Make external connector on a USB dongle

Hi.
I've a Zydas based USB WiFi 802.11g dongle.
http://tinypic.com/huj5v6.jpg

Chipset Zydas ZD1211
http://www.zydas.com.tw/product/ZD1211.asp

I would make an external connector but I don't know where I can put the
signal.

Where is the antenna?
Where I can make the solder?

Thanks!

On Sat, 26 Nov 2005 19:19:58 +0100, "Tazzulella"
<(E-Mail Removed)> wrote:

>Hi.
>I've a Zydas based USB WiFi 802.11g dongle.
>http://tinypic.com/huj5v6.jpg
>
>Chipset Zydas ZD1211
>http://www.zydas.com.tw/product/ZD1211.asp
>
>I would make an external connector but I don't know where I can put the
>signal.
>
>Where is the antenna?

It's the tiny rectangular blue "chip" thing in the upper right hand
corner of the photo labelled WTC. It's a "meandering wire" ceramic
substrate monopole antenna. This isn't the exact make and model, but
it's the same type:
http://www.centurion.com/home/antennaProd/bluechip.asp

>Where I can make the solder?

Unsolder the blue chip antenna. Use TWO soldering irons like a
tweezer. The trace near the point labelled A1 is the center conductor
of the coax. The large ground area nearby is to the shield. Keep the
exposed center conductor of the coax *VERY* short.

You may need to add an isolating series capacitor if the antenna has
DC applied to it from somewhere. I can't tell from here.

If you want to be crude, cut two pieces of stiff copper wire to 31.1mm
long. Solder one to the hot lead (one end of L7). The other to
ground on the opposite side of the board. Instant dipole. Not great
but much better than the original chip antenna. Add a reflector and
you have a possible dish antenna feed.

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

On Sat, 26 Nov 2005 11:24:24 -0800, Jeff Liebermann
<(E-Mail Removed)> wrote:

>On Sat, 26 Nov 2005 19:19:58 +0100, "Tazzulella"
><(E-Mail Removed)> wrote:
>>I've a Zydas based USB WiFi 802.11g dongle.
>>http://tinypic.com/huj5v6.jpg
>>Chipset Zydas ZD1211
>>http://www.zydas.com.tw/product/ZD1211.asp

>Unsolder the blue chip antenna. Use TWO soldering irons like a
>tweezer. The trace near the point labelled A1 is the center conductor
>of the coax. The large ground area nearby is to the shield. Keep the
>exposed center conductor of the coax *VERY* short.

Better idea. Leave the chip antenna in place. Cut the trace near the
top of FL1 as close to FL1 as possible. Attach the coax center
conductor to the top lead of FL1. Connect the ground to the large
ground area to the left of FL1. Keep the exposed center conductor
*VERY short. C53 apparently acts as a DC isolator from the PIN diode
diversity switch chip (half way hanging out from under the shield).

--
Jeff Liebermann (E-Mail Removed)
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:
> On Sat, 26 Nov 2005 19:19:58 +0100, "Tazzulella"
> <(E-Mail Removed)> wrote:
>
>
>>Hi.
>>I've a Zydas based USB WiFi 802.11g dongle.
>>http://tinypic.com/huj5v6.jpg
>>
>>Chipset Zydas ZD1211
>>http://www.zydas.com.tw/product/ZD1211.asp
>>
>>I would make an external connector but I don't know where I can put the
>>signal.
>>
>>Where is the antenna?
>
>
> It's the tiny rectangular blue "chip" thing in the upper right hand
> corner of the photo labelled WTC. It's a "meandering wire" ceramic
> substrate monopole antenna. This isn't the exact make and model, but
> it's the same type:
> http://www.centurion.com/home/antennaProd/bluechip.asp
>
>
>>Where I can make the solder?
>
>
> Unsolder the blue chip antenna. Use TWO soldering irons like a
> tweezer. The trace near the point labelled A1 is the center conductor
> of the coax. The large ground area nearby is to the shield. Keep the
> exposed center conductor of the coax *VERY* short.
>
> You may need to add an isolating series capacitor if the antenna has
> DC applied to it from somewhere. I can't tell from here.
>
> If you want to be crude, cut two pieces of stiff copper wire to 31.1mm
> long. Solder one to the hot lead (one end of L7). The other to
> ground on the opposite side of the board. Instant dipole. Not great
> but much better than the original chip antenna. Add a reflector and
> you have a possible dish antenna feed.
>
Of course, if you only want to have an antenna with better send/receive
characteristics, and highly directional would be OK, you could place the
intact dongle inside a tin can and thus making a tin-cantenna.
http://members.cox.net/tulsaalstons/...Adapter%20.htm

http://members.cox.net/tulsaalstons/...-cantenna2.htm

Bob

Jeff Liebermann <(E-Mail Removed)> wrote:
> Better idea. Leave the chip antenna in place. Cut the trace near the
> top of FL1 as close to FL1 as possible. Attach the coax center
> conductor to the top lead of FL1. Connect the ground to the large
> ground area to the left of FL1. Keep the exposed center conductor
> *VERY short. C53 apparently acts as a DC isolator from the PIN diode
> diversity switch chip (half way hanging out from under the shield).

I'd say that was c35, but I might be reading upside down ;-)

What about a 35mm monopole sticking up from the board, at the top of FL1,
poking into a cantenna? I suggest 35mm presuming that the shield seen in
the photo would be soldered to the side of the can, leave 31.1mm exposed
inside the can.

http://www.turnpoint.net/wireless/cantennahowto.html

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5

"Jeff Liebermann" <(E-Mail Removed)> ha scritto nel messaggio
news:(E-Mail Removed)...

> it's the same type:
> http://www.centurion.com/home/antennaProd/bluechip.asp

Or this:
http://users.utu.fi/slaur/smc2632w-v2-6.jpg
http://www.passivecomponent.com/Images/ant_2450mhz.jpg

http://www.passivecomponent.com/docu...t_Overview.pdf

http://www.passivecomponent.com/Docu...atalogue01.pdf




> Better idea. Leave the chip antenna in place. Cut the trace near the
> top of FL1 as close to FL1 as possible. Attach the coax center
> conductor to the top lead of FL1. Connect the ground to the large
> ground area to the left of FL1. Keep the exposed center conductor
> *VERY short. C53 apparently acts as a DC isolator from the PIN diode
> diversity switch chip (half way hanging out from under the shield).

I don't know... why there is also L7 and C3?
I would to unsolder the bluechip, cut the waste area under the bluechip
(it's not used!), put on the chassis an SMA-RP connector and connect it at
L7+ground by RG316 (or RG196) teflon cable.

It seems a good idea...

Tomorrow I'll try...
Thanks for support.

"Tazzulella" <(E-Mail Removed)> ha scritto nel messaggio
news:43890236$0$8500$(E-Mail Removed)...

>
http://www.passivecomponent.com/docu...t_Overview.pdf
> http://www.passivecomponent.com/Docu...atalogue01.pdf

What's the meaning of WTC?

On Sat, 26 Nov 2005 21:55:35 +0000 (UTC),
(E-Mail Removed) wrote:

>Jeff Liebermann <(E-Mail Removed)> wrote:
>> Better idea. Leave the chip antenna in place. Cut the trace near the
>> top of FL1 as close to FL1 as possible. Attach the coax center
>> conductor to the top lead of FL1. Connect the ground to the large
>> ground area to the left of FL1. Keep the exposed center conductor
>> *VERY short. C53 apparently acts as a DC isolator from the PIN diode
>> diversity switch chip (half way hanging out from under the shield).

>I'd say that was c35, but I might be reading upside down ;-)

Y'er right. It's C35.

>What about a 35mm monopole sticking up from the board, at the top of FL1,
>poking into a cantenna? I suggest 35mm presuming that the shield seen in
>the photo would be soldered to the side of the can, leave 31.1mm exposed
>inside the can.
>
>http://www.turnpoint.net/wireless/cantennahowto.html

Incidentally, John Navas wrote a page on build your own antennas:
http://en.wikibooks.org/wiki/Wifi:Building_an_antenna

The monopole will work, but not as good as a dipole. The reason is
not very subtle. The way the waveguide can antenna works is that the
dipole is roughly 1/4 wave from the bottom of the can. The bottom
acts as a reflector. When the signal from the dipole hits the bottom
of the can it reverses phase and bounces back toward the dipole. When
it hits, it's exactly 360 degrees (in phase) at 2.4GHz. That causes
any signal at the dipole to be reinforced by the reflected wave
bouncing off the bottom of the can. Reinforcement mean gain (a good
thing).

However, if the bottom is not exactly the correct distance from the
dipole feed, then one gets partial reinforcement or at worst,
cancellation. That's the problem with a monopole versus a dipole.
Half the signal is missing and there's no place for anything reflected
off the bottom, on the ground side, to provide signal or gain. The
monopole side of the USB adapter will work, but the antenna gain is
that of an antenna half the diameter.

Drivel: With the common side mounted monopole, the reflecting bottom
is not exactly 0.250000 wavelengths from the dipole feed. It's
usually a bit farther. With a dipole, it will be closer to 0.25
wavelengths. In my non existent spare time, I've been tinkering on a
proper model for the coffee can antenna:
http://members.cruzio.com/~jeffl/crud/coffee-can05.xls
based upon work by Ivor Hewitt.
http://www.ivor.it/wireless/cantenna.html
I can change the monopole feed to a dipole or suspended monopole and
see what happens. The spreadsheet still needs LOTS of work and
checking and is nowhere near done. The results looks something like:
http://802.11junk.com/jeffl/pics/ant...400/index.html
Note the conical monopole feed. Volunteers and criticism graciously
accepted.

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

On Sun, 27 Nov 2005 01:47:49 +0100, "Tazzulella"
<(E-Mail Removed)> wrote:

>Or this:
>http://users.utu.fi/slaur/smc2632w-v2-6.jpg
>http://www.passivecomponent.com/Images/ant_2450mhz.jpg
>http://www.passivecomponent.com/docu...t_Overview.pdf
>http://www.passivecomponent.com/Docu...atalogue01.pdf

Thanks. That's the part by Walsin. I couldn't find the manufactory.
0 to 2dBi gain.

>I don't know... why there is also L7 and C3?

It's part of a Pi section matching network or low pass filter (or
both). The RF path starts at the PIN diode diversity switch (half
exposed from under the shield). It then goes to FL1, which is a
2.4GHz bandpass filter. C35 and C33 provide DC isolation. Usually,
there's a u-FL test connector next, but it appears to be missing. The
Pi matching network consists of C34, L7, and C33. Then, it goes to
the 50 feed at the antenna. The Pi matching or lowpass network is
probably there because the residual pad to ground capacitances and
uncompensated lead inductances result in not quite a 50 ohm system.
The lowpass function is also handy to help meed FCC spurious and
harmonic content specs.

>I would to unsolder the bluechip, cut the waste area under the bluechip
>(it's not used!), put on the chassis an SMA-RP connector and connect it at
>L7+ground by RG316 (or RG196) teflon cable.

That was also my original suggestion. However, I wanted to take the
long leads and the filter out of the circuit and connect as close to
the bandpass filter as possible.

Good luck.

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

On Sun, 27 Nov 2005 02:19:51 +0100, "Tazzulella"
<(E-Mail Removed)> wrote:

>"Tazzulella" <(E-Mail Removed)> ha scritto nel messaggio
>news:43890236$0$8500$(E-Mail Removed)...
>
>>
>http://www.passivecomponent.com/docu...t_Overview.pdf
>> http://www.passivecomponent.com/Docu...atalogue01.pdf
>
>What's the meaning of WTC?

Walsin Technology Corporation.

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