H field ferrite shielding

[cutty]

Hi,

This has been copied over from the internal forum, station hardware firmware antenna section, 32 hours without response on a subject that if done wrong, I think, would compromise your detector. Someone within the broader followers of Blitzortung may be able to assist.

""Some very interesting posts on the various ways of shielding H field ferrites. It seems that copper foil and ribbon cable are evenly matched in popularity. If I need to shield my H field ferrite antennas, I will use ribbon cable, which will be easiest to obtain. I can see that you solder one edge of your ribbon cable and then attach that earth wire to your negative connector of the antenna connectors on the pcb, for both relevant channels/antennae.

What is not so clear is how the 2 edges of the ribbon cable relate to each other. Do you have to leave a space, similar to what is done with the copper foil or do you just wrap the unsoldered edge of the ribbon cable around your conduit and just terminate in adjacent to your soldered edge (lying beside it). I assume you don't solder the other edge to the first one or do you?? The photos I have seen, do not show how the 2 edges of the ribbon cable end up around your conduit.

regards,

Jeff (nearly ready to mount on the roof!!!)""

First... before even thinking about shielding... find the location with the lowest overall H field noise level at recommended gain settings, for example 10x10. You probably don't even need shielding, or it has little overall effect. "Noise" is effectively handled by the system, for the most part.
Second... shields should have a gap.... otherwise the H field won't get into the antenna. So the 'edges' should not touch or crossover lengthwise, a gap of a mm or so is probably sufficient, and the ends should be open.... Regardless of either ribbon or foil., ferrite or wire loop, coax or whatever. Otherwise you've placed your antenna in a Faraday Cage. All the shield does is (effectively) is 'short' some M components ,... some of them.
I'd say a major percentage of us don't use shielding... it certainly made no difference in my high H field noise environment... so I run 'unshielded' and apparently have an effective station, despite that.

Don't make this more complex then it needs to be! relax... enjoy.... try 'naked antennas' in your chosen location for several days... you can shield later if you determine it's necessary. Probably won't be.

If you decide to shield without doing that, just leave the 'ends' separated by a mm or so, make sure the tube is open at both ends, and go for it....

You're talking about 'interference' with your station operation. We all live with it at different times and for different reasons... some more than others
... try this... http://www.wxforum.net/index.php?board=115.0
and most anything you'll run into, we region 3 operators (and others worldwide) have already chased down....
Interference discussed here... http://www.wxforum.net/index.php?topic=20439.0
Mike