Laptop interference

[steffen]

I have aquired a laptop and an SSB receiver with the purpose to receive RTTY, Navtex and weatherfax. Set it up at home to start with.
I coupled the output of the receiver to the line-in of the laptop, both fed from the mains. External antenna connected via RG58 coax.

Problem is that the laptop causes interference on the receiver to the extend that reception -especially Navtex and weatherfax- becomes impossible. The interference differs with the actions of the laptop i.e. disk running or not and which program is running. Even mouse movements can be clearly heard through the receiver.
Disconnecting the audio interface does not really make a big difference.

Anybody knows how to prevent this interference????

Happy sailing, Steffen

 

[ParaHandy]

Steffen
Try without the laptop mains power supply connected. Switch off any fluorescent lighting.

Had the same problem. At sea no problem from mains (connected direct to boat's 12v and don't use a converter) but got interference from the boat's fluorescent lighting - probably a bad starter.

The other possibility is that you have interference (presume you are trying the set away from the sea?) from all sorts of other sources which you can do nothing about.

Have you an active aerial? I think they are much better.

Try the set at dusk. Reception at the moment during the day is not good - too much sun!! The higher frequencies of DWD & Nortwood are working much better (for me) than the lower ones.

Douglas

 

[luckyjimbo]

I wonder if some kind of spurious filter is available to keep at bay unwanted radio signals, such as the type available for radio transceivers?

 

[Bergman]

There are a number of possible routes for noise to get into receiver.

Mains is one. Try operating laptop from internal battery to see if that makes a difference. If not can receiver operate from 12 V battery.

If noise is as bad with both bits of kit operating on batteries then noise is getting into receiver either through earth or through aerial.

First point - is the receiver earthed. If not try that. Not to mains earth but to a separate bit of wire to a water pipe or earth rod.

If this has no effect then probably through aerial. Cure depends on type of receiver and type of aerial.

Most likely noise picked up by outer braiding of co-ax, assuming co-ax used to connect aerial to receiver. Could try disconnecting outer and just have inner connected.

If that helps a Faraday loop may be the best cure. Easy to make from bits of co-ax - send me a private e-mail and I will send diagram.

Other possibility is overload of front end of receiver causing intermodulation. Physical separation of computer and receiver may help this.

Depending on type of aerial you use a balun may also help. If you have a balanced aerial such as a dipole then fit balun close to receiver and feed aerial with balanced twin feeder (otherwise called lighting flex).

At least you have something to play with for a while.

 

[steffen]

Thanks guys for the reactions sofar. I will try the suggestions and come back to you.

Happy sailings, Steffen

 

[Guest]

Is this the Danish guy going from Fuengirola to Greece?
Peter

 

[steffen]

I wish i was. No such luck.

I am a dutch guy going out on the IJselmeer this weekend.

Happy sailing, Steffen