Television reception in the car

[Panrock]

Of course, a television picture viewable from the driving seat of a moving car is illegal, and rightly so.

Many years ago I used to have a Sony 9-90UB in the back of my car. When the car was in motion, I found I could get steady reception on 405-lines with a long whip aerial, but not surprisingly the AM signals were spoiled by ignition interference (except when very strong).

The situation on UHF was different. Here there was little interference, but the picture would flutter very badly.

I understand television has long been an option for use in the back of limousines and the like. Am I right in imagining that, using diversity reception, the flutter on analogue UHF can effectively be eliminated?

What about Freeview digital? How does this perform in comparison with analogue when on the move? Has anyone had experience with these installations?

By the way, I'm not talking about watching DVDs or viewing in a stationary car here. I'm interested in what is to be expected from real-time television reception in a moving car.

Thanks,

Steve

[Hybrid tellies]

Reception of uhf tv in a moving car will be a very fluttery affair (on analogue tv) due to the nature of uhf propagation. Because you are moving along at almost ground level the field strength pattern will be continually varying due to reflections and screening effects of buildings, hills, & trees etc. Only in very very favourable locations will you get reasonable results.

As you said, electrical interference from the car ignition system is much less on uhf than on the vhf bands but the propagation disturbances are far worse. As for freeview, the problems won't so much be a fluttering picture, but one of blank screens and at best freezing or severely pixellating pictures.
Unfortunately, the uhf tv system was not designed for mobile use but more for viewers with fixed receivers and aerials. This was the same for vhf radio until they upgraded all the FM stations back in the 1980s to improve reception on portable and car radios.
I would imagine recepton on any tv in the back of a limousine would be the same, even with an external aerial fitted, and I think they are more for people to watch recorded programmes on a vcr or a dvd.

[paulsherwin]

It would be interesting to try DTT reception. DTT is much more tolerant of multipath reception than analogue, but if you lose the signal you'll get a nasty glitch (arguably no worse than analogue though). It would only work at all in strong signal areas of course.

Paul

[Danny]

Hi
When I was younger, I had a Range Rover and fitted a Mitsubishi tv between front seats. This was fed with an Omnimax (the early one).
The set worked well, but in some dark parts of town you couldnt get any reception.
I fitted a video and fed it through the car stereo; this was cool at the time in the early eighties.
Danny

[newlite4]

I often wonder how good the TV reception would have been in those big American limousines of the '60s and '70s. They were all fitted with those boomerang aerials on the rear boot lid, I suppose the shape of these made them omnidirectional to some degree.
Of course, during this period, portable VTRs would have been available from the likes of Sony and National so there would have been some alternative to live-fed TV.
Neil

[Mike Phelan]

When I worked in Manchester on field service, a colleague modified a Bush TV53 by wiring the heaters in parallel and making an inverter for the HT.

When he drove around with it in his company Mk 1 Escort, and using a whip aerial from the RT, it sort of worked (on Band I and Band III), but there was a lot of ghosting (obviously) and "aircraft flutter".

The battery lasted about ten minutes with the engine switched off, as well.

Ian abandoned the idea quite soon.

[murphyv310]

Hi.
I have tried all possible systems in the car here in the UK.
Band one using a whip mounted on the roof of my Skoda 100 in the 70's fed to my Philips TV-ette gave good results, with occasional fade outs, Band three was far more unreliable with uhf giving flutter.
Freeview is a no go, one frame being built up every 20 seconds or so sometimes just total pixelation.
Band 1 for me.
Trevor

[murphyv310]

Originally Posted by Heatercathodeshort

On one of these mad excursions we took an Ekco TMB272 with us and had it operating in the back of my old van. It worked very well but started to fade around twenty miles from London. I switched to channel 4 about 10 miles south of Birmingham and received a very good picture. We were using the vans radio aerial that usually fed an ancient Radiomobile valve set! It was all so simple then. Regards John.

Brilliant John!!!! Just as it should be!
Trevor