----- Original Message -----
Karl Larsen <[EMAIL PROTECTED]> wrote:
<snip>
The TI chip uses 5 volts at 18 mA in a Mixer configuration. I need to
study all the information I have now on my computer and then write up an
actual proposed receiver mixer for the KX1 that will knock out nearly all
third order image signals.
--------------------------------------------------------------------------
In 2005 a simple modification was made to the H-mode mixer using the
FST3125, as used in the CDG2000 receiver, a mod I have yet to find on any
website, which involved adding a potentiometer to adjust the switching
thresholds between the two pairs of FETs. According to one of the designers
of the receiver this mod raised its IIP3 on 40m to +50dbm (do not know
offset) for an input noise floor of -130dbm ( do not know the bandwidth),
thus achieving on 40m a third order dynamic range of close to120db - not
phase noise limited. Apparently the IIP3 of the CDG2000's preselector and
first 9MHz IF filters 'bottom out' at the same point. Can send you details
off list if of interest.
The four transformer version seems to work best for me using Mini-Circuits
transformers, although hand wound transformers on binocular cores work well
also.
73,
Geoff
GM4ESD
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
