[MLB-WIRELESS] World Wifi record

Sat Dec 31 19:29:13 EST 2011

Hi Peter,

Yes, you are right about -88 being a bit low, that leaves very little 
margin.

I'd propose this setup...

* +30 dBm transmit power (Routerboard RB711UA-2HnD) Did Mike say he was 
interested in sponsoring?
(it's a dual chain radio, probably get +27 from a single port?)

* 24 dB gain grid antennas (Hills etc) I have several
or 2.4m dish - about 34 dB gain?

* 1 dB loss in cables/connectors at each end, radios mounted directly to 
the antennas.

*  Use CH1, where transmit spectrum is all below 2450 MHz.  EIRP not a 
problem.
13 Centimetre Amateur Band is 2300.000 MHz - 2450.000 MHz (I also have 
an advanced license.)

* 155 Km (Donnabuang, but will need to check the clearance over trees 
from the observation tower)

Which will give about -70 dBm with the grids and if we use the big 
antenna at one end, maybe -60 dBm.

Here's what Radio Mobile thinks of the hop, a couple of dB lower than my 
calcs.

Radio Mobile Plot <http://www.ratbaggy.net/wireless/long_hop.png>

I'm back at work on Tuesday which really only leaves the weekends open 
for me.

Regards

Dave

On 31/12/2011 12:50 PM, Peter Berrett wrote:
> I have just done the path loss calculations assuming
> - 17 dbm transmission power (50 mw)
> - 20 db gain transmission antenna
> - 20 db gain receiving antenna
> - 3 db loss in cables
> - 2400 Mhz frequency
> - 127 km distance
> I calculate a received signal after antenna gain of about -88 dbm 
> which is a bit low for my liking.
> We probably would need to look into higher gain antennas.
> Mind you I have assumed that each of our antennas has 20db gain. I 
> don't know what the gain figure would be for a 90cm offset dish at 
> 2400 mhz? Higher maybe?
> It is possible that your 2.4m dish has a higher gain figure than 20db 
> which would help give some margin.
> cheers Peter
>
>     ----- Original Message -----
>     *From:* Peter Berrett <mailto:vk3pb at optusnet.com.au>
>     *To:* David Nuttall <mailto:wireless at smithsgully.net> ; MW
>     Wireless <mailto:melbwireless at wireless.org.au>
>     *Sent:* Saturday, December 31, 2011 12:35 PM
>     *Subject:* Re: [MLB-WIRELESS] World Wifi record
>
>     Dear Dave
>     I have a 90cm offset dish that I could tack my cantenna onto and I
>     live right by Mt Dandenong.
>     I am off work until 10th January. Want to try for the record? You
>     would head out to Ballarat and I'd park myself up at Skyhigh.
>     The only issue is what dongle or router should I use at my end?
>     cheers Peter
>
>         ----- Original Message -----
>         *From:* David Nuttall <mailto:wireless at smithsgully.net>
>         *To:* MW Wireless <mailto:melbwireless at wireless.org.au>
>         *Sent:* Wednesday, December 28, 2011 1:18 PM
>         *Subject:* Re: [MLB-WIRELESS] World Wifi record
>
>         Hi Peter,
>
>         How about we start out with the Australian WiFi record?  I
>         believe the W.A. guys established a fairly long link out to
>         Rottnest Island some time back.  However, I know of no longer
>         link than Peter Buncle's hop from Kallista to the original
>         Highton location at around 100 Km's.
>
>         A Picnic/BBQ trip to Mt Buninyong would give us a path of 127
>         Km back to node GHO at Mt Dandenong.
>
>         I donated a 2.4 m domestic sat dish and Rob B built up a 2.4
>         GHz feed and tripod for the dish.  They are still sitting in
>         my shed ready for such a project.
>
>         Regards
>
>         Dave
>
>
>
>         On 27/12/2011 10:30 PM, Peter Berrett wrote:
>>         Hi all
>>         Would anyone out there be interested in attempting the world
>>         unamplified 2.4 ghz wifi record?
>>         The record I think is held by some Venezuelans (some Italians
>>         hold the 5.7 Ghz record).
>>         The strategy would be as follows
>>         1. Use an established MW node such as GHO North as one end of
>>         the link.
>>         2. Go about 400 km+ in the direction the node antenna is
>>         pointing and erect a node and directional antenna, perhaps
>>         solar powered, with a small computer and high gain antenna
>>         pointing at the MW node. Perhaps our friends at the Adelaide
>>         wireless group could set up a node in their group pointing at
>>         us?
>>         3. Monitor 2.4 ghz beacons and when there is some
>>         tropospheric ducting try the link. Or better still just
>>         automate things so that when the station is heard it
>>         automatically tries to transfer a video from one end of the
>>         link to the other.
>>         Successful transfer of video = world record
>>         cheers
>>         Peter VK3PB
>>
>>
>>         _______________________________________________
>>         Melbwireless mailing list
>>         Melbwireless at wireless.org.au
>>         https://wireless.org.au/mailman/listinfo/melbwireless
>
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