Hi All, I have put a description of my AD9832 DDS VFO on my web site. It is a small VFO module, about 50x30 mm. Schematic diagram is in PDF format (Adobe Acrobat) PCB layout is in Postscript format.
Congratulations Christer! Probably the first international two-way LF amateur QSO ever made from Sweden! (I made the first one-way when I first heard OH1TN some time ago ;-) Just worked OH1TN on 136k
Hi All, The new swedish ham regulations, which includes the 135.7 - 137.8 kHz band, will come into effect the 1:st of April (no joke, honestly!). Unfortunately, the paper states a maximum OUTPUT powe
Hi All It's easy to produce an E (electric) field and It's equally easy to produce an H (magnetic) field. However, it is quite difficult to "convince" these two separate fields to join and create a P
Yes Roger, you are right and I agree. I guess the CFA was an attempt to produce a "ready made" flying far field already in the antenna structure. G3JKV was right too. Please let us stop this discussi
Hello The mysterious FSK signal on 137 kHz is quite strong here in Sweden too (wednesday 23.15 UTC), but it is much weaker than the Greek Marathon signal on lower band edge. 73, Johan SM6LKM
Hello, I remember reading about a TDA2030 PA for 137 kHz but I cannot find the text now. I found a few TDA2030s in my junk box and decided to try them in a small linear PA for PSK31 experiments. I th
Hello Rik and others. A selective voltmeter can be built using a gyrator. If you have "The LF Experimenters Source Book" (RSGB), take a look at the gyrator tuned VLF receiver on page 3.7. The gyrator
Hi Marzio and the group Later at 136.15 I made qso with OZ1KMR ; his report was 539 with deep qsb. First I to OZ on LF? I heard your QSO with OZ1KMR here in JO67MR. Your signal was difficult to copy
Hi All, I just had my very first two-way LF QSO. What a thrill! (my hands are still shaking...) I was experimenting with a rotatable shorted turn in my loading coil. I increased the supply voltage to
Hello all, We are not fixed to 137.3 kHz, but this is a QRM free gap in our area. The outher silent range is around 136.3 kHz but I think there is lot QRM in the North-West region. I think it would b
Hello all, I have uploaded a schematic diagram of my 74HC4053 up-converter to my web site. http://home4.swipnet.se/~w-41522/lfconv/lfconv.html I haven't made any measurements on it but it seems to wo
Hello dear Lowfers, Richard Horne sent me a note about his release of Spectrogram v5.0. I asked him about forwarding his message to this reflector and here is his answer: Yes, please forward my email
Also note that it is ineffective to use a separate noise receiver to derive noise blanking drive, as it does not "reverse" the situation that once a noise spike has become a noise blob (due to band
Hello, Further to my note on Radiation Resistance formulas, the highly respected 160m expert ON4UN uses 1450 instead of "160 (or 60) multiplied by pi squared" in his excellent book Low Band DXing. Th
Hello all, I have uploaded a description of a simple antenna impedance bridge to my web site. http://home4.swipnet.se/~w-41522/bridge/bridge.html 73 de Johan Bodin, SM6LKM
From Johan, SM6LKM Connecting the mains earth to the RF earth INCREASED THE RF RESISTANCE OF THE ANTENNA. We re-checked several times, and also checked that the voltage across the capacitor was low (
