RF interfence from fridge

[sahona]

Have suffered from RF interference from Waeco fridge on last two installations. Noticed on medium & long waves on domestic radios and HF band on ham equipment. Thought it was eletronic controller used in conjunction with holding plate, but now have simple thermostat installation and have identified basic compressor (Danfoss) as the culprit.
I fitted a filter ( from the old CB days!) in the 12v line and it sounds a lot cleaner.
Why am I posting this waffle ? Because I believe the interference probably killed the navetex and weatherman reception as well.
All too often we talk about 'dead spots' when we don't get a listing on the navtex, but it may well be that the problem is on board.
We'll suck it and see if things get better.

[DaveS]

I would agree re. interference. I lost my Navtex reception when I fitted a Sterling smart battery charger. I fixed it fairly easily by putting ferrites on the charger's output wires. (It does raise the question as to why EC labelled kit creates interference in the first place, but there you go...)

I've wondered about Weatherman, but the sites I've looked at seem a little coy about defining just what sea areas are covered, and I've been wanting to ask an actual user. Specifically, can it be set up to show Malin and Hebrides?

[sahona]

Unfortunately, the weatherman receives only the Hamburg transmissions, and as such, is more concerned with the North Sea. There is a little about the Atlantic, but not enough to justify it here ( IMO). I got it as a result of time in the Med, which it was good for as well. I can interpolate a wee bit by assuming the north sea is a day or two behind the west of Scotland, and guess from the 5-day. Now the fridge is quieter, I will probably investigate more.
Interesting comment on the sterling. I have one of those as well. Was it the white wire you suppressed?

[DaveS]

To clarify: my sterling unit is a 20A "3 independent output" (sic - I have reason to doubt this) mains powered battery charger, not a smart alternator controller. You have to supply your own wires between its output terminals and the battery bank(s). I found that clipping a ferrite on near each end of each positive wire (2 in my case) and each end of the common negative wire did the trick, i.e. 6 ferrites in total: maybe overkill, and one on each wire would have done, but they were only a few pence each.

I knew that the Weatherman only picked up Hamburg, and that the N Sea coverage seemed fine. It was their description of the Atlantic coverage which seemed woolier. Malin Head broadcasts the high seas forecast for the eastern Atlantic on Navtex, which I find very useful for trying to predict what's likely to be on its way further out than mentioned on the Shipping Areas forecast, and sometimes to compare with the extended outlook when this deigns to appear on my single frequency Navtex (once or less per day in my recent experience).

[sahona]

Ah, mains chargers... there be dragons. I can understand the need for supression with switched-mode "smart" chargers, but since you're in a marina (to get the mains power) you're subject to everyone else's radiated cr@p as well. (so navtex can be poor) One thing I do when connected to shorepower is drop an extra anode over the side to try and share depletion with the fixed one. This may give extra grounding as a bonus. You've got me interested though, I think I'll 'scope the charger output sometime (nine's a french mastervolt, but I'm sure they're similar)

[ash]

You've got me interested though, I think I'll 'scope the charger output sometime (nine's a french mastervolt, but I'm sure they're similar)

Have you got an oscilloscope? You'd be a handy guy to keep in with.

We haven't heard anything about Nick's echosounder woes lately, but a man with a 'scope might track down his interference.

Ash

[sahona]

Ahh, my anorak has many sleeves...
I usually analyse echosounder problems with a tranny radio on the long wave.

[ash]

I usually analyse echosounder problems with a tranny radio on the long wave.

No, no This problem needs the 'scope.

Ash

[sahona]

did you know that if you have sound card, you can turn your windowsbox into a scope using a free programme called osc251? I have a zip of it, maybe I should get it onto the BM download page.

[ash]

did you know that if you have sound card, you can turn your windowsbox into a scope using a free programme called osc251? I have a zip of it, maybe I should get it onto the BM download page.

I found it very easy to download from Here

I would be a bit worried about how high a voltage you could safely apply to the lappy.

A mic level input would be in the order of mV.

I'll need to read a bit more.

Ash

[sahona]

I made up a lead with a volume control in it. One day I'm going to fit a real scope lead to a decade box and use that.( if I ever get a round tuit)