cb radio handset sets off wipers

just wired in a thunderpole t-600, mounted on the slant under the dash above the fuse box (bad idea now) and below the radio.
when i transmit it sets off the wipers, i wrapped tinfoil around the coax cable and that didnt change anything.
wrapped the fuse box cover in tinfoil and that stopped it - found out its the mic/handset that causes it when i transmitted with the mic between my legs and out of line of sight of the fuse box and the wipers didnt set off.
so basically i either put the mic to the right of my legs, behind my head or i wrap the fuse box cover or microphone in tinfoil - none of those i really want to do.
just wondering if anyone has any bright ideas as to how to stop this?
dont know if swr could affect this but it measures at about 1.2

Ollie_Mif said:

just wired in a thunderpole t-600, mounted on the slant under the dash above the fuse box (bad idea now) and below the radio.
when i transmit it sets off the wipers, i wrapped tinfoil around the coax cable and that didnt change anything.
wrapped the fuse box cover in tinfoil and that stopped it - found out its the mic/handset that causes it when i transmitted with the mic between my legs and out of line of sight of the fuse box and the wipers didnt set off.
so basically i either put the mic to the right of my legs, behind my head or i wrap the fuse box cover or microphone in tinfoil - none of those i really want to do.
just wondering if anyone has any bright ideas as to how to stop this?
dont know if swr could affect this but it measures at about 1.2

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Since it stops when you move the mic away it rules out my first thought that you've got a short somewhere or maybe a bad earth.

You could try just wrapping the relay in foil. Better might be buying a new relay with a metal case, maybe from a classic car electricals supplier. If it's doing the wipers though, I'd be concerned that it might start flashing lights and would want to prevent that too.

I can understand it activating the relay on transmit if the screen on the antenna wire was a bit rubbish, but surprised that it could be coming from the mic - any dodgy wiring in that?

@TheQ might be the man for this, I never really got into radio tech.

boguing said:

Since it stops when you move the mic away it rules out my first thought that you've got a short somewhere or maybe a bad earth.

You could try just wrapping the relay in foil. Better might be buying a new relay with a metal case, maybe from a classic car electricals supplier. If it's doing the wipers though, I'd be concerned that it might start flashing lights and would want to prevent that too.

I can understand it activating the relay on transmit if the screen on the antenna wire was a bit rubbish, but surprised that it could be coming from the mic - any dodgy wiring in that?

@TheQ might be the man for this, I never really got into radio tech.

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I’ve ordered some foil tape and am going to wrap the relay, hopefully that solves it.
Mic is a sealed unit so no way of knowing if it’s dodgy until I can try and chat to someone make sure it works.
I’m fairly confident it’s the mic as like I said if I take the mic out of line of sight of the relay they don’t come on.

Get a better mic, or wear a tinfoil hat

I’ve got a T-600 in exactly the same place and haven’t noticed any electrical issues

Take the relay out. Check the mic
Swap relay. Check mic

Can’t see how the cb is affecting the relay though.

My hand held sits above relays and the fixed cb also sits above relays.both scan multi bands with no problems

This stuff is great.
You can run wiring through it and leave a "tail" to bond to earth.
It opens out to be big enough to push your finger through, and when you stretch it back out it closes up to a fine basket-weave around the cable.

DanClarke said:

This stuff is great.
You can run wiring through it and leave a "tail" to bond to earth.
It opens out to be big enough to push your finger through, and when you stretch it back out it closes up to a fine basket-weave around the cable.
View attachment 312150

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If you want a quiet time.. cut about 5 inches of this stuff & push a finger in each end. More you struggle the more it holds on.

wrapped the relay in a fair few layers of foil tape and i can now put the mic next to the relay and it doesnt trigger them. bosh!

Ollie_Mif said:

wrapped the relay in a fair few layers of foil tape and i can now put the mic next to the relay and it doesnt trigger them. bosh!

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Love to know why the relay is been triggered.

Hicap phill said:

Love to know why the relay is been triggered.

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Could it be a shared live or earth?

Def90man said:

Could it be a shared live or earth?

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Even with a 200watt burner in the cab I never “buzzed” a relay.

All comms were wired direct from battery to prevent any back feeds.

A friend said may be it’s the mag mount been too close to the relay… I said you ever seen a mag mount on a landy.

Hicap phill said:

A friend said may be it’s the mag mount been too close to the relay… I said you ever seen a mag mount on a landy.

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Not for long.

Hicap phill said:

Love to know why the relay is been triggered.

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Really did surprise me aswell, it’s an original red wiper relay from 1996

Type "clip on Ferrite rings" into Amazon.
Should stop strange transmissions, clip one round your DC feed wires to the CB set, and with your mic problems one round it's cable would be a good idea too.