Need CF19 antenna

I am looking for wlan antennas for a CF19. There are some differences between mks.
I would like 2 sets of them so I can experiment with wifi antenna locations.
Ebay sellers are insane.

 

I must has a set here somewhere. Let me look. I think know I have 8 19 'some all apart .

 

Do you have any of the C1? antennas labeled DFUP1865ZA PbF
WWAN Aux+GPS
Fairly short lead...I soldered one and have a few spares. I assume they are for Gobi (considering the WWAN on the label)
Sorry for OT.

 

I am actually working on a CF31. I want to replace the Wimax antenna on the lid with a wifi antenna. I want to get the 2nd wifi antenna off the palmrest and away from the fan.
Length of the antenna is 3". A CF19 has a 3" antenna that has WWAN on one end and WLAN(wifi) on the other end. I want to use one of those to solder in to replace the CF31 stock antenna which has WWAN and Wimax on it.

Jeff, Do you need one for a C1 or are you offering me ideas?

 

How about out of an F-8 also,I have a couple of junkers.

 

As long as they are close to 3" I can experiment.

As you look at a CF31 screen, the antenna cover on the left is the antenna I want to swap.

 

Question...difference between wifi antenna and a bluetooth antenna?

 

Good question. BT and G/N range Wifi both use 2.4mhz. But Wifi can also use 5mhz. Wifi is usually longer distances than Bluetooth.
Larry, (CWB32) can answer this question much better than I can.

 

here is some basic info that is needed to understand what is going on :
http://www.radio-electronics.com/info/wireless/bluetooth/radio-interface-modulation.php

the article mentions "frequency hopping" ... pretty easy to visualize ...
this is also known as "spread spectrum" (in some circles) and is a basic premise for secure/encrypted communications .
also , by virtue of the fact that "noise" is random and is proportional to bandwidth of the "channel" , spread spectrum clamps down the bandwidth because only a very narrow pass band is needed and this can be shifted to stay in sync with the hopping .
this increases the signal to noise ratio .

the other trick that is used is the manner in which the signal is modulated (intelligence placed on a carrier) .
the article explains a couple of these methods in brief .

one could use the same length antenna for the frequency spectrum that bluetooth and wifi both use ...
in theory, it is always best to use an antenna that is resonant at the frequency/band you wish to deal with .
if the same antenna is used at double the frequency then the antenna becomes what is known as a "full wave" ... not the best but ok .
another method that is used is to use inductance and capacitance networks to shift the resonant frequency of a given antenna .
yet another method is to place multiple resonant antenna elements on a common feed ... each set of elements will "pick up" the frequency range they were made to resonate at ...
a look at a "bird catcher" tv antenna demonstrates this principle nicely .

the bandwidth of an antenna can be made to the correct frequency range desired ...
it is a function of frequency and the "Q" of the antenna .
the larger in diameter or surface area of an antenna element with respect to frequency , the broader the covered range will be .
a length of 12 ga. wire may have an acceptable resonance of (say) 50 KHz at 7.5 MHz while a length of 1" copper tubing will have a bandwidth of 100 KHZ .
a length of 12 ga wire can be made to resonate at 28 MHz and will have a bandwidth of 500 KHZ while a length of 1" copper pipe will have a bandwidth of 1.5 MHz .
the rule of thumb is that as frequency goes up the bandwidth becomes greater for a given system elements .
there are a few more particulars to this , but this covers the basics .

the higher in frequency the more "odd or unlike lower frequency antennas they look .
some of the wifi/wlan/wwan antennas look like a piece of metal that is cut and bent all to hell .

these are the basics of the principles involved .

@ shawn ...

you can use the wlan antennas from just about anything .
for best results , make sure they originally covered the band(s) you wish to use or use antennas that cover all the bands desired .
yep ... just about anywhere is better than the palm rest ... except for BT which is primarily short range on laptops .
there is no reason that there could not be an antenna that is designed to cover the three frequency bands ...
even if it were three individual antennas (similar to the first picture) .
perhaps the easiest would be to get what you need except for the bluetooth ...
a bluetooth antenna can be made by exposing .5" of braid on that microax and folding it back on the coax and exposing the center (think peeling back foreskin) .
tack the shield to "ground" on the antenna board or secure the coax "where ever" and bob's yer uncle .

 

Thanks Larry.

I would prefer a CF19 antenna because it is a dual antenna with an element at each end. The CF31 antenna I want to replace is a dual antenna also. The CF19 is wwan and wifi. The CF31 is wwan and wimaxx. I want to exchange the wimaxx for wifi. That keeps the wwan option available. I do have a single wifi antenna I could rig in place if I need to.
Maybe a CF-F8 will fit. I never owned one so I do not know what they look like.
A dual element with bluetooth and wwan would work also because it's the same frequency.

 

This is what I want to replace.