About that wireless CF-28 mod...

I've got a CF-28 with a RIM R902m modem. I'll be adding Wi-Fi by following mnementh's mod that uses the factory RIM antenna. I just need to pin down some details.

Antenna in the upper left corner is around 7cm (2.7") long - is it long enough? Some models seem to have a way longer one.

In this thread, you're saying to replace the factory wire with one with a U.fl connector on one end and have the other end soldered to the passthrough connector. In this thread, mnementh simply used the factory wire and connected its MMCX end to the U.fl connector on the Wi-Fi board using a homemade adapter. My question is: if I find one, is it really OK to use such an adapter and keep the factory wire? If I don't find one, is it OK to use instead a MMCX female to U.fl pigtail cable?

Also, I noticed that mini-PCI Wi-Fi cards like the Engenius EMP-8602+S have two U.fl antenna connectors. From what I understand using only the modded RIM antenna should be enough. How much of an improvement would a second antenna bring, for example one attached to the side of the laptop?

 

There are several possibilities.

One is that your ToughBook came with Wireless A/B connected to that external antenna; that 2.7" antenna would be just about right for that. I've never actually SEEN this model, but I am told it exists.

It is possible there is something wrong with the antenna such that it doesn't extend all the way.

Perhaps someone put an antenna from a different model on your ToughBook; if you look at my instructions, you'll see that it unscrews easily from the antenna base. I believe they use the same base across several family lines.

The homemade adapter I used is deliberate; hacksoldering coax together CAN cause impedance matching problems, especially for those inexperienced with soldering. The pieces I used are DESIGNED for such use; and the cables I used are factory made. One with uFL connectors at each end, one built into the ToughBook. My desire was to get it working for testing without taking everything apart; 3 years later, it's still working perfectly with great signal gain.

Yup. Using only the modded antenna will be plenty for most; you CAN add a bulkhead mount antenna to connect to an external antenna, but I never cared for the "easily-breakable-off-ness" of such setups.

Inspect the antenna base very carefully as I've shown in the close-up pictures of the SMD coil/resistor array. If it differs from the configuration shown in the photos, it may very well be you have one of the WiFi antenna models. If it is the same, then you probably have the CDPD antenna base and someone has put the wrong antenna on it.

I say connect it up and try it if it's the former; you're not going to fry anything and I'd be curious to see how it works. If the latter, do the SMD coil removal hack as I've outlined THEN try it with your antenna. This is a case where all the armchair engineering in the world won't come close to a little trial & error. If it sucks, THEN look for a regular long antenna; I'm sure there are members here with a few lying around. I might have one myself, but I have no idea where.

If it helps, the extensible WiFi antenna on my old ViewSonic tablet is just about 2.7" long; so that is probably a reasonable resonant length for 1/4 wave use.

mnem
Wahey! WiFi!

 

The antenna base is slightly different than the one in your mod.

The antenna is a bit over 7 cm.

The Toughbook model is CF-28S3QGBDM. Inside the laptop there's a grey cable with a MMCX connector going to the RIM modem. On the back of the Toughbook the modem is mentioned as RIM R902M-2-0.

Again, would it be OK to use a short MMCX to uFL cable, to link the MMCX connector of the grey cable (that is now connected to the modem) to the uFL jumper of the mini-PCI card? I don't see the need for an additional uFL to uFL cable...

 

MMMhmmm...

It looks like your antenna base is indeed wired completely differently than the typical CDPD antennas I'm familiar with. It's using a capacitance/inductance bridge as a bandpass filter, while mine use an inductance/inductance bridge.

The interesting thing is that the RIM R902M-2-0 is listed as a 900MHz radio module for Mobitex Carrier; this is the same band as the other RIM modules I've seen with my antenna configuration.

I have no idea why the antenna configuration is so different between the two models operating on the same band; I need to think on that a bit.

Yes if you can find an adapter cable with MMCX female on one end and uFL on the other, or if you are sufficiently adept at soldering to solder one end of a uFL cable on the end of the output connector robbed from that RIM MODEM, then by all means use it. That semi-rigid cable is VERY low loss; that's why they use it. The main reason I made the adapter I made was because I had a uFL to uFL patch cable handy. If I hadn't, I'd probably have made an adapter cable myself.

Make very sure you are getting the right end on your adapter however; look very closely at your RIM MODEM to be sure you're getting a female connector, not male.

mnem
Balanced load.

 

From IIB Central (Ignorance is bliss) that sure looks like a CF-29 Antenna.

 

Hello. Interesting thread. Long time ago, when Mnementh's mod was hot, I was going to do it, but my antenna was different. The computer has the same, short pull out antenna and antenna base same as cib3k's. The wireless modem is different. It's Sierra wireless CDPD model SB300. The complete computer model is: CF-28S3JGZDM. Regards, Voytek.

 

The CF-29 antenna is shorter. CF-28 is 77mm , CF-29 is 70mm. This is total lenght of the unscrewd, pull out. The antenna base on CF-29 is different, but the "little coils etc." look similar. My CF-29 antenna is used with HSDP 3.6 WWAN. Complete model#: CF-29LTQGZBM. Any verdict yet if the one from CF-28 can be used as decent WIFI antenna? Regards, Voytek.

 

Ummm... What? You mean the short one like cib3k has? The difference between 70mm and 77mm is most likely fine tuning for a particular radio module. What we're talking about is the difference between that and the more common CDPD MODEMS for the CF-28 which use a 160mm (approx) antenna.

We know the 160mm antenna works great with my hack; I haven't ever gotten any of the 70mm-ish type antennas to putter with, but no reason to believe they won't.

Worst case scenario: you mod the antenna base and find that reception sucks, then you replace the short antenna mast with a longer one from a CF-28. You're not going to hurt anything by trying.

mnem
Empirical engineering: it's what's for breakfast.

 

My CF-28 antenna is 77mm long not 160mm. The antenna base is the same as on the pictures in this thread. Any alterations to be done there to make it work as WIFI antenna? More and more CF-29 are comming on the market and I belive, that newer models have short antennas. Full investigation into this matter of moding it is beyound my abilities. If you like, I will send you the antenna and the rest to look at it. Just let me know. Regards, Voytek.

 

Yes, mine is 77mm.

It seems the PCB of the base of my antenna is the same as the one in mnementh's original hack. I'd say that regardless of what one has on this PCB, the idea would be to remove all the capacitors/coils and try to make this connection by using your own 0 ohm resistors or wire/solder.

Then, time to check how it works with the 77mm antenna. If it works fine, great! If it doesn't, the 77mm antenna could be replaced with an 160mm one. Which I don't have, so this would be a problem for me. Not many people have toughbooks here, and nobody sells this on fleabay.

Anyway, I won't be able to make any kind of tests for a month or two, until I get a MMCX-uFL wire. I'll probably be using a stock Intel wifi card from another laptop; I already asked on another thread if somebody would help me get an Engenius from the US, but nobody is willing.

 

There is a Cisco internal wifi card and antenna for sale now ....

Panasonic Toughbook CF-28 CF28 Wireless Antenna & Card - eBay (item 120676681865 end time Feb-25-11 09:11:34 PST)

 

Ummm - NO.

Your antenna base is wired COMPLETELY differently; see the revised schematic below. The base itself is very likely the same; but they've gone from an inductor-inductor bridge to a capacitor-inductor bridge configuration.

Use the new schematic as your guide for this experiment.

mnem
Aerial-ness.

 

Again, what I was saying is that the PCB is the same. Just that you had coils on yours, and I have capacitors and coils, in different positions. If I remove all the capacitors and coils from mine, than add a 0 ohm resistor where the first capacitor used to be, then add a second 0 ohm resistor connecting this one to the solder blob above, I should get the same hacked antenna base as you, but with a shorter antenna.

And that whatever coils/capacitors one has, in whatever positions, as long as the PCB is the same, removing them and adding two 0 ohm resistors in the upper left corner as in your hack, would produce the same hacked antenna base.

Also, I see your drawing a bit different.

 

Yeah, I neglected to include the connector traces between the upper row and bottom row of components; I was drawing it by hand real quick. You clearly got the idea, so it's all good.

Well done!

mnem
Desperately seeking... something.