Hi Stefan, VLF
>Oh this is not ideal and it may rise the QRM and lowers the signal levels significantly. How long is the cable?
About 35m RG58
>>RR. I suggest to put the transformer on the roof and connect the antenna there. Then the shack earth is decoupled from the 'roof earth' ;-)
I will test it. Keeping the transformer in the shack makes it very easy to use the antenna for Tx again
avoiding a trip to the top terrace to remove it
There is no such a thing as ground or earth here at 80m heigh. The groung is still far away down the pipe
So the pipe is really part of the antenna and it works as a top feeded, top loaded vertical. At least in MF/LF
Anyway will test it and see the difference
I have the overnight spectrogram at 1min per pixel. The gap on the left at about 21h is the test
without antenna
https://www.dropbox.com/s/ojhdcjskefomda2/Benidorm%2090m%20vertical%20LF%20tuned%20VLF%2024KHz%201min%20x%20bin.JPG?dl=0
The elevators QRM is clearly identified and drops from about 00utc to 05utc. Best, lower noise from 03 to 05utc
Anyway amazingly quite, considering this is urban enviroment and the building tower holds 78 neighbours with all kind
of noisy sources at each home. And a couple of 3 phase 380V variators for the lifts just a few meters under the antenna
73 de Luis
EA5DOM
