Comment by caseyy

Comment by caseyy 10 hours ago

8 replies

> I don’t think the idea for using transparent conductive materials as an antenna existed before

Many slightly older cars (2000-2020) had antennas embedded in glass. The idea is solid. Antennas in glass are protected, so they can be very thin and almost invisible, more aesthetically pleasing than a shark fin or a rod on the roof.

I would consider this an aesthetic choice, not so much engineering. A small antenna sticking out on the roof solves the engineering problem adequately.

HPsquared 10 hours ago

They still do, I believe. Cars usually have several antennas embedded in e.g. the rear glass. Even something like the FM radio often has 3+ antennas in different locations and the receiver switches between them to get the best signal. One shark fin isn't enough.

  • caseyy 10 hours ago

    Now shark fins are in vogue again because they house multiple antennas — FM/AM, DAB, GPS, and recently more importantly, 4G. Maybe even WiFi — weird as it sounds, I saw some strings for WiFi antennas in a popular stock media/head unit’s firmware.

    Though you are probably right and many cars with just FM/AM and DAB still put them in windshields.

    I’m not sure about that 3+ antenna claim for FM. Do a fact-check there. ;) I think most diversity antenna systems that you describe use 2. And they are still considered “premium”. 3 is a bit overkill for FM, FM is very resilient against obstacles.

    If I’m wrong, would be interesting to see an example of a car that uses 3 or more. Probably far outside of my pay grade to say the least.

    • HPsquared 9 hours ago

      I'm going by the BMW E90 (Top HiFi option) which has 3 physical FM antennas FM1, FM2 and FM3, all in the rear glass, and a fourth "FM4" which is not a physical antenna but a combination of FM1 and FM2.

      They really didn't want you losing signal!

      This isn't even mentioning the festoon of other antennas for DAB, mobile (which has a backup too and phones home in a crash: in case the shark fin is broken in a crash)

      • caseyy 6 hours ago

        I could be wrong, but E90 with the best HiFi package is a very rare exception to the rule. I wouldn’t say you often see such configurations.

        It’s cool they did that but it’s almost like they are trying to prove some point — maybe to be the best in the market for FM by a hair. :) One antenna is more common than 3 to my knowledge, by far.

        • HPsquared 4 hours ago

          Fair enough, I just happened to have an E92 and one day I read all about its systems when it had some major electrical issues :) (Turned out they were due to someone forgetting to clip a piece of harness back in place after some work, and as a result the harness rubbed against something in a wheel arch, eroding the insulation and letting water in intermittently screwing up the CAN bus!)

    • anthomtb 5 hours ago

      > WiFi — weird as it sounds, I saw some strings for WiFi antennas

      This is probably so the car can act as a Wifi hotspot, with the Wifi antennas located in the interior rather than in the sharkfin.

      • caseyy 3 hours ago

        I've seen strings for selecting a WiFi network in an SSID list :) I'm guessing for OTA updates when the car is at home or there is another use that involves your phone's hotspot.

        I've seen what you are talking about, too. My VW RNS had settings to use the car's 4G for passenger WiFi.

        Cars really want to phone home these days

      • vel0city 5 hours ago

        Sometimes both. My car can connect to my home's WiFi for its software updates. I doubt that antenna is inside the cabin of the car.

        It also can act as a hotspot if I bothered paying for its data plan. I'd rather if I could just load an eSIM for my existing service to have it be a hotspot for me. Since its antennas are on the outside it should get way better GPS and cellular connectivity than my phone in my pocket deep in a metal box.