VKS737 Ch 2 tuning activates my central locking

It seems to be earthed pretty well, and works reliably... I have no idea how to check the earth potential at 5MHz, except to get the installer to take a look at it...

Why would it only happen at 8022 MHz?

Because that's the resonant frequency of "something" in your system (could be a PCB track - who knows?) which is inducing sufficient current to trigger the electronics.

The installer may struggle with such an issue - check and, if necessary, replace or improve the earth connections. These sorts of RF issues cannot be easily attributed to any one issue.

Mike Harding

Thanks Mike.

I think I can decipher that ;-)

So you are saying that the current triggered ends up going back through the system somehow to the remote locking?

Cheers
Andrew.

As mike said the easiest path is to redo all the earth connections throughout the vehicle paying special attention to whatever the antenna is grounded to. bullbars are renowned for having poor connections to the chassis and body.
Take at least one bolt out, clean mating surfaces to shiny metal then refit.
If the central locking still plays up put an earth strap across from the door pillars to the door itself, removing a couple (one on the door, one on the pillar) of bolts from either side of the hinge, clean to bare metal and refit with an earth strap on all doors and bonnet.

Thanks Peter.

I'll get the installer to take another look at it.

I forgot to add to make sure the chassis/case of the HF is earthed to the vehicle seperately from the power feed and the same for the antenna and remote head if fitted. This is often overlooked as the transmitter is often mounted to plastic inside the vehicle.
This last problem can also occur with UHF CB's, the case of the radio must be earthed if it is mounted to a plastic or wooden console. Makes an amazing difference to reception and noise in general.

Andrew, it's not uncommon for RF to get into car stuff, and visa versa. It's almost always the accessory that's at fault.
It's a long complicated road that might involve "bypassing" various points with Rf bypass capacitors, extra shielding and earth's for the accessory electronics etc..... etc. etc..
Start with those earths that others have mentioned.
Is the control box for your C/L plastic ? Try an earthed metal box.
Sorry I couldn't be of better value.

Mike
He should have well tuned doors

What you say? Whir Clunk.

My 1HZ is clearly a lot more refined than your Pootrol 4.2TD ;-) I don't get engine interference issues even when using it while mobile.

I notice you've got Twilight Cove on your rig photos - nice spot hey! What I found amazing is that when we drove out onto the sand we were 2km "out to sea" when looking at the NATMAP rasters! I guess it is a while since they did those maps, but that sand must be moving heaps and fast.

Cheers
Andrew.

Ah Andrew, I see you have the non-turbo, non-electronic 1Hz!! Lots of people have had HF interference probs with the electronic injection version.
Re Twilight Cove photo, yes, certainly is a nice place. That was back in the days when I had the Maverick. We drove the beach from Eyre to Twilight, just to make it more interesting. Found a distainful sea lion relaxing on the beach that day, watching us suspiciously as we took a swim.
On that trip we drove the telegraph track along the cliffs, then the 80km of beach to Israelite Bay. Great run, but nearly lost the old Mav in very soft sand near the western (Pt Culver) end of the cliffs.
I used to work the region for a couple of years back in the early 70's doing a radio maintenance run, so have a fondness to the area.
Re 2km out to sea, now you weren't running the HF auto-tune when getting a GPS fix were you? ;-)
I was running my trusty Garmin GPS II+ and Fugawi mapping software back on that trip and had no problems with being "all at sea". Ah, but now recalling the trip, I was using the original 7-cd set of Auslig maps, and I had trouble in the area from a mis-calibrated map, but that was of my own doing.
Cheers, Gerry

We did pretty much that same trip in May '06 and had a great time, although it was too cold to go swimming and there were no seals we saw.

I had no HF then, so the auto-tune probably didn't affect it.

We drove the beach from Eyre Bird to Twilight as well - all pretty much just slow chugging over the seaweed and avoiding the washaways. We then drove the telegraph track along the cliffs, Bulbunyah which was great and the beach to Israelite Bay - no problems at Point Culver, but then the Western end jump-ups along the way were each challenging to find and challenging to negotiate - I can't remember where, but I can remember some spine tingling figure 8's on the beach trying to find the right exit and not get bogged in the process turning tight.

Cheers
Andrew happily driving a wonhaichzedasaurus.

Thanks Robin.

Strangely the black box you speak of is in the dash amd the aerial at the rear and transciever under driver's seat.

Not sure if distance makes any difference... perhaps the interference gets transmitted down the power feed?

Cheers
Andrew.

It can come down the power feed Andrew, or out of the outside of the aerial cable.

I am restricting my comments here to simple things that involve no soldering/ wire cutting.

Another thing that can be easily tried if Alfoil doesn't do much is to try a couple of snap on supression chokes around potentially sensitive wires.

E.G. Jaycar U-25 cat no. LF1290 about $5 each.

These things snap over a cable of up to 1/2 inch and reduce the RF flow , but they don't do a lot at your frequency unless the wire can be looped thru them at least once.

One of these devices may even be clamped over the aerial cable that comes out of the radio, however if this is done the tuning of the radio needs to be checked, because what can happen is that if aerial is not tuned in correctly then RF current can flow on the outside of the aerial cable and this U-25 device supresses that and effectivily changes the tuning.

Robin Miller