extending the range of the '30 wireless

the recent thread where the OP asked what the antenna on the left top of the display was for got me thinking ...

i am using my '30 in the recently revamped shed ... it is the only laptop i have that connects reliably to the wireless router .
signal strength is the issue ... a fair distance and intervening "stuff" .
sooo ... i am going to open up the '30 and connect the rod antenna to the WLAN card .
i can fine tune the extension length for maximum signal .
resonating to the frequency of interest should prove interesting as the antenna has a theoretical impedance of about 32 ohms (true for most ground plane + vertical element and center feed dipoles) .
i should be able to get the vertical portion to resonate at 5/8 wave length and this will provide 2 dB of gain over isotropic (as i recall and allowing for my first cup of tea) .
it may be possible to use the antenna as a multiple wave length (think 2 or 3 half wavelengths) , this will provide some gain .
the nice thing is that at the frequencies involved , the "Q" of the antenna itself should be low enough to make it fairly broad band .

more information as i progress .

 

When you get the antenna out, look at the base. There are surface mount devices to tune the frequency.
There is a thread somewhere discussing it..

Or you can be like me and install a 400mw WLAN card...SR71e

 

Oh boy I am listening!

I seem to remember reading that thread Shawn speaks of. It quickly went way over my head lol... That is what I love about this forum though, there are some seriously smart people hacking these machines and making them more than they were from the factory. Not an easy feat on such awesomeness to begin with.

But yeah I would think it could be put to better use than for the WWAN sled.

 

I believe the thread you are looking for was started by Paul (M nementh) and was in regards to the old pop-up antennas on the CF-28. Some of them were for the OEM WiFi and some, the long ones, were for the WWAN card. Happy hunting,
CAP

 

The Dwagon did some experiment with a CF-28 WWAN antenna. He bypassed and/or changes several of the coils or caps on the flex circuit at the base. I tried the mod with an EnGenius 8206 (?) 600mW wifi and it got a decent signal 1/2 way down my block, about 3-4 houses away.

 

snaking the coax back out of the installation path required the use of a razor/exacto knife to cut a piece of black plastic tape and the clear plastic that covers the coax leads in the channel of the cast frame/plate .
my results were way less than i expected ... now i know why ...
as my time was limited yesterday (yesterday ? HAH!) , i will tackle the problem late this afternoon .

it may be possible to build a "duplexer" or bandpass/diplexer circuit that will allow using the antenna for WLAN and WWAN simultaneously .
if the disparity between the two frequency ranges is substantial it will make the task much easier .
can we say "stripline" ... uuuggghhh .

any ideas on the past thread that was mentioned ?

/ me pulls vacuum on bottom of first cup of tea

 

it's in here somewhere..
This is a start, since I am time limited at the moment..
Work actually expects me to show up...
http://forum.notebookreview.com/search/852523/?q=antenna&o=relevance&c[node]=1012&c[user][0]=113679

 

here..

http://forum.notebookreview.com/threads/about-that-wireless-cf-28-mod.549561/#post-7079841

http://forum.notebookreview.com/threads/built-in-wireless-advanced-mods.215522/page-2#post-2981851

http://forum.notebookreview.com/threads/about-that-wireless-cf-28-mod.549561/page-2#post-7097587

 

Which led me here:
http://www.digitalairwireless.com/wireless-blog/t-5ghz/calculating-wavelengths.html

 

thanks for the links ...
my sked went upside down and backwards yesterday .
i might have better luck today ... it is raining ... no yard work !
i have to go over to a friend's house and off-load a couple of digital *old timers* stories and then edit them on my equipment .
"it's ok to plan the plan ... just don't plan the outcome"

i suppose i could build a "cantenna" ... but the tripod does not lend itself to portability .

 

I can help you out with an official Cantenna. Tripod unscrews....PM me....

 

i think i just PMed you ... or it went to something in the "profile" page ...
don't ya just love major software changes ?

 

having read/seen the pertinent poop in those links , it is quite east to see why a direct connection from the WWAN antenna coax and the wireless card will not work worth a tinkers dam .
interestingly enough the subject of using the antenna as a multi-band type is briefly discussed .
i would think that any "simple" bandpass/lowpass/highpass combinations that were not shielded from each other would have "leakage" problems .
the concern is not just getting the antenna to resonate in the given bands but also keeping the rx/tx of one card out of the rx/tx of the other cards ...
if there is insufficient isolation between "all parties involved" it is going to be an intermodulation mess with desensing of the receivers of each band .

sooo ...
it looks like "stripline" work would be in order here ... and the fact that an antenna that is simply "made to load up" by magic circuitry is not efficient .
i can load a rusty nail to a 100W transmitter on 15MHz but it wont "hear" or transmit worth a flip .
the best route in this case (for multi band operation) is to make the antenna into a "band trap" type ...
this design uses a parallel inductance and capacitance (think tank circuit) to divide the antenna into two resonant lengths ...
the trap circuit effectively divorces the longer section of the antenna when the inserted frequency is higher than the low frequency resonance .

all in all ...
this project looks like it is turning into a tough piece of steak ; the more you chew on it , the bigger it gets .

 

You, my friend are not the first to take a bite out of that steak...
I just pulled the pass throughs out and put a rp-sma connector there.
I screw an external WLAN antenna on if I need to. I have a thread on it here somewhere..