well, I figured out why my configuration does not work well at 3mhz. My LO is at 104Mhz. It turns out that there is a strong FM station at 107mhz that comes thru with even NO connections of any kind so the front end is way overloaded no matter what. I suspect that if I look around outside I'll see its antenna, :(
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I've got a crystal at 43mhz. I think I'll use it to make a tripler for the LO. That will shift everything up another ~ 30mhz.
After reading the E4000 spec I also concluded that there is quite a bit of value add with its capabilities. In short, I've put the direct mode stuff on the back burner. I'm sure I'm can make what I have work better.
--- In SDRSharp@..., "don_wa5ngp" <m240zz@...> wrote:
yeow, those are tiny wires.
--- In SDRSharp@..., WB8CJW <dale.elshoff@> wrote:
The dongle I modified didn't have any capacitors or pads to connect the
balun to for pins 4 and 5 so it was a real challenge trying to solder 30
AWG wires to the pins that are not only next to each other but are as
wide as the wire I was using. Now thinking back I should have used #38
or smaller which would have been a little more flexible to connect
between the IC and the 4:1 transformer IC plus less prone to bridge
solder between. Also could have used some Capton tape, super glue or
Tac-Pac to hold the wires in place while soldering. Of course if I had
access to a descent stereo microscope or a surface mount inspection
camera that would have make things a bit easier as well.
After all that difficulty it turns out my home brew up-converter is far
superior and I found it wasn't worth the effort making a direct
connection. This was just something I wanted to try. Had there been a
stub connection on the board from pins 4 & 5 to a pad or via that would
have made it a breeze in comparison.
Just my 2 cents thrown in.