Hi all,
I saw a site where a fellow designed a unit to measure impedance at 2.4
ghz, for use on wifi antennas. I don't recall if it was return loss or
impedance.
It gave detailed instructions on how to build and he also had ready built
units
for sale.
I think it was a ham that designed the unit. I also think he was not in the
states, possibly a P or PY call sign, but the memory is not good!
Any help would be appreciated.
Thanks, Mike

In message , amdx
writes
Hi all,
I saw a site where a fellow designed a unit to measure impedance at 2.4
ghz, for use on wifi antennas. I don't recall if it was return loss or
impedance.
It gave detailed instructions on how to build and he also had ready built
units
for sale.
I think it was a ham that designed the unit. I also think he was not in the
states, possibly a P or PY call sign, but the memory is not good!
Any help would be appreciated.
Thanks, Mike

This it ?

http://www.frars.org.uk/cgi-bin/render.pl?pageid=1085

73 Brian GM4DIJ
--
Brian Howie

"Brian Howie" wrote in message
...
In message , amdx
writes
Hi all,
I saw a site where a fellow designed a unit to measure impedance at 2.4
ghz, for use on wifi antennas. I don't recall if it was return loss or
impedance.
It gave detailed instructions on how to build and he also had ready built
units
for sale.
I think it was a ham that designed the unit. I also think he was not in
the
states, possibly a P or PY call sign, but the memory is not good!
Any help would be appreciated.
Thanks, Mike

This it ?

http://www.frars.org.uk/cgi-bin/render.pl?pageid=1085

73 Brian GM4DIJ
--
Brian Howie


A piece of Sage Wireline and a PCB to terminate it would be easier.

Chris

On Sun, 18 Oct 2009 13:41:23 -0500, "amdx" wrote:

Hi all,
I saw a site where a fellow designed a unit to measure impedance at 2.4
ghz, for use on wifi antennas. I don't recall if it was return loss or
impedance.
It gave detailed instructions on how to build and he also had ready built
units
for sale.
I think it was a ham that designed the unit. I also think he was not in the
states, possibly a P or PY call sign, but the memory is not good!
Any help would be appreciated.
Thanks, Mike


This is a copy of my reply to your duplicate posting to
alt.internet.wireless. Please don't do that again:



This one?
http://pe2er.nl/wifiswr/index.htm
or one of these:
http://www.qsl.net/n9zia/wireless/appendixF.html

What I do is use a return loss bridge as in:
http://www.qsl.net/n9zia/wireless/pics/rtrn_loss_bridge.png
I've built several out of chip resistors and junk parts. I have one
that works well up to about 8GHz. Great for testing antennas. That's
what's inside a Telonic Rho-tector (which can usually be found on eBay
for cheap). A few models go up to 2.4Ghz.

You'll also *might* need a microwave load or three. 50 ohms for a
reference, but also some other known values for calibration.

The problem is that you'll need an RF sweep generator to use this
effectively. It's also not a VNA (vector network analyzer) so it
won't tell you if any reactance is capacitive or inductive.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
On Sun, 18 Oct 2009 13:41:23 -0500, "amdx" wrote:

Hi all,
I saw a site where a fellow designed a unit to measure impedance at 2.4
ghz, for use on wifi antennas. I don't recall if it was return loss or
impedance.
It gave detailed instructions on how to build and he also had ready built
units
for sale.
I think it was a ham that designed the unit. I also think he was not in
the
states, possibly a P or PY call sign, but the memory is not good!
Any help would be appreciated.
Thanks, Mike


This is a copy of my reply to your duplicate posting to
alt.internet.wireless. Please don't do that again:


Sorry, I thought about putting it on these other groups just as I hit send.


This one?
http://pe2er.nl/wifiswr/index.htm
or one of these:
http://www.qsl.net/n9zia/wireless/appendixF.html

What I do is use a return loss bridge as in:
http://www.qsl.net/n9zia/wireless/pics/rtrn_loss_bridge.png
I've built several out of chip resistors and junk parts. I have one
that works well up to about 8GHz. Great for testing antennas. That's
what's inside a Telonic Rho-tector (which can usually be found on eBay
for cheap). A few models go up to 2.4Ghz.

You'll also *might* need a microwave load or three. 50 ohms for a
reference, but also some other known values for calibration.

The problem is that you'll need an RF sweep generator to use this
effectively. It's also not a VNA (vector network analyzer) so it
won't tell you if any reactance is capacitive or inductive.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Brian Howie" wrote in message
...
In message , amdx
writes
Hi all,
I saw a site where a fellow designed a unit to measure impedance at 2.4
ghz, for use on wifi antennas. I don't recall if it was return loss or
impedance.
It gave detailed instructions on how to build and he also had ready built
units
for sale.
I think it was a ham that designed the unit. I also think he was not in
the
states, possibly a P or PY call sign, but the memory is not good!
Any help would be appreciated.
Thanks, Mike

This it ?

http://www.frars.org.uk/cgi-bin/render.pl?pageid=1085

73 Brian GM4DIJ
--
Brian Howie

Thanks for the site Brian, that is not the one I was thinking though.

Jeff found the one I wanted,
http://pe2er.nl/wifiswr/index.htm
Mike

On Sun, 18 Oct 2009 13:41:23 -0500, "amdx" wrote:

Hi all,
I saw a site where a fellow designed a unit to measure impedance at 2.4
ghz, for use on wifi antennas. I don't recall if it was return loss or
impedance.
It gave detailed instructions on how to build and he also had ready built
units
for sale.
I think it was a ham that designed the unit. I also think he was not in the
states, possibly a P or PY call sign, but the memory is not good!
Any help would be appreciated.
Thanks, Mike



For the price of 1 tranceiver

http://www.youtube.com/watch?v=N0w5U0Xj1MU

w.

On Mon, 19 Oct 2009 09:22:17 +0200, Helmut Wabnig hwabnig@ .- --- -.
dotat wrote:

For the price of 1 tranceiver
http://www.youtube.com/watch?v=N0w5U0Xj1MU

Clever but I think the OP wanted test equipment, not tuning methods.
Also, I noticed that the markers were set to 2400.500 and 2900.500MHz
instead of US band limits of 2400.0 and 2483.5Mhz.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
On Mon, 19 Oct 2009 09:22:17 +0200, Helmut Wabnig hwabnig@ .- --- -.
dotat wrote:

For the price of 1 tranceiver
http://www.youtube.com/watch?v=N0w5U0Xj1MU

Clever but I think the OP wanted test equipment, not tuning methods.
Also, I noticed that the markers were set to 2400.500 and 2900.500MHz
instead of US band limits of 2400.0 and 2483.5Mhz.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

So did the (plexiglas?) change the velocity factor for tuning.
Ya, I'll take his test equipment.
Mike

On Mon, 19 Oct 2009 06:34:06 -0500, "amdx" wrote:

For the price of 1 tranceiver
http://www.youtube.com/watch?v=N0w5U0Xj1MU

So did the (plexiglas?) change the velocity factor for tuning.

The plastic raised the dielectric constant of the space between the
patch and the ground plane. In effect, it increased the effective
wavelength of the patch slightly, thus lowering its tuned frequency.
You can (accidentally) get the same effect by tuning the antenna, and
then placing it inside a PVC radome, which will also slower its tuning
frequency. The author will probably find himself re-tuning the
plastic piece after he's installed the patch antenna in an enclosure.

Ya, I'll take his test equipment.
Mike

Build your own test equipment first. When that fails, mortgage the
house, wife, kids, car, dog, cat, toys, etc and buy something better.
However, beware of test equipment envy. Once you get on the test
equipment upgrade path, nothing you own will be good enough, and there
always will be something better.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558