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stuartbh
EVDO Fledgling
Joined: 03 Aug 2005
Posts: 15
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 Posted: Wed Nov 08, 2006 10:07 am Post subject: EVDO USB bus power report thread - Why the Y Cable? |
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EVDO Users:
A complete review of the postings here would seem to assert the conspicuously apparent fact that no one has really pondered why and in what circumstances a Y-Cable would be requisite in leveraging a U720 with different machines.
Thus, I wonder how much power the U720 draws, and with which machines this Y-Cable is requisite?
Additionally, it would be nice to gain some intelligence on what kind of power most USB ports with popular machines where such a device would have applicable usage (MacBooks, etc...) provide in terms of the provisioning of appropriate power using a single USB port to drive the U720, vice using two USB ports to do the same?
I have a PowerBook G4 with a USB port on each side, making a Y-Cable quite the inconvenient accessory!
What say you?
Stuart, N3GWG
Beverly Hills, CA
[Anyone wishing to report on SUCCESS/FAILURE when using single-port USB power for EVDO devices, feel free to chime in. Likewise for anyone using/making/modding USB 'powersum' cables for their USB EVDO device. This is the thread to discuss it. -Admin] |
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Scott
EVDO Junkie
Joined: 18 Jul 2005
Posts: 530
Location: Central Coast of California
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| Posted: Wed Nov 08, 2006 11:14 am Post subject: |
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That subject has been discussed in the Franklin CDU-550 thread(s). The same information would be applicable to the Novatel Ovation U720.
This thread could serve as the "USB bus power report thread" if you're so inclined.
The challenge is efficiency: 1xRTT/EVDO radio transmitters/receivers need some current to do their job (especially the transmitting). 5V/500mA presents some challenges.
USB port DC voltage and current availability ranges between all the different notebook models and manufactures, hence the USB power-tap cables (yes... even though there is supposed to be a standard - 500mA).
For instance: I have a 12" Powerbook that will spin up an external notebook hard drive allowing access. Plug the same drive into my 15" Powerbook and it won't spin up.  Odd. Use a power-tap cable to sum power from another USB port and it works fine.
Similar thing on many PC notebooks: an old NEC notebook here in the office has USB ports that don't have the needed current to run the drive, so I have to use USB or PS/2 power-taps. Not a slick solution. A new Sony VAIO has plenty.
While the little Franklin works fine with most notebooks, there are a few that have weak bus power requiring the power-tap. In some cases we have experienced better TX rates when using the power-tap: more power for the transmitter (typically the bigger challenge in the 1xRTT/EVDO game).
I suppose Apple users can dream a little dream and hope for a Firewire EVDO radio. 12v/1.25A is plenty of power to do the job right, yet somehow I don't think we'll see a Firewire EVDO device anytime soon. |
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Michael
Site Admin
Joined: 13 Jan 2005
Posts: 5086
Location: Cary, IL
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| Posted: Wed Nov 08, 2006 12:50 pm Post subject: |
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The other big advantage of using the USB cable, is that you can increase your signal. By getting the "modem" at least 6 inches aways from the RF noise of the computer can have a pretty impressive increase in signal.
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Scott
EVDO Junkie
Joined: 18 Jul 2005
Posts: 530
Location: Central Coast of California
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| Posted: Wed Nov 08, 2006 1:22 pm Post subject: |
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Very true^.
Here's an interesting one: I spoke with a customer up in Connecticut who had both a MacBook Pro and MacBook and the Franklin CDU-550 EVDO modem.
Plug the Franklin CDU-550 directly into the MacBook: he sees green LED indicating good signal.
Pull out the CDU-550 and plug it into a MacBook Pro two feet away: he sees only the red LED flashing, indicating low signal.
Walk around the room with either notebook and the MacBook continues to display stronger signal. Its either voltage/current on the USB bus and/or system RFI/EMI effecting signal.
The splitter cable addresses BOTH issues: increases power and provides some physical distance from a computer's RFI/EMI noise output.
But alas, neither the power-tap cables that ship with the Franklin CDU-550 nor the Novatel U720 have type A plugs with long enough wires to accommodate the USB port separation on 15" or 17" Powerbooks or MacBook Pros. Trivial to modify one leg for the longer jump, but still a PITA for most folks (and an oversight by the manufacturers... HEY SPRINT/NOVATEL/FRANKLIN... ARE YOU READING THIS!?). |
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stuartbh
EVDO Fledgling
Joined: 03 Aug 2005
Posts: 15
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| Posted: Wed Nov 08, 2006 2:26 pm Post subject: EVDO USB Device bus power report thread |
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| Scott wrote: | That subject has been discussed in the Franklin CDU-550 thread(s). The same information would be applicable to the Novatel Ovation U720.
This thread could serve as the "USB bus power report thread" if you're so inclined.
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I was unaware of this, though, I would be perfectly happy to have this change asserted accross the entirety of this thread, making the new subject "EVDO USB bus power report thread".
| Scott wrote: |
The challenge is efficiency: 1xRTT/EVDO radio transmitters/receivers need some current to do their job (especially the transmitting). 5V/500mA presents some challenges.
USB port DC voltage and current availability ranges between all the different notebook models and manufactures, hence the USB power-tap cables (yes... even though there is supposed to be a standard - 500mA).
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Well yes, however, I would wonder if it would be possible to have a cable that pulls power from a FW 400 or FW 800 port, and then provides a USB power only connector on the other end (female?) to take power from the Firewire port on the same side of the laptop (if unused) vice running USB cables all the way around the laptop.
| Scott wrote: |
For instance: I have a 12" Powerbook that will spin up an external notebook hard drive allowing access. Plug the same drive into my 15" Powerbook and it won't spin up. Odd. Use a power-tap cable to sum power from another USB port and it works fine.
Similar thing on many PC notebooks: an old NEC notebook here in the office has USB ports that don't have the needed current to run the drive, so I have to use USB or PS/2 power-taps. Not a slick solution. A new Sony VAIO has plenty.
While the little Franklin works fine with most notebooks, there are a few that have weak bus power requiring the power-tap. In some cases we have experienced better TX rates when using the power-tap: more power for the transmitter (typically the bigger challenge in the 1xRTT/EVDO game).
I suppose Apple users can dream a little dream and hope for a Firewire EVDO radio. 12v/1.25A is plenty of power to do the job right, yet somehow I don't think we'll see a Firewire EVDO device anytime soon. |
In terms of a Firewire EVDO radio, I doubt this is a viable or even desirable choice, given only one or two Firewire ports on a Mac laptop notwithstanding the lack of implementation of Firewire ports (with power even) on most other laptops.
However, the ability to draw power (as I indicated herein above) from unused Firewire ports within proximate distance of a single USB port certainly would be assistant to this cause.
As an aside to all this, I am considering to build a small router (using a Linux openbrick based PC) to provide routing/firewall services to me, since additionally it can route AX.25, and provide packet services (with the sound card) as well but this would not be a portable solution obviously, more for my home Amateur/Ham station.
Very Respectfully submitted,
Stuart, N3GWG
Beverly Hills, California |
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Chuck
EVDO Heavy User
Joined: 21 Mar 2005
Posts: 149
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| Posted: Wed Nov 08, 2006 7:56 pm Post subject: |
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| Scott wrote: |
But alas, neither the power-tap cables that ship with the Franklin CDU-550 nor the Novatel U720 have type A plugs with long enough wires to accommodate the USB port separation on 15" or 17" Powerbooks or MacBook Pros. Trivial to modify one leg for the longer jump, but still a PITA for most folks (and an oversight by the manufacturers... HEY SPRINT/NOVATEL/FRANKLIN... ARE YOU READING THIS!?). |
If they wanted to be "nice" they could have included a built in retractable USB cable to accomodiate for every possible USB location.
Even if they included one of these:
http://www.jr.com/JRProductPage.process?Product_Id=4106990&JRSource=googlebase.datafeed.CBU+ZIPUSB2-CO2
It would have been a nice. |
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southbound747
EVDO User
Joined: 24 Jul 2006
Posts: 85
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| Posted: Thu Nov 09, 2006 2:20 am Post subject: good idea |
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| Chuck wrote: | | Scott wrote: |
But alas, neither the power-tap cables that ship with the Franklin CDU-550 nor the Novatel U720 have type A plugs with long enough wires to accommodate the USB port separation on 15" or 17" Powerbooks or MacBook Pros. Trivial to modify one leg for the longer jump, but still a PITA for most folks (and an oversight by the manufacturers... HEY SPRINT/NOVATEL/FRANKLIN... ARE YOU READING THIS!?). |
If they wanted to be "nice" they could have included a built in retractable USB cable to accomodiate for every possible USB location.
Even if they included one of these:
http://www.jr.com/JRProductPage.process?Product_Id=4106990&JRSource=googlebase.datafeed.CBU+ZIPUSB2-CO2
It would have been a nice. |
That seems like a a nice cable for the money, but the S & H is more than the cost of the unit! But you are absolutely right that they should have included it. This site (evdoinfo.com) should sell it $5.00 and include it with an order for no additional shipping. Now since we are talking about power draw, anybody know about the Sony UX micro PC power draw from the one usb port it has?
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Chuck
EVDO Heavy User
Joined: 21 Mar 2005
Posts: 149
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| Posted: Thu Nov 09, 2006 3:19 pm Post subject: |
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I posted pics here of a ux180 running with the USB EVDO modem witohut the splitter and the screen showing a boradband speed test. So I would think any of the UX series should be fine.
I was looking at the Fuji p1501D along at the UX280 at Microcenter today... there isn't a lot of size difference between the two when you consider the subnote Fuji is a lot thiner and the UX280 has just a bit less length and height.
Hard choice, but the CF card in the Fuji looks nice. |
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southbound747
EVDO User
Joined: 24 Jul 2006
Posts: 85
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| Posted: Thu Nov 09, 2006 10:36 pm Post subject: David Ciccone? |
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If you mean you posted a pic of a UX 180 that you lifted from David Ciccone's website, Mobility Today, no thanks. He is a shill for whoever sponsors his blogs. I'd rather have some 3rd party truly independnet verfication. I want a real user's experience. I am looking for a user here who has a UX themself and have done their tests and measurements.
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Scott
EVDO Junkie
Joined: 18 Jul 2005
Posts: 530
Location: Central Coast of California
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| Posted: Thu Nov 09, 2006 10:52 pm Post subject: Re: EVDO USB Device bus power report thread |
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| stuartbh wrote: | | I would be perfectly happy to have this change asserted accross the entirety of this thread, making the new subject "EVDO USB bus power report thread". |
Done. |
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Scott
EVDO Junkie
Joined: 18 Jul 2005
Posts: 530
Location: Central Coast of California
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| Posted: Thu Nov 09, 2006 11:05 pm Post subject: Re: good idea |
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| southbound747 wrote: | | This site (evdoinfo.com) should sell it $5.00 and include it with an order for no additional shipping. |
We hear ya. We're looking into solutions (for powersum cables). |
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jackrodgers
EVDO Addict
Joined: 23 Mar 2006
Posts: 1131
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| Posted: Fri Nov 10, 2006 5:03 am Post subject: Re: good idea |
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| Scott wrote: | | southbound747 wrote: | | This site (evdoinfo.com) should sell it $5.00 and include it with an order for no additional shipping. |
We hear ya. We're looking into solutions. |
Apple has in the past supplied a USB extension cable with a Powerbook. I still have one. You can also buy extension cables at your local superstore. |
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Scott
EVDO Junkie
Joined: 18 Jul 2005
Posts: 530
Location: Central Coast of California
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| Posted: Fri Nov 10, 2006 9:58 am Post subject: |
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I was actually referring more to a powersum USB extension above.
We're aware that the some USB ports are too close to other ports making it hard to directly plug in EVDO USB radios like the Franklin CDU-550 or Ovation U720 due to lack of space. So an extender makes sense.
The USB extender linked above ^ would make a poor choice though. Those use very small gauge cable to allow winding, which results in DC current loss. This would starve a USB EVDO radio lowering receive/transmit power and due to the cables length and lack of shielding, may needlessly pick up RFI/EMI as well.
I have a couple of the Apple USB extenders and some other cheapo models that came with various USB devices. Some of these of use tiny unshielded or poorly shielded cable, not the best choice. The Apple model has nicely shielded cable at least. |
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Scott
EVDO Junkie
Joined: 18 Jul 2005
Posts: 530
Location: Central Coast of California
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| Posted: Tue Dec 05, 2006 4:01 pm Post subject: |
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From page 12 of the new Sprint Ovation U720 Quick Start Guide:
| Quote: | Note:An external USB Y-shaped extension cable is included for your convenience. The external USB Y-shaped cable is not required for use but is recommended for increased performance. The cable allows you to use two USB ports to provide the device with up to 1mA of power when needed. The Y-shaped cable should be needed only in fringe coverage areas. In addition to the increased power, the RF interference issues may be reduced because the cable allows for the device to be used up to 3' from your computer. Your computer creates RF interference that affects the signal. You can improve the performance of the device by using the USB extension cable and moving the device away from the computer.
To use the USB cable:
1. Plug the single end of the Y-shaped cable into the Sprint Mobile Broadband USB Modem.
2. Plug the two connected ends of the Y-shaped cable into two separate USB ports on your PC.
3. The device is powered as soon as the USB cable is connected to the appropriate USB ports. (The LED indicator on the device will turn green.)
4. Launch Sprint PCS Connection Manager and click Connect. |
With regard to "...provide the device with up to 1mA of power...", they likely mean 1000mA not 1mA.
The device specs list that peak draw is 700mA and IS2000 current standby is 150mA.
The 'USB Y-shaped cable' is 3 feet long. One end has a USB Type A receptacle, the other end has two USB Type A plugs, one of which is the 'main' plug connected to the primary piece of USB serial cable, and one is connected via a short, 3 inch long smaller gauge jumper that only connects to USB port power to allow additional DC power.
We will do further testing from rural areas to see if the cable makes a significant impact. So far, however, the U720 on its own without a power 'goose' appears to have pretty good sensitivity.
Due to the elevation of my office, my signal is typically a little low on both VZW and Sprint, and speeds suffer unless I use external antennas. Yet with the U720 my first five download/uploads ranged from a low of 453/121 to 633/122 without a Y-shaped cable. That rivals the best EVDO card in the office (KPC650 on VZW). Nice. |
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southbound747
EVDO User
Joined: 24 Jul 2006
Posts: 85
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| Posted: Tue Dec 05, 2006 9:28 pm Post subject: thanks for the info |
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ok. that was kind of like a mini review. good. thanks. i'd like to know as much as i can about u720. good to know that one usb is often enough since my ux computer only has one, and i will be using the u720 half the time with that pc and half with my regualr vaio 14 inch laptop which conveniently has 2 usb ports side by side 
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