Jeff wrote:
Out of the box, the 221 had a noise figure somewhat north of 12db. I've
seen vacuum tube radios that were not much worse.
I have never seen an FT221 with a NF anywhere near that. They normally cone
in at about 5-6dB as standard and about 1.5 with the Mutek front-end board
fitted.
I'd agree with 5-6dB as much more typical, but more like 2-2.5dB when
the muTek board is simply plugged in. Another 0.5dB can be gained by
avoiding the card edge connector, and installing a direct coax link from
the antenna relay onto the board.
As the person who designed the original FT221 board (which Chris Bartram
at muTek re-engineered for production) I wore out two dial drives
chasing 2m DX with that rig! But in all that time, I never saw S9 sun
noise. The only time I've seen anything approaching that level, it has
been from a major solar flare.
--
73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek