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Re: VLF: Carrier on 4470.005 Hz!

To: [email protected]
Subject: Re: VLF: Carrier on 4470.005 Hz!
From: Markus Vester <[email protected]>
Date: Sun, 20 Aug 2017 05:11:49 -0400
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Hi Stefan,

this morning, an unambiguous peak has come up on the DL0AO cardioid in 31 uHz:
The signal level (-140 dB) seems to be similar to that previously observed on 3675 Hz (noting that the gain of the synthetic cardioid summation has since been reduced by 6 dB to make it equal to the single antennas).  We can probably hope for improved SNR during the day.

Well done again!

Best 73,
Markus (DF6NM)   

-----Ursprüngliche Mitteilung-----
Von: DK7FC <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Sa, 19. Aug 2017 15:01
Betreff: Re: VLF: Carrier on 4470.005 Hz!

...Rather 5 uW.

Am 19.08.2017 14:28, schrieb DK7FC:
Hello VLF,

I un-wound the defective stack of the large coil which was used for 2970 Hz. It took about 4 hours to carefully unwound about 1000 turns, or about 1 km of wire. The wire will be used for new coils which are already planned.

Now, the remaining 4 stacks should hold at least 15 kV. I connected the coil to the antenna and found the resonance close to 4470 Hz.
Now i'm running (since 12 UTC) a carrier transmission on 4470.005 Hz. The antenna current is just 150 mA. That's an ERP of about 3 uW. A first signal on the 67 km band from here :-)
Let's see how long it holds until there is the next fault :-/

Reports/Spectrograms welcome...

As usual there is a monitoring of the signal in 3.5 km distance from my tree grabber:

73, Stefan

Am 13.08.2017 22:17, schrieb DK7FC:
The repetition of yesterdays message failed. At 15:38 UTC the safety function tripped. I've just been on the roof, when re-starting the transmission i can see a spark in the center of one of the stacks. So now there is another one which has a flash over! :-(
It must be replaced, which is a lot of work. So the tranmissions on 3675 Hz will stopp for some time. At least we have some carrier detections and even EbNaut decodes.

I need to think about a different coil concept.... More current, more voltage, more power, more more more!
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