I finished my active antenna this afternoon and stuck it on top of a 3 meter pole to see if it would work (to start with) and be an improvement (a bonus).
Since it was still daylight, the only NDB I could hear was the strong local (YD Smithers, 78 km). It was the same signal strength on both my HF-2V and the active antenna at S7. It passed the first test … it works. No more testing this afternoon as I have to go to town.
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04:00z
After returning from town just as dusk was falling I wanted to see if the more distant stations I had heard on my vertical on previous nights would be audible on the new active antenna. After much fumbling around with questionable adapters I could hear the louder NDB stations (300 km or so) but no distant ones were audible yet. Time to wait for full dark.
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05:00z
An NDB station I had heard only once some weeks ago … briefly audible above the noise … was 8C, Fairview Alberta (585 km). I had no problem picking it up tonight as it was quite a bit above the noise floor. For comparison, I switched back to the HF-2V where I had heard it before and it was gone … the noise had completely swallowed the signal. Nothing I could do with IF or audio filters could dig it out. Back to the active antenna and 509 (no measurable signal but excellent readability and clarity of tone).
Unfortunately (fortunately?) my noise level with either antenna is quite a bit below S zero so I cannot give any comparative numbers. What I can say is that signals that were in the noise and barely readable before are clearly audible now. The noise level is significantly lower on the active antenna. I don’t need as narrow a filter to achieve the same results as before. Narrowing the filter will probably give me more distant stations.
The active antenna is currently in a pill bottle on the 5 meter test mast (60 degree tilt) leaning on my carport roof. This is not the final packaging, permanent location nor the final height.
I’ll be reporting on how this affects my NDB station count in the coming weeks even though the darkness is waning now. The active antenna will be my main LF/MF receive antenna until the new station numbers start to fall off again. By then I may be ready for a vertical loop … null out the loud ones … who knows?