UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Marconi 2022 2955 OM345 OM360 Replacement

G0HZU_JMR · 8th Jun 2013, 1:29 pm

If you want to stick with a MMIC then maybe consider the VAM-7+ or the RAM-7+ from MiniCircuits.

They are meant to be biased at 22mA but you might still get close to 12dB gain at 12mA bias. Certainly worth a try.

The VAM-7+ is in a smaller and cheaper package but the gain is slightly less than the RAM-7+ below.

http://217.34.103.131/pdfs/RAM-7+.pdf

My slight concern with this approach is that a darlington based MMIC won't offer quite the same linearity. But at least they are easy to fit on a tiny PCB and they should be unconditionally stable with a decent RF layout.
I guess it depends how they get used in the sig gen. Do they just see a steady cw signal or can it be AM modulated?

8th Jun 2013, 1:29 pm	#5
G0HZU_JMR Dekatron Join Date: Sep 2010 Location: Cheltenham, Gloucestershire, UK. Posts: 3,077	Re: Marconi 2022 2955 OM345 OM360 Replacement If you want to stick with a MMIC then maybe consider the VAM-7+ or the RAM-7+ from MiniCircuits. They are meant to be biased at 22mA but you might still get close to 12dB gain at 12mA bias. Certainly worth a try. The VAM-7+ is in a smaller and cheaper package but the gain is slightly less than the RAM-7+ below. http://217.34.103.131/pdfs/RAM-7+.pdf My slight concern with this approach is that a darlington based MMIC won't offer quite the same linearity. But at least they are easy to fit on a tiny PCB and they should be unconditionally stable with a decent RF layout. I guess it depends how they get used in the sig gen. Do they just see a steady cw signal or can it be AM modulated?