Re: VLF: DK7FC close to SAQ

["Max IK0VVE" <ik0vve@ik0vve.net>]

GE dears,

I'm also following your TX, Stefan, with a 424 uHz grabber with no result at the moment. I'll try also the 42 uHz one. 
As antenna I'm using the MF TX marconi because whip and loop are ready for the qsy in the "silent-qth". Noise with this antenna is very high but I'm in RX anyway.
Thanks for transmission.

73, Max IK0VVE 

______________________________

 

...here some of my HAM Radio projects...

www.ik0vve.net

Da: owner-rsgb_lf_group@blacksheep.org

A: rsgb_lf_group@blacksheep.org

Cc:

Data: Thu, 30 Nov 2017 13:50:54 +0100

Oggetto: Re: VLF: DK7FC close to SAQ

Hello VLF freinds,

 

I spent some day in Berlin, thus the late reply, sorry.

The carrier is actually running since 25.Nov 23 UTC witout any

interruption! I have/had control over the TX via the samrtphone. I can

follow the antenna current and can access the PC to stop the

transmission if something would be wrong. Also there is the safety

function that stops the transmission as soon as the antenna current

drops by more than 30 mA under the target level of 700 mA.

 

Thanks to all stations who gave a feedback and RX report of the first

amateur transmission on 17.47 kHz.

Special congrats to IW4DXW who made his first amateur VLF reception at

all (i think)!

 

Riccardo, is that spectrogram really set to 3.8 mHz FFT bin width, as

stated in the text field?

Your simple antenna matching schmatic is apprechiated. It may be helpful

for further stations. I note that no special preamp is needed.

 

Luis, your few bright pixels look most promising. But maybe it is better

to wait until tomorrow before claiming that new distance record on the

17 km band. It would be a first amateur detection on VLF between DL and

EA! This evening i will finally rise the ERP by 3 dB, going from 700 mA

to 1 A antenna current... With 3 dB more, the few pixels should become a

solid line.

BTW all this helps to see how 'far' you are away from getting a

detection on 8270 and below..

 

Sq5BPF has set up a grabber but didn't see a trace so far. I started a

grabber window at RC4HAA running at 212 uHz. There is no trace at all! I

did expect much better results over that distance.

Also KL7L has set up a grabber window, without results so far.

My first impression is that the band offers less better propagation than

expected! So let's hope that QRO will help :-)

 

Before loosing these informations i set up a small list containing

informations about RX stations and SNR reports, see attachment. Tell me

if there is something wrong or if i forgot something.

 

I will inform when the signal level has changed or when interruptions

happened. So far the transmission is still running. Ah yes the antenna

current ca be followed at

http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/TX.png Quite

unspectacular but some kind of feedback...

 

73, Stefan

 

 

Am 29.11.2017 22:46, schrieb Riccardo Zoli:

> Hi Stefan, VLF

> 

> I got your signal in JN64bw, dear Stefan. Depending on the QSB and/or

> QRN, you're peaking 15dB over noise. Fantastic! :-))

> I'm using my LF antenna tuned on your QRG with a (approx.) 200mH coil.

> The 17470.5 signal (locally generated by a GPS disciplined DDS) is

> used for Spectrum Lab SR correction.

> Schematic and capture attached.

> 

> 

> Congrats, Stefan, and keep up the good work!

> 

> All the best,

> 

> 73 de Riccardo IW4DXW

> 

> 

> 

> 2017-11-26 0:40 GMT+01:00 DK7FC<selberdenken@posteo.de>:

>

>> Hi VLF,

>> 

>> Since 23 UTC a 700 mA carrier is running on 17.4701 kHz!

>> 

>> It is a little surprise to the VLF community i think ;-)

>> 

>> Legal? Yes:

>> http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/17,47kHz_Sonderlizenz.jpg

>> Actually the document has 3 pages but the other ones are no so relevant.

>> My ERP is limited to 5 mW. I did not request more because more isn't

>> possible anyway with this antenna.

>> 

>> I wound a big single layer coil with 0.5 mm enameled wire on a PVC tube with

>> 315 mm outher diameter.

>> 

>> 0.7 A is just a first careful step. The coil is designed to hold 1.5 A 'key

>> down'.

>> 

>> The carrier will run the whole night and even tomorrow at daytime.

>> 

>> Worldwide reports are welcome ;-)

>> 

>> It is not sub-9-kHz but still VLF, the 17 km band!! So give it chance :-)

>> 

>> The tree has still some solar power to stream the signal from the EW loop

>> down to the city, so there is a feedback spectrogram at

>> http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html

>> 

>> 

>> 73, Stefan

>> 

>> PS: I still can hear that tone of the coil. It is terrible! Be happy when

>> you are older than me!

>>