bigclive
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How I used to link to the "net" while travelling
🕑 Added 2024-09-08 13:45:54 +0000 UTCIn the early days of the Internet, finding a connection was often very tricky while travelling.
I used this antenna to find open networks, as a mobile Internet connection was not a thing back then. I often had to hold it out of open windows and try and grab my mailing list and newsgroup updates with Demon's Turnpike software.
Comments
Big Clive
A small coaxial connector for the WiFi USB dongle I used.
Andreas Schuderer
What‘s at the other end of the mystery cable?
Mike Page
Not that I do RF but it might have been fun to connect a network analyser to it.
Ronald Peterson
This web page gives some clues on how to design a simpler version of this patch antenna: https://teaandtechtime.com/2-4-ghz-patch-antenna-design-with-matlab/ Matlab can be quite expensive. The slots where the cable attaches are used to adjust the impedance of the connection point to 50 ohms. The width of the antenna seems to be the primary adjuster of frequency. The ground plane does indeed have to be a precise distance away to get the right frequency.
Richard Pruen
It has been a long while, I think you are correct, it would act a little like the beam forming antennas made from just coaxial cable, the shorted sections at the end add capacitance, but also are active parts of an array. Those are 10-20m band so way bigger of course. I would be interested in the results if you do look into this further. Thanks.
NN Thomas
If I remember correctly the metal on the PCB is the antenna and the parts where the metal is missing act as a capacitor for tuning.
richard ockman
Yes a patch antenna , people also made antennas from Pringles Potato chip cans for WIFI, google it.
Seán Byrne
I have an old Ubiquiti Powerbeam M5 from a previous wireless ISP I was with 9 years ago that used it as their CPE. They used 802.11a Wi-Fi P2P instead of WiMAX that most other wireless ISPs used. I did a factory reset and then a network scan set up on a camera tripod aimed at my brother's house about 200m away. My phone sometimes lists his Wi-Fi network standing out side, but cannot connect. The Powerbeam M5 not only connected on the weaker 5GHz band (after providing the Wi-Fi password), the signal meter was maxed out, although can't remember the dB reading.
Andromeda Turnbull
Yes, I made those back in the day! They worked surprisingly well, actually. In this particular design, the two side elements are functioning as part of an array rather than "cuts" as it were into a single element patch. I believe (though I haven't modelled this yet) that it is the gain at the peak cross section in the centre of the field that is improved through better directivity but I would need to check that.
Richard Pruen
I used to use a dipole spaced off the metal bottom of a well known snack that comes in a tube with foil lining. AKA the cantenna You have a patch antenna, that does the same thing, but without the tube as the directional element. The cuts in the edges of the copper will help to stop signals from the side swamping out the more distant signal. The cantenna would work up to 1 mile at full speed, with just a normal antenna on the AP, with 2 cantennas 5 miles was easy, I didn’t really try any further, not needing any extra. Of course another AP in the line of sight would mess things up, but back then it was unlikely.
Andromeda Turnbull
Yes, I (not so fondly) remember trying to get my email on a Psion Series 7 via IrDA - anyone remember that? - using a Nokia 6210. It really was like trying to accomplish some form of religious ritual.
Andromeda Turnbull
Nice to see you here again, Keri! Laughs, sadly it's actually boringly witchcraft free with this one (see explanation above) but some of the newer low profile dielectric antenna designs really *are* witchcraft in my book.
Andromeda Turnbull
Oh, and as a p.s. I actually made something a bit like this once in a hotel room using copper tape for the stripline and a piece of raw PCB board, with the patch antenna outline cut out using a craft knife. The tape was put on the non-conductive side of the board allowing the unetched PCB copper on the other side to act as a ground plane. In this case it was to try to get better 3G reception for a little mobile hotspot unit so it was tuned for GSM, but it's the same principle. The results were kind of disappointing (slightly improved gain and SNR, not much) but the antenna did work.
BeatboxNorwich
I use an old ironica dish hooked up with to a WiFi device. Picks up Signals up to 3km away
Andromeda Turnbull
This is something called a patch antenna built as a microstrip, but of the extremely old fashioned variety (similar to some I've seen from the 80s): https://en.wikipedia.org/wiki/Patch_antenna - in this case with two tuned extensions made similarly to a dipole to improve the polar plot, called a high gain array. More modern designs in use for similar microwave applications tend to have more complex geometries but for the original 802.11a/b type Wi-Fi this would work fine, I guess. The only issue with the design is that the effective radius of what the antenna can "see" will cut off very sharply at the edges, although this might have been intentional to reduce unwanted reflection since the sensitivity of transceivers back then was rather "touchy," I recall. If you could get a vernier out and measure the dimensions of each element of the array and their positioning, I can calculate a polar plot diagram for you.
Dave Roberts
Ah the steam days of computing! It seemed like incredible technology at the time. Looking back now it’s a bit laughable but when you’d never been able to do this sort of thing before it was like science fiction!
Keri Szafir
Witchcraft? The vacuum tube witch got ya covered.
