The K3565 dongle that Vodafone supply with their pay as you go plan is excellent, but frustratingly the external antenna connector is hidden under the casing. Here's how to hack the casing to get at that hidden connector - and for those who want to go the extra step, how to wrap the dongle in a neat little enclosure for a professional look.
(Please note that you won't be able to access the SIM card or the onboard Micro SD socket if you go for the enclosure.)
Step 1: Parts and Tools
Vodafone K3565 / Huawei E160X USB 3G dongle
Huawei 3G Plug to SMA Socket pigtail (PIG-HUAWEI-SMAS-30 from Solwise in the UK, other suppliers unknown?)
75mm x 50mm x 27mm enclosure (Unscreened or Screened)
3G external antenna with SMA connector
5mm drill bit
Small Phillips / Pozidrive screwdriver
Fine-grain sand paper
Nut & washer for SMA connector OR epoxy resin (depends how lazy you want to be about fixing the external antenna connector to the enclosure!)
Step 2: Make Our LED Brighter
If the 3G dongle is to be mounted within the enclosure, we need some more light from our status LED, currently barely visible through the semi-opaque casing.
I simply took a flat file to the area above the Vodafone logo to remove the semi-opaque coating, and then polished with some fine-grain sandpaper.
For maximum light you'll want to drill a hole in the upper shell of the casing and led the LED shine bright into the enclosure; this approach will give a much brighter indicator.
Step 3: Disassembling the Dongle: Remove Screws
There are two small cross-headed screws on the underside of the dongle - remove them with your screwdriver.
Step 4: Prise Open
Starting from the end with the screws, prise the casing apart. A plastic pry tool used for opening mobile phone casings is ideal for this, just try to use something other than a screwdriver (which would damage the casing). You can afford to be fairly rough with the casing, just make sure you're not flexing the circuitboard inside.
Step 5: Look for External Antenna Connector
Here's our prised-open dongle, and our external antenna connector's hidden under the second white tab from the left on the circuit board. Hopefully it's in the same place on yours.
Step 6: Connector Close-up
Here's what we're looking for - this small cylindrical connector in the centre of the frame. Doesn't look too robust, which is why I consider the enclosure a worthwhile effort.
Step 7: Mark Up the Area for Filing
The lower half of the casing's going to bear the brunt of our filing. A pre-emptive attack with cutters might make the end result a little neater, but a file will make short work of the casing.
Step 8: File Away Until the Connector Fits
A little rough around the edges, but as you can see from the photo the pigtail connector now fits snugly.
Step 9: Enclosure: Create Hole for USB Connector
We don't have much space in our enclosure, so it's important the hole for the USB connector is placed correctly. Cut the hole using your method of choice - mine is shown on the right, by drilling a couple of 5mm holes and then filing them out.
Step 10: Drill a Hole for the SMA Connector
A 5mm hole drilled 9.5mm away from the side of the enclosure will help lock the hexagonal connector against the side of the enclosure, preventing the pigtail connector rotating when the external antenna connector is screwed / unscrewed. It's up to you whether this connector is mounted on the opposite side of the enclosure to the USB connector or on the same side.
Step 11: Insert the Dongle Into the Enclosure.
Filing the USB connector hole at an angle towards the top of the box on the inside will help here - just connect up the pigtail connector, coil the wires at the bottom of the box as best you can (a better job than I did here would be nice!) and slide the dongle in while bending the heatshrink on the pigtail. Try and make the connector at a right angle as well - the configuration shown below is putting a little more strain on the dongle's antenna connector than necessary.
As you can see here, I elected to keep the SMA connector in place with epoxy resin. A nut and washer would have done the job a little more neatly if I was able to source them.
Step 12: Drill a Hole in the Lid for the Status LED
That 5mm drill bit will come in handy once more; providing a good-sized hole for our status LED. (You want to make sure the LED is directly below). The label will diffuse this light and hopefully give us a visible indicator, but you can always drill out the top of the dongle's casing above the LED if you need more light.
Step 13: The Finishing Touch
Avery template L7165; an A4 sheet with 8 99.1x67.7mm stickers, provides a very good size for giving the finishing touch to your 3G modem. (PDF / Adobe Illustrator file attached.)