It may seem an odd ambition, but I've had for a few years an intense desire to have a TV in my car.
Nope, not a 69cm stereo-with-teletext loungeroom model, but an on-dash screen matched with sound coming from all of the car speakers. And while I know that there are automotive off-the-shelf TV tuners and LCD pop-out screens available, it's always seemed to me that I could do it a lot cheaper by introducing a DIY element.
So about a year ago, I started experimenting. Adelaide electronics company Labtronics (the mob that we do the intercooler water spray controller with) had imported a single example of a small LCD TV - screen size about 10cm, I think. The package was compact enough to find its way inside a car, although it wasn't intended specifically for car use - instead being just a general purpose portable. But how well would it work inside a moving car?
Kind of acceptably, it turned out.
But good quality car TVs employ a diversity antenna system, where usually two antennas are used and the tuner selects the signal from whichever is stronger. As you drive along, the input can be seamlessly changing from one to another, so avoiding ghosting. And, with just the single telescopic whip aerial on the Labtronics portable TV extended inside the cabin, the signal varied quite a lot as I drove around. 'Course, when you opened the sunroof and stuck the aerial out, things improved considerably!
Hmmm. I went off and bought a pair of rabbits' ears - the inside-type antenna that uses two telescopic whips. Using double-sided tape, I attached the base of this aerial to the top of the rear glass and then extended the aerial elements upwards at about 45 degrees. With this antenna connected to the TV, I then went test-driving. Reception was again improved - up to nearly acceptable, in fact.
But what about an amplified antenna, I thought? My next visit was to an electronics store to buy a caravan/boat antenna that came complete with an internal amplifier. It was easy enough to power the amp from the cigarette lighter, and with the white fibreglass disc-shaped antenna sitting on the rear deck, I again went testing.
And what did I find? It was better to stick to the old rabbit ears...
About this time, Labtronics decided that they wanted their sample TV back, so I was stuck without a guinea pig. Time passed, I moved interstate - and acquired myself a very good quality colour LCD in-car screen in the shape of the VDO Dayton navigation system that I (at great expense) had bought. At even greater expense I could have at the same time acquired the multi-media box and TV tuner that is available for the system, but the extra cost was stretching things just too far. Plus, it's hard to claim as a tax deduction an in-car TV....
But when reading the VDO Dayton handbook I did discover one thing. It turned out that there is a direct PAL video input socket to the screen - just connect it to a video source and away you go! Hmm, I thought. All I need now is a tuner with video and audio outputs! Maybe a VCR (they have tuners in them) converted to run off 12V? Transplant the video's remote control sensor to the dash and then just use the handheld remote to change channels, the video feed from the VCR going to the Dayton screen and audio output going to an FM modulator so I can tune it in on the radio.
But what about an even simpler idea? Why not just buy a really small portable LCD TV secondhand - and use that as the tuner?
It seemed a good idea so I wandered along to a local secondhand store and found a handheld TV. While not pristine (one line of pixels was out right across the screen), its reception inside the store was fine - a good test as the store electrical wiring often degrades the signals to the extent that the screen in unwatchable. The unit also had a 3.5mm socket marked "video/audio" positioned on the side. Now whether that was audio/video in or audio/video out was anyone's guess. I wanted it to be an output socket - but if it was the wrong way around, it shouldn't be that hard to access these signals inside the unit... should it?
This was an important gamble because in my quest for an in-car TV this was the first time I'd had to spend real money. The first TV had been borrowed, the rabbit ears had been cheap, and the amplified aerial I had - ermm! - returned to the shop for a refund after my testing showed that it didn't work all that well in a car. But this secondhand handheld TV was $150, so it had better work...
I plonked down the plastic and then wondered across the road to another store to buy a 3.5mm > 3.5mm stereo lead. Add another ten bucks. Still parked outside the secondhand store, I excitedly plugged the cord into the TV socket and the other end into the VDO Dayton screen. I turned on both the TV and the car's ignition....and nothing happened. Hmmmmmmm.
Back home I measured the output from that video/audio socket - nothing. So it must be an input socket, not an output. That's unfortunate, I thought, starting to pull apart my newly acquired and apparently useless TV. Inside, there were about a million wires connecting the PCBs to the screen - so much for my forlorn hope that there might be just a single coaxial cable transmitting video to a screen module.... But anyway, at least I had a nice little portable TV - and while it was open, I thought, I may as well try to fix that line of blanked pixels running across the screen. Probably just a loose wire. I undid screws until the screen was accessible, noted the wire connections down each side of the display and ran my thumbnail down one of the ribbon connectors, seeing if this would restore that connection.
But the affect was altogether unwanted. Instead of fixing the missing line, this action created a swathe of blankness across the screen! I took the TV guts to an area of better lighting, looked really closely, and realised with utter chagrin that my moving fingernail had bodily torn away hundreds of almost microscopic wires from the edge of the screen.
I'd just totally buggered it.
Thinking hard about more worthy things on which I could have spent my $150, I discarded the ruined screen and stared down at the TV insides. My last hope was that the video/audio socket was in fact an output, but that the video and audio connections on the socket were reversed over that being used by the Dayton screen, thus resulting in the hook-up not working. I did some more testing, looking for the non-existent signals - without the screen, ones now not able to be seen, either. As I futilely probed for video that didn't exist, the broken screen stared sullenly up at me from the wastepaper basket.
A few minutes later the rest of the TV joined the screen in the bin...how to blow $150 in just 60 minutes.
So right now I am kinda out of ideas. In fact, after that last bloody episode I've gone right off personal R&D for an in-car TV.
But surely there must be an easy way of getting a cheap PAL-output car TV happening? If I ever find it, I'll let you know...
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