KR1 with external antenna to cover a 20 acre ranch

Scott · Posted: Fri Feb 17, 2006 4:25 pm Post subject:

There is often confusion created by the different decibel conventions used to quote units of power. [A lot of hype too... or little tricks like quoting 'system gain' rather than specific frequency gain for dual or multi-band antennas... ex: "my antenna is 20dB"... which is really 10dB for 900 and 10dB for 1900... well folks, you only USE one of those, so you're getting 10dB max (downhill with a tailwind!)]

dBm (milliwatt) is power referenced to one milliwatt and dBi (isotropic) represents gain with respect to an isotropic source. Not the same thing.

That WiFi supply site I linked to earlier has a page with some useful info on dBm to mW conversion. Google is your friend as well. Gotta love online calculators. *wink*

In your case, assuming you use good low-loss coax, you will more likely lose more signal through the sum of your connectors than through your actual cable (unless you use too long of a pigtail), so I would focus on antenna choice and placement.

Be aware that just because a cable is big and thick it still may have high loss. There are some types that are LMR 400/RG8 size yet have stranded center cores for flexibility. Or some lack the quality sheilding and insulator and sheath that the better coax has.

Considering the coastal valley environment of Somis, you'll want to use some mastic and electrician's tape to keep out moisture on your final connection at the outdoor antenna. If you add a lightning arrestor/suppressor and grounding, wrap those connections as well.

You will have to experiment with antenna power and height for your application. Increasing an omni's power tends to make them less effective for extreme downward angles (ever notice that even those VERY expensive multi-panel cell tower antennas are angled down...). When I see specs stating high amounts of gain and fantastic down tilt or beamwidth, I sort of wonder (doubt). There are antennas that will be more 'right' for your application than others.

In the KR1 Linux thread tz1 linked to an image of his KR1 setup. He snuck a data cable through the housing next to the PC card. Nice place to pass an antenna cable too.

A couple of deft arcs with an exacto knife would give you enough room for a U.FL to N-Male pigtail cable to easily sneak through alongside the EVDO card. Zip-tying the cable somewhere internally would help keep strain off of the tiny connector (small self-stick nylon posts or cable guides can help as long as they're stuck on well).

Try attaching your high-power external omni to AUX and then attach the existing RP-SMA bulkhead connector's lead to MAIN (so the included 'rubber ducky' antenna when mounted is now the near-field antenna... and the little sheet metal on-board antenna element isn't attached at all).

Like I said above, getting the KR1 (or any single radio WiFi device/antenna setup) to cover near and far will be challenging. Still worth experimenting, since you're going to use/need coax cable and an outdoor omni regardless.

hxmiller · EVDO User Joined: 30 Jun 2005 Posts: 46

I installed a Senao 3054MP card which is seen at 20db rather than the 18db on the stock card with iwconfig.

wdfs · EVDO Newbie Joined: 28 Oct 2005 Posts: 8

go to quickertek.com and call them.