On Tue, 04 Jul 2006 05:50:02 -0400, Rôgêr wrote:
Do folks here recommend the pringles cantenna or the pie tin antenna for my
2-antenna router 802.11b,g directional application where I need to also
feed the computers within the house in addition to the shed 300 feet away?

I use panel antennas almost exclusively, exceptions being some 24dbi
mesh antennas for backhaul.

Hi Rôgêr,

After reading all the articles posted, I now understand that:

a) The pringles can is hip; but it's the worst performer
http://www.oreillynet.com/cs/weblog/view/wlg/448
(it's not even metal foil lined and it's too small in diameter)

b) The coffee cantenna is more effective than the pringles cantenna
http://www.oreillynet.com/cs/user/view/wlg/1124

c) The dish antenna is the simplest of all and almost as good
http://www.freeantennas.com/projects/template
http://www.freeantennas.com/projects...te2/index.html

I also see, as Rod Speed so kindly noted, that the give and take is that we
lose range in some directions in favor of range in the desired direction.
Fair enough.

My one question is a practical one.

Why are there two antennas on my router anyway? Is one transmit and the
other receive? Or are they both transmit and receive?

Given I have TWO omnidirectional antennas on my wireless router, if I put
the parabolic dish antenna on one to direct it to my shed, does that allow
the OTHER antenna to radiate around the house to handle the other computers
roving around the house?

Beverly

Beverly Erlebacher wrote:
On Tue, 04 Jul 2006 05:50:02 -0400, Rôgêr wrote:
Do folks here recommend the pringles cantenna or the pie tin
antenna for my 2-antenna router 802.11b,g directional application
where I need to also feed the computers within the house in
addition to the shed 300 feet away?

I use panel antennas almost exclusively, exceptions being some 24dbi
mesh antennas for backhaul.

Hi Rôgêr,

After reading all the articles posted, I now understand that:

a) The pringles can is hip; but it's the worst performer
http://www.oreillynet.com/cs/weblog/view/wlg/448
(it's not even metal foil lined and it's too small in diameter)

b) The coffee cantenna is more effective than the pringles cantenna
http://www.oreillynet.com/cs/user/view/wlg/1124

c) The dish antenna is the simplest of all and almost as good
http://www.freeantennas.com/projects/template
http://www.freeantennas.com/projects...te2/index.html

I also see, as Rod Speed so kindly noted, that the give and take is
that we lose range in some directions in favor of range in the
desired direction. Fair enough.

My one question is a practical one.

Why are there two antennas on my router anyway?

That gives a more reliable coverage than with one.

Is one transmit and the other receive?
Or are they both transmit and receive?

They're normally both transmit and receive.

Given I have TWO omnidirectional antennas on my wireless router,
if I put the parabolic dish antenna on one to direct it to my shed,
does that allow the OTHER antenna to radiate around the house
to handle the other computers roving around the house?

Yes.

Rod Speed wrote:
Is one transmit and the other receive?
Or are they both transmit and receive?

They're normally both transmit and receive.

That's a shame. Here in Israel we are limited to 100mw EIRP, which
severly limits the transmit antenna. There is NO limitation on the
receive antenna.

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

Geoffrey S. Mendelson wrote
Rod Speed wrote

Is one transmit and the other receive?
Or are they both transmit and receive?

They're normally both transmit and receive.

That's a shame. Here in Israel we are limited to 100mw EIRP, which severly
limits the transmit antenna. There is NO limitation on the receive antenna.

A receive antenna has no EIRP, it doesnt radiate any real power.

Rod Speed wrote:
Geoffrey S. Mendelson wrote

Rod Speed wrote


Is one transmit and the other receive?
Or are they both transmit and receive?


They're normally both transmit and receive.


That's a shame. Here in Israel we are limited to 100mw EIRP, which severly
limits the transmit antenna. There is NO limitation on the receive antenna.


A receive antenna has no EIRP, it doesnt radiate any real power.




Actually, when properly matched, it radiates half the received power.

"John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01...
Rod Speed wrote:

A receive antenna has no EIRP, it doesnt radiate any real power.

Actually, when properly matched, it radiates half the received power.


How do you get that?
If the receiver input impedance is matched to the antenna, all the
received power is absorbed. There is no reflection. There is no radiation.

If the receiver matching is for optimal noise figure, there may be
some reflection and reradiation, but there's nothing pinning it to
be half the received power.

Don

John - KD5YI wrote:
Rod Speed wrote:
Geoffrey S. Mendelson wrote

Rod Speed wrote


Is one transmit and the other receive?
Or are they both transmit and receive?


They're normally both transmit and receive.


That's a shame. Here in Israel we are limited to 100mw EIRP, which
severly limits the transmit antenna. There is NO limitation on the
receive antenna.


A receive antenna has no EIRP, it doesnt radiate any real power.




Actually, when properly matched, it radiates half the received power.

Wrong.

On Sat, 08 Jul 2006 16:08:23 GMT, John - KD5YI
wrote:

Rod Speed wrote:
Geoffrey S. Mendelson wrote

Rod Speed wrote


Is one transmit and the other receive?
Or are they both transmit and receive?


They're normally both transmit and receive.


That's a shame. Here in Israel we are limited to 100mw EIRP, which severly
limits the transmit antenna. There is NO limitation on the receive antenna.


A receive antenna has no EIRP, it doesnt radiate any real power.




Actually, when properly matched, it radiates half the received power.

True, but it's such a low level as to normally be considered
insignificant. Unfortunately some take that to mean there is none.

If there were none, a Yagi antenna which used all passive elements
save for the driven element would not work. On receive that driven
element plays an active (pardon the pun) roll.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Roger