Hi Luis,
Am 12.05.2017 11:43, schrieb VIGILANT Luis Fernández:
I can add an SMD ferrite bead (0805) in the gate
Worth to try.
The voltage in the coax down in the shack after
the 390R is 6V. Power supply is 14V. So there must be some current
trought the FET
Will measure the current
Yes it is 8V/390R = 20 mA. That's a bit much. You could increase that
resistor to get about 10 mA, maybe 680 Ohm is a good value.
This is the picture of the 5m mast, which
is metal. The last section is a PVC pipe which holds the MiniWhip. The
VLF probe is hold in a plastic box
containing the FET and attached to the
metal mast using a metal adaptor. So it is quite close to the metal
mast, which can provide high capacity ?
Probe lenght is 1m
Looks like a good place. The 1m probe should be fine. The capacity is
given by the probe, about 5 pF/m is the rule. 1m should be fine when
the antenna is at this location.
The only problem seems to be the contaminated ground. You just need to
experiment and find the best results.
Maybe it helps to isolate the probe ground from the mast and feed the
cable down to the ground where it has its own earth and an isolation
transformer between the TV cable and soundcard... You know...
Yes. Using the battery there was no difference,
once the ground loop was removed.
Sounds good!
That will be fine ! File is here
Modified file in attachment.
Will try also a twisted pair instead of the
coax
There will be no improvement. I would stay at coax.
Good luck for getting a cleaner background...
73, Stefan
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VLF_Soundcard_32KHz_2.zip
Description: application/compressed
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