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n1aw@...>> wrote:
? ? Also would like know about total weight - obviously I would want a
? ? lightweight enclosure, and would appreciate
? ? ideas on ideas for that.
I just weighed the whole kit in the plastic box that it came in at 15
ounces. It's hard to imagine a much lighter enclosure.
? ? ?The documentation on line has suggestions about? adding? a narrower
? ? filter for CW; has anyone done this? And
? ? does the main circuit board provide for adding an alternate filter
? ? without having to cut traces on the board?
There are two easy options for doing this. One is to use a narrow audio
filter essentially at the headphone jack. There are kits from SOTABeams,
4SQRP and many others. Since the uBitx doesn't have AGC, there aren't
any issues from strong signals in the RF passband that don't appear in
the narrower audio passband.? The other approach is to use M0XPD's
dual-IF setup where a second 4 MHz crystal filter is paralleled with the
existing 12MHz crystal filter that serves for SSB. Then since the BFO is
software controllable, a firmware could be written where the the IF
moves to 4MHz in CW mode.
? ? I think IRF510s can probably be used at voltages higher than 12V.
? ? Has anyone experimented with using a higher
? ? voltage for the final amplifier to get more than 10 watts out?? That
? ? would maybe not be useful for SOTA, but perhaps
? ? for home station or mobile use?
Many people have done this on their Bitx40s with around 20 watts out at
24-28V supplying the final output transistors.
-Neil N0FN
