LF: 0.5km with 1kHz 4W earth mode this evening

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Today I made some more slight improvements to my loop and audio receiver and did a further walk test listening by ear. This time I managed to hear the signal just at 0.5kms. At 0.4kms it was a very solid signal. This was in the middle of a field well away from cables and pipe work. The TX is still the TDA2003 with 4W into the 20m spaced electrodes. At 0.4km where the signal was good still I tried placing the loop on the ground to see what happened. The signal was about the same level as when orientating the loop for best signal when held vertically. At the limit of range the limiting factor was 50Hz mains hum. I will try another Sallen-Key HPF in circuit to take this down another 20-30dB, which should be enough.

I've a friend with a long back garden (no pipes or cables well away from the house) who is almost exactly 1km away from my QTH and he is in my best direction. As soon as I can (grandchridren permitting) I may take my laptop and set this up in his garden to look for the signal. I may also try listening/looking on electrode pairs too from the same location. 

There are so many things to try still but I just don't have enough time in the next week.

73s
Roger G3XBM

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