You can remove internal antenna, but I would not try to turn on WIFI without external antenna, it would be the worst decoupling you could build. I do not know if internal circuit is prepared for that.
I have no idea about BT antenna, it could be the same but I do not think so.
Does anyone located BT antenna?
The BT antenna is beside the microphone and the WiFi antenna is beside the wireless status LEDs
I have considered retrofitting my CF WiFi card with an antenna; this would work without the same risk of causing damage to my PDA, and the CF card only cost me $20 or so. Gonna start sawing now...
Has anyone else tried this and if so did they notice any improvements
with an external antenna? Where there any problems with both
antennas connected at the same time?
For taking your PDA apart, voiding the warranty and have a chance of breaking it. I would like to see the affects of having another aerial atached but first of the signal is only 802.11b meaning it doesn't have a great range to start off. Even with an added directional aerial there isn't going to be much improvement. I have a network where my PC is located about 200 meters away (line of sight) and I have an 8db wireless dish (802.11g) a D-Link extra range wireless point and a directional 4db aerial plugged into it and i get a good to very good signal, so even if you do have an extra aerial its not going to make much difference if you dont have a high range on your router or wireless point. Would be great if you could extend the range on the bluetooth though! Oh and the finished PDA looks like it was suppose to have a aerial connector on the side.
If your looking at doing this project though heres a website for wireless gear
lol, you want to talk about adding distance? Check out WiFry, a group of college students used standard metal woks to amplify and direct WiFi and made massive improvements in distance, to the point that in one expariment, using the old 4-6' satelite dishes, they got 1 -5 Km of range!!! and even a 1km BT range!
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lol, you want to talk about adding distance? Check out WiFry, a group of college students used standard metal woks to amplify and direct WiFi and made massive improvements in distance, to the point that in one expariment, using the old 4-6' satelite dishes, they got 1 -5 Km of range!!! and even a 1km BT range!
I'm interested in this topic as I'm wanting to find out if I can shield myself from the WiFi signals more effectively as well as shielding from the 'non rf' signals produced internally in the Axim. The reason being is that I seem to be electrosensitive. I know this is a controversial claim that has not yet been proven scientifically in studies that have so far been done, but I'm sure I'm noticing unpleasant effects from the signals produced by this device, amongst other devices like it, and therefore want to see if I can do something about it and still enjoy using the device.
So, how can I better control the path of the WiFi signal? In my opinion, these devices should have been built with provision for an external WiFi antenna in the first place. I'm not too sure about hacking into it to see if I can modify it the way it has been described in this thread even though I have constructed electronic kits and the like before. It's a bit tricky and assuming it were successful, I wouldn't want to end up with an impedance mismatch. Does anyone have any other suggestions? Mine is the X51v model. Thanks :)
I had a similar idea. A small dipole antenna to couple the energy to a connector
for an external antenna. I was going to build the coupling antenna onto
the base of a "chip clip" one of those clothespin type devices to seal the bag
of a potato chips. I was thinking all I had to do is clip it to the top of the x51v.
Ken
Originally Posted by bigbop
Correct.
Also, by connecting an external antenna in parallel with the internal antenna, you will create an impedance mismatch on the output of the RF amplifier module. This increases the VSWR (voltage standing wave ratio) which is an indication of how much RF energy will be reflected from the antenna circuit back into the amplifier, causing reduced output and possible damage to the RF output.
Ideally, you need to disconnect the internal antenna when you connect the external one. When you're dealing with RF energy in the microwave region, you need to be careful how you match the components.
If you look carefully at the PCB, you will notice a small round connector just below the internal WiFi and BT antennas. Those are the manufacturing RF test points. They are actually switches that disconnect the internal antennas when the board is connected to the manufacturing test equipment.
My original thought on an external antenna was to design small RF transformer that would sit on top of the case just above the internal WiFi antenna. That way you would not have to open the case. This would be similar to the way that cellphone antennas on cars are coupled through the windshield.
I have attached a photo of the WiFi antenna area showing the test connector. You will see there is an impedance matching circuit that consists of a coupling capacitor, an inductor and an RF stub (the part of the WiFi antenna between ground and the spot where the trace connects to it from the capacitor). Even the length of the trace between the capacitor and the antenna affects the impadance at 2.4GHz. Connecting your external antenna to this point will screw up the matching and might cause problems, so please be aware of this.
If you want to connect to the input of the connector, you will need to add a coupling capacitor of about 100pF (picofarad). The best way is to use an electronic switching circuit that uses biased PIN diodes to switch between the two antennas. Unfortunately, that is out of the scope for 99.99% of most forum members here.
I had a similar idea. A small dipole antenna to couple the energy to a connector
for an external antenna. I was going to build the coupling antenna onto
the base of a "chip clip" one of those clothespin type devices to seal the bag
of a potato chips. I was thinking all I had to do is clip it to the top of the x51v.
Ken
Without having a good ground connection to the Axim's main board, your idea won't really work.
My idea was essentially a passive radiator loosely coupled to the main antenna. The coupling has to be really good which means you have to get right up against the existing antenna.
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