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Today's Topics:
1. Re: 12V to 6V Converter for USRP Supply (HHH)
2. Re: questions about the antenna LP0965 (gang li)
3. Re: questions about the antenna LP0965 (Qifanski)
4. start_of_burst=true missing in timed receive bursts
(John Buetefuer)
5. Re: 12V to 6V Converter for USRP Supply (Radio User)
6. Re: 12V to 6V Converter for USRP Supply (Jeff Lambert)
7. Re: 12V to 6V Converter for USRP Supply (Marcus D. Leech)
8. Regarding noise power calculation using SBX board
(senthil murugan)
9. Re: USRP Matlab Target Installer not working (Jayanta Datta)
10. Whitch are the ports used by the usrp2 for sending and
receiving data? (Julio Hector Aguilar Renteria)
----------------------------------------------------------------------
Message: 1
Date: Mon, 18 Feb 2013 01:48:59 +0800
From: HHH <[email protected]>
To: Radio User <[email protected]>
Cc: [email protected]
Subject: Re: [USRP-users] 12V to 6V Converter for USRP Supply
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
Would just find an adjustable regulator from ebay cost only several USD
more cost effective?
On 17/2/2013 8:07, Radio User wrote:
> I use my USRP in the field with a deep cycle marine battery.
> All the other equipment runs at 12V DC, and until now I've
> had to plug the USRP's wall wart into a small 120V AC inverter.
> I've been looking for a DC to DC converter to replace the wall wart,
> and found one recently.
>
> Vicor/PICOR makes a switching regulator and an evaluation board
> that provides a pretty reasonable 12V to 6V DC to DC converter
> that can supply up to 10A to the load. (see
> http://cdn.vicorpower.com/documents/datasheets/Picor/ds_pi33xx.pdf )
>
> The PI3302-00-EVAL1 is available for $50.51 from Digikey, and
> may be available elsewhere for less.
>
> The standard configuration of the P13302-00-EVAL1 produces
> 5V at the output. By putting a 4700 ohm resistor in the RADJ2
> position (between the ADJ pin and the SGND pin) the output
> changes to 6V. Regulation appears to be good, and I've been
> testing this for about a week.
>
> I added the optional input decoupling (about 80uF) on the
> 12V line to provide a little more input stability. The spec for
> the device says that it will maintain regulation down to 11V
> input at no load, and may work at lower inputs provided
> sufficient load on the output.
>
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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Message: 2
Date: Sun, 17 Feb 2013 16:04:53 -0500
From: gang li <[email protected]>
To: Qifanski <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] questions about the antenna LP0965
Message-ID:
<cakro2l00rfwa3oqnfcaf7nc36rx5jztb-eaudksuuutvia0...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I asked Kent. He said the beamwidth in the horiz plane is about 120
degrees, 160 deg in the Vertical. I hope that helps.
On Sat, Feb 16, 2013 at 8:10 PM, Qifanski <[email protected]> wrote:
> I'm also interested in knowing the the datasets about the directionality of
> this antenna.
> Where can I get it?
>
> Thanks,
> Qifan
>
>
> On Wed, Feb 13, 2013 at 11:07 AM, Matt Ettus <[email protected]> wrote:
>>
>>
>> The datasheet for that antenna is here:
>>
>> http://www.wa5vjb.com/pcb-pdfs/LP8565.pdf
>>
>> If you need further info on it, Kent would be the people to ask.
>>
>> Matt
>>
>>
>> On Wed, Feb 6, 2013 at 7:38 PM, gang li <[email protected]> wrote:
>>>
>>> Hi, guys,
>>>
>>> I have some questions about the antenna LP0965 purchased fromEttus. I
>>> know it is made by Kent Electronics. Should i contact Kent or
>>> justEttus? Thanks.
>>>
>>> Best,
>>> Gang
>>>
>>> _______________________________________________
>>> USRP-users mailing list
>>> [email protected]
>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>>
>>
>> _______________________________________________
>> USRP-users mailing list
>> [email protected]
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>
------------------------------
Message: 3
Date: Sun, 17 Feb 2013 13:12:13 -0800
From: Qifanski <[email protected]>
To: gang li <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] questions about the antenna LP0965
Message-ID:
<CAPVg14Z=TOnS_7ah01L61VCuXNk8iSpYY0=ih7px2vf4rwb...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Thanks , this helps!
Qifan
On Sun, Feb 17, 2013 at 1:04 PM, gang li <[email protected]> wrote:
> I asked Kent. He said the beamwidth in the horiz plane is about 120
> degrees, 160 deg in the Vertical. I hope that helps.
>
>
> On Sat, Feb 16, 2013 at 8:10 PM, Qifanski <[email protected]> wrote:
> > I'm also interested in knowing the the datasets about the directionality
> of
> > this antenna.
> > Where can I get it?
> >
> > Thanks,
> > Qifan
> >
> >
> > On Wed, Feb 13, 2013 at 11:07 AM, Matt Ettus <[email protected]> wrote:
> >>
> >>
> >> The datasheet for that antenna is here:
> >>
> >> http://www.wa5vjb.com/pcb-pdfs/LP8565.pdf
> >>
> >> If you need further info on it, Kent would be the people to ask.
> >>
> >> Matt
> >>
> >>
> >> On Wed, Feb 6, 2013 at 7:38 PM, gang li <[email protected]> wrote:
> >>>
> >>> Hi, guys,
> >>>
> >>> I have some questions about the antenna LP0965 purchased fromEttus. I
> >>> know it is made by Kent Electronics. Should i contact Kent or
> >>> justEttus? Thanks.
> >>>
> >>> Best,
> >>> Gang
> >>>
> >>> _______________________________________________
> >>> USRP-users mailing list
> >>> [email protected]
> >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> >>
> >>
> >>
> >> _______________________________________________
> >> USRP-users mailing list
> >> [email protected]
> >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> >>
> >
>
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Message: 4
Date: Mon, 18 Feb 2013 11:30:38 +1030
From: John Buetefuer <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [USRP-users] start_of_burst=true missing in timed receive
bursts
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
I'm using timed receive bursts in an application and have noticed that
start_of_burst is not being set to true in the receive metadata
(rx_metadata_t) returned in the first recv() call on the stream.
end_of_burst=true is being set in the last 'packet' of received samples
- and thus I do have a work-around - ie, the first batch of samples
received /after/ the end_of_burst=true must be the start_of_burst for
the next timed receive command. It would be nice if start_of_burst was
set however
Just wondering if anyone else has seen this, or if it has been fixed
recently?
Using UHD version UHD_003.004.003-1-g64d15538
Cheers
John
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Message: 5
Date: Sun, 17 Feb 2013 20:16:37 -0500
From: Radio User <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] 12V to 6V Converter for USRP Supply
Message-ID:
<ca+rmjif_5cihq4z9wiudtn4oq8alzsacans5m5_jbpvepox...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
HHH wrote:
> Would just find an adjustable regulator from ebay cost only several USD
more cost effective?
Good question. Answer: Not likely.
The regulators I've seen on eBay are all based either on the LM317 or the
LT1764.
These are linear regulators.
1. The LM317 is good to about 1.5A with careful attention to thermal
engineering.
(This includes fiddly stuff like the kind of thermal compound, careful
application,
the right surface finish on the heat sink, and the right fasteners and
torque.
You'll no doubt find folks who say "it works fine for me, and I use
discarded
bandaids and paperclips to hold it to the heat sink." Good for them.)
2. The specified drain for the N200 and WBX together is about 2.6 amps.
That's
3 in round numbers. 3 > 1.5.
3. The LT1764 is a little beefier, but the thermal challenge remains. Max
spec'd
output current is 3A. Too close to the requirement for my tastes. The
low drop out is a nice feature (and the compelling one if your real problem
is
a battery voltage that is close to the output requirement). But it is still
a
linear regulator.
4. Linear regulators have three major problems in this application
I) Given a 12V input and a 6V output at (let's say) 2.5A, we'll
dissipate
6*2.5 = 15W in the series pass device (the regulator package). In
still
air (no fan) with a really good contact to the heat sink, that's
going to produce
a temperature rise at the heat sink surface of T = 5000 deg C / S
where S is the
exposed surface area of the heat sink in square centimeters.
(Source --
Reference Data for Radio Engineers converted from the constant 55
deg C per watt per in^2.)
The sample I looked at seems to have about 40 cm^2 of heat sink
(charitable)
so the still air temp rise at 2.5A is going to be about 125C. So
this solution
requires a fan, where the temp rise is much much smaller than 5K
C/W/cm^2.
(And if you think I'm being conservative, note that real models can
predict
substantially higher temp rises for this load and heat sink. 5K deg
C/cm^2
may be quite optimistic...)
I don't want a fan.
II) At 2.5A a linear will waste one watt for every watt delivered to
the radio. That's additional
drain on the batteries. Compare this to the switcher efficiency at
90 to 95% where
a switcher will waste 100mW or less for each watt to the radio.
III) Linear regulators tend to produce lots of broadband noise,
especially when
you push them. The decoupling on these supplies is not adequate for
a radio
application. Assuming all the other problems could be addressed,
careful users
will want to add significant decoupling/bypass caps to the output
of any linear
regulator. A bazillion uF cap is not sufficient, it ceases to
behave as a capacitor
well below frequencies of interest. And most cheap power supply
manufacturers aren't using the highest quality caps in any case.
So, yes there are inexpensive linear regulator solutions here. They require
moving air past them to stay within thermal limits, they are running close
to (or over)
their capacity, they may produce broadband noise that needs to be knocked
down,
and they are only 50% efficient on a good day.
Given the cost of a USRP, saving $30 or even $50 by buying a cheap power
supply
seems like a false economy.
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Message: 6
Date: Sun, 17 Feb 2013 19:31:46 -0600
From: Jeff Lambert <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] 12V to 6V Converter for USRP Supply
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
You could reduce the dissipation by using some zener diodes to drop the
voltage before the regulators. And you can parallel regulators to
provide higher output. At the end of the day, a linear regulator is
likely to be less noisy than a switch-based DC to DC converter. More
expensive does not mean better performance. There is already a linear
regulator on the board, so you really don't need the best power supply
anyway, unless for some reason you need better noise performance than it
already offers.
-Jeff
On 13/02/17 19:16, Radio User wrote:
> HHH wrote:
>
> > Would just find an adjustable regulator from ebay cost only several
> USD more cost effective?
>
> Good question. Answer: Not likely.
>
> The regulators I've seen on eBay are all based either on the LM317 or
> the LT1764.
> These are linear regulators.
>
> 1. The LM317 is good to about 1.5A with careful attention to thermal
> engineering.
> (This includes fiddly stuff like the kind of thermal compound, careful
> application,
> the right surface finish on the heat sink, and the right fasteners and
> torque.
> You'll no doubt find folks who say "it works fine for me, and I use
> discarded
> bandaids and paperclips to hold it to the heat sink." Good for them.)
>
> 2. The specified drain for the N200 and WBX together is about 2.6
> amps. That's
> 3 in round numbers. 3 > 1.5.
>
> 3. The LT1764 is a little beefier, but the thermal challenge remains.
> Max spec'd
> output current is 3A. Too close to the requirement for my tastes. The
> low drop out is a nice feature (and the compelling one if your real
> problem is
> a battery voltage that is close to the output requirement). But it is
> still a
> linear regulator.
>
> 4. Linear regulators have three major problems in this application
>
> I) Given a 12V input and a 6V output at (let's say) 2.5A, we'll
> dissipate
> 6*2.5 = 15W in the series pass device (the regulator
> package). In still
> air (no fan) with a really good contact to the heat sink,
> that's going to produce
> a temperature rise at the heat sink surface of T = 5000 deg C
> / S where S is the
> exposed surface area of the heat sink in square centimeters.
> (Source --
> Reference Data for Radio Engineers converted from the constant
> 55 deg C per watt per in^2.)
> The sample I looked at seems to have about 40 cm^2 of heat
> sink (charitable)
> so the still air temp rise at 2.5A is going to be about 125C.
> So this solution
> requires a fan, where the temp rise is much much smaller than
> 5K C/W/cm^2.
> (And if you think I'm being conservative, note that real
> models can predict
> substantially higher temp rises for this load and heat sink.
> 5K deg C/cm^2
> may be quite optimistic...)
>
> I don't want a fan.
>
> II) At 2.5A a linear will waste one watt for every watt
> delivered to the radio. That's additional
> drain on the batteries. Compare this to the switcher
> efficiency at 90 to 95% where
> a switcher will waste 100mW or less for each watt to the radio.
>
> III) Linear regulators tend to produce lots of broadband noise,
> especially when
> you push them. The decoupling on these supplies is not
> adequate for a radio
> application. Assuming all the other problems could be
> addressed, careful users
> will want to add significant decoupling/bypass caps to the
> output of any linear
> regulator. A bazillion uF cap is not sufficient, it ceases to
> behave as a capacitor
> well below frequencies of interest. And most cheap power supply
> manufacturers aren't using the highest quality caps in any case.
>
> So, yes there are inexpensive linear regulator solutions here. They
> require
> moving air past them to stay within thermal limits, they are running
> close to (or over)
> their capacity, they may produce broadband noise that needs to be
> knocked down,
> and they are only 50% efficient on a good day.
>
> Given the cost of a USRP, saving $30 or even $50 by buying a cheap
> power supply
> seems like a false economy.
>
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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Message: 7
Date: Sun, 17 Feb 2013 20:46:01 -0500
From: "Marcus D. Leech" <[email protected]>
To: Jeff Lambert <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] 12V to 6V Converter for USRP Supply
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
On 02/17/2013 08:31 PM, Jeff Lambert wrote:
> You could reduce the dissipation by using some zener diodes to drop
> the voltage before the regulators. And you can parallel regulators to
> provide higher output. At the end of the day, a linear regulator is
> likely to be less noisy than a switch-based DC to DC converter. More
> expensive does not mean better performance. There is already a linear
> regulator on the board, so you really don't need the best power supply
> anyway, unless for some reason you need better noise performance than
> it already offers.
>
> -Jeff
You can only parallel linear regulators if you have fractional-ohm,
high-watt, "spreader" resistors linking them together. If you
direct-wire them,
nearly-invariably, one regulator tries to source nearly all the current.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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Message: 8
Date: Mon, 18 Feb 2013 19:03:15 +0530
From: senthil murugan <[email protected]>
To: [email protected]
Subject: [USRP-users] Regarding noise power calculation using SBX
board
Message-ID:
<CAAEL=p_bc1j-kqb3f3u1cy_iedsq0vay3mxerja68vp6der...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
hi,
I am trying to estimate noise power without injecting any signal in SBX
board with USRP N210.
1. Carrier frequency is 2.452GHz with BW of 10MHZ.
2. Gain = 0dB and using Tx/Rx port.
noise power = (sum of 64 samples of amplitude squared)/64.
I am getting around -78 dB. If I try to evaluate dBm/Hz, I am getting
-78 - 70 = -148 dB/Hz. Hence , it will be -118 dBm/Hz.
Its not matching with theoretical value of -174 dBm/Hz + 5 dB = -169 dBm/Hz.
Where am I going wrong with my calculations?
Thanks
sencen
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Message: 9
Date: Mon, 18 Feb 2013 16:35:06 +0000 (UTC)
From: Jayanta Datta <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] USRP Matlab Target Installer not working
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Mike McLernon <Mike.McLernon@...> writes:
>
> Hi Michael,
>
> Can you verify which release you are using, and which platform (Windows, Mac,
Linux)?
>
> Thanks,
> Mike
>
> -----Original Message-----
> From: USRP-users [mailto:usrp-users-bounces@...] On Behalf
> Of Michael Yan
> Sent: Friday, February 15, 2013 2:02 PM
> To: usrp-users@...
> Subject: [USRP-users] USRP Matlab Target Installer not working
>
> Hi,
>
> I am trying to install USRP radio support in MATLAB (using targetinstaller),
but am unable to do so. The
> instructions tell me to click "next" in order to open a web browser so that I
can log in to MathWorks and fill
> in a form. I do so, but I cannot click next in the installation. Is this a
bug? Is there anywhere else I can
> download the USRP support package from?
>
> Thanks
>
> _______________________________________________
> USRP-users mailing list
> USRP-users@...
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users@...
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> Hello,
Same problem here. Using matlab 2012b and usrp n210 rev 4. 'target Installer'
at
the matlab command prompt does not complete the installation. Even after
filling
the form, the 'next' button in the installation window does not appear.
Actually, I had previously installed the USRP support package successfully but
had recently re-installed MATLAB and after that looks like USRP package had not
been installed. Currently, using 'targetinstaller' the USRP support is not
getting installed. I don't know how to proceed. Please help.
Sincerely
Jayanta
------------------------------
Message: 10
Date: Mon, 18 Feb 2013 11:55:28 -0500
From: Julio Hector Aguilar Renteria <[email protected]>
To: [email protected]
Subject: [USRP-users] Whitch are the ports used by the usrp2 for
sending and receiving data?
Message-ID:
<cacbki8cdh48rulv0n2onkqt6qmhdaovowropvz4_voaw_0k...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Dear,
Hi, All
Which are the ports used by the usrp2 for sending and receiving data?
Julio H.
------------------------------
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