Coathanger GPS Antenna - Page 1
Forum section: electronics / general

author: @rt
author_rank: Super Contributor
timestamp: December 04, 2016, 02:28:09 am
content: Everyone knows that terms like Resonance, Tuning, Impedance Matching, etc.are just big words that RF people use to sound smarthttps://www.youtube.com/watch?v=JCHmJBmL0WQ&feature=youtu.be

author: Rerouter
author_rank: Super Contributor
timestamp: December 04, 2016, 02:34:17 am
content: You can technically use anything as an antenna, it doesn't mean it will be a very good one,especially with stuff like GPS or 3G data modems, where the receivers are insanely sensitive, In part i would have expected that just with the piece of wire you cut left it would still hold lock for some time, as i have seen it myself when a device giving intermittent positions turned out to have the antenna snipped by someone. and was just recieving off the lead.

author: @rt
author_rank: Super Contributor
timestamp: December 04, 2016, 02:45:06 am
content: Yes, the wire did maintain the fix, but couldn’t be used on it’s own to acquire one.Just something I’ve been meaning to try, and finally got round to it.I want to compare various helical and ceramics in constant position drift tests, so I suppose I have a new contenderIn a recent mod to one of my projects, connecting a new ceramic to an SMA turned the pin at the recepticle enoughto break the wire on the PCB side. That had me worried till I found it, and was actually the cause of my making a spare module up.It could get the time/date, but never a fix. There would perhaps have still been some capacitive connection though.Cut from here, the largest electronics forum, pasted into a FB amateur radio group for Australia only, and of course,that’s where the winner comes from

author: Halcyon
author_rank: Unknown
timestamp: December 04, 2016, 07:04:23 am
content: Please, Aussies have been using metal coat hangers as antennas for decades!

author: @rt
author_rank: Super Contributor
timestamp: December 04, 2016, 08:52:29 am
content: That has a very expensive ground plane though, and extra points for 1575MHz

author: Howardlong
author_rank: Super Contributor
timestamp: December 04, 2016, 09:32:01 am
content: Judging by the methods used to "feed" the antenna, I'd hazard a guess that this would work just as well if not better without any coat hanger at all, the feeder looks like it's a reasonable antenna all on its own!

author: salbayeng
author_rank: Frequent Contributor
timestamp: December 04, 2016, 09:45:18 am
content: I've made 2.4gHz antennas by ringbarking some rigid coax at 1/4 wavelength, and pushing through a hole in some copper clad PCB and soldering it, worked as good as any purchased antenna.It was being used with some analog video sending gear, so fairly easy to see 1 to 2dB of difference.

author: VK5RC
author_rank: Unknown
timestamp: December 04, 2016, 10:00:25 am
content: I like the quote re microwave feed horns, "built with a micrometer, tuned with a hammer" - well actually a ball bearing, magnet then drill a screw in.

author: Fraser
author_rank: Super Contributor
timestamp: December 04, 2016, 12:19:21 pm
content: Receiving antennas have always been less critical in terms of dimensions. The tiny Mini HF 'probe' type antennas that just use a FET impedance converter to match the impedance to the receiver prove that tiny postage stamp receiving elements will work (within limits) to receive signals of large wavelength.The challenges occur when you want to transmit into a radiating element. Impedance matches do matter then and efficiency can be important. Transmitter antenna design can be black art when you deviate from common formats like monopoles, dipoles, and loops.As has been stated, some of the GPS like SIRF III have amazing sensitivity and can even achieve lock within some buildings.I wonder who was the first person to stuff a metal coat hanger into a cars aerial base and in what yearSadly that was often required as a result of some turd ripping the antenna off 'for kicks'.I have always been interested in antenna design and performance at Microwave frequencies. Nice and small, and quite critical in terms of dimensions when transmitting into them. You can have a lot of fun experimenting with antennas .... especially those that need to be directional. I applaud experimentation and design through practical testing rather than just using maths.Take a look at the Vivaldi antennas..... a mathematical work of art. Then there is the Spiral dipole antenna that was created through practical experimentation long before the PC or even 8 bit computers existed.Fraser

author: rrinker
author_rank: Super Contributor
timestamp: December 04, 2016, 08:19:18 pm
content: Quote from: Halcyon on December 04, 2016, 07:04:23 amHmm, is that an Aussie Antenna, or an Antenna Aussie?