Daughterboard

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
daughterboard?

Thanks,
Brook

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On Thu, Mar 4, 2010 at 12:48 PM, Brook L. [email protected] wrote:

Brook

As my dad used to say, “You can do whatever you want as long as you
are willing to face the consequences”. So go nuts.

If you aren’t interested in FCC fines, then yes, you have to abide by
FCC rules, with the RFX900 you can transmit safely in the ISM band.
And others as long as you are below the transmit power thresholds
(which are quite low).

To find out the rules about where you can and can’t transmit you
should check http://www.fcc.gov/oet/spectrum/ specifically, check the
“Frequency Allocation Table”.

Jason

On Thu, Mar 4, 2010 at 10:48, Brook L. [email protected] wrote:

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
daughterboard?

You are responsible for complying with any and all FCC rules regarding
intentional transmitters. The USRP is not FCC type-accepted and does
not come with any pre-authorized licenses on any frequency bands.

One recommendation is to obtain an amateur radio license, which would
allow transmission with the RFX900 in the 902-928 MHz band in the US
within the rules and requirements of the amateur radio service. This
does not address the cellular bands you were asking about.

Many people, of course, ignore the above and assume that at a few
milliwatts transmit power in an indoor environment, nobody will notice
or care.

Johnathan

On Thu, Mar 4, 2010 at 11:24, Jason U. [email protected] wrote:

…with the RFX900 you can transmit safely in the ISM band.
And others as long as you are below the transmit power thresholds
(which are quite low).

I (perhaps mistakenly) thought that in order to be in compliance with
FCC rules to intentionally transmit within ISM bands using low power,
the transmitter needed to be “pre-approved” by having an FCC type
acceptance certification. I’ll will be happy to be found wrong on
this count, as it has been a long time since I’ve studied the
regulations. Even so, this doesn’t address the original poster’s
question about cellular bands.

Johnathan

On Thu, Mar 4, 2010 at 1:40 PM, Johnathan C.
[email protected] wrote:

this count, as it has been a long time since I’ve studied the
regulations. Even so, this doesn’t address the original poster’s
question about cellular bands.

Johnathan

You are right, unless your device is pre-approved by the FCC you can’t
legally transmit in unlicensed bands.

I was under the impression that the USRPs status as ‘test equipment’
allowed transmission in unlicensed bands (like the ISM) without
needing the part 15 approval as long as it was below a certain
effective radiated power level, as if a user were developing a new
product prior to part15 certification. That may not be true.

Jason

On Thu, Mar 4, 2010 at 12:15, Jason U. [email protected] wrote:

You are right, unless your device is pre-approved by the FCC you can’t
legally transmit in unlicensed bands.

I was under the impression that the USRPs status as ‘test equipment’
allowed transmission in unlicensed bands (like the ISM) without
needing the part 15 approval as long as it was below a certain
effective radiated power level, as if a user were developing a new
product prior to part15 certification. That may not be true.

And I thought the USRP’s status as “test equipment” is just what
allowed them to be sold without type acceptance. This is similar to a
signal generator, which could transmit on a wide variety of
frequencies just by putting an antenna on the output.

Anyway, enough speculation; I don’t wish to steer anyone wrong, I am
not a lawyer, and clearly I don’t speak for Ettus R…
Government imposed rules are often unintuitive, arbitrary and subject
to case-by-case interpretation, so I’ll let Matt address the question
if he chooses.

Johnathan

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
daughterboard?

When the OpenBTS folks transmit in the cellphone bands, such as at
Burning Man last year, they get an STA (Special Temporary
Authorization) from the FCC. They also get permission from the chief
engineer of one of the incumbent cellular licensees in the area, to
avoid interference with already-licensed traffic.

I don’t recommend proceeding without those precautions.

I believe no license is needed to do bench testing with a dummy load
that doesn’t radiate beyond the tabletop. Merely opening the metal
cover of your PC probably causes more electromagnetic radiation than
that.

John

To echo what John sent. There are provisions to do testing and very
limited radiation from “intentional radiators”. You can see them
outlined in Part 15 of the FCC Rules and Regulations…

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=0df10ae68df3af4194db436740229487&rgn=div5&view=text&node=47:1.0.1.1.14&idno=47

Depending on the frequency/band you are going to use, there are levels
that you can operate under. Typically, levels are rated in how many
microvolts per meter that is induced on an antenna that is X number of
meters away from the radiating device.

If you just want to test a product, it is better to bench test it using
a closed system with coax and attenuators to simulate free space loss.
This way you can be assure you are not leaking out RF energy that could
be causing interference, you can be assured that you are testing with
known RF levels to confirm receiver sensitivity and transmitter power
levels and you are shielded from outside interferences that could affect
your testing.

If you need to test in free space, depending on the band you are using,
you may be under Part 15 rules to produce very low levels of RF.
Anything beyond that would require, as John said, an Special Temporary
Authorization for an experimental license. You can see some details at:

http://www.fcc.gov/oet/faqs/elbfaqs.html
http://www.fcc.gov/oet/info/filing/elb/

If you are going to be operating on a frequency that is already in use,
you will need to coordinate with that license holder and get permission
to use it. You will need to demonstrate this to the FCC when applying
for your STA. This is one of the reasons why the OpenBTS picked Black
Rock and Burning Man to test. It gave them a rather isolated area with
that would be easier to coordinate with and a population to test with.

A brilliant move if I may say so.

If you want to get an STA, I suggest you work with a telecom attorney
that has some experience in this area as it will speed the process up
considerably. The OpenBTS folks may be able to help. I can point you
at lawyers in this area if you like.

Tim

on 3/4/10 3:28 PM John G. said the following:

avoid interference with already-licensed traffic.

I don’t recommend proceeding without those precautions.

I believe no license is needed to do bench testing with a dummy load
that doesn’t radiate beyond the tabletop. Merely opening the metal
cover of your PC probably causes more electromagnetic radiation than
that.

John


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Just to kick in our experience at Virginia Tech, we have several STA’s
because we do a lot of wireless work. I believe this link will take you
to our license:

https://fjallfoss.fcc.gov/oetcf/els/reports/ViewGrant.cfm?id_file_num=0013-EX-ST-2010&application_seq=43699

The process is not as bad as I had originally thought coming into all of
this. In fact, we used to have a graduate student fill out the online
forms and manage them. You do need to provide the FCC with a
significant amount of info, some of which is a little hard to do when
working on numerous completely different software radio applications
with varying waveforms and frequencies. The important items are
obviously location, radiated power and frequency.

We just assume if it’s going over the air we’ll need a license, although
like Tim mentioned earlier, it’s certainly possible to stay under the
Part 15 limits.

Tim

There are two things that tend to get conflated here. One is the
ability to market and sell products like the USRP and the other is the
ability to operate it.

Items that radiate and are marketed and sold in the US, typically are
subject to certification. Test equipment is subject to certification.
Test equipment is tested with dummy loads in the expectation that it
will be used in a lab environment. It is not expected that the user
will intentionally and willfully radiate beyond Part 15 levels by
putting an antenna on it.

Tim

on 3/4/10 12:30 PM Johnathan C. said the following:

Johnathan


Discuss-gnuradio mailing list
[email protected]
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Brook L. wrote:

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” (§97.1). 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.

Regards,

Kelly (AB9RF)

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