hi reflectees !
In the past weeks the question about preamps for low gain rx antennas came up
frequently. Although there are a few units avialable commercially, i think
homebrewing is the appropriate step for any avid topbander.The ARRL handbook
has
numerous designs and the basic knowledge every ham has, should be sufficient to
nail a gadget like that together in a jiffy. As noise figure is not of concern
one can go for readily available simple bipolar transistors like the famous
2N2222 or any small signal type/medium to high gain type transistor.
One can put in as many LC-type filters in front of the stage to meet his own
needs for Out-of-band rejection,nearby AM-stations are nicely suppressed and
one
can even put in "attenuation-poles" in case he sits "fence-to-fence" with a
100kW AM transmitter. I built filters like that with Arne/N7KA in ABQ and he
neighbors a few hi pwr AM stns there. One will be surprised how nice and easy
the filters are adjusted and he will receive a great deal of satisfaction if he
can include each and every extra function that he needs.Amplification can be
switched or smoothly adjusted just the way You like it. I strongly recommend
homebrewing here as no special test equipment is needed and only the stuff
already in the shack does the job. For my own needs i have a homebrew
filter/preamp autoswitched gadget that fully satisfies me with each and every
QSO i run thru it. Good luck homebrewing !
73 de wolf -df2py-
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