Mar
18
WRITTEN BY:
Peter Martin
Friday, March 18, 2011
Note: We have recently moved away from suggesting that 2.1GHz (only) antennas are the best choice for VBB customers. It used to be the case that the faster speeds were obtained with UMTS and HSDPA on the 2.1GHz band and the slower speeds GPRS on the 900 MHz bands.
However Optus/Virgin have now reallocated some of their 900 MHz spectrum away from GPRS to give faster speeds on this band too. So now we are steering users towards multi-band antennas ( our triangle antenna) which works at both 900MHz and 2100MHz. see here
However, if you are sure that your reception is on 2100MHz, for any of the 3G services, there are advantages to single band antennas, and the following still applies:
Questions and Answers
Q Can an antenna give me a better connection for VBB?
A. If you are getting a hint of UMTS or HSDPA then, probably, yes. Just look at the display panel of your VBB modem. If you can only get GPRS then it's not looking too good.
Type http://192.168.1.1 into your browser. Just the same as when you were setting it up for the first time.
see also http://www.virginbroadband.com.au/support/broadbandathome/top-10-tips.aspx
the default network name (SSID) of the router is "virgin broadband" and the default passphrase is "preinstall"
the default username is 'virgin' and the default password is 'password' and these can be found on the sticker underneath the router.
Note that it is possible that these default settings may have been changed. If so, you will need to check with whoever installed the modem originally.
Even with a good GPRS (900MHz) signal you won't get a very fast connection, maybe just slightly faster than dial-up speed. The VBB connection speed you can expect with a good signal on UMTS/HSDPA (2.1GHz) is about 700kbps or around 14 x dial up speed. . You may need to do some tests on your roof with the modem to check for evidence of UMTS/HSDPA. We've just heard of an injury to one of our customers, falling from a roof, so please take care and use the proper safety equipment! :-)
The antennas below are for UMTS/HSDPA (2.1GHz) only. If you wish to improve your GPRS (900MHz) reception and are happy with the slower speed, please email us. See also the comments on using VBB in wet weather below.
Two bars on the signal strength meter ( -90dBm) should give you reasonably solid connection. Try to get a reading in dBm rather than just looking at the number of bars. If you look through whirlpool posts you'll see what people are typically getting. http://forums.whirlpool.net.au/forum-replies.cfm?t=799422
Try turning off GPRS: http://www.zdnet.com.au/blogs/securifythis/soa/Kill-GPRS-to-make-Virgin-Broadband-fly/0,139033343,339281471,00.htm
Q. Which antenna should I choose?
A. We have a range of grid antennas which are designed for this frequency (2.1GHz). The two smaller sizes will fit on to the type of J pole commonly used with TV antennas, even with a TV antenna fitted also. The two frequencies are quite different and no interference should occur. Available from Bunnings or a TV antenna supplier such as Hills or (pick up only) from RFShop. Also these can fit on to solid ventilation pipes or balcony rails.. The larger size, 87cm x 66cm, will still fit on to this pole but due to its addition weight additional guy lines may be needed. As far as we know, the setup should be for Vertical polarisation. See ASSEMBLY INSTRUCTIONS . The RFS_6040_2.1 is the one we normally recommend.
In addition we have tested out some smaller panel antennas.
Panel Antenna for 2.1GHz 3G band. SPL-1900-2300
These will also fit either on a wall, or on to a pole, In general, the higher the gain, the more carefully you need to point them and the stronger the required mountings.
Getting a good signal from VBB is very much like getting a good signal for your TV. If you live in a weak signal area you'll need a decent sized antenna on your roof. If you just need a slight improvement then a small panel antenna should be enough.
Q. Can I have the cable terminated on a wall plate to make it look neater?
A. Yes. We can also supply customised cables, such as this one with a bulkhead connector and wall panel:
 |
N male to N female (bulkhead fitting cable)
Just let us know if you need a different length to what you can see on the cart.
You'll also need a
N30MC39-RG316-300 300mm
or
N30MC39-LMR100-1500 1.5mtrs
DRILLED WALLPLATE
|
 |
HOODED WALLPLATE
|
Q. What about the length of the cables?
Try to keep them as short as you can. The signals are at 2.1 GHz (2100MHZ) so do not travel down cable as easily as TV signals which are at approximately 1/10th of the frequency. We use LMR195 cable as standard. This has a relatively low loss. 10 metres is usually OK. 5 metres is better.
Consider moving your modem closer to your antenna and run ethernet RJ45 CABLE ASSEMBLIES to your computer and phone cable to your phone.
Q. Do I need pigtail adaptors to the modem?
A. Yes.
PATCH CABLE FOR GLOBE SURFER ON CART (LINK)
PATCH CABLE FOR E169 ON CART (LINK)
Q. What if I can't get an improvement?
A. Plug the pigtail into the modem with nothing else connected. You should see the signal drop down to zero. This tests out the modem's internal switch. Then when you do connect the antenna to the pigtail you should get a signal and you will know that the signal you are measuring comes from the external and not the internal antenna.
Plug the pigtail into the modem with nothing else connected. You should see the signal drop down to zero. This tests out the modem's internal switch. Then when you do connect the antenna to the pigtail you should get a signal and you will know that the signal you are measuring comes from the external and not the internal antenna.
You will also have to experiment with the direction that you point the antenna. The polarisation should be vertical but it may be worthwhile rotating the antenna to test this.
Try to avoid running on GPRS. Even with a good signal the internet speed will be poor.
Q . How do I make an order?
A. You need three things.
1) An antenna of your choice.
2) A Pigtail adaptor. if you aren't sure and need help See : PICS OF VIRGIN USB DATA CARDS AND MODEMS (LINK)
just quote your modem model with order
3) EXTENSION CABLE ON CART (LINK)
The shopping cart shows lead lengths up to 10 metres. Just email us if you need anything longer.
Either order through the shopping cart or send us an email if you aren't sure and we'll check it all makes sense.
Q. What's the cheapest option?
A. You can BUILD YOUR OWN CANTENNA:
with pigtail lead FOR GLOBESURFER MODEM WITH MC CONN
It doesn't look the most hi-tech piece of equipment but it works surprisingly well :-)
You can also use this cantenna to increase the range of your home wireless (2.45Ghz) network or the '3' network. You'll probably need different pigtails though.
Q Can you do installations?
A. We may be able to help. Either contact us or:
Brisbane
Ian Pollock
Carina
0435 135 315
ianpollock@optusnet.com.au
If you can offer this service in other areas. Pls just let us know and we can add your details. We'd be happy to suppy you with antennas etc in addition to customer leads.
Q How do I read my connection signal strength?
A On the Virgin Management Console with the Globesurfer Modem, this should give a more accurate reading than the number of lights. For example: -87dBm or -77dBm . Note -77dBm is a better signal than -87dBm
Q What sort of signal do I need?
A At least -90dBm for a reasonably solid connection. This can vary depending on the amount of interference in the locality. Better than -80dBm is better. There is no real benefit in fitting an external antenna if you are better than
-70dBm. It should natuarlly change between UMTS and HSDPA according to the amount of download data. GPRS will not give you fast speeds even with a good signal but it is OK for telephone calls.
Q. My VBB connection is OK when its dry but falls over in the wet.
A. During wet weather the UMTS /HSDPA (2.1GHz) signal, especially if it has to pass through wet trees, may fade and you may be better switching back, temporarily, to GPRS (900 MHz). The triangle antenna does both frequencies and may be a better choice.
Q Can I just put the modem up on the roof without using an external antenna?
A Yes. You can put it in a weatherproof box .
The disadvantage of this method is that you may find it harder to make a wireless connection between the modem and your PC. Also, the signal strength may still need boosting with a larger antenna. One advantage is that the cable loss is minimised and a combination of this method and a large antenna would be the way to go when you were really struggling to get a good signal.
Q. I have connected the antenna and it doesn't seem to make any difference. What can I do?
We have heard this comment from time to time. Try this procedure:
1) Just connect the small pigtail adaptor to the modem. Nothing else. No antenna or extra cable.
Make sure it pushes fully in.
2) Check to see if the signal has gone to down to zero. There should be a switch in the modem which switches over from the internal antenna to the external antenna. If it the signal level has not dropped a lot it is an indication that this switch is faulty.
3) Now when you connect the external antenna you know that any signal you do see is coming through the external antenna. The antennas are directional and for UMTS/HSDPA only so disregard any previous GPRS
Q. What is the cost of freight
A. Freight will depend on the size of the antenna and location but it'll be around $10 for a panel antenna + cables , $12 -$15 for a medium sized grid, $18 for a large grid to Sydney and Melbourne. The total cost for a medium grid (+ cables & pigtail) is going to be around $165 including GST and freight.
This link may be useful to help you locate a tower transmitting on 2.1GHz
http://web.acma.gov.au:80/pls/radcom/register_search.main_page
But, probably you'll need to try it and see. If you are even getting a hint of UMTS or HSDPA reception without an external antenna then things are looking promising.
Q. What if I can't get VBB even with an external antenna?
There are several other possibilities.
In Adelaide: these guys are very good. www.nuskope.com.au
On the North NSW coast/Gold Coast Area there is www.wwwires.com
Please let us know if you'd like a free link to your community wireless network included here.
Pics of an Installation 
