Hi Funfinder.
Can you please post the frequencie of this divice.
May be i can help with my expirence on modeling and constructing antennas.
Regards
Nelson
Quote:
Originally Posted by Funfinder
@ fenixdigger
thx for the good idea. It is just the question how many antennas we have to incorporate into the final one detector. We could use some parabolic reflector as electrostatic antenna and the coils or ferrites in front are for the metal.
@ Geo
I have the FET version - it has a better audio-signal throughput. btw. that bag was from the greek restaurant, and it is very lightweight. 
Yesterday I built the antenna you can see below with a size around 40cm, but it has only around 30% gain concerning the distance compared with the 20cm diameter one.
I think the easiest and most lightweight solution would be simply to stick some sheets of alu-foil onto a stable cardboard that has a size of ca. 1m. Connecting this in my case with a cinch (RCA) plug I would have the best portable and even foldable solution (as long as it isn't windy outside!  )
btw. The very lightweigh alu-pipe-circle has around the same gain as the 38x22cm sat-receiver case-cover.
It detects the 1,5m long 220v electricity cable (2 wires unshielded) of a hanging lamp from ca. 1meter. If I switch on the variable capacitor and turn it to fully 180 pF I can reduce the distance to just 15cm (as it would be without any antenna).
But yet it's more important getting better sensitivity. |