Testing outside building with our USRPs

GNU Radio
1

Hello, all!

We are utilizing USRPs to test the transmission range under some certain
circumstances, say different modulation schemes. We are planning on
testing the range outside, say in a football field since that condition
is similar to the free space environment.

But how can we get power for USRPs when we are testing outside? Could
anybody tell me a decent way to power USRPs up without connecting the
power cable to the extension board inside the building? What kind of
batterypack can we use for the USRPs if battery is doable? Thanks a lot!

Bill

2

On Mon, Dec 1, 2008 at 4:20 PM, Bill S.
[email protected] wrote:

Hello, all!
…
But how can we get power for USRPs when we are testing outside? Could
anybody tell me a decent way to power USRPs up without connecting the power
cable to the extension board inside the building? What kind of batterypack
can we use for the USRPs if battery is doable? Thanks a lot!

a) Use sealed 6v batteries. Get a charger when you buy the batteries.
Check the mAh rating to make sure you’ll get the runtime you need.
Try to avoid using them in parallel unless you have to.

b) Use car batteries plus inverters (or even cars, inverters and a
couple long extension cables). Heavy, expensive, inefficient, but you
might have the kit already.

Regards,

Blair.
3

Heavy, expensive, inefficient, but you might have the kit already.

If you are doing fixed measurement, you should also look around the
office for some of the computer back up UPS things. They are designed
to allow a computer a short time to save and shut down, but can also
supply a low draw device several hours (we used them to power label
printers). It’s something you probably already have that you can just
‘borrow’ for your experiment.

Jason

4

Bill -

I’ve done this with a 12v deep cycle battery and a good quality 12-6
DC-DC converter. We ran off-grid for a week like that, recharging
the battery in place as needed with whatever power sources were handy.

– David

On Nov 30, 2008, at 7:20 PM, Bill S. wrote:

building? What kind of batterypack can we use for the USRPs if
battery is doable? Thanks a lot!

Bill

Discuss-gnuradio mailing list
[email protected]
Discuss-gnuradio Info Page

David A. Burgess
Kestrel Signal Processing, Inc.

5

David -

Thank you, I understand it! But how did you get your computer powered
when you were doing experiment outside? The laptops in our lab are very
limited. Thank you!

Bill

From: David B. [email protected]
To: Bill S. [email protected]
Cc: [email protected]
Sent: Monday, December 1, 2008 12:02:39 PM
Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs

Bill -

I’ve done this with a 12v deep cycle battery and a good quality 12-6
DC-DC converter. Â We ran off-grid for a week like that, recharging the
battery in place as needed with whatever power sources were handy.

– David

On Nov 30, 2008, at 7:20 PM, Bill S. wrote:

Hello, all!

We are utilizing USRPs to test the transmission range under some certain
circumstances, say different modulation schemes. We are planning on
testing the range outside, say in a football field since that condition
is similar to the free space environment.

But how can we get power for USRPs when we are testing outside? Could
anybody tell me a decent way to power USRPs up without connecting the
power cable to the extension board inside the building? What kind of
batterypack can we use for the USRPs if battery is doable? Thanks a lot!

Bill

Discuss-gnuradio mailing list
[email protected]
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio

David A. Burgess
Kestrel Signal Processing, Inc.

6

David-

Thank you for your information about the laptop power rig. But our
problem is we have to use eight USRPs as our nodes in our
experimentation, and we do not have so many laptops, so do you know how
to get 110-220 voltage input for our computers when testing outside?
Thank you!

Bill

From: David B. [email protected]
To: Bill S. [email protected]
Sent: Monday, December 1, 2008 6:59:00 PM
Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs

Bill -

I got a laptop power rig designed for automotive and air travel and then
I wired a cigarette-lighter-style socket to the battery. You can get
everything you need for that at any autoparts store.

Also remember that a lead-acid battery runs anywhere from 12-14 volts
depending on its charge state. If you charge in place, you should also
be aware that some chargers might run up to 16 volts or more in some
modes, so know your equipment before you try it. (But if you don’t need
continuous operation, you don’t need to charge in place.)

– David

On Dec 1, 2008, at 3:23 PM, Bill S. wrote:

David -

Thank you, I understand it! But how did you get your computer powered
when you were doing experiment outside? The laptops in our lab are very
limited. Thank you!

Bill

From: David B. [email protected]
To: Bill S. [email protected]
Cc: [email protected]
Sent: Monday, December 1, 2008 12:02:39 PM
Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs

Bill -

I’ve done this with a 12v deep cycle battery and a good quality 12-6
DC-DC converter. We ran off-grid for a week like that, recharging the
battery in place as needed with whatever power sources were handy.

– David

On Nov 30, 2008, at 7:20 PM, Bill S. wrote:

Hello, all!

We are utilizing USRPs to test the transmission range under some certain
circumstances, say different modulation schemes. We are planning on
testing the range outside, say in a football field since that condition
is similar to the free space environment.

But how can we get power for USRPs when we are testing outside? Could
anybody tell me a decent way to power USRPs up without connecting the
power cable to the extension board inside the building? What kind of
batterypack can we use for the USRPs if battery is doable? Thanks a lot!

Bill

Discuss-gnuradio mailing list
[email protected]
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio

David A. Burgess
Kestrel Signal Processing, Inc.

David A. Burgess
Kestrel Signal Processing, Inc.

7

From: David B. [email protected]
To: Daniel O’Connor [email protected]
Cc: Bill S. [email protected]
Sent: Tuesday, December 2, 2008 1:27:07 AM
Subject: Re: [Discuss-gnuradio] testing outside building with our USRPs

Thank you, David and Daniel! I found a very handy power system that
could be easily used for outside testing. It might be useful for other
Gnuradio fans who want to test for free space comm.

http://www.batteriesareus.com/index.php?main_page=product_info&cPath=139_25&products_id=113

Bill

True. The brute force approach is to get a few big-a RV batteries and
an inverter. We got a good deal on a 400 W inverter a couple of months
ago, $30 for a 400 W unit at Home Depot. The inverter draws at least 10
W just sitting idle, so you’ll take a hit on efficiency, but that might
not matter for your application. Put it all on a cart and roll it back
to the lab/shop/whatever every evening for recharging.

– David

On Dec 1, 2008, at 8:37 PM, Daniel O’Connor wrote:

–Daniel O’Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
“The nice thing about standards is that there
are so many of them to choose from.”
 – Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C

David A. Burgess
Kestrel Signal Processing, Inc.

8

On Tuesday 02 December 2008 13:23:49 Bill S. wrote:

Thank you for your information about the laptop power rig. But our problem
is we have to use eight USRPs as our nodes in our experimentation, and we
do not have so many laptops, so do you know how to get 110-220 voltage
input for our computers when testing outside? Thank you!

You could parallel up a few car batteries and run the PCs off an
inverter.

The power requirements are variable depending on your PCs of course :slight_smile: