Hi Stefan and VLF,
well, I am now officially hooked! My signal on 29.5 kHz (VLF's edge)
has been detected 22.3 km away in Canberra by Dale VK1DSH. Only
casualty is the russian mica capacitors (K31-11-3) which got really
hot (I was focusing on the amplifier and neglected the poor caps). I
had 4 of them in parallel, each 4700 pF. Maybe they will recover if I
let them cool down :-)
That's probably a first for Australia, I haven't heard anyone else
doing tests like this.
I now have to wait for properly sized caps that should be coming in
the mail.. Then we can continue the exploration of VLF :-)
73, Dimitris VK2COW
Στις Σάβ, 9 Φεβ 2019 στις 1:20 π.μ., ο/η DK7FC <[email protected]> έγραψε:
>
> Hi Dimitris,
>
> Am 07.02.2019 22:59, schrieb Dimitrios Tsifakis:
>
> You must have a much larger antenna than me as in my current 140 m^2,
> 3-turn loop, I can reach a bit over a 1 uW with a 1 kW input!
>
> On which frequency? Didn't you tell about a 120m x 3m single turn loop?
>
> There
> are many physical limitation that cannot be exceeded that will never
> allow me 200 uW with this antenna. Of course, that's just the start,
> once I get some success, I will be looking for larger antennas (and I
> do have some ideas which extend past my fence).
>
> One of the first steps could also be to place a receiver in the far field, a
> good receiver. You are working in Canberra, right? So you can place a RX
> there and make a webpage showing spectrograms?
> Ah BTW are you skilled with Linux or do you arlready know that you'll never
> give it a try?
>
> You know the
> addiction!
>
>
> Hehe, yes!
> I already looked arround in your location. It is a QTH for dreamers! You know
> the history about the 'DREAMERS'? ;-)
> What is that stuff in QF44OX02XI ? Is it water? Or there in QF44OX01US ?
> Water, that is water! Horray!! There you could throw some wire into, your
> aluminium wire.
> Oh and here in QF44NW99XV That's excellent! There is just a little effort
> and you will be able to leave a trace on Edgars RX, TXing with 200 uW.
> If you can lay a wire from here to there, see
> http://k7fry.com/grid/?qth=QF44OX01US&from=QF44NW99XV that's 1000m already
> and you can get a good conductivity. Try to find metallic plates, maybe 1
> sqare metre. That could work fine. 1 km is not so much, you could even roll
> it up again after transmitting.
> It would be interesting to see how much current you can get at DC or at
> various frequencies up to 30 kHz.
>
> Anyway, my plan is to start at 29.999 kHz (the entrance to VLF!)
> first. My antenna works a lot better on that frequency. I will them
> move down in frequency. For the legal limit of 7.5 uW, what distance
> would you expect a QRSS10 signal to cover at 29.99 kHz? We'll find out
> this weekend but I can start taking bets today! :-)
>
>
> If you have a well working RX, sensitive antenna, both H field, the right
> position and 'no' nearby QRM sources, it think you can make 10 km. That's my
> guess, without doing calculations.
> If you run 50 uW on 17.47 kHz (Edgar is skilled on that frequency!) you will
> reach Edgar, if your loop points into his direction. If you can run just 500
> mA into that 1 km long wire, on that frequency, you will be there!
> Do you have enough wire for the weekend? :-) I use that cheap CCA loudspeaker
> cable which has 0.75 mm2. A 100m ring (i.e. 2x 100m) costs about 13 EUR here,
> quite affordable.
>
> 73, Stefan
>
> 73, Dimitris VK2COW
>
>
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