RADIO INTERFERENCE

[neil4030]

My Traveller is fitted with a half decent radio and I have a vague memory of buying a certain type of HT Lead and/or other gizmo way back when I was a teenager for my MG; to stop the 'put-put-put' interference over the radio transmissions, caused by the ignition system firing away. This annoying noise (spoiling Classic FM/Gardener's Question Time/The Archers/Desert Island Discs etc etc!) increases/decreases with acceleration/deceleration, if that makes sense. Can such things still be bought to cut this out and if so, what and where??! Many thanks chaps.

[bmcecosse]

Modern HT leads are made from 'carbon string' which should provide the protection you need. But you can also get plug caps with suppressors built in - and 'resistive' plugs too. Put them all on, and the car will never start.

[MarkyB]

Make sure that the earth part of the aerial is actually earthing to the bodywork.
The aerial lead is coax cable which should shield it from external noise.
Having said that, if the plug caps are the bare metal type, all bets are off!

[JOWETTJAVELIN]

On some cars with a radio fitted I have seen a condensor attached to the coil which I understand does something to cut interference?

[lambrettalad]

you can buy suppressers I got a few at a parts jumble ,but never had to use them on the moggie

[bmcecosse]

If you put the suppressor (condenser) on the Ignition fed side of the coil - it may help to kill back feed spikes. On the dizzy side - it will boost the condenser inside the dizzy. May give bigger sparks - but won't do anything for the radio. It may cause overheating of the coil.....
A 'half decent' radio should be able to reject interference anyway...........

[moggiethouable]

The possibility is the interference is working its way down the cable connected between the antenna and the radio, an inexpensive way (£3.00 ish) to help, is to buy a large polo mint shaped ferrite ring from your local Tandy or radio shack shop.
Disconnect and Wind the cable in and around the ferrite ring, reconnect and things should improve.

[lambrettalad]

Iv'e tried the ferrous ring on my groups amp and I didn't notice any improvement ,so it's worth a try but don't hold your breath,good luck

[moggiethouable]

Iv'e tried the ferrous ring on my groups amp and I didn't notice any improvement ,so it's worth a try but don't hold your breath,good luck

The big difference is the cable between the antenna and radio, it is coaxial cable, its job is to transmit from the antenna to the set,it can also be of course the interference is travelling up the power cable, its worth a try to ring both, one at a time to see if any improvement is made.
RF finds its way through the outer shielding of the cable, the ferrite ring gathers that interference,it wont eliminate anything travelling along the core of the cable via the centre, thats where suppression kits come in.
I did once cure interference on a neighbours TV (created by my transmissions) with Ferrite rings by using a ring on both the mains cable and the antenna coax cable.
Regarding amplifiers, guitar or otherwise, they can be "wideopen" some more than others, to R.F. signals, R.F. can find its way via the guitar jack lead, but no amount of suppression can help for instance in the case of cheap Taiwanese Video recorders.
Or in the case of my wifes I pod when docked, I simply knock it out when I transmit.
But ferrite rings are a cheap way to try and cure interference.

[lambrettalad]

agreed worth a try and cheap