UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Keith · 28th Nov 2020, 5:13 pm

Hi,
I've always had trouble getting my head around this AGC arrangement - not helped by the way it is drawn. I agree there do seem to be a lot of time constants involved. I've also never seen an explanation for the inclusion of V24. Presumably it is a further "delay" for the AGC to the front end.

Mine had been working pretty well on SSB, so much so that I couldn't really see a requirement for a separate SSB adaptor. Just recently, however, something has changed and now the long TC seems way too short. I believe there is also a mod to speed up the attack time.

I think it's time to heave it onto it's side and get the scope on it again.

28th Nov 2020, 5:13 pm	#2
Keith Heptode Join Date: Jan 2003 Location: Tewkesbury, Gloucestershire, UK. Posts: 693	Re: Racal RA17C12 AGC Hi, I've always had trouble getting my head around this AGC arrangement - not helped by the way it is drawn. I agree there do seem to be a lot of time constants involved. I've also never seen an explanation for the inclusion of V24. Presumably it is a further "delay" for the AGC to the front end. Mine had been working pretty well on SSB, so much so that I couldn't really see a requirement for a separate SSB adaptor. Just recently, however, something has changed and now the long TC seems way too short. I believe there is also a mod to speed up the attack time. I think it's time to heave it onto it's side and get the scope on it again. __________________ Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm