Jerry,
Looking at the datasheet the active part of the attenuator runs from a
control voltage of .3v to 2v with a loss of 5db to 60db. Is that 5db
baseline loss acceptable after the 45Mhz filter?
tim ab0wr
On Mon, 26 Mar 2018 13:56:01 -0700
"Jerry Gaffke via Groups.Io" <jgaffke@...> wrote:
A BAP64Q pin diode attenuator gives 60dB of dynamic
range:??/g/BITX20/message/32066 Attenuating back in
RF?gets around the limited dynamic range that Henning points out in
the first post of that thread. Note that the control voltage is
inverted with respect to the 2n7002 FET, higher voltages give less
attenuation. Could get a slightly lower noise figure for the receiver
if the attenuator is inserted at a later stage of the RF chain.
The BAP64Q is relatively expensive at $0.50 single piece,
the frugal among us will note it's down at $0.20 if you buy a few
thousand. Mouser and Digikey both stock it, Mouser points you to the
wrong BAP64* datasheet. There are other similar small signal pin
diode attenuators out there from other manufacturers.
Jerry, KE7ER
On Mon, Mar 26, 2018 at 01:18 pm, Don, ND6T wrote:
The "problem" isn't the detection, rather the range of a single
control element (the MOSFET in this instance). 20 dB is pretty good
but I shall always crave more.
