:rolling: would those stickon cell phone antenna's help to improve the wifi signal?
Those stickon cell phone 'antennas' are fake. :exc:
They are nothing more that non-conductive ink printed on plastic. I know - I've test several of them. So has the FTC in the US, which ordered a number of companies to stop selling them.
Kind of the same subject I owned a HP 5555PPC a few years back. This unit had a black nub on the top with an internal wire on the inside. With this external antenna I had amazing wifi reception, never owned a better unit for wifi range.
I see the space you are talking about between the SD and CF cards. I admit that this is gettig a little over my head on the technical aspect of it, however, I am very interested in finding out if this is possible. I would love to help you brainstorm or test anything you can come up with.
[EDIT: I should clarify I am using an x50v. I just noticed that this thread originally related to the x51v. Don't know if there is a difference]
Doug
Antenna gain is a great thing for a point-to-point link, but not particularly good for a mobile device. Gain is derived by taking signal that would otherwise go in various dirctions and focusing it into one direction (think of the reflector in your flashlight). If you take the reflector off a flashlight the bulb is equally dim in all directions, with the reflector it is bright in one direction, that's gain, just on very short wavelengths.
For a mobile device it means you'd have to point your Axim in the right direction to get the main lobe of the antenna pointed where you wanted it, it doesn't sound particularly useful.
On the other hand I don't know what kind of radiator they use inside the Axim, the best choice might be to look at that and see if it could be improved. Lots of mobile antennas are terrible. Those "rubber duckies" on top of mobile radios are often 10dB or more down from a real quarter-wave radiator, meaning only 1/10th as efficient. For the axim a couple of 1/4 wave radiators or a couple of dipoles at that wavelength, etched onto a circuit board, would be a good high efficiency diverse antenna and easy to do.
If you're talking about improving reception at home, antennas can be useful. My property is long and relatively narrow, with the house at the very front. I have a 17 dB patch antenna hooked to my wireless access point that is aimed down the length of my property so I can be out in the back yard or up to about 300' from the house and still have wifi. The gain of the antenna focuses the signal where I want it, aimed from front to back of my property, and the gain works both on transmit and receive. That's an example of where gain antennas can be of use.
I see the space you are talking about between the SD and CF cards. I admit that this is gettig a little over my head on the technical aspect of it, however, I am very interested in finding out if this is possible. I would love to help you brainstorm or test anything you can come up with.
[EDIT: I should clarify I am using an x50v. I just noticed that this thread originally related to the x51v. Don't know if there is a difference]
Doug
Thanks - I have an X50v as well and the internal construction is identical to the X51v.
mdanehart - there is no antenna connections or audio connections on the CF slot or the SD slot. The WiFi antenna is located on the top edge behind the word AXIM on the front cover of the PDA. The bluetooth antenna is located in front of the earphone jack behind the front cover of the PDA.
Antenna gain is a great thing for a point-to-point link, but not particularly good for a mobile device. Gain is derived by taking signal that would otherwise go in various dirctions and focusing it into one direction (think of the reflector in your flashlight). If you take the reflector off a flashlight the bulb is equally dim in all directions, with the reflector it is bright in one direction, that's gain, just on very short wavelengths.
For a mobile device it means you'd have to point your Axim in the right direction to get the main lobe of the antenna pointed where you wanted it, it doesn't sound particularly useful.
On the other hand I don't know what kind of radiator they use inside the Axim, the best choice might be to look at that and see if it could be improved. Lots of mobile antennas are terrible. Those "rubber duckies" on top of mobile radios are often 10dB or more down from a real quarter-wave radiator, meaning only 1/10th as efficient. For the axim a couple of 1/4 wave radiators or a couple of dipoles at that wavelength, etched onto a circuit board, would be a good high efficiency diverse antenna and easy to do.
If you're talking about improving reception at home, antennas can be useful. My property is long and relatively narrow, with the house at the very front. I have a 17 dB patch antenna hooked to my wireless access point that is aimed down the length of my property so I can be out in the back yard or up to about 300' from the house and still have wifi. The gain of the antenna focuses the signal where I want it, aimed from front to back of my property, and the gain works both on transmit and receive. That's an example of where gain antennas can be of use.
Good points.
Actually, I'm looking at using an omni-directional antenna that is inductively coupled to the internal. Have a look at the internal photos in the FCC link in my prev post. You can see that the internal antenna is positioned at the edge of the PCB and that a small (thin) inductive pickup (most likely a short matched stripline) could be positioned in parallel just above it, just inside the case.
It would be nice if there was a 50ohm takeoff inside as I would just bring an SMB connector outside the case. However, I'm looking at something that could be made without opening the case. The biggest coupling issue is impedance matching.
Uh, isn't a 17dB gain slightly above what the FCC allows for type 15 equipment?:)
Could you put an antenna into the stylus slot on the Axim?? That is very close to where you describe the internal wifi antenna as being. Then, you coudl have some kind of a sliding antenna that you could slide in and out of the stylus slot. Or, is that space shielded??
Could you put an antenna into the stylus slot on the Axim?? That is very close to where you describe the internal wifi antenna as being. Then, you coudl have some kind of a sliding antenna that you could slide in and out of the stylus slot. Or, is that space shielded??
Doug
Now why didn't I think of that?
Actually, the second problem with my antenna idea is how to attach it to the case. By using the stylus slot as a base, the antenna could be made longer as it would have a solid mechanical fit into the housing of the PDA.
This is a good idea. Thanks.
Now to work on the RF matching design. I'm going to try and find the source for the antenna used in the X50v so I can get the specs.
This idea will only work with WiFi. The BT antenna is on the opposite side and uses a ceramic chip as a radiator. BT is intended as a short distance protocol anyways, so it's not really that important. I can get about 25-30 feet between my Axim and BT headphones.
Yeah, I don't really need more range on my BT, I was just curious.
Its funny how ideas come to you sometimes. I was just grbbing my stylus and looked in the hole and went, this would be a great place for a retractable antenna. :) Like I said, I can help you out with the design and function. The technical aspects, I'll just nod and agree a lot. :) And, just put my name on the patent and the idea is all yours. :)
Yeah, I don't really need more range on my BT, I was just curious.
Its funny how ideas come to you sometimes. I was just grbbing my stylus and looked in the hole and went, this would be a great place for a retractable antenna. :) Like I said, I can help you out with the design and function. The technical aspects, I'll just nod and agree a lot. :) And, just put my name on the patent and the idea is all yours. :)
Doug
Can't patent it - too much prior art. Maybe a design patent (what it looks like), but not a utility patent (functionality). Also, once something has been described in a public forum, there are critical time constraints to getting a patent, if at all.
But hey, we're doing this for the good of all, right?
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