Hi,
I was thinking about discrete switching devices like a good fast transistor
that operates at a lower base voltage rather than logic levels.
Another thing I was considering was going back to using an SD5000 with two AC
cmos gates driving a transformer in bridge mode to get higher gate swing rather
than 7 volts on a flip flop. frank
Giancarlo <[EMAIL PROTECTED]> wrote:
--- In [email protected], FRANCIS CARCIA <[EMAIL PROTECTED]>
wrote:
>
> Anybody ever try using 2N5109s in an Hmode mixer with RF drive.
Frank WA1GFZ
>
Hi Francis,
I am not sure I understood your question... do you mean if anybody
has tried an RF amp at the H-Mode Mixer RF input?
If this is the question.... an H-Mode Mixer is a Hot device (vy low
conversion losses <=5dB. In low HF bands you do not need preamp as
the requirements vs band noise are strong to IMD. In high HF bands
you may be OK with a preamp where you may require also sensitivity
and you can be OK dropping the IP3 from +40dBm(+/-) to >+30dBm.
A low noise lossless feedback RF amp using 2N5109 should be OK. Keep
gain not higher than 10dB and with the highest IP3 possible.
I have an low noise RF preamp in my overmodified IC751 with a 14dB
gain replacing the original Icom pre- using 2x BFR91 in parallel. No
problems... I usually keep it off.
73
Gian
I7SWX
