Re: [Discuss-gnuradio] FCC CDR/SDR Order from a PC site

[michael taylor]

On 7/6/07, Robert McGwier <[EMAIL PROTECTED]> wrote:

Here is a PC site for the paranoid:



Thanks Bob. It looks pretty boring as far as I can tell. Here's an
excerpt of the part
about amateur radio:

   6. In regard to MSS' request for clarification about the regulatory
treatment of amateur radio equipment, the Commission did not intend to
impose any new certification requirements for amateur radio equipment
in the Cognitive Report and Order. External RF amplifiers that operate
below 144 MHz that are marketed for use with amateur stations will
continue to require certification before they can be marketed. Other
amateur radio equipment, including equipment that meets the definition
of a software defined radio and that has software that is designed or
expected to be modified by a party other than the manufacturer, will
continue to be exempt from a certification requirement. However, as the
Commission noted in the Cognitive Report and Order, certain
unauthorized modifications of amateur transmitters are unlawful. It may
revisit the issue of the certification of amateur equipment with
software modifiable features as identified above in the future if
misuse of such devices results in significant interference to
authorized spectrum users.



-Michael, VE3TIX


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Re: [Discuss-gnuradio] GNU radio: where to start?

[michael taylor]

On 12/6/06, Mario Rossi <[EMAIL PROTECTED]> wrote:

GNUradio looks very interesting, but I haven't found too much
documentation for very beginners (I'm not en engineer, and I've
problems understanding many things behind radio and frequencies).


I think of it very much as a project still (at this point in time
anyhow) mainly aimed at people who have some engineering, DSP
programming, or radio experience. I guess I'm saying it's pre-beta on
the whole. It isn't a turn-key like say Myth-TV (Linux based personal
video recorder), but more tinker / hacker level.


It looks to me a great idea! Having one single receiver useful for all
sort of signals! Instead of chasing all new standards of digital and
analogue broadcast!


That's the appeal of software defined radio, using a fairly generic
and flexible RF (radio frequency) hardware front-end, and doing all
the information theory processing (encoding / decoding, modulating /
demodulating) in software which is far cheaper / low-barrier to
change.


But it looks too good to be true, since I haven't understood whether
such a receiver exists. It looks one has to assemble it personally,
but then again I have no idea of how to do it. And would it be good
for all frequencies? What is a reasonable range for a single device?


As I suggested, it is not (in my opinion) a consumer application at
this point in time. Hardware does exist, and you can purchase it (i.e.
a USRP from Ettus Research), and a variety of daughterboards covering
common frequencies are available.

The basic USRP is good for the GNU/Radio project, the daughterboard(s)
determine what frequency range(s) you can use.

"Range"? Distance (transmitter/receiver distance)? or frequency
range?, dynamic range?

If you are looking for a software based radio receiver, I'd say
something like WinRadio (/LiNradio) or the like might be more what you
are looking for. .


Another question: the project http://drm.sourceforge.net looks to be a
subset of GNUradio, decoding only DRM.
There as well a receiver is needed. Unfortunaltely I cannot understand
whether the same sort of device is required for DRM and GNUradio. Has
anybody seen it?


the DReaM project is only software to decode an audio signal from a
shortwave broadcast(*) signal that is DRM encoded, and outputs
(typically from the speaker) the human intelligent audio content.

The DRM / DReaM software would typically use an average quality
shortwave receiver, such as the made by Grundig / Eton, Sangean, and
Kaito. US online store:
.

*) I'm only aware of DRM - Digital Radio Mondiale being used for
international shortwave broadcast transmissions. It could be used for
AM/MW I believe, but I don't know if that is being used anywhere.

I hope that clarify things a bit.


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Re: [Discuss-gnuradio] What antenna for WWV/WWVB?

[michael taylor]

On 12/7/06, Heiko Jones <[EMAIL PROTECTED]> wrote:

What is the minimum antenna(s) I would need to pull in WWV (5/10/15Mhz)
and WWVB at 60KHz with my USRP with the Basic RX daughtercard? I was
wanting to look at decoding the BCD time code.

How about if I wanted to get my local airports ATIS at 126Mhz?


Short answer: It depends.

Slightly longer version: It depends upon three main factors 1) RF
frequency 2) distance from source (signal lost based on distance), and
3) atmosphere conditions ("propagation") which is frequency dependent.

WWVB at 60KHz would normally use a loop antenna around a ferrite core,
similar to those found an AM radio. Depending on where you are (cont
US vs. Europe) a small AM loop antenna might work, or a large outside
antenna might be needed if you are in EU.

A VHF signal like 126MHz is roughly line of sight plus 5% (I think), a
1/4-wave vertical would normally work if mounted outside above a large
percentage of nearby buildings and terrain. So a 42cm (~16.5 in)
vertical antenna with a metal ground plane mounted at roof height
would likely work if you are "near" an airport.

A useful starting point is the ARRL's Technical Information Service web pages,
<http://www.arrl.org/tis/tismenu.html>. A copy of the ARRL Handbook
can also be an accessible reference for many common RF related
questions written in an accessible form (compared to standard EE / RF
engineering references), so if you plan on doing a fair bit of SDR
work I would recommend getting a recent copy.

-Michael Taylor, VE3TIX


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Re: [Discuss-gnuradio] FM Radio USB Dongles?

[michael taylor]

On 11/10/06, Johnathan Corgan <[EMAIL PROTECTED]> wrote:

On Fri, 2006-11-10 at 14:19 -0500, michael taylor wrote:

> :-) Silicon Labs makes one chipset used in some. It has a 8051
> microcontroller and a FM Tuner chip. I think all those chips output
> Left/Right audio, not I/Q.
>
> 
http://www.silabs.com/tgwWebApp/public/web_content/products/Broadcast/Radio_Tuners/en/Si4700-01.htm
>
According to the reference design (AN264), they are taking the analog
out from the Si4700, putting it through a single pole 23 KHz lowpass
analog filter, then using the 10-bit ADC on the 8051 to go back to
digital.  The samples over the USB are at 96 Ksps, 4 bytes each (two
channels.)

10-bit audio doesn't sound fantastic but there is probably room for some


The bigger limitation, in terms of flexibility, is "Worldwide FM band
support (76–108 MHz)" from their Features page of the Si470x single
chip FM receiver. I don't see the interest, it is a FM-only receiver
basically with the broadcast band (worldwide). The 96Ksps over USB is
irrelevant given the "IF" (output from the Si470x) signal is being
(lowpass) filtered at 23 KHz. You could add it to gnuradio, but it
would be for novelty's sake only, as you cannot make use of GNU
Radio's DSP features other than just with the audio output. GNU Radio
does not aim to be an audio DSP package, as far I know. There are
version of the chips available to do RDS (Eur) and RBDS (US) decoding
anyhow, so I don't even see any use there even.

That's my thoughts anyway.


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Re: [Discuss-gnuradio] FM Radio USB Dongles?

[michael taylor]

On 11/10/06, Dave hartzell <[EMAIL PROTECTED]> wrote:

I've seen a lot of these $50 devices lately and I'm wondering if they
would be compatible with GnuRadio...


No support currently. Not likely.


Anyone ever used one, and/or know how they operate?  Hopefully they're
just a front-end with a ADC that sends I/Q to the CPU for
processing


:-) Silicon Labs makes one chipset used in some. It has a 8051
microcontroller and a FM Tuner chip. I think all those chips output
Left/Right audio, not I/Q.

http://www.silabs.com/tgwWebApp/public/web_content/products/Broadcast/Radio_Tuners/en/Si4700-01.htm
http://www.silabs.com/tgwWebApp/public/web_content/products/Microcontrollers/en/USBFMRadio.htm

The Toolkit is available from Mouser for $35 USD.



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Re: [Discuss-gnuradio] to prevent damages

[michael taylor]

On 9/27/06, Brian Padalino <[EMAIL PROTECTED]> wrote:

It might not be a bad idea for Ettus Research to also stock some other
items such as SMA cables/adapters/attenuators.


Attenuators might a good idea. I think a model to match the 100mW
transmitters would be Mini-Circuits' VAT-15 (50 ohm, SMA, 1W, 15dB,
usable up to 4GHz) if I've done my loss calculations correctly
. A 9 or 6 dB for the BasicTX should be  usable
if I haven't messed up my calculations.



It might also be handy to have some nice block diagrams with max power
recommendations and recommended attentuations for cabled setups as
well as a table in the Wiki with such recommendations.


Here is what I think the calculation is:

transmit power converted to dBm (1 dBm == 1 mW) minus the attenuator
loss = output power in dBm.

E.g.
 100 mW -> 20dBm
 20dBm - 15 db att = 5 dBm
 5 dBm -> 3.2 mW

So if the receiver can handle 3.2 mW input, this would be adequate
attenuation. Off hand I don't know what is acceptable input power
range.

dBm ref: 


That might save some of the more software oriented people from burning
out their hardware without intentionally doing so.


Agreed.


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Re: [Discuss-gnuradio] BasicRX frequency selectivity

[michael taylor]

On 5/30/06, Matt Ettus <[EMAIL PROTECTED]> wrote:


The ADT1-1WT transformer from mini-circuits is in the signal path.  DC
definitely won't go through, but you will get some response down to
about 100 kHz.  You can get specs on it from them.


http://www.mini-circuits.com/ADT1-1WT-1.pdf

I assume that's the correct module.


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Re: [Discuss-gnuradio] Opinions on best choice for project...

[michael taylor]

On 2/18/06, Jovan Mostanovski <[EMAIL PROTECTED]> wrote:
> Michael, thanks for the link. I've checked that out, and I think it's a
> good idea that I get an amateur radio licence, as the frequencies that I
> require for long distance communications (~2 - 30Mhz)

Sounds good.

> that I need the main node to communicate with many client nodes. From
> what I understand, HAM protocols allow point to point communications
> only?

One common digital amateur (ham) protocol is AX.25
 which does allow broadcasts (point
to multipoint operation). There is plenty of free software available
that supports AX.25, including the Linux kernel and userland tools
.


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Re: [Discuss-gnuradio] Opinions on best choice for project...

[michael taylor]

On 2/16/06, Jovan Mostanovski <[EMAIL PROTECTED]> wrote:
> I'm doing a uni project which entails me building an RF data comms
> network. The network must facilitate communications between many nodes
> and a single main hub, node to node communications is not required. The
> nodes can be moving, may be implemented in an aeroplane, car, etc.
>
> The network must be able to operate over very long distances, past line
> of site. Therefore must use ionospheric bouncing to achieve this. Hence,
> the nodes and hub must be able to select the best frequency for
> communication. In addition to this, I must design a protocol which

If you plan to do any field testing, you may need a license. For
strictly non-commercial use (i.e. your university project) an amateur
radio license may be the best choice. I do not have any details on
licensing in Australia but most students (e.g. in US and Canada) with
some physics or engineering knowledge can study and pass an exam in a
weekend. Check with the Wireless Institute of Australia
 for details. Local amateurs (hams) may be
willing to help you, see if there is a uni amateur radio group.

I do not know of any HF frequency (bounce off the ionosphere)
license-free or license except TX/RX modules with built in modems.
Most of the devices I have seen are UHF and higher (~440MHz ISM band
in US/Canada or 1.2GHz) and low power (typically <= 100mW).

-Michael
 VE3TIX


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Re: [Discuss-gnuradio] Do I need a FCC license?

[michael taylor]

On 1/9/06, Eunsoo Seo <[EMAIL PROTECTED]> wrote:
> Hi, guys. I'm a newbie.
> I'm planning to buy some USRPs and start learning gnu radio.
>
> By the way, somebody told me that I need a license from FCC to use gnu radio.
> And he said that getting a license is not the manufacturer's duty but mine.
>
> Is this true?
> Do you guys have licenses?

The FCC requires licenses for users of "intentional radiators"
(devices designed to emit RF) in many cases (broadcast, amateur,
experimental, fixed mobile service, etc.) , unless the device has been
approved as meeting a classification of license except device (e.g.
Part 15 devices such as 802.11 wireless cards, RF garage door
openers). The device acceptance would be the responsibility of the
manufacturer.

Matt Ettus's USRP is sold as test equipment, and given the low level
(I believe 10 or 100 mW of RF is the highest emission from any of the
current daughter cards from Matt) this is not a concern IMHO without
the usage of high gain antenna or power amplification.

FCC rules


FCC Wireless Telecommunications Bureau



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Re: [Discuss-gnuradio] LW/MW/SW TiVo

[michael taylor]

On 12/19/05, cswiger <[EMAIL PROTECTED]> wrote:
> On Mon, 19 Dec 2005, Chuck Swiger wrote:
>
> > then commit them into the repository with:
> >
> > cvs -z3 -d:pserver:[EMAIL PROTECTED]:/sources/gnuradio ci
> > gnuradio-examples
> >
> >
>
> Well, of course not an anonymous commit. If I use CVSROOT:
>
>   export CVSROOT=:pserver:[EMAIL PROTECTED]:/sources/gnuradio
>
> then:
>
>   cvs -z3 co gnuradio-examples
>
> I get:
>
>   no such user cswiger in CVSROOT/passwd
>
> and same thing with:
>
>   cvs -z3 -d:pserver:[EMAIL PROTECTED]:/sources/gnuradio co \
>   gnuradio-examples

While I don't have an account on cvs.sv.gnu.org, I expect the commits
can only be done using ssh rather than pserver method.

export CVS_RSH=ssh
export CVSROOT=:ext:[EMAIL PROTECTED]:/sources/gnuradio


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Re: [Discuss-gnuradio] AM receiver

[michael taylor]

On 10/31/05, michael taylor <[EMAIL PROTECTED]> wrote:
> On 10/31/05, Gituma Nturibi <[EMAIL PROTECTED]> wrote:
> > I'm back again with a few questions about GNU radio. As I had said earlier I
> > was thinking about creating an Fm receiver. However cost and complexity
> > considerations have made me think about trying AM reception instead. Taking
> > into account I'm based in Kenya so shipping would be an issue and a budget
> > of about $120, very small!
> > The problem is that I'm on a tight time schedule and require to get the
> > project up and running soon. So I would like to know what is the best I can
> > achieve using a PC sound card or some other cheap ADC board.

Sounds like you want a SoftRock-40, unfortunately the kits are gone.
The kits were something like $28 USD.

<http://www.amqrp.org/kits/softrock40/>

QUOTE:
  The hardware downconverts and quadrature samples a 48 kHz swath of
RF that is fed to the soundcard of the computer.  Referring to the
block diagram shown below, a crystal-controlled oscillator generates a
28.224 MHz reference signal that gets buffered and divided in half
twice to produce reference clock frequencies at 14.112 MHz and 7.056
MHz.  These clocks are fed to a simple-yet-effective circuit called a
Quadrature Sampling Detector, or QSD for short, which samples the
bandpass-filtered RF signal coming in from the antenna.  As a result
of the sampling, the QSD outputs two signals at audio baseband
frequencies representing the downconverted RF signal, where the two
signals have the same frequency components but are related in
quadrature to each other, meaning they have a 90°  phase difference. 
The in-phase signal 'I', and quadrature signal 'Q' are amplified and
are then delivered as audio input to the line-in input on the PC for
processing ...

Perhaps you could build your own from the schematic. Most of the parts
are not exotic (74HC74, LT1719, OPA2228, and FST3126) and available
from sources like Digikey, Mouser, and Farnell.

Don't know if that is of any help, but maybe it is of use to you.


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Re: [Discuss-gnuradio] AM receiver

[michael taylor]

On 10/31/05, Gituma Nturibi <[EMAIL PROTECTED]> wrote:
> I'm back again with a few questions about GNU radio. As I had said earlier I
> was thinking about creating an Fm receiver. However cost and complexity
> considerations have made me think about trying AM reception instead. Taking
> into account I'm based in Kenya so shipping would be an issue and a budget
> of about $120, very small!
> The problem is that I'm on a tight time schedule and require to get the
> project up and running soon. So I would like to know what is the best I can
> achieve using a PC sound card or some other cheap ADC board.
>
> I would also like to know where I can find the code for AM reception
> particularly the MW band.
>
> I'm also looking for information on FM tuner cards- Is there a way to tap
> the IF from the card and use it as a front end? I would appreciate input on

I think using a FM tuner card is overkill, you are better off going to
a "Dollar Store" or "Pound shop" (a place that sells low-quality cheap
items, often manufacted in China) and buying a cheap battery powered
radio there to modify so you can tap the IF of the radio with no
worries about ruining an expensive tuner card.

If you have access to a modest source of electronic parts, two easy to
build radios designs are:
 
  (no longer available
as a kit from AmQRP)


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Re: [Discuss-gnuradio] N1Bt software board and front end design

[michael taylor]

On 10/22/05, Gituma Nturibi <[EMAIL PROTECTED]> wrote:
> Greetings  to all GNU radio enthusiasts. I'm an electronics and computer
> engineering student currently undertaking a sofware radio project for my
> final year. I would like to receive broadcast FM but the task seems to be
> quite daunting as I don't have the resources to use the USRP or the PCI card
> for reception. Is there anybody out there who has created an FM or even AM
> front end from components? I would really like to get some info on that.

Well people have been building stand-alone superhet radios for years,
but I assume you mean for GNU Radio. No, you will need some hardware
beyond a stereo sound card for the reasons Eric mentioned (i.e.
bandwidth of wide band FM is greater than the ADC of a sound card).

You could build a single or dual stage superheterodyne VHF receiver
with an IF output low enough (say 1 or 10 MHz) that you could with a
USRP and BasicRX, or your could just use the USRP + TVRX for broadcast
FM directly. You could also build a RF Front end (e.g. superhet down
conversion) and a David Carr's SSRP .

I assume that for a final year electronics engineering student
building a superhet radio is not too hard.

Chuck has a stereo FM application for GNU Radio at
.

> I would also like to find out more information on the N1BT software radio

Sorry, I am not familiar with this.


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Re: [Discuss-gnuradio] USRP connectors

[michael taylor]

Note: added discuss-gnuradio to cc:

On 10/10/05, Robitaille, Michael <[EMAIL PROTECTED]> wrote:
> These don't look like to connectors on my USRP.

Doh! Sorry, I leave the daughterboards plugged into my USRP so when
you asked I looked at it saw the header pins off the daughterboards.

See "Mechanical" section of .


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Re: [Discuss-gnuradio] USRP connectors

[michael taylor]

On 10/7/05, Robitaille, Michael <[EMAIL PROTECTED]> wrote:
>
> Can someone let me know what the part number and manufacturer for the
> connectors that connect to the USRP are.  I am guessing that it's a female
> connector since those on the USRP look like male connectors.  Also, where
> can I bye them.

I believe they are .1" (inch) headers, and you can buy the female
headers from any electronics distributors, such as Digikey, Mouser,
Newark, Farrell, and RS Components.

E.g. Sullins .1" Dual Row Female Headers PPTC052LFBN (10 pins),
PPTC082LFBN (16 pins), and PPTC102LFBN (20 pins).

The other common manufactor of such connections is Molex.


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Re: [Discuss-gnuradio] Libalsa2-devel

[michael taylor]

On 8/18/05, Eric Blossom <[EMAIL PROTECTED]> wrote:
> > for other Linux systems we have to use LIBASOUND2-DEV? I cannot find
> > Libalsa2-devel for Fedora 3
> 
> I don't know about alsa package naming on FC3.  Any FC users out there???

rpm -q alsa-lib
alsa-lib-1.0.6-8.FC3

rpm -q alsa-lib-devel
alsa-lib-devel-1.0.6-8.FC3


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Re: [Discuss-gnuradio] linux soundcard modem

[michael taylor]

On 5/23/05, Jaap Stolk <[EMAIL PROTECTED]> wrote:
> and a mobile phone (without IR or connector). I would like to use
> the sound card as a modem (using acoustic coupling). 300 Baud is ok,
 
> Does anyone know about any win-modem-like source code that can be
> used for this kind of thing, or should i just write something from
> the ground up using some FFT code? i figured that i don't need to

> a Linux laptop just isn't complete without at least some way to
> stay it touch with the rest of the world. This could even work

Tom Sailor's Multiplatform Soundcard Packet Radio Modem


It is not plug and play, and some people have no sucess with it, but
you might want to experiment with it. Read the documentation, and ask
questions on the linux-hams mailing list[1].

Good luck

[1] 


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