[MLB-WIRELESS] Re: Microwave links (fwd)

[evilbunny]

Hello Shane,

I keep planning to code one, but anyways... you just add the dB up...

legal limit for channels 1 to 9 is 36dBm, channels 10 to 13 is 23dBm

100mW = 20dBm, LMR has ~0.22dBm loss per metre... + 1dBm loss in
connectors...

20+24-6.6-1=36.4 or slightly over the legal limit for channels 1 to
9... and completely over for channels 10 to 13...

-- 
Best regards,
 evilbunny                            mailto:evilbunny at sydneywireless.com

http://www.SydneyWireless.com - Exercise your communications
freedom to make it do what you never thought possible... 

Tuesday, September 3, 2002, 9:24:47 AM, you wrote:

SC> On the topic of EIRP.

SC> Does anyone know of an online calculator for working out output ie: EIRP
SC> - in particular one which will take into account cable loss so you would
SC> feed in info such as this: 
SC> Card output: 100mw
SC> Antenna gain: 24dB
SC> Cable type: LMR-400
SC> Cable length: 30Meters
SC> And you would be presented with a figure as your total output.

SC> Shane

SC> -----Original Message-----
SC> From: Michael Nardella [mailto:michael at nardella.com.au]
SC> Sent: Tuesday, 3 September 2002 12:45 AM
SC> To: melbwireless at wireless.org.au
SC> Subject: RE: [MLB-WIRELESS] Re: Microwave links (fwd)



SC> Yeah, and I like how it's "just under 4w eirp"

SC> Michael

SC> -----Original Message-----
SC> From: owner-melbwireless at wireless.org.au
SC> [mailto:owner-melbwireless at wireless.org.au]On Behalf Of sanbar
SC> Sent: Tuesday, 3 September 2002 12:04 AM
SC> To: melbwireless at wireless.org.au
SC> Subject: [MLB-WIRELESS] Re: Microwave links (fwd)


SC> Is this claim right?
SC> It's from another mailing list ... bit at the bottom too about a 30km
SC> link.
SC> - Barry

SC> --
SC> barry park
SC> http://wireless.bur.st/ ||| community wireless project
SC> http://wireless.org.au/ ||| melbourne wireless node bca
SC> -=all your http_get are belong to us=-

SC> ---------- Forwarded message ----------
SC> Date: Mon, 02 Sep 2002 20:51:34 +0800
SC> Subject: Re: Microwave links

SC> Microwave links would only interfeer with eachother if they are running
SC> on the same freqency(channel). with 802.11b, you have 11 channels to
SC> chose
SC> from. Only 3 of these are truly individual due to the overlap. Ch 1, 6
SC> and
SC> 11.
SC> However, on ch 11, if you output 4W EIRP(legal limit) you are actually
SC> putting out more power than is legal due to the overlap into ch 12+
SC> which
SC> AFAIK
SC> isn't legal to transmit on.

SC> Speaking of microwave links, we have just established a link that
SC> stretches
SC> just
SC> under 30km here in WA. It goes from the 'HillsHub' to a site i manage
SC> (DVNet) in
SC> Doubleview. presently we are having a few small problems due to a
SC> firmware
SC> on the
SC> card at HillsHub, but other than that, we have a very usable link (at
SC> 5.5Mbit)
SC> This is using an 18dBi Galaxy dish and a 35mW Cabletron card at HH, and
SC> a
SC> Cisco 352 series
SC> card (100mW) and a 24dBi Galaxy dish at DVNet(with a long cable run, so
SC> its
SC> just under 4W EIRP).



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