http://n1bug.com/n1debug/ASB_LF_Amp-20171223.jpg Recall that last week I had increased turns on the output transformer from 3x5 to 3x10. That reduced heating of the FET but did not help to stabilize
What core ? What dimensions ? Does it obey the fundamental equation for saturation in a core ? Vrms = 4.44 .F . N . A . B F Hz, N turns, A core area area in m^2 B Tesla Keep B < 0.1 and ferrit
Thanks Andy. I need more time to get my head around that equation. I'm still struggling with a near vertical learning curve on all of this. I never worked with ferrite (except in RFI suppression) unt
All, I've been, sort of, following this as I have a similar problem with the amp at <http://www.qrp-labs.com/ultimate3/u3mods/lfamp.html> I have not used the 2n4 cap to ground on the gate (yet) but I
Bad form to follow up my own post so fast but - just had a play and there is no obvious difference between the scope match at the shack or the aerial - except its a lot colder at the aerial :-) Howev
Nick, I was very interested to read your email. I am sorry that you are also having problems with this PA but at least it isn't just me. A few comments threaded in below... I've been, sort of, follow
Hi Paul , Nick and any others using that PA design, (I 've being subscribed to the RSGB LF feed for 4-5 years ? and of course seen reference to the blacksheep feed but interpreted that as being a leg
Just as a reply to another message - yes a dummy load in perfect up to silly voltage I had not really thought that the reactance 'off frequency' might be an issue but I can see it could be a possibil
Hello Nick and Paul N1BUG Should this amp be driven by sine waves?? I assumed you were driving it direct from CLK0 of the Si synthesizer in a U3S, with square waves? -- Best regards, Chris mailto:dea
Hello Chris, Nick, and thanks Alan for your additions to this discussion. Should this amp be driven by sine waves?? I assumed you were driving it direct from CLK0 of the Si synthesizer in a U3S, with
Hi All, If you are using an LPF in front of the PA then regardless of U3 / U3S 'variability you are doing everything right to ensure a clean fundamental only signal to drive the PA. Not recently but
