a commercial product, you should obtain an STA to do any free space testing; you'll need to deal with the FCC anyway to get the eventual certification, and doing the STA will put the OET on notice of your product development, which might possibly facilitate the eventual certification of your device for commercial sale (or not). If you're just playing with radio out of personal interest, get an amateur radio license and use the amateur allocations, or if your particular investigation cannot be conducted on the amateur bands, use your amateur radio license as an entry to get an amateur STA. (The FCC may, in some circumstances, waive its usual fees for an application for an STA from an amateur licensee.) If your investigation or experiment is such that it can be conducted within the scope of a Part 15 intentional radiator not requiring certification, then just do it, although in that case I still recommend that you get an amateur radio license, because it will make your life slightly easier if you do find yourself dealing with the Enforcement Bureau.


Kelly (AB9RF)

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