Hello LF and VLF folk! I have built a couple of Softrock Lite II IF frequency receivers, normally they would be used to view another receiver's IF on a bandscope, but popularly they are also used on
Hi Chris. It may be worth going back to the oscillator and making sure the frequency there is what you expect. Could be that the divider is working fine, but the input to it is shifting around. 73 Da
The linearly biassed gates used to buffer the input of the Softrock LO fail at low frequencies, breaking up into spurious oscillations at the threshold changeover, not operating the divider properly
OK thanks will take another look at this. Best Regards Chris Wilson On 26 Jan 2018 3:10 pm, "David Bowman" <[email protected]> wrote: Hi Chris. It may be worth going back to the oscillator and mak
Hi Despite Andy Talbots (who I respect highly and feel unworthy making this comment) comment which I am sure will solve the issue. However my experience with several of these kits in the V6.2 format
I replied to Chris elsewhere on this and I agree about the oscillator being fishy. When it was working his numbers seemed right... 115.364 LO * 4 = oscillator at 461.456, seems right for a 461.5 kHz
Thanks for the replies! Should the `scope show the issue? I have access to a very good SA but am always loathe to use it in case I blow the front end, as at this low a frequency it needs the "absolut
I just completed two scope measurements at R17 to pin 3 of the divider IC. One of the faulty LF Softrock, and one on my MF one that works fine. the resultant wave forms are quite different. But I am
Hi all The important thing is that the frequency is correct (which it is) the wave form looks OK and the peak to peak volts are enough to drive the flip/flop There is a bit of second order distortion
Hi all Compare and contrast the schematic (attached ) of Jim M0BMUs MF/LF Softrocks I have built these with no issues. The V6.2 had two dual flip/flops /4 and /8 I have made them using just the /4 be
Hello Tobias and everyone else. Thanks for the detailed info, much appreciated. I managed to change the divider again, but this is probably the last time as a pad is lifting. I also put back a 22k re
Hi again Well all seems well if you are getting a good wave at the flip flop output. Just a comment about your input wave forms yes the MF does show a second harmonic petty low and as you have said t
The scope is DC or AC coupled? I see a negative low level in both printout. 73 Claudio ik2pii -- ZE-Light e ZE-Pro: servizi zimbra per caselle con dominio email.it, per tutti i dettagli clicca qui S
Hello all. Today when powered up there was rarely any output from the divider at all, so I started again. I decided to try two things, build a little test rig with a spare xtal of the same 461.5kHz a
Looking at the schematic, I see a 74AC74 divider is used which works at over 100MHz clock frequency. You are hitting its edge triggered clock inputs with low frequency waveform (461kHz) with a slo
a proper shaped logic level to such high speed divider chips. There really is no getting round that fact. They won't work properly otherwise - just look at the specifications for AC series logic.
Hello Andy, I am having to admit defeat and defer to your diagnosis, I have managed to lift two pads removing the SOIC divider IC again, so await some bare boards from the US. I will modify one to ta
Hello Andy, I cannot test into the divider as I lost a pad off the PCB and have no more IC's left, but some are coming and I can jury rig the board for testing even if it won't be pretty, but I added
