I saw something a few Hz above 136500 between 0000z and 0100z last night. In a 0.1 Hz bandwidth something was definitely visible with some on-off structure to it, but was keying too fast to make out
Last night was a 40Hz wide signal centred on 137770.0. Two different fonts appeared throughout the evening, the simple 8x5 one initially then the 10x8 font. Power was up as the antena has dried out a
Jim - Can I have a copy in .DXF format please. If after this evening, can you please send it to my home EMail address [email protected] as this account won't be available over the solstice holiday period
I have been generating VE2IQ compatible waveforms stored as .WAV files and making use of a constant amplitude envelope and raised cosine phase transition. Last night I tested some MS100 generated sig
Another way of looking at the guard circuit operation is this : As the load resistance decreases, so the loaded Q of the Tank circuit goes up and the voltage across the L / C rises, (cf. more current
That was 10Hz bandwidth, 0.2s pixel interval at about 500W output. Any requests for other modulation types (Hand / High speed CW is not an option) ? Andy G4JNT Hi all nice copy of Andy's Hell beacon
Tnx for that Jim, think I can see how it works. Now have to think how to translate into a 340V supply half bridge version - hopefully link and L values will stay realistic. Andy --Original Message--
What's the Decca guard circuit ? - seems it may be what I'm looking for. Andy As far as short-circuit protection for Andy's amplifier goes, the Decca "guard" circuit does this very nicely - when test
Still the same power, but wet surroundings may make the antenna less efficient. The load R has risen so looks valid. The BPSK message is stored in PIC so won't change in the immediate future, I was s
This was sent direct to me but I feel should be diseminated : Andy G4JNT == Hi Andy, your signal in ID this morning was about 589 here. By tuning my loop to 73kHz and putting it at right angles to yo
Has anyone any simple hardware designs for a continuously variable phase shifters for these frequencies. A varicap and tuned circuit is a bit messy at 137kHz and I/Q generation gets complicated imple
We're thinking along the same lines. I tried a PWM modulator a few months ago - it is shown in the latest LF experimenters book - but this required an 8 bit digital input for the PWM. It could modula
Thanks to the recent RadCom article, the first batch of DDS boards has now sold out and a second set have been ordered from the PCB manufacturers. We bought the entire stock of AD9850 chips from one
Bill et al-- Re your CRUNCH algorithm: Why not downconvert to zero frequency and preserve I/Q pairs in the positive and negative frequency domains, rather than a 'low' frequency that determines the a
Yes I do use such a beast for testing, couldn't use a scope safely on the Tx otherwise ! But afterwards, since the PA is isolated by well insulated transformers at input and output, the isolating tra
The parasitic diode is no good in this configuration for catching the spikes from what I call the transient soak choke, I use separate clamp diodes up to the rails effectively 'crosing over' the cent
Peter et al - I guess the main reason for the three transmitter module design of the Decca Txs is to allow a large element of redundancy or soft degradation to be built into the design, in that PA un
Some of us don't have such large antennas as you, Peter. For 1 Watt ERP I would need approx 4kW RF. Anyone got any cheap 3 phase 500V bridge rectifiers ? The Litz wire around surplus now will do a be
Hello all - Mal and others have been asking for details of the high power amplifier I described earlier. At the moment only the QRP 650W version has been tested and the 2-3kW design concept was a bes
Hello all - Mal and others have been asking for details of the high power amplifier I described earlier. At the moment only the QRP 650W version has been tested and the 2-3kW design concept was a bes
