Setting up a 24dBi antenna to my Senao card, couple questi..

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1) Will it hurt my Senao card if I use a 24dBi antenna with it? I
haven't seen any other people using such a powerful antenna.

2) Will RG-6 work to run between my basement and roof (about 30 ft) ?
I'd have to use a few adapters, so would I lose too much signal? How
much signal strength would I lose?

Thanks,
Mike

 

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Archived from groups: alt.internet.wireless (More info?)

On Wed, 28 Jul 2004 19:57:04 -0400, Michael Shaffer
<michaelshaffer@cox.net> wrote:

>1) Will it hurt my Senao card if I use a 24dBi antenna with it?

No. The card feels no pain.

>I haven't seen any other people using such a powerful antenna.

You haven't looked very hard. 100mw (+20dBm) is actually fairly low
power as WISP radios go. Typical is 1 watt (+30dBm) into a 6dbi omni
or panel antenna. With a 24dBi dish, your maximum legal transmit
power is +24dBm.

>2) Will RG-6 work to run between my basement and roof (about 30 ft) ?
>I'd have to use a few adapters, so would I lose too much signal? How
>much signal strength would I lose?

Yes, but your losses will be severe. LMR-400 would be better.
RG-6/u comes in many different flavours ranging from disgusting
garbage to "satellite grade" coax. At 2.4GHz the loss of the better
stuff is 0.38dB/meter or about 4dB for your 30ft run. Add 0.5dB of
loss for each connector and pigtail for about 2dB additional loss.
The impedance mismatch will be good for an additional 1dB of loss.

Grand total is about 7dB of loss, which means that you're losing about
80% of your transmit power in the plumbing. That's not all that
horrible if you're only interested in close in connections but is
fatal for long distance links.

Methinks you would do better to put the radio near the antenna and
eliminate the cable losses.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice http://www.LearnByDestroying.com
# jeffl@comix.santa-cruz.ca.us
# 831.421.6491 digital_pager jeffl@cruzio.com AE6KS

 

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"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
news:50hgg09g43dkm4t6nq74kb2pa5roee40l2@4ax.com...
> 100mw (+20dBm) is actually fairly low
> power as WISP radios go. Typical is 1 watt (+30dBm) into a 6dbi omni
> or panel antenna. With a 24dBi dish, your maximum legal transmit
> power is +24dBm.

Jeff, can you help me with the math? A 24dBi dish is 18dBi more than a
typical 6dBi omni. 18dBi equals a multiplier of 63. The maximum EIRP
allowed with a directional antenna is 4 Watts. One 63rd of 4 Watts is 63.4
mW, which is +18 dBm. How did you get +24 dBm? Thanks.

Ron Bandes, CCNP, CTT+, etc.

 

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On Thu, 29 Jul 2004 05:04:37 GMT, "Ron Bandes" <RunderscoreBandes
@yah00.com> wrote:

>"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
>news:50hgg09g43dkm4t6nq74kb2pa5roee40l2@4ax.com...
>> 100mw (+20dBm) is actually fairly low
>> power as WISP radios go. Typical is 1 watt (+30dBm) into a 6dbi omni
>> or panel antenna. With a 24dBi dish, your maximum legal transmit
>> power is +24dBm.

>Jeff, can you help me with the math? A 24dBi dish is 18dBi more than a
>typical 6dBi omni. 18dBi equals a multiplier of 63. The maximum EIRP
>allowed with a directional antenna is 4 Watts. One 63rd of 4 Watts is 63.4
>mW, which is +18 dBm. How did you get +24 dBm? Thanks.
>Ron Bandes, CCNP, CTT+, etc.

So much for getting to sleep before midnight...

FCC Part 15.247 at:

http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=15&SECTION=247&YEAR=2001&TYPE=TEXT
sayeth:

(3) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of this
section, if transmitting antennas of directional gain greater than 6
dBi are used the peak output power from the intentional radiator shall
be reduced below the stated values in paragraphs (b)(1) or (b)(2) of
this section, as appropriate, by the amount in dB that the directional
gain of the antenna exceeds 6 dBi.
(i) Systems operating in the 2400-2483.5 MHz band that are used
exclusively for fixed, point-to-point operations may employ
transmitting antennas with directional gain greater than 6 dBi
provided the maximum peak output power of the intentional radiator is
reduced by 1 dB for every 3 dB that the directional gain of the
antenna exceeds 6 dBi.

The first part is straight forward. 1 watt (+30dBm) is the maximum
xmitter power under all circumstances. Attached to a 6dBi omni gives
a maximum EIRP (effective radiated power) of +36dbm or 4 watts for an
omni or point to multipoint system. IF the antenna gain is greater
than +6dBi, then the xmit power needs to be reduced by the same number
of decibels.

However, 15.247(b)(3)(i) offers point to point links substantial
leniency in their EIRP. For every 3dB of antenna gain over the
maximum +36dBm radiated, the xmitter power need only be reduced 1dB.
This yields the following chart of max gains and corresponding max
xmit power:
xmit antenna EIRP EIRP
power gain
+dbm +dbi +dbm watts
30 6 36 4
29 9 38 6.3
28 12 40 10
27 15 42 16
26 18 44 25
25 21 46 40
24 24 48 63

Note the last line. That's where the +24dBm xmit power into a +24dBi
dish came from.

The FCC has been rather liberal in their interpretation of
15.247(b)(3)(i) and has allowed beam steering access points to qualify
under the point to point rule.
http://www.vivato.com/download/VP12001210%20Datasheet.pdf
Note the EIRP of +44dBm (25 watts) with a 25dBi steerable antenna.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558

 

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Archived from groups: alt.internet.wireless (More info?)

"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
news78hg011s9kqkgfkqodl9p45rpah24p7kf@4ax.com...
> On Thu, 29 Jul 2004 05:04:37 GMT, "Ron Bandes" <RunderscoreBandes
> @yah00.com> wrote:
>
> >"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
> >news:50hgg09g43dkm4t6nq74kb2pa5roee40l2@4ax.com...
> >> 100mw (+20dBm) is actually fairly low
> >> power as WISP radios go. Typical is 1 watt (+30dBm) into a 6dbi omni
> >> or panel antenna. With a 24dBi dish, your maximum legal transmit
> >> power is +24dBm.
>
> >Jeff, can you help me with the math? A 24dBi dish is 18dBi more than a
> >typical 6dBi omni. 18dBi equals a multiplier of 63. The maximum EIRP
> >allowed with a directional antenna is 4 Watts. One 63rd of 4 Watts is
63.4
> >mW, which is +18 dBm. How did you get +24 dBm? Thanks.
> >Ron Bandes, CCNP, CTT+, etc.
>
> So much for getting to sleep before midnight...
>
> FCC Part 15.247 at:
>
>
http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=15&SECTION=247&YEAR=2001&TYPE=TEXT
> sayeth:
>
> (3) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of this
> section, if transmitting antennas of directional gain greater than 6
> dBi are used the peak output power from the intentional radiator shall
> be reduced below the stated values in paragraphs (b)(1) or (b)(2) of
> this section, as appropriate, by the amount in dB that the directional
> gain of the antenna exceeds 6 dBi.
> (i) Systems operating in the 2400-2483.5 MHz band that are used
> exclusively for fixed, point-to-point operations may employ
> transmitting antennas with directional gain greater than 6 dBi
> provided the maximum peak output power of the intentional radiator is
> reduced by 1 dB for every 3 dB that the directional gain of the
> antenna exceeds 6 dBi.
>
> The first part is straight forward. 1 watt (+30dBm) is the maximum
> xmitter power under all circumstances. Attached to a 6dBi omni gives
> a maximum EIRP (effective radiated power) of +36dbm or 4 watts for an
> omni or point to multipoint system. IF the antenna gain is greater
> than +6dBi, then the xmit power needs to be reduced by the same number
> of decibels.
>
> However, 15.247(b)(3)(i) offers point to point links substantial
> leniency in their EIRP. For every 3dB of antenna gain over the
> maximum +36dBm radiated, the xmitter power need only be reduced 1dB.
> This yields the following chart of max gains and corresponding max
> xmit power:
> xmit antenna EIRP EIRP
> power gain
> +dbm +dbi +dbm watts
> 30 6 36 4
> 29 9 38 6.3
> 28 12 40 10
> 27 15 42 16
> 26 18 44 25
> 25 21 46 40
> 24 24 48 63
>
> Note the last line. That's where the +24dBm xmit power into a +24dBi
> dish came from.
>
> The FCC has been rather liberal in their interpretation of
> 15.247(b)(3)(i) and has allowed beam steering access points to qualify
> under the point to point rule.
> http://www.vivato.com/download/VP12001210%20Datasheet.pdf
> Note the EIRP of +44dBm (25 watts) with a 25dBi steerable antenna.
>
>
> --
> Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 AE6KS 831-336-2558

Thanks Jeff. Apparently my error was using the 4 Watts for transmitter
power when it should have been the EIRP. You really cleared it up and
explained it better than I've seen before.

Ron Bandes, CCNP, CTT+, etc.