I once made an overnight recording of (the carrier of) some HF broadcast signals around 3MHz arriving via a skywave path. The recording was done using G3PLX's Dopplergram software, and was made a
I've lost the specification for the additional header used inside the low rate .WAV files. The one that defines the floating-point sample rate and values and other parameters. Can anyone help. I int
For transformers the core is not terribly critical provided you use a grade of ferrite designed for the frequency of interest. And at LF that means SMPSU cores If I see a certain size core being use
First thing I noticed is that your turns ratio on the output transformer doesn't look right. You quote " ... with primary winding of 15 turns and secondary of 12 turns..." 180V DC in a half bridge
Yes. As you'll see in my original write up, I originally forgot that the peak of the fundamental sine component of a square wave is GREATER than the peak by a factor of 4 / pi and initially my PA del
I've just looked again at the circuit diagram you sent - on there the values are different from your statement in the email. It shows primary 5 turns, secondary 12 turns so a load resistance in the
7:19 turns (assuming 50R output) means you have a load resistance of 6.8 ohms which for 180V DC (81 V RSM fund sine) is nearly 1kW I don't think you really mean to go that extreme do you? 13 ohm
If the conditions change as the PA is operating, it looks like capacitors heating up and changing its value. I can't think of any other component that will change with dissipation / heating. What
There is a famous quote by Sherlock Holmes that goes "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth." You have shown by your substitutions that the
Something like this ... http://www.g4jnt.com/QRO_LF_DoesThis.JPG 'jnt :-) On 4 June 2017 at 16:25, Chris Wilson <[email protected]> wrote: Hello Alan, No, what he needs is a video camera, and the c
Yes. You need to adjust the link so current is driven back into the supply when RF amps exceed the maximum that you have designed for. Up to that point there should be no guard current as the induc
Never use nylon as an RF insulator, it's horribly lossy. Back in the 73kHz days I used nylon strimmer cord as an insulator for my Tee antenna; 200Watts and about 15kV on the antenna. One day , in
Hi Mike I am not up-to-date with the lates whizzy PCs but one factor in your current pc spec leaps out as a problem. 1GB of ram is nowhere near enough to run multiple windows like you were doing.
Looking back in my logbook I see on the 12 July 1997 that I made a transmission on 73kHz that was received by G3PLX 393km away in a bandwidth of a few tens of milli-Hz. Peter was using the new fangle
Not intended for LF, its targeted at, for example, 10m and 6m to exploit short duration openings like SpE Take a look at the WSJT web site for more info Andy On 1 July 2017 at 17:46, Chris Wilson <de
Having just put the 137kHz system back together, cobbled together an on-off modulator and reprogrammed a beacon keyer module for QRSS... I [think] there's a SlowCW-30 signal going out on 136.179kHz
RR I've moved to 136.1738 Andy 'jnt On 15 July 2017 at 14:08, Markus Vester <[email protected]> wrote: Hi Andy, just shifted my Eu-grabber a few Hz up, and Bingo there's your fine signal. Albeit
Near enough. Its only a TCXO controlling the frequency, so a ppm or two of error can be expected Andy On 15 July 2017 at 14:32, F6CNI - Andy - JN19QB <[email protected]> wrote: Hello Andy G4JNT Go
Yes, I think so. I haven't done anything on 137 for a couple of years now, so going back to basics is rather refreshing. Only snag is, a while ago I'd have thought nothing of leaving this system una
