Finally my signal came out from continental Europe reaching Iceland.
44 stations copied my signal and 3 times TF3HZ received my weak signal:
The distance of 3355 Km is a new record for my 100W transmitter and the “clotheshorse” antenna in MF. For sure conditions were very good and no strong thunderstorms over the Europe last nigth as two nights before.
Last night was my second “serious” TX test on 136 kHz, transmitted Opera32 mode after an upgrade to the matcher.
To tune the antenna on 136 kHz I’ve build a couple of inductors over two hand cleaner soap bins. The first one was wound with enameled copper wire of about 1 mm diameter, the second with PVC copper wire of 1.5 mm diameter.
The first has an inductance of 2.2 mH while the second is around 400 uH.
Moving up and down the two bins I’ve reached a coarse value just to use my variometer for tuning. The maximum value that I can reach is about 4 mH.
From left: remote controlled variometer (for fine tuning), matcher, 136 kHz tunable coil. The next step will be to remote switch the two bands from my radio room.
Due the lack of public MF grabbers on the net, last night I’ve tried to receive my signal in qrss10 with remote WebSDR system. I alternated the two transmission mode so to have an idea about where my signals were received.
With great surprise receiving myself on Twente WebSDR my signal was audible and even a bit stronger than IQ2MI signal (used always to compare mine). The audio record follows:
My signal is on higher frequency because WebSDR software uses reverse CW.
For the expected solar storm of last 3rd August, I’ve planned a continuous 72 hours transmission of my MF station as QRSS10 beacon since 1st of August afternoon.
Here another picture with IK1HGI signal, too:
Even though I’m 500 Km farther from Stefan my signal seems quite solid.
This is my umpteenth upgrade to the TX antenna to try to get better general performance and get the possibility to work on 136 kHz without tons of electrical wires outside the terrace.
The telescopic pole by now is not more a radiating part of the antenna, this simplified my life because I don’t need to insulate the base of the pole for high voltages.
Now the target is to tune the antenna for the 136 kHz that should it be possible with a 4.4 mH coil.
Since my antenna was born as monoband for 630 meters, until today I’ve used an autotransformer built around the variometer.
It has a quite hi initial permeability and the work frequency is exactly for our game, from 10 Khz to about 400 Khz. Somebody could turn up one’s nose but since turns on toroid are only ten or so and mine is not a KW station I’ve decided to try to build my new matching unit.
For first I’ve winded 10 turns for primary and then 14 for secondary, here is what I’ve gotten:
I’ve soldered 10 wires for as many as different impedence taps and painted the welds with insulating paint.
The next step was to put the “spider” inside a box to be protected from rain and dust (and cats…).
Every screw is provided of an OR rubber.The wingnut give me the possibility to fast retune the antenna The first test on 136 kHz was an immediate success, SWR was 1.14 at first “wingnut touch”! The same coming back to 474! WOW!
Just started the trasmission on 136 I’ve seen power going down “rhythmically”: there was something was arching! Testing on 630 the music was about the same. A brief look on my external ammeter was clarifier. My old autotrasformer was not insulated from coaxial cable, common mode current probably was running over the braid. This new solution now shows me a 3 times bigger current on ammeter. The voltage is of course also higher and the antenna wall insulators cannot resist to this new hi voltage.
So at the moment antenna is perfectly tuned but I can use only about few Watts.
Next step is to increase the insulation to use more than few Watts.
Stay toroidal tuned!
Fantastic virtual tour inside the SAQ building
Just arrived (10 days from Japan) I’ve worked for a couple of hours to assemble the U3S Deluxe kit from QRP Labs, later I wanted to try the GPS receiver for my LF activity by Spectrum Lab, so I made the smoke test giving 5 volts to the GPS receiver.
The GPS receiver was positioned inside my lab room, close to the window, it was capable to find 7 or 8 satellites.
1pps and Data Out has been connected to the input of sound card of my laptop and finally I saw a perfectly synchronized system.
An now it’s time to try the rest of the kit after winding the LPF.
Here is the U3S without the LPF:
Copyright © 2016 IK0VVE Max - All Rights Reserved
Powered by WordPress & Atahualpa