This evening I fired up the FT817 and the small 15mm diameter ferrite rod tuned with a 365pF air-spaced variable and have been spotted on WSPR even further away. This time a couple of spots from Norway, the best being
LA9JO 2096km away. As someone pointed out, I
may be coupling into local wiring and this might help, but the ferrite rod behaves just like a loop with good directivity and matching just as you would expect i.e. a very low impedance tap point is needed for a good match and tuning is extremely sharp. Personally I believe the radiation is all coming from the ferrite rod and nowhere else.
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| WSPR reports with a ferrite rod TX antenna on 40m (5W into rod) |
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