[ale] USB Wireless

Chris Fowler cfowler at outpostsentinel.com
Fri Aug 19 14:22:34 EDT 2016


> From: "Steve Litt" <slitt at troubleshooters.com>
> To: ale at ale.org
> Sent: Friday, August 19, 2016 1:46:47 PM
> Subject: Re: [ale] USB Wireless

> On Fri, 19 Aug 2016 11:01:39 -0400 (EDT)
> Chris Fowler <cfowler at outpostsentinel.com> wrote:

> > Can you even radiate 2W in Part 95 wifi spectrum? Regardless, I'm not
> > sure I buy that it can off the USB port. If you try you need to use a
> > powered hub. I'm skeptical if that device really can do 2W. I'll bet
> > they are getting that by gain and not output of the final?

> Could you please explain "by gain and now output of the final?" Are
> talking about some sort of quantification where the power actually
> dissipated into the antenna multiplied by the gain factor of that
> antenna?

> I found this description of output power measurements:

> http://www.ni.com/newsletter/51446/en/#toc1

> The article in the preceding link doesn't contain the word "gain".

ERP is the Effective Radiated Power and is calculated by using the amount of power received by the antenna and the gain of the antenna. 

http://www.rfidsb.com/antenna-field-calculations/ 

To increase the ERP you increases the gain. 

http://www.tp-link.us/FAQ-3.html 

The 'final' is slang for the last amplifier before load (antenna). Known as the final amp. 

Good info 

http://www.techrepublic.com/blog/data-center/80211-time-to-clear-up-some-antenna-misconceptions/ 

Colinear is the way to go. Here is one on Ali where the seller is showing you proof that it is. 

http://www.aliexpress.com/store/product/2-4ghz-10dbi-omni-wifi-antenna-high-gain-SMA-40cm/217323_782806967.html?aff_platform=aaf&sk=imayv33vb%3A&cpt=1471630772731&af=1005171000000000242022015&cn=aliexpress&cv=banner&dp=19TZ1JhulCZ51xn&aff_trace_key=d64ff48219e44bcf84b581a5f7380fed-1471630772731-06526-imayv33vb 

There are some great tutorials showing how to make a nice colinear. You want the USB dongle as close to the antenna as possible. If you use coax then all the gain you created will be lost in the coax. At that frequency loss is great on coax. 
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