TV Interferance,

Post by **Coops** » Fri May 09, 2008 12:46 pm

HI,
been getting a few complaints from neighbours who are now using digi boxes, that the capri blanks the TV out and also stops there wirless broadband while the engine is running,
any one else had any similar probs?
is it my hyfire on a similar signal as top bowes?

bodger · Post by **bodger** » Fri May 09, 2008 12:56 pm

not quite the same , but as soon as my engine fires the compass on my dash turns round about 30degrees , it was ok when i had the diesel in it

so stuff the comapss

kiwicar · Post by **kiwicar** » Fri May 09, 2008 7:14 pm

Its time for resistor caps, or resistor plug leads, or screening kit off a 101 FC, or stuff the neighbours and tell them it's a feature of windows that it gets scared of red capris and shuts down.
Mike

Post by **Coops** » Fri May 09, 2008 9:00 pm

its weird, its ok on normal tv or sky/sky digital
but set top box forget it lol,

kiwicar · Post by **kiwicar** » Sat May 10, 2008 6:56 am

Tony so its "windows safe", "Open safe" (your Sky box), but the freeview(?) box is dodgy? If so it is obviously not a problem with the capri its the dodgy M-Heg middlewear in the free sat box!

I believe the process is called Blamestorming

Mike

kiwicar · Post by **kiwicar** » Sat May 10, 2008 7:13 am

On a slightly more practical note, off the back of your LNB on the Sat dish, you get about 1.4v of signel, to get any noise in there from the capri electrics you have to be either directly in front of the dish or about 12 to 16 degrees off, either way as the dish points at the sky......
Normal satalite TV you get a reasonable amount of RF power into your reciever airial that will swamp out the small amount of RF leaking out of your ignition system (1 volt out of the demod stage of the reciever).
With Freeview the digital signel sits "on top" of the analogue TV signel, it is about 1% of the power of the analogue signel and guess what... your ignition system clearly leaks RF in this band and is enough to swamp the digital signel (I also bet the Hyfire generates multiple pulses to fire the coil in the 500 to 600 Mhz range which the freeview will hate).
Mike

Post by **Coops** » Sat May 10, 2008 9:07 am

i will see if i can find out what the hyfire pulses at,
it does do multiple pulses in the lower rev range,
looks like i may be going over to coil packs sooner than i thought.

will this be the same for the wireless broadband prob too mike?

any one got a base ignition map for a RV8

kiwicar · Post by **kiwicar** » Sat May 10, 2008 9:29 am

Hi Tony
the wireless broadband runs in the 1.8 to 2.4 Ghtz range (from what I remember) but it is a burst transmission(in pulses like the energy from your coil). This is also quite low power so again is likley to be swamped by the RF from your ignition. you could try potting small velue decoupler caps, .01uFarad ish, (across the supply leads to the ignition box and the drive to your coil0, this may reduce the ignition power a bit though. The real source of the noise is likley to be the plug leads though and there the best bet is to use suppressor caps or screen the plug leads.
Mike

Post by **Coops** » Sat May 10, 2008 9:34 am

im using the mallory prowire leads,
and resistor less ngk plugs.

kiwicar · Post by **kiwicar** » Sat May 10, 2008 1:39 pm

Oh Bu***r that should have covered it

.
Right Screen the thing then, metal box over the ignition control unit, isolated from the body, cable screens over the leads to the coils connecting into the metal boxes at both ends, metal box over the coil again isolated from the body big grommet over the main coil lead, 101fc screened distributor cap cable screens over all the plug leads and the main lead from the coil and connect all the screens in a daisy chain back to the heads with shields over the plug caps. The army did it on the 101FC radio vans, all the kit to do it can be bought from craddocks but man it dont look pretty

you just replace the original plug leads and caps with your nice stuff.
Mike

Post by **Coops** » Sat May 10, 2008 5:55 pm

i think it can wait until i go coil packs me thinks.

mrcheese · Post by **mrcheese** » Sun Jun 29, 2008 4:41 pm

I just came across this thread and thought it interesting. There is nothing on your car that would generate noise that would directly affect your neighbours kit.

Noisy alternators and ignition rarely goes much over 200MHz

Terrestrial TV - 600-800MHz
Wireless LAN - 2.4GHz (2400MHz
Sat TV - 10GHz

Having said that, these frequencies are down converted to lower frequencies
before the data contained in them is retrieved. It is possible that the noise is getting in there. This is the thing with digital, you don't get a gradual degradation, it is either there or it is not.

Do you have a radio in your car? If it was that noisy you would hear it on it. A little on AM is normal, but lots on FM means there is a problem. If you can't hear anything in the car then it is not you.

As digital terrestrial TV is a weaker signal, lots of people have fitted antenna boosters. These are notorious for causing problems as they are not well designed or built.

If have got some wideband receiving kit if you want me to have a listen. I would need to be a little closer than Reading to hear you though.

Paul.

Post by **Coops** » Sun Jun 29, 2008 5:43 pm

there is a little interferance on my fm radio but not enough to bother me mate

,

v8man · Post by **v8man** » Sun Jun 29, 2008 8:31 pm

tony i want one of those just to annoy the old git next door that sits all day watching tv

Post by **Coops** » Sun Jun 29, 2008 8:37 pm

where you live mate?
could always bring the cappa round